Loading...
4 - Update: Grassland Ecosystem Management Plan MEMORANDUM TO: Open Space Board of Trustees Michael D. Patton, Director FROM: Joe Mantione, Acting Division Manager Planning and Technical Services Mark Gershman, 1;nvironmental Planner DATI+;: December 27, 2007 SUBJECT: Grassland Ecosystem Management Plan (January 9, 2008) PURPOSE OF STUDY SESSION The purpose of this study session is to provide the Open Space Board of Trustees (OSBT) an opportunity to review and discuss various aspects of the proposed Grassland Ecosystem Management Plan (Grassland Plan). The focus of this study session will be staff's identification of the project scope and conservation targets, assessment of target viability and a preliminary look at critical threats. Staff will also introduce some of the key community concerns associated with the Grassland Plan. QUESTIONS FOR THE BOARD 1. Will the project's conceptual and geofnaphic scope enable staff to address Board members' concerns about grassland ecosystem management? (pgs. 3-4) 2. Is the Board satisfied that the palette of conservation targets is representative and will encompass the appropriate management issues and community concerns? (Attachment B) 3. Are the issues of grassland conservation appropriately identified in the summary of viability issues and threats? (pg. 6; Attachments C and D and information to be presented at the study session) 4. Are there other key community issues that should be addressed in the plan in addition to those outIincd in this memo? (pgs. 6-7) BACKGROUND Grassland Management on Open Space and Mountain Parks The city began its grassland conservation efforts with the approval of the Open Space sales tax in 1967. Due to fitnding and staffing limitations at that time, grassland management was initially focused on working with local farmers and ranchers to continue traditional agricultural practices with some oversight by staff. In 1975 the city established explicit management goals for agricultural operations by hiring a consultant to develop farm and ranch management plans. Management planning began to explicitly incorporate species conservation as the department learned more about the conservation values of Boulder's tallgrass prairies and prairie dog colonies in the 1980s. Ecologists from the Colorado Department of Natural Resources and the US Forest Service acknowledged the value of the grasslands along South Boulder Creek which were officially designated as the Colorado Tallgrass Prairie State Natural Area in 1984. Two years later, in 1986, City Council accepted the Tallgrass Prairie Management Pian. Around the same time, a growing appreciation of the importance of public open lands for l prairie dog conservation in a rapidly developing landscape coupled with concerns regarding the perceived impacts of prairie dogs on open space led to the development of a prairie dog management plan. A prairie dog management plan was approved by the OSBT in 1987. The Open Space Department's capacity to manage grasslands increased through the 1980s and 1990s with the development of a resource conservation staff, including agricultural specialists, plant ecologists, and an Integrated Pest Management (IPM) program. The development and OSBT approval of the Black-tailed Prairie Dog Habitat Conservation Pian in 19)6 was intended to be the first component of a broader Grasslands Ecosystem Plan. Ilowever, much ~f the following decade was spent working to implement the prairie dog plan on the Open Space land system and addressing the issues surrounding growing populations of prairie dogs in Boulder's urban core. With the beginning of the new century, the city Planning Department led an effort to reconcile urban land uses and wildlife habitat values. Both the policy guidance for the Urban Wildlife Management Plan (UWMP) and the prairie dog component of the UWMP were accepted by the C.'ity Council in 2006. In the fall of 2006, Council identified the completion of the OSMP Grassland Ecosystem Management Plan (Grassland Plan) as a high priority task of the UWMP. At the same time, OSMP staff and community members were discovering the need for specific conservation objectives to inform the implementation of the Visitor Master Plan (2005}, and the Trail Siudy Area Planning process. An 18 month timeline was developed for the completion of the OSMP Grassland Ecosystem Management Plan. APPROACH Staff began work on the Grassland Plan in the fall of 2006, adopting a process which was developed by "I'he Nature Conservancy and is now in use by many conservation organizations around the world. The process, as adapted by OSMP, has seven steps: 1. Defining the Project Scope, Team, and Conservation Targets 2. Assessing the Viability of the Conservation Targets 3. Identifying Critical Threats 4. Developing Strategies 5. Defining Measures of Success 6. Developing a Workplan for Actions and Measures 7. Taking Action and Measuring Success Step One: Dcfinin~ the Project Scope, Team, and Conservation Targets Because of OSMI''s long history with grassland management, the Grassland Plan provides an opportunity to address both City Council's direction, and needs identified by community stakeholders and departmental staff. OSMP staff met to discuss the project scope at the outset of the project and developed the follvwing statement of purpose. 2 The purpose of the Grassland Ecosystem Management Play: is to provide a framework for on the ground management, public policies a~:d lands/water acquisition priorities to conserve the ecological values of lands witliin the Grassland Planning Area and to ensure on going agricultural production. Soon after determining the project purpose, a departmental team was formed to develop the plan. "I'he team includes participants from several workgroups focusing upon resource managers, information analysts, planners and outreach staff. The roster of the staff team members, advisers and external stakeholders is included as Attachment A. 7'he next step was to draw boundaries around the Grassland Planning Area. The project team examined vegetation, soils, and topography to develop a western boundary to separate the Grassland Planning Area from lands managed under OSMP's Forest Ecosystem Management Plan. 'The geographic scope of the Grassland Plan encompasses approximately 25,000 acres of lands managed by OSMP east of this boundary, and another several thousand acres protected through conservation easements. Figure 1 shows the Grassland Planning Area. The scope of the Grassland Plan includes all species, natural communities, ecological systems, and agricultural operations on USMP-managed lands in the project area as well as selected conservation elements on OSMP conservation easements. After determining the project scope, the team began work on narrowing the focus of the plan. Open Space and Mountain Parks is known to support more than 800 species of vascular plants and over 400 species ofvertebrates. In addition there are many lesser known (or unknown) invertebrates (insects, spiders, crustaceans, etc.) and non-vascular plants (algae, mosses, etc.) on OSMP. "frying to address even the known species individually is impractical. Instead the project team identified a small number of ecological communities and ecological systems chosen to represent and encompass the biodiversity and ecological services provided by USMP grasslands. These eight "conservation targets" are the basis for setting specific objectives, taking action on the ground and measuring success. Target identification involved examining vegetation mapping and historical accounts of the Boulder Valley to describe the terrestrial, wetland and aquatic communities that dominate the project area. The planning team then determined which communities and species would not be adequately dealt with by planning within the broad-scale ecological systems or species groups. OSMP staff's preliminary ideas about conservation targets were shared with a group of grassland ecologists and conservation professionals during a day-long workshop in the winter of 2006. The recommendations from this expert's workshop were used to establish the following list of conservation targets. I. Mixed Grass Prairie Mosaic 5 . Wetlands 2. Xeric '1'a11 rass Mosaic 6 . Shale Barrens 3. Black-tailed Prairie Do and Associates 7 . White Rocks Cliffs 4. PlainslFoothills Transitional Ri arian 8 . A ricultural O erations 3 A description of the targets along with maps showing their approximate location and distribution is included as Attachment B. ./%f-' } - f • ~ y ( ~ , r ~r ~ ti~ . u.; ~ J ) f. 1 ' . ' ~ / ~ ,?r Legend f ~ 7..' - - -hplN~m17!?rr~siareFF CIe{E~I P)Und)ry ~ Oras4and Flan GP9grap~¢ u0(B • J _ Frrest CarK15 (FEnIF) :,_11 nuk /I Figure 1: C7eographic Scope of Grassland Plan (acronym "FEMP" in key forest ecosystem Management Plan) 4 Step Two: Assessing the Viability of the Grassland Plan Targets "Viability assessment" is a way of using the relevant principles of ecology (or in the case of agriculture, both ecology and business) tv identify the current status and the desired future condition of the Grassland Plan targets. The process begins with the identification of "key attributes" for each target. A key attribute is "an aspect of the target that if modified or removed results in loss or significant degradation of the target over time". Typically key attributes address some aspect of size (how large, how many, etc.), condition (structure, composition, interactions, etc.) or landscape context (setting, disturbance regime, etc.). For example, water quality is often a key attribute of an aquatic system such as a creek; species composition is a key attribute of the tallgrass prairie. If water quality in a creek is degraded, the creek loses its ability to support native insects and fish. When native species of plants or animals are displaced by invasive exotic species in a tallgrass prairie parcel- --the ecological value of the area is diminished or if the change is significant enough-lost. Since key attributes like "water quality" or "composition" are too general to measure efficiently, viability assessment involves identifying specific indicators that are consistently responsive to change and can be measured relatively easily. OSMP will use indicators to track the status of key attributes. Attachment C summarizes key attributes and indicators that have been identified by staff for the Grassland Plan targets. By identifying key attributes and indicators, OSMP will describe the viability (health) of each target and determine how the current status of each indicator compares to the desired condition.. Because ecological systems and communities arc complex, there is typically uncertainty about appropriate "desired conditions". Because data about indicators is not always available, the current state may need tv be inferred until it can be more accurately measured. The issues of uncertainty and lack of data are addressed through documentation of assumptions, the use of best available information and establishing monitoring projects. In an attempt to improve the quality of available information OSMP engaged the Colorado Natural Heritage Program (CNHP) to develop an Ecological Integrity Assessment (1;IA) of several of the Grassland Plan targets. These EIAs are available upon request or can be downloaded from the CNHP website (http:!!w~~-w.cnhp.colostate.edtz're~>rts.htn~l One of the outcomes of the viability assessment phase of the project is a table showing the relationship of each target to its key attributes and indicators, as well as the desired conc}ilion, current condition and documentation including references, assumptions and follow-up research needs. tAn example of this information is included for the mixed grass prairie mosaic in Attachment D. Step Three: Identif~n~ Critical Threats Estimates and measurements of indicators for some Grassland P}an targets fall below the threshold of acceptability (i.e. rated "fair" or "poor"). This can be a result of persistent stresses from historic degradation even when the source is no longer active (e.g. historic gravel mining, livestock grazing, farming practices, predator controls). Degradation may also result from "active" threats due to cun-cnt human activities. 5 Once the viability assessment is completed, threat identification is relatively straightforward. Staff examined each of the key attributes that is degraded or is likely to be degraded during the planning horizon (l U years for the Grassland Plan). The stresses on the target (types of degradation) as well as their sources were identified. In order to determine the mast significant threats, staff evaluated the severity and scope of each stress. Severity means the level of damage that can reasonably be expected over the planning horizon if the situation does not change. Avery severe stress is one that is likely to destroy the target over some part of its occurrence. A stress with low severity is likely only to slightly impair the target. Similarly, a stress with a high scope rank is likely to be widespread and affect the target in many or all of its occurrences, whereas localized stresses are ranked Lower. Each stress has at least one, and often multiple sources. Staff has brainstormed the direct threats behind each source and evaluated to what degree a source contributes to a particular stress and the degree to which the effects of the source can be undone. Sources of stress that are dominant contributors and/or are not easily undone are more likely to be critical threats--especially if the stress produced is widespread and severe. The more targets a threat affects significantly, the more likely it will be identified as a critical threat. A summary of threat information will be provided at the study session. ISSUES There are some "big picture issues" that have been part of the Grassland Plan since its inception, or have arisen during the development of the plan. These issues will need to be further analyzed by staff and recommendations developed for discussion at subsequent public meetings. Ilowever, they are presented here to give the Board an indication what staff sees as some of the prominent community concerns and to stimulate conversations about other key issues of which the Board is aware. Need for a Best Opportunities Analysis--Where Will OSMP Take Action? Because of the mu]tiple uses of OSMP ,the Conservation Action Planning model needs not only to identify the most strategic conservation actions, but it also needs to identify the places in the Grassland Planning Area where conservation activities (including acquisition) are likely to have the greatest benefit. This "Best Opportunity Analysis" is currently underway to find scenarios that provide a range of options for integrating the sometimes conflicting goals of conserving native biological diversity (including prairie dogs}, preserving agricultural uses and areas, and providing facilities and opportunities for a wide range of recreational activities. G Conserving Front Range Grasslands--How Much is Enough? The Grassland Plan seeks to establish thresholds of acceptability for a range of attributes for eight conservation targets. One question that has come up already in conversations with stakeholders is "Ilow much of a target's occurrence are we attempting to conserve?" In some instances, OSMP may have adequate information about targets' ecology and significance to develop detailed conservation objectives. In other cases, managers do not know exactly what is needed. Incomplete understanding may influence community support for policies affecting neighboring land use, or the management of visitor use on OSMP. "1'o what extent should grassland management activities be protective ensuring the long term viability of the Grassland Plan targets when managers are operating with an incvmplete understanding of how these systems work and such an approach could curtail certain agricultural or visitor use activities? lntegration with the Urban Wildlife Management Plan In 2006, the City of Boulder's i7rban Wildlife Management Plan (UWMP) classif ed active prairie dog colonies in Boulder's urban core as either long-term protection (l49 acres), near-terns removal (96 acres), or interim protection (361 acres). The city's policy is to avoid lethal control whenever possible. The Grassland .Plan will include a habitat suitability model for prairie dogs and relocation criteria to identify when relocation to OSMP is a viable alternative to lethal control for the prairie dog populations affected by the UWMP. NEXT STEPS Following this study session, staff will revise and complete the viability analysis for all Grassland Plan targets and the threat analysis. The full set of information will be made available for public review. USMP staff will meet with interested members of the community to gather feedback. Comments will be used as the basis for revision, and for the development of strategies and a monitoring program for the Grassland Plan (steps 4 and 5). Steps 1-5 will be combined to create the draft plan which will be circulated for review before being brought to the OSBT and City Council in late February and March. "fhe work prop-ram for the plan will be developed as part of the final plan which will be reviewed by the public, the USBT and City Council in late spring of 2048. ATTACHMENTS Attachment A: Summary of Participants in the OSMP Grassland Ecosystem Management Plan (2 pages) Attachment B: Grassland Plan Target Descriptions (38 pages) Attachrrxent C: Summary of Key Attributes and Indicators for Viability Analysis (4 pages) Attachment D: Sample Viability Table for Mixed Grass Prairie Mosaic (2 pages) 7 Attachment A Summary of Participants in the OSMP Grassland Ecosystem Management Plan Project Manager: Mark Gershman, Environmental Planner Project Sponsors: Joe Mantione, Jim Reeder and Dean Paschall Project Team: Core Group Andy Pelster, Agricultural Resource Specialist Don D'Amico, Wetlands and Riparian Ecologist/Resource Conservation Supervisor Eric Fairlee, IPM Coordinator Heather Swanson, Wildlife Ecologist/ Wil! Keeley, Wildlife Ecologist Lynn Riedel, Grassland Plant Ecologist Lynne Sullivan, Education and Outreach Staff Marianne Giolitto, Resource Monitoring Coordinator Mark Gershman, Environmental Planner Whit Johnson, GIS Supervisor Affiliated Staff and Advisors Steve Armstead, VMP Coordinator Megan Bowes, Plant Ecology Technician Roy Bell, Agricultural Resource Specialist Bob Crifasi, Water Resources Specialist Laurie Defter, IPM Coordinator Steve Germaine, Wildlife Ecologist Ann Goodhart, Real Estate Services Bill Grabow, Resource Conservation toe Mantione, Environmental Planner Jennifer Sherry, GIS Analyst Chris Wanner, Forest Ecologist Annie McFarland, Recreation Resource Coordinator Key Stakeholders: Decision Makers~Drivers • Boulder City Council/City Manager`s Office • Open Space Board of Trustees • OSMP Management Team Potential Agency Partners • City of Boulder Parks and Recreation • Boulder County Parks and Open Space: Larissa Read, Rob Alexander, Mark Brennan, Claire deleo • Jefferson County Open Space • National Oceanic and Atmospheric Administration (Table Mountain) A-1 • Rocky Flats o DOE Contractors: Jody Nelson o US Fish and Wildlife Service: Amy Thornburg, Steve Kettler • Colorado Natural Areas Program: Brian Kurzel • Natural Resource Conservation Service: Don Graffis, Harvey Sprock • Colorado Division of Wildlife: Mike Sherman • US Forest Service • National Oceanic and Atmospheric Administration (Table Mountain): Mark George Community of Researchers • CU: Sharon Collinge, Alex Cruz, Tim Seastedt, Lauren Livo, Dave Armstrong, Virginia Scott • CSU: Rick Knight, Alan Knapp • Kathy Keeler Non Governmental Organizations • Rocky Mountain Bird Observatory • The Nature Conservancy Colorado Field Office: Terri Schulz • Society for Range Management: Rob Alexander • Colorado Native Plant Society • Boulder County Audubon: Steve Jones • Boulder County Nature Association: Scott Severs • Sierra Club Indian Peaks Chapter: Deidre Butler • Rocky Mountain Animal Defense: Lynne Sprague • Prairie Dog Coalition: Lindsey Sterling Krank • BATCO member orgs.) • FIDOS Others • OSMP Lessees • Neighboring Property Owners • Neighboring Municipalities Local Consulting Naturalists • ESCO Associates: Dave Buckner • Ecotone: Pat Murphy • Colorado Natural Heritage Program • 8iohabitats: Alan Carpenter A-2 Attachment B: Description of Conservation Targets OSMP has established an overall goal of conserving the native biodiversity in the planning area while managing for compatible agricultural operations. The grasslands of Boulder's Open Space and Mountain Parks are known to support more than 800 species of vascular plants and over 400 species of vertebrates. !n addition there are many species of invertebrates (insects, spiders, crustaceans, etc.) and non-vascular plants (algae, mosses, etc.) and relatively few of these have been identified on OSMP lands. In order to develop specific conservation strategies, staff has posed the question "What biodiversity are we trying to conserve?" To answer this question, OSMP, with input from local and statewide experts, identified a set of "conservation targets". Conservation targets are the native species, natural communities and ecological systems that represent and encompass the biodiversity of OSMP grasslands. These conservation targets are the basis for setting specific objectives, taking action on the ground and measuring success. Target identification involved examining vegetation mapping and historical accounts of the Boulder Valley to describe the terrestrial, wetland and aquatic communities that dominate the project area. The planning team then determined which communities and species would not be adequately captured within the broad-scale ecological systems or species groups. OSMP staff's preliminary ideas about conservation targets were shared with a group of grassland ecologists and conservation professionals during aday-long workshop in the winter of 2006. The recommendations from this expert's workshop were used to establish the following list of conservation targets: Conservation Target Approximate Acreage • Mixed Grass Prairie Mosaic ca. 7,45 i acres • Xeric Tallgrass Prairie ca. 5,550 acres • Black-Tailed Prairie Dog And Associated Species • Plains Foothills Transitional Riparian ca. 1,]74 acres • Wetlands and Mesic Tallgrass ca. 1,985 acres • Shale Barrens ca. 93 acres • White Rocks Cliffs ca. 120 acres • Agricultural Operations2 ca. 4,469 acres Unmapped or Unknown ca. 4,342 acres Total ca. 25,000 acres Agricultural Operations is included as a target because the Grassland Plan seeks to integrate the long- term sustainabiiity of natural systems with agricultural operations on OSMP lands. Objectives for visitor use, another critical OSMP service, are stated in the Visitor Master Plan and Trail Study Area (TSA) plans. Visitor use has implications for grassland conservation, and the integration of OSMP services will be addressed in the Grassland Plan as well as in Trail Study Area planning. Since the extent of occupied prairie dog acreage fluctuates, and prairie dogs occupy many of the other targets, no acreage figures are given here. Information about the extent of prairie dog occupation is included in the description of the Black-Tailed Prairie Dog and Associates target a Acreage of OSMP lands where agricultural operations (irrigation, seeding, annual cropping systems, etc.) have resulted in a dominance of exotic vegetation. Other OSMP lands are also in use for agriculture (e.g. livestock grazing) or the result of irrigation practices (some wetlands and mesic tallgrass prairie). B-3 Nested Targets Each of the major grassland conservation targets includes many species of plants and animals as well as a variety of plant associations. Some of these are of conservation concern in the Boulder Valley. Conservation concern means that a species is threatened or endangered according to state or federal law, that they are considered rare or imperiled by the Colorado Natural Heritage Program, or that they have been found to be rare or in need of special conservation action at the local level. Local level conservation status is documented in the Boulder County or Boulder Valley comprehensive plans, or in documents developed by OSMP staff. A list of the species of conservation concern found in the planning area along with their conservation status rankings is included as Attachment B1. The species of concern are "nested" beneath the major conservation targets} with which they are associated. This nested target table will be updated and revised throughout planning and implementation of the Grassland Plan to reflect evolving understanding of OSMP grasslands. Extirpated Species Some species, such as bison, prairie wolves and grizzly bears, no longer occur in the Grassland Planning Area. The planning team and expert's group considered a variety of ways to represent these extirpated species. Some felt that ail extirpated species such as wolves, grizzly bears, black-footed ferrets and bison should be grouped together as a focal target because of their ecological importance. OSMP staff also heard from those who felt that including extirpated species would inappropriately divert resources from the species currently inhabiting the planning area which are in need of conservation. OSMP staff has addressed the issue by including a second nested target table showing the relationship of extirpated species with conservation targets (Attachment B2). While the restoration of most of these species is currently beyond the scope of OSMP; staff proposes to participate in restoration efforts whenever the city's grasslands can reasonably make a meaningful contribution to reintroduction efforts for species extirpated from the Boulder Valley. DESCRIPTION OF MAJOR CONSERVATION TARGETS These descriptions are intended to provide anon-technical summary of the nature, distribution, composition, and ecology of the Grass/and Plan conservation targets. When describing 'natural" conditions or processes, OSMP has attempted to illustrate the conditions or processes that most closely ref/ect the range of variation under which the target and the nested plant and animal species evolved. These conditions, when ariainab/e, are thought to offer good opportunities for long-term sustainability with the /east amount of management input. Certainly there are Hove/ecosystems (see agriculture target description pg. 24 for more about this) within the Grassland Planning Area which provide biodiversity and are, to a large degree, the result of human modification of the landscape. As the Grass/and Plan objectives are developed, it is likely that they will include conserving the natural range of variability as we// as the conservation of novel ecosystems. OSMP will be guided by an approach which optimizes the conservation services that can be delivered to the community. B-4 Mixedgrass Prairie Mosaic The mosaic of foothills mixedgrass communities on OSMP represents plant associations occurring over a wide area of North America. The mixed grass prairie mosaic includes plant associations similar to those occurring in the central, southern and northern Great Plains, as well as in the southwestern and intermountain regions of the Western U. S. The foothill prairies of the Boulder area include mixedgrass prairie communities occurring in large matrix forming stands or in small patches intermingled with xeric tallgrass. About 25%, or 6,000 acres, of OSMP prairie grasslands are currently mapped as the mixedgrass prairie mosaic. Some plant associations represent the western edge of High Plains vegetation, while others are related to communities of the northern or southern Great Plains. At the forest-grassland interface or ecotone, mid- and short-grass prairie species blend with Rocky Mountain species to form a distinctive and localized set of plant associations (see Figure B-1). At the foot of the mountains, diverse topography, soils and geology, combine with climate to create habitat for grassland plant associations characterized by mid-height species such as western wheatgrass, needle and thread grass, green needle grass, New ~ ~ _ Mexico feathergrass, sideoats , , . _ grama, little bluestem, and Rocky ~ ~ ~ Mountain bluegrass. The - a ' mixedgrass prairie also includes r'- shortgrass species such as blue - ' ' ' grama and buffalograss. • _ I - Stands dominated by western wheatgrass occur in fine-textured ; clay soils on mid to lower hill I slopes, valley bottoms, and shallow, seasonally wet _ - - ~ _ drainages. In rocky sites, needle 1-~ and thread grass co-dominates ` ~ • .~'y - _ with western wheatgrass and/or _ ~ L~ . ~ - blue grama. New Mexico _ feathergrass dominates small ~ ~ ~ patches of calcium-rich soils, and - little bluestem and sideoats grama j ~ - , , are characteristically dominant on = •~'-__11 - - north facing edges of low mesas. ~ ~ ~ _ ~ r' , - ' - ' _ l Sub-shrubs such as fringed sage, dwarf rabbitbrush, and = s' li _ . snakeweed are common in S f , __,_tl~,.,__ - - western wheatgrass associations. '._f M;xeagrass Prairie mosaic e Three-leaved sumac occurs ~ col,servar;on rarer frequently in mixedgrass prairies ~ ~.,~..,ac~,::r:,,~~,er+os:.~~ on Open Space and Mountain ~ Parks lands. Winter fat and `''°"'.""'r'""F"'~~cta,e; saltbush shrublands, although - more widespread elsewhere in the Figure B-1: Location and extent of the Mixed Grass Prairie high plains, are rare in the Mosaic in the Grassland Plan Boulder Valley. B-5 Mixedgrass communities combine with xeric tallgrass prairie patches to form a biologically rich foothills grassland mosaic. The mixed grass prairie mosaic occurs on a variety of sites but typically in areas where precipitation, geology and soils combine to create relatively dry growing conditions. The major ecological processes influencing mixedgrass prairie are fire, ungulate grazing, and black-tailed prairie dog burrowing and grazing. Natural disturbance regimes have been significantly altered with European settlement. Historically, fires probably occurred more frequently and covered larger areas than in today's landscapes where fuel loads were reduced by livestock grazing and people actively suppressed wildfires (Sherriff and Veblen 2004). Spatial patterns, seasonality and intensities of pre-settlement grazing by deer, elk and prairie dogs differ from those of post-settlement livestock grazing, pasture fencing and water source redistribution. Combined grazing by livestock and prairie dogs in fenced pastures also creates unique high intensity grazing regimes that did not occur under presettlement conditions. In highly fragmented urban areas, where emigration opportunities are rare or non-existent, population densities of prairie dog colonies increase and grasslands are subject to extended periods of unusually high grazing pressure (Johnson and Collinge 2004). These modified disturbance regimes are reflected in the current composition of vegetation. Native plant species diversity has probably been reduced in many areas as a consequence of frequent livestock grazing or prescribed burning at the same time of year, or due to the lack of ungulate grazing and/or fire. Shrub and tree species are probably more common. The cycling and distribution of nutrients have been influenced by altered disturbance regimes and urban/industrial nitrogen deposition. These changes combine with additional biotic and abiotic factors to affect the resilience and resistance of mixedgrass plant communities in the face of stresses such as drought and the invasion of aggressive non- native plant species. Some mixedgrass plant communities in the Boulder area are relatively common in Colorado, others are rare. Especially good examples of grassland associations within the Western Wheatgrass Herbaceous Alliance are of conservation concern, as are all occurrences of communities within the Needle and Thread -Blue Grama Herbaceous Alliance, the Little Bluestem-Sideoats Grama Herbaceous Alliance, and the Green Needlegrass Herbaceous Alliance. The mixedgrass mosaic supports a rich fauna including uncommon species such as the short-horned lizard, olive-backed pocket mouse, Nebraska Tiger beetle, and several rare butterfly species. Large blocks of mixedgrass prairie provide habitat for numerous grassland nesting birds, the American badger, and elk. Much of the land inhabited by black-tailed prairie dogs in the planning area occurs within this target. Wetlands, riparian corridors, streams and small water bodies that are contiguous with upland prairie, support amphibians and other wildlife that require both upland and wetland or aquatic habitat to complete their life cycles. Mixedgrass patches with high native plant species diversity provide for aspecies-rich invertebrate fauna. Taller stature patch types are important habitat for some bird and small mammal species, while other species prefer short stature vegetation. Conservation of Boulder's grassland plant and animal diversity is directly related to maintaining and restoring the compositional and structural diversity of prairie vegetation. B-6 Xeric Tallgrass Prairie Upland tall grass plant communities, dominated by big bluestem, are found in the Boulder Valley and vicinity from the forest edge to the eastern fringes of the outwash mesas. (n Colorado, tallgrass communities are found in rocky soils at elevations between 5,400 and 7,600 feet along the northern Front Range at the foot of the mountains, and in the southeastern part of the state. Some of the largest areas of tallgrass remaining in the state are in the Boulder area. The Colorado Tallgrass Prairie State Natural Area was designated on OSMP land in 1984, in recognition of the state-wide importance of Boulder's tallgrass prairies. The foothills tallgrass communities in the Boulder area share similarities with the tallgrass prairies of the eastern Great Plains, but also have distinctive characteristics of their own (baker and Galatowitsch 1985, Bock and Bock 1998, Buckner 1994, Hanson and Dahl 1957, Livingston 1952, Moir 1969, Vestal 1914). Tallgrass prairie is considered rare and imperiled globally, and is one of the most endangered vegetation types in the world (Hoekstra et al. 2005). The conservation rankings for the communities that occur in Colorado range from "critically imperiled" to "imperiled". Xeric tallgrass communities have been highlighted and identified as conservation targets by The Nature Conservancy's j _ ' ecoregional assessment of the ~ ~ ' ` e ~ . Southern Rocky Mountain area. Southern Boulder County and r ~'~i.a_ northern Jefferson County may _ ~ p`' have the largest areas of these _ ~ ~ xeric tallgrass communities ~ _ - 1 remaining in Colorado. _ ,i - <r~ r _ . The xeric tallgrass prairie mosaic ~ t is characterized by several ~ - ~ community types occurring in „----._r~' - _ . - open meadows, savannas at the - ~ ti,,, prairie-forest interface, and as ,~y•' _ ,l . jr,.,• matrix-forming grasslands on . ' ~ f'?• prominent mesa tops. Patches ~ _ ' _ along the prairie-forest interface t - - are relatively small; generally ~ ~ ~ ' from 3 to100 acres in size (see ~ ~ . Figure B-2 Occurrences on mesas ~ .r Cr , - ~ can be large, for example there : are over 2,000 acres of xeric • 'M tallgrass prairie on the Rocky Flats 1 ~ w. ~ ,.r . Mesa (the majority of which is on ~.tLv _ ~ ~ ''~~~,i ~ .~<<l lands managed by the US Fish and . r'~ ~ ~ Wildlife Service). There are r .f - ,l~ ._s ~ :i~ri . Xer/c Tallgrass e currently approximately 4,500 ~ ~ Corisetva(/on Target acres of xeric tall rass ma ed u g pp r~' ®>:Cn,. Tallure~>ble~„~. r m1 r Forca I:L:un~l on OSMP managed lands. ~ ~ • Tallgrass and mixed grass prairie ~ = plant species blend with higher elevation species, forming unique Figure B-2: Location and extent of the Xeric Tallgrass Mosaic ecotonal grassland plant in the Grassland Plan planning area Grassland Planning Area B-7 communities. These distinctive prairie communities have species in common with Great Plains tallgrass prairie (big bluestem, yellow Indian grass, little bluestem, prairie dropseed, and porcupine grass) as well as plant species more typical of the Rocky Mountain montane life zone (Porter aster, mountain muhly grass, and grassy slope sedge). Precipitation levels at the base of the mountains, combined with the geology and soils, provide habitat for tallgrass plant communities in the Boulder area. Tallgrass stands on slopes, mesas, and ridges occur in soils with large amounts of rock and gravel in the upper profile. The high rock content allows for rapid infiltration of rainfall and snowmelt resulting in more available soil moisture when compared to ad'lacent finer textured soils supporting other plant associations (Branson et al., 1965). The abundance of coarse materials near the surface also reduces evaporation, and concentrates moisture and soil in spaces among the rocks. Beneath this "rock mulch" clay rich soils absorb and retain enough moisture to support tallgrass prairie and montane plant species. North-facing slopes, which experience less direct exposure to sun, retain snow longer and provide the most mesic habitat for upland tallgrass. Big bluestem prairie communities are shaped and maintained by fire, grazing, drought, wind and other natural processes. The dominant driving forces are ungulate grazing, fire and drought. Elk, pronghorn, bison and other native grazing animals were more common in the Boulder Valley. Historically fires probably burned foothills grassland communities every five to ten years (Sherriff and Veblen 2004}, based on fire frequency estimates derived from nearby forests. After settlement, domestic livestock became the dominant grazers and fires were suppressed. Settlers were not able to plow the rocky soils of mesas and rocky ridges, leaving the tallgrass prairie in these areas intact. Over the last century, urban development, mining, grazing, and fire suppression have degraded or eliminated much of the xeric tallgrass along the northern Front Range. The influences of grazing, fire, and drought on tallgrass communities have been modified with the alteration of natural disturbance regimes since fire suppression and the introduction of domesticated livestock. Prior to widespread and regular fire suppression activities, fires occurred more frequently and covered larger areas than in the fragmented post-settlement landscapes where wildfires have been suppressed. Pre-settlement ungulate grazing patterns and intensities would have been different from post-settlement livestock grazing regimes after fencing fragmented the landscape and water sources were redistributed. The seasonal timing of these disturbances has also been altered since settlement. Changed disturbance regimes are reflected in the current composition of vegetation with patterns similar to those described for the Mixed Grass Prairie Mosaic. In spite of past-settlement changes, relatively large areas of xeric tallgrass persist in the Boulder area, preserved by public open space programs and other government ownership. Nearly 22%, (more than 5,000 acres) of the Grassland Planning Area is covered by the xeric tallgrass mosaic. Several plant communities tracked by the Colorado Natural Heritage Program (CNHP) are well-represented, including the Big Bluestem-Little Bluestem Western Great Plains and Big Bluestem-Prairie Dropseed Western Great Plains Herbaceous Associations, and additional xeric communities within the Big Bluestem (-Yellow Indiangrass) Herbaceous Alliance. Tallgrass provides habitat for the CNHP-tracked butterflies, the Ottoe skipper, Arogos skipper, Crossline skipper, and the Regal fritillary. These butterflies depend on characteristic tallgrass plant species like big and little bluestem, prairie violet, and New Jersey tea, and are rare throughout the Great Plains. Dwarf leadplant, grassyslope sedge, narrow-leaved milkweed, and prairie violet are CNHP-tracked pant species occurring in the xeric tallgrass mosaic. The grassy slope sedge, a montane plant that reaches its lowest elevational extent on outwash mesas in the Boulder area is ranked "critically imperiled" (S1) in Colorado. The remaining rare plant species are central and northern Great Plains elements at the western edge of their range. Large, un-fragmented patches of xeric tallgrass create seasonal habitat for a suite of grassland nesting birds, and an elk herd. B-8 Shale Barrens Shale barrens occur in small patches associated with shale outcrops of the Niobrara and Pierre geologic formations in the northern Boulder Valley, and at a few other locations along the forest-grassland interface near Boulder {See Figure B-3 Bell's twinpod, a Front Range endemic plant occurs exclusively in shale barrens in Boulder and Larimer County (Kothera 2006}. Boulder area shale barrens occupy less than one percent of OSMP prairie grasslands and are usually embedded in a matrix of mixedgrass prairie. Currently about 60 acres of OSMP managed lands are mapped as shale barren. Barrens range in character from very sparsely vegetated areas (<1 0% plant cover} in dark, coarse shaley soils, to areas of moderate vegetation cover (>50%) in finer, shale- derived soils. Aspects for shale barrens are commonly north and east facing, though barrens patches also occur on other exposures. Slopes vary from less than 5% to greater than 50%. Micro-topography within barrens frequently results in sparsely vegetated ridges and rills with higher plant cover. Many "barrens" plant species have extensive root systems and are well adapted to the water-limited environment created by coarse, shallow soils over shale bedrock (Kelso et al. 2003). The flora of shale barrens includes ~ a variety of forb species, grasses, ~ ~ ~ ~ • • and small shrubs. Bell's twinpod, _ a rough sunflower, prairie sage, ~ side-bells penstemon, three- fingered milk vetch, woolly _ Hymenopappus, and spike Gilia pre characteristic forbs. Common `y~'`~S .l ~ • r ~ grasses are Indian ricegrass, New r~ ~ ~ ' Mexico feathergrass, needle and ~ ~ ~ threadgrass, blue grams, western ~ wheatgrass, little bluestem and ' , purple threeawn. Shrubs and sub- ~ . ~ ~ ' shrubs include sand cherry, three- ~i leaved sumac, serviceberry, yucca, ~ , snakeweed, and yellow ; _ buckwheat. Western hackberry ~ ~ ~ . trees sometimes occur in small ~ - ~ stands on some barrens. _ ~ Key factors influencing the ~ character of barrens are soils, ~ grazing ungulates, prairie dog ~ burrowing and grazing, and „h ~ periodic fire. Dark, coarsely textured shale soils, consisting r largely of small rock fragments, ~ . ^ Slrale Barrens e Conservation Taryer remain sparsely vegetated even in / __~.>hale F.'.arrenz ~-nmrnurnC~ the absence of grazing and fire. ~ ~ Finer textured soils are often more >,uid f Ian ~r,~~e~_t:.; productive and go through ~ ~ , successional stages of increasing vegetation cover during periods without grazing and fire. Figure 8-3: Location and extent of Shale Barrens in Grassland Observations at one barrens site in Planning Area B-9 north Boulder noted a steady increase in vegetation cover during a five to ten year period following a wildfire, prairie dog die out, and consistently higher than average precipitation levels (Carpenter 1997). Increased competition from grasses at this site appeared to reduce Bell's twinpod densities. ?n subsequent years, as prairie dogs returned to the site and drought conditions were more common, plant cover was reduced to less than 25%. The amount of suitable habitat for plants that are poor competitors for resources such as Bell's twinpod varies over time with the dynamics of natural disturbance regimes. The major threats to shale barrens along the northern Front Range over the last several decades have come from urban development and noxious weed invasion. Diffuse knapweed, Mediterranean sage, and increasingly myrtle spurge represent the primary threat to shale barrens on C>SMP land. As visitation increases on C>SMP in North Boulder Valley, social trail development and new trails have the potential to impact shale barrens. Boulder's shale barrens contribute significantly to the biological diversity of foothills grasslands in The area. These barrens provide habitat for a large portion of Bell's twinpod along the northern Front Range of Colorado. This S1 /G2-ranked Colorado endemic species does not occur anywhere else in the world, and is identified as a conservation target by The Nature Conservancy's Central Shortgrass Prairie Ecoregional Plan. Two rare plant communities, the Indian Ricegrass Shale Barrens and the New' Mexico Feathergrass Herbaceous Associations, are affiliated with the shale barrens. 8-10 The White Rocks Cliffs The White Rocks are a Boulder County natural landmark. The cliffs are named for outcrops of light colored Fox Hills sandstone exposed by wind erosion and the undercutting of Boulder Creek (see Figure B-4). The Fox Hills typically erodes soon after exposure to wind and water, and extensive outcrops are uncommon. The White Rocks is an unusual exposure of the Fox Hills sandstone because the formation persists here as massive 30-50 foot high cliffs. The ecological interest of the White Rocks is related to its geologic origin. Many erosional alcoves and niches of varying sizes have formed in the soft sandstone of the cliff face. Intermittent flows across the surface of the exposure have formed shallow cracks in the surface of the rock. Steep gullies have formed along fault (fines in the sandstone. The cliffs are surrounded by an area of "sandstone breaks" and sandy slopes derived from the erosion of the cliffs. The Fox Hills sandstone is an aquifer, and the White Rock cliffs are known to be a discharge zone. Seeps and springs are found along the cliff face and in the deeper gullies that run through the sandstone (Gotham 1981) The White Rocks area is small. It occupies an area of approximately 150 acres about 5.5 miles northeast of the center of Boulder. As such it represents far less than one percent of the _ Grassland Planning Area. The exposure is ~ . i limited to an area beginning just east of North 75'h Street in the vicinity of Boulder u I: Creek and extending eastward toward North ~ - 95"' Street. The White Rocks cliffs are ~ ' . " - relatively narrow, their southern limit are the near vertical cliffs just north of Boulder Creek. ~ ~ ~ ~ J` s The exposed surface is visible for less than ~/4 ' , _ mile to the north before disappearing under u ~ . an overburden of soil and vegetation. The exposed horizontal surface of the sandstone J is marked by distinctive polygonal cracks that -'t~~"`~-~~ l ~t f~,J • form so-called "turtle backs". (Netoff 1 971). ~C ~ - - The unusual geologic substrate, southern •~~~o~` - exposure, shading from rock ledges and 1 • ; year-round availability of water all ~ - contribute to conditions capable of supporting ~ ~ , , vegetation more common in the sandy ~ ~ - prairies of eastern Colorado (Weber 1948, ~ 1. ~ 1 1983) and moister environments of t ° ~ ~ ~ • northeastern North America. Two rare plant species grow in grotto-tike conditions of a . large alcove eroded in the cliff face. The ~ - ~ - black spleenwort (Asplenium adiantum- nigrum) is known from only a handful of ~/~f r - - widely separated localities in North America. _ White Rack Cilfls Once thought to be a unique species, ~ ~ ~ .S Conservatlai Target Asp/enium andrewsii, the occurrence at White ~ " "`'""''``'y - ,:ip~l: Rocks was established to be indistinct from A. ~~,~,~r• ; ~ ;:r.. adiantum-nigrum (Ranker et al. 1994). ~ ~ Another uncommon species found in the moist eroded alcoves, American ground-nut (Apios americana) is more common in the eastern Figure B-4: Location and extent of the White Rocks within the Grassland Planning Area B-1 1 deciduous forest. Groundnut is found no further west than Boulder County-where it occurs in moist and cool microclimates. The cracks in the surface of the sandstone also provide habitat for a wide range of plant species (Clark et al. undated). These include the fork-tipped three awn {Aristides basiramea) known from very few sites in Colorado. The sandy soils and sandstone breaks around the cliffs provide ideal conditions for the growth of many high plains species plants not found anywhere near White Rocks (Weber 1948). These include narrowleaf four o'clock (Oxybaphus decumbens), silky sophora (Vexibia nutta/liana), lemon scurf-pea (Psora/idium /anceo/atum) and the plains black nightshade (Soianum americanum) (Clark et a/. 2001). Open Space and Mountain Parks ecologists have identified an uncommon species of bee balm (Monarch pectinata) at White Rocks as a sensitive plant species. The steep soft cliffs, sandy substrate, and juxtaposition near Boulder Creek creates animal habitat not available elsewhere in Boulder County and uncommon throughout Colorado. For many years beginning in 1941 birders noted that the alcoves in the cliffs were among the only "natural" nest sites for Barn Owls in Colorado (Stoecker 1972). The only local records of the six-lined racerunner are from beneath salt brush shrubs at the base of the cliffs. The depressions in the hummocky surface of the white rocks fill seasonally with water and support populations of fairy shrimp (Branc%inecta packardi) and an uncommon crawling water beetle {Pe/todytes} (Bushnell 1983). Also associated with the soft sandstone of the White Rocks is a solitary bee which feeds upon prickly pear pollen and excavates its nests in the rock. When first discovered this species (Perdita opuntiae) was thought to occur nowhere else (Custer 1928); but has been subsequently collected elsewhere. A 1970 profile of the White Rocks also identified four rare ant species recorded from the area (Aphaenogaster fu/va, A. huachucana, Formica criniventris, and Lasius ocddentalis). A, huachucana is considered to be potentially globally imperiled according to the NatureServe database. Historical human land use of the area surrounding the White Rocks cliffs has been dominated by agricultural. To the north where irrigation is impractical, the primary agricultural land use has been for growing wheat and other small grains. Irrigable lands to the south of the cliffs and subirrigated areas in the Boulder Creek floodplain have been used to raise hay and pasture grasses. Cattle have historically grazed the sandy breaks at the base of the cliffs and on the exposed rocky surface atop the cliffs. In recognition of the value of the White Rocks as habitat for plant species uncommon in Colorado, a portion of the formation was designated a Colorado Natural Area in 1979. The City of Boulder owns conservation easements on the full extent of the White Rocks cliffs. From 1974 through the present, the City of Boulder has purchased land or acquired conservation easements in the vicinity of the White Rocks to protect its conservation values of the cliffs as well as the Boulder Creek floodplain and Gunbarrel Hill. Livestock grazing of the natural area has been reduced as part of OSMP's management of the conservation easement. B-12 Plains~Faothills Transitional Riparian OSMP has included creeks with the riparian area target because these two elements share many key attributes, face very similar threats, and are likely to require similar conservation strategies. Riparian areas are characterized as transitional between permanently saturated wetlands and upland terrestrial areas. Riparian areas typically occur adjacent to creeks and rivers or along the shorelines of lakes and reservoirs. Historically, the most widespread riparian areas in the planning area are found along the larger creeks (Boulder Creek, South Boulder Creek, Coal Creek) where overbank flood events occur. Smaller riparian areas are also distributed along numerous intermittent creeks and drainages where flood flows are uncommon but elevated ground water levels support riparian vegetation. Riparian areas occurring outside the large or small floodp(ains are either associated with irrigation ditches or springs. There are about 1,200 acres of OSMP managed lands mapped in this target. Riparian areas make up about two percent of the land cover in the arid west, and about eight percent of the Grassland Planning Area (see Figure B-5). This relatively large proportion of riparian land cover is at least in part due to Boulder's intentional acquisition of open space to prevent development on floodplains. Riparian areas on OSMP reflect the ai ~ " changing environmental gradients 1 - from the foothills to the plains. ~ Foothills creeks characterized by - high gradient channels and ~1 - . - dominated by gravel and cobble t - ~r substrates gradually give way to _s-~~= slower flowing, lower gradient streams with sandy sediments. The ~ - • ' . - composition of plant and animal F_ ~ - species inhabiting riparian areas ~ . r ~ - ~ . changes along this elevational ~ _ •.~7: F~ gradient. - "k'' - - ~j ..-i- - Riparian areas are typically dominated by woody vegetation, - ; either trees or shrubs. (n forested -'^i ~ ; -~,.,f` riparian areas narrowleaf ,t~ f ~ . ~ ~ cottonwood dominates the higher ~ ~ r'- ~~,~~~r elevation sites. Plains cottonwood ~ ~ ~ ~ I . and peach-leaved willow dominate > ` ~ _ _s the overstory along lower gradient _ _ creeks further east. A hybrid of the i'~y two cottonwood species is found in / j~;:-, this transition zone. A similar pattern P/a/res/Footltll/s Trans/t/ara! is repeated beneath the tree canopy Rlparla~t Conservation Taryet e as composition of the shrub and • herbaceous layers shift from ~ Q sras:Jand, r'~~r.~,,t Cinundary• ~ ~ ~f~~P4ms/FOn;hilh Tr 3nshonal l?It!.vii,in montane to plains species. Diverse _ ; ;,._~,r,,;,, r,_rr,l,,t,r~, topography, soil conditions and f o z a gradients of available moisture along an east-west continuum sustain a wide range of plant species. Figure $-5: Location and extent of plains/foothills transitional riparian system in the Grassland Planning Area B-13 Riparian areas dominated by shrubs occur where soil moisture is not high enough to support the establishment and survival of trees. Riparian shrublands are common along intermittent drainages and in small depressional basins in the northern Boulder Valley and along ditches and small creeks throughout the planning area. Willows (Sa/ix species) are typically the dominant shrub in these systems. The major ecosystem processes influencing riparian areas are the availability of moisture, periodic flooding and grazing. These factors have changed significantly since European settlement. Water diversions and impoundments have had the direct effect of de-watering creeks, altering the extent, composition and structure of riparian vegetation. The redistribution of water has created novel riparian vegetation along ditches, and wetlands in area where irrigation water accumulates. Reduced flows have also reduced or eliminated flooding, which in turn altered patterns of erosion and deposition needed for riparian vegetation succession. Streambank stabilization and channelization projects have also reduced riparian extent and changed aquatic habitat. In pre-settlement times periodic, intense grazing by native ungulates probably occurred from time to time in riparian areas. With European settlement and the concurrent extirpation of many native ungulates, riparian areas were grazed by domestic livestock. This likely resulted in prolonged and intense grazing regimes outside the range of natural variability. Agricultural practices have also resulted in changes to water quality from the runoff of soil, manure and agricultural chemicals. While the riparian areas in the Grassland Planning Area have been negatively impacted by human activity they have not been destroyed. Some have also been recently restored to improve their ecological condition. However, most Front Range riparian systems have been severely degraded or eliminated by incompatible agricultural practices, gravel mining, road construction, residential, commercial and industrial development as well flood management and water development projects. More recently, the gentle topography, the presence of water and availability of shade have made riparian areas popular locations for recreational trails and greenways. Consequently, properly functioning (in the sense of Prichard et al. 1993, 1994} foothills transitional and plains riparian systems are rare along the Colorado Front Range, and in the Boulder Valley (Wohl 2001 } Some plant communities that are found in OSMP riparian areas are particularly uncommon and considered imperiled in Colorado. The narrowleaf cottonwood/ bluestem willow (Popu/us angustif/oia/ Sa/ix irrorata) plant association is found only along foothills streams of the Colorado Front Range and in the Rio Grande Valley of New Mexico. The hawthorn (Crataequs macracanthavar. occidenta/is} plant association was described in a 1998 report by CNHP on the South Platte River Basin as being known from Colorado only along Coal Creek. Although they comprise less than two percent of the land cover, riparian areas supply habitat for approximately 80 percent of birds, mammals, reptiles, amphibians and fish native to Colorado (Knopf 1985). Many of these species depend almost entirely on these streamside and aquatic habitats for their survival. Several examples of these riparian species are found in the Grassland Planning Area including the federally threatened Preble's Meadow jumping mouse and Ute ladies- tresses orchid. Foothills riparian shrublands support the highest breeding bird densities of any OSMP ecosystem. Several breeding bird species of foothills shrub patches are shrub specialist, including green-tailed towhees, Virginia's warblers, luzuli buntings, and blue-gray gnatcatchers. Creeks support habitat for aquatic organism including a variety of native and non-native fish, amphibians and invertebrates. Creeks in the planning area support a number of uncommon or rare fish species including brassy minnow, northern red belly dace, common shiner, plains topminnow and orange-spotted sunfish. B-14 The northern leopard frog is a Colorado Species of Special Concern. Despite recent population declines, Leopard frogs are found in a number of aquatic habitats on OSMP including Boulder Creek, South Boulder Creek and Coal Creek. Although the native mollusks cylindrical papershel( and umbillicate sprite have not been recorded from OSMP, aquatic habitat exists for these aquatic species of concern. B-15 Wetlands 8~ Mesic Tallgrass Wetlands occur where soil is inundated or saturated periodically during the growing season. Soils must be saturated long enough to create anaerobic (oxygen free) conditions within the rooting zone of plants. These conditions limit the types of plants that are capable of growing to those adapted to low oxygen environments. In the semi-arid climate of the Boulder Valley places where the ground is saturated or flooded wetlands are relatively uncommon. Nevertheless, these areas have ecological importance well out of proportion to their size or abundance. Figure B-6 shows the approximate location and extent of wetlands within the Grassland Planning Area. There are currently about 2,500 acres mapped in this target. Wetlands vary widely because of regional and local differences in soils, topography, climate, hydrology, water chemistry, vegetation, and other factors, including human disturbance. These differences create a diversity of wetland types. The most common wetland types found within the larger grassland matrix on OSMP land are marshes, wet meadows, and riparian wetlands. Seeps and springs also exist on OSMP land, but are much less common and cover a smaller portion of the project area. Marshes are characterized by the _ _ ' presence of permanent or semi- y permanent shallow water (less than _ 6.6 feet in depth). On OSMP land, ~ . - ~ marshes commonly occupy the ~ I ~ . edges of ponds and lakes, and ~ , although rarer, marshes also occur ~ - ! , in some depressions with fine ~ ' ' textured soils. Emergent plants such - :r : ~ r as cattails (Typha /atifo/ia, T. ,•~„i angustifo/ia) and bulrush _ ` ~ (Schoenop/ectus spp.) and -~,--•---4.~` ~ ~ : ~ J Z. ~ - submerged species such as _ • ~ - ondweed Potamo eton s 1,'~:r-!~j ' typically dominate the vegetation ~ ' in marshes within the Grassland Planning Area. Marshes often form where ground water or ~ , irrigation water accumulates. In ~ ' many places in the planning area ~f ~ ;f~' irrigation practices and seepage ~ ~ ~ ~ r from irrigation ditches have ` ,f introduced sufficient water for long ~ ~ f ~ ~ ~ ,.r . enough to create wetlands in areas - 1/'~ ~ that would otherwise be dry. Wetland 8 Meslc Tallyrass e r~"^ Conseivatia~ Taryet . y, ~ Alkali marshes, a special subset of ~~"'""'1;:'n`I'''`~`~':1.rugras" marshes, also exist on OSMP land. Alkali marshes support halophytic, QGraS:,ndlFCrr.;Iea:rr~r:aiy or salt-loving, vegetation including - ~ GrasSJand Pon Nrup~d 1. nit alkali bulrush (Bo/boshoenus ' ° maritimus) and inland saltgrass (Distichi/is stricta). Combined with Figure B-6: Location and extent of wetlands and mesic tallgrass wet meadows, marshes cover target in the Grassland Planning Area. B-16 approximately 1,500 acres of the project area. Wet meadows are drier than marshes having seasonally or permanently high water tables but lacking permanent standing water. They often occur due to flood irrigation practices and are common in low- lying floodplains adjacent to creeks. Soil type and water chemistry influence the type of vegetation found in wet meadows. Sedge meadows form in the larger grassland matrix where organic soils are present and mineral rich groundwater is near the surface. The most common sedge meadow type on OSMP land is the Nebraska sedge meadow (Carex nebrascensis), covering approximately 150 acres of the Grassland Planning Area. Clustered field sedge (Carex praegraci/is) and Emory sedge (Carex emoryi) meadows are also found on OSMP land, but these meadows comprise a smaller portion of the grassland. Nebraska sedge meadows and Emory sedge meadows are relatively rare in Colorado and are tracked by the Colorado Natural Heritage Program. OSMP's mineral soils also support wet meadows. Artic rush (./uncus ba/ticus) meadows, the most common wet meadow type on OSMP land, occur where high fresh groundwater tables saturate mineral soils. Inland salt flats can develop in mineral soils infused with an alkali water source. Depressional basins with marine sediment soils often support inland salt flats. Precipitation, geology, soils and supplemental irrigation support habitat for mesic (moist) tallgrass prairie. Mesic tallgrass meadows typically lack sufficient wetland hydrology and may not meet the jurisdictional definition of wetlands. However, OSMP grasslands support ecologically important mesic tallgrass meadows. Prairie cordgrass (Spartina pectinata) meadows are common in flats along the lower reaches of South Boulder Creek and along Boulder Creek. Mesic big bluestem-yellow Indiangrass (Andropogon gerardii-Sorghastrum avenaceum) meadows occur at higher elevations in drier and courser soil. Mesic tallgrass meadows cover approximately 700 acres in the Grassland Planning Area. Riparian wetlands occur adjacent to running water. Within the planning area, riparian wetlands can be found along Coal Creek, South Boulder Creek, Dry Creek, Bear Canyon Creek, Boulder Creek, Four Mile Canyon Creek and other perennial and ephemeral streams. The adjacent creek or stream is a major, if not the sole, source of hydrology to the wetland. Erosional and depositional forces of the adjacent creek influence the soil conditions and vegetation in these wetlands. While riparian wetlands can have herbaceous vegetation, woody vegetation characterizes many OSMP riparian wetlands. The most common riparian vegetative alliances within the Grassland Planning Area are chokecherry (Prunes virginiana) shrubland alliance and ill-scented sumac (Rhus tri/obata) herbaceous alliance. Riparian wetlands co-occur and with non-wetland riparian areas. Seeps and springs are found where hydrology, geology and topography allow groundwater to reach the soil surface. In the study area, these are typically associated with outwash mesas where the upper layers consist of Pleistocene alluvial deposits and are underlain by low permeability Pierre shale formations. Precipitation infiltrates the upper course sediments and percolates downward until reaching the impermeable shale layer. As groundwater reaches the edges of the mesas where the alluvial soils and shale meet, water seeps out and creates small wetlands typically dominated by coarse herbaceous vegetation. This wetland type is relatively uncommon in the planning area. Spring-fed wetlands also occur in fow lying areas where shallow ground water flows are interrupted by impermeable soil or bedrock and percolate to the soil surface. Water chemistry in these wetlands is strongly influenced by contact with soil or bedrock of marine origin and often has high concentrations of dissolved minerals. Salt tolerant plants (termed halophytes) dominate the plant communities in these wetlands. Representative examples of these types of wetlands occur on the Gallagher and Lousberg properties in the Grassland Planning Area. B-17 Local and landscape hydrologic regimes are the major ecological processes influencing wetlands. All wetlands depend on water for their existence. Although wetlands can withstand natural periods of drought, permanent dewatering, prolonged lowering of the water table, or removal of a wetland's water source results in a shift toward degraded upland ecological communities. For wetlands that rely on surface water, changes in the frequency and intensity of flooding can after wetland community composition and structure. Changes in the frequency and intensity of flooding can also alter the flow of nutrients and sediment to riparian wetlands further impacting their community composition and structure. While their influence is not as great as the hydrologic regime in shaping wetlands, fire and grazing also play a role in maintaining wetland composition and structure. Periodic fires, particularly in the mesic tallgrass and wet meadows, influence the community composition and structure often by limiting woody growth. Ungulate grazing has a similar affect. Fire suppression and replacing native ungulates with domestic livestock has modified these natural disturbance regimes. Despite their many social, economic and ecological values, wetland losses due to human exploitation have been extensive. Many wetlands have been significantly degraded or destroyed by activities such as conversion to cropland, dewatering for agricultural, municipal and industrial purposes, overgrazing by livestock, encroachment by residential and commercial development, channelization, as well as contamination from pollutants. There are about 2,500 acres currently mapped in this target on OSMP managed lands. This target includes wetlands that meet the jurisdictional definition for protection under the Clean Water Act and Boulder's wetlands protection program as well as mesic tallgrass prairie and open water. In recognition of the many ecological functions and human values provided by wetlands, and the significant global threats to wetlands, their function and values, Boulder's City Council endorses a program of wetland protection which includes the preservation of wetlands on City-owned property. This program regulates or prohibits certain types of activities in wetlands unless a permit is first obtained. The City of Boulder wetlands policy is articulated in the Boulder Va//ey C'omprehensive P/an, regulatory provisions of the City's land use code (the wetlands protection ordinance), and Open Space and Mountain Parks' Long Range Management Policies Because wetlands support both aquatic and terrestrial plant and animal species, they contain a disproportionately high level of biodiversity relative to other ecosystems. A number of rare plant species, including federally threatened Ute ladies'- tresses orchid and Colorado butterfly plant (Laura meomexicana) as well as state rare toothcup (Rota/a ramosior), inhabit OSMP wetlands. Several rare butterfly species, prairie Arogos skippers (Atrytone arogos iowa), prairie regal fritillaries (Speyeria ida/ia), and two-spotted skippers (Euphyes bimacula), rely on wetland plant species for habitat. Bobolinks (Do/ichonyx oryzivorus) and savannah sparrows (Passercu/us sandwichensis), both species of special concern in Boulder County, nest in OSMP wet meadows. OSMP wetlands also support the northern leopard frog, a species special concern in Colorado. 8-18 Black-tailed Prairie Dog and Associated Species The Black-tailed prairie dog and Associated Species target is unique in its focus on and requirement for the presence of a single species, the black-tailed prairie dog. Black-tailed prairie dogs have (ar- ranging impacts on the grassland which they inhabit and their presence provides prey and landscape structure necessary for the presence of associated species. Because of these tar reaching effects, prairie dogs are often considered "keystone" species. As a result, they are a species that defines the basis of a unique animal community on Open Space and Mountain Parks lands- the "Black-tailed prairie dog and Associated Community". The black-tailed prairie dog is a medium sized, colonial ground squirrel inhabiting subterranean burrows in suitable grassland habitat. The black-tailed prairie dog historically inhabited much of the central plains but through loss of habitat and direct extermination, its habitat has been reduced by nearly 98% (Miller et a1.1990, 1 994). Black-tailed prairie dogs exist on Open Space and Mountain Parks throughout grassland areas with large complexes of colonies clustered on the northern half of OSMP lands (see Figure B-7 Error! Reference source not found.). ~ .I ' In 2005, approximately 4,000 acres of . OSMP grassland habitat was inhabited --Y ~ _ ~r~~ :`:ice by Black-tailed prairie dogs. Since this _ , j ' time, an active epizootic of sylvatic ~ ~ ,o~ - . - - ~ plague has reduced the number of acres =-I T' " ' C3 - ' . - occupied by approximately 1,500 • - ~ ~ ' - acres. The conditions present on these - rairie do towns ran a from areas P 9 g g that support a healthy native plant I ~ - - community and several animal species associated with prairie dogs to areas - _ ~ where surrounding land use, underlying I vegetation communities or other factors ~ have led to prairie dog towns - ~ ~ ~ y0 characterized by a high density of = - - burrows, diminished native vegetation, - _ . i i I a d v' f `t local zed so loss n no a ldence o Q the vertebrate species considered to be _ dependent upon prairie dogs. I 1 e ~ - - On OSMP lands, Black-tailed prairie dogs prefer short to midgrass prairies with suitable soils (not rocky) and ~ relatively flat terrain. However, in BTPD & Associated Cornrrrrrrrlty ~ Carservatlorr Taryet areas where development or other factors have restricted the s atial r Prained~~~ r~IGni<> growth of prairie dog colonies, they ` U SMaximumPranadoycol~nyzxt:»t(':+~i may inhabit less suitable sites (rocky ~ _ `r'"=~.'~,°P'~~r~r~„`;`n"`:'' _ A,~Ir' Lang "A _7ra~a ~^a bv'\rr?It'~:~r soils, steep slopes or higher stature , _ a vegetation). These patterns of - i`~-'t~~~~'" - development and conflicting land use along with sylvatic plague have shaped Figure B-7: Maximum Extent (1996-2006) of Black-sailed Prairie the location, condition and extent of Dogs in the Grassland Planning Area. B-19 Black-tailed prairie dog colonies along the Colorado Front Range and on Boulder OSMP. Because of their ability to engineer the land on which they live (ground burrowing disturbance as well as clipping of vegetation), and to create habitat and food for a variety of other species, Black-tailed prairie dogs have been considered a keystone species in the grassland habitats they occupy {Kotlier et al. 1999, Hoogland 2006). The existence of several other closely associated species which rely on Black-tailed prairie dogs contributes to their function as a keystone species. These species benefit from the prairie dogs directly as prey, indirectly through use of their burrows, or both. These associated species are considered nested targets and include species that are common on OSMP as well as some less common, and several extirpated species. Burrowing Owl, American Badger, Ferruginous Hawk, Golden Eagle, Nebraska Tiger Beetle and the Black-footed Ferret pre animal species associated with healthy prairie dog colonies. As mentioned above, some of these species are predators of Black-tailed prairie dog colonies because prairie dogs are used as prey. These species include the American Badger, Ferruginous Hawk and Golden Eagle. These three species are also sensitive to human disturbance and are frequently found to be using only prairie dog towns distant from development and human disturbance. Other associated species use prairie dog burrows as habitat, most notably Burrowing Owls. Burrowing Owls are most frequently found using abandoned prairie dog burrows for shelter and nesting. Many other species may also use the burrows in prairie dog colonies including a variety of insects, small mammals, reptiles and amphibians. In addition to these associated species are several species that have been extirpated from black-tailed prairie dog towns in the Boulder Valley, Colorado or the high plains. These include the plains sharp- tailed grouse and the pronghorn antelope (extirpated from the Boulder Valley} as well as the black- footed ferret and the gray wolf (extirpated from the high plains). In most cases reintroduction sites better suited to the recovery of these species exist elsewhere in their range. In addition, suitable habitat for these animals is typically considered to be large contiguous blocks of habitat--in most cases recovery has focused upon areas larger than the entire Grassland Planning Area. Black-tailed prairie dogs have a long history of interaction with humans. Because of real or perceived conflicts with humans, they have been the targets of control and extermination. OSMP has a long history of assessing the conservation status of Black-tailed prairie dogs as well as conflicts between prairie dogs and surrounding or adjacent land uses. The most recent attempt to assess the viability of prairie dogs on OSMP and plan for the best management actions to conserve functioning and sustainable prairie dog colonies while minimizing conflicts is contained in the 1996 Black-tailed prairie dog Management Plan. The protection of open space lands has provided for areas in which Black- tailed prairie dog communities can function without the threat of development or extermination due to conflicts with competing land uses. As a result, OMSP and other public lands present the best opportunity for protecting Black-tailed prairie dogs along the highly urbanized Colorado Front Range. However, impacts from surrounding lands and sylvatic plague are poorly understood and present a largely uncontrolled threat to prairie dog populations. Although the presence of prairie dogs is necessary for inclusion in this conservation target, it does not automatically make a colony appropriate for inclusion. Naturally functioning prairie dog colonies often exist in a matrix of grassland habitats with only a portion of the available habitat occupied by prairie dogs at any time. This allows prairie dogs to respond to food availability and other habitat conditions by expanding, contracting their colonies and moving across the landscape to forage or find new colony sites. The movement of prairie dogs also results in shifting variety of grassland conditions. Under more natural conditions, prairie dog burrowing and grazing create apatchwork-like disturbance to the B-20 prairie landscape-a fine scale mosaic of plant species and animal habitat diversity. (n the urbanized setting of the Grassland Planning Area, the interval between occupation events is probably shorter than under natural conditions as prairie dogs have fewer places into which to they can migrate. It is also likely that both the amount and the proportion of the natural landscape unoccupied by prairie dogs at any time are smaller now when compared to historic conditions. Urbanization in the Boulder Valley has also decreased the value of grassland habitat for several of the species s associated with prairie dogs (e.g. mountain plover have been extirpated; ferruginous hawks avoid areas in proximity to urban or suburban development). Consequently some prairie dog colonies offer better opportunities for conserving prairie dogs in the ecological context most likely to allow for long term sustainability of vegetation and the support of associated animal species. The location, competing and surrounding land use and condition of the habitats in which prairie dog communities exist help to define the best opportunities for conserving prairie dogs and their associates in a sustainable ecological context. 8-21 Ag ricu Itu ra I Operations Ensuring on-going agricultural production is a well established function of Open Space and Mountain Parks lands. The city charter lists the "preservation of agricultural uses and land suitable for agricultural production" and "preservation of water resources in their natural or traditional state as open space purposes. "Water resources in a traditional state" includes the use of water rights for agricultural production on OSMP. Irrigated land and water resources available for agricultural production are critical for maintaining viable agricultural operations on OSMP lands. Up to 18,000 acres of OSMP land has been used for agricultural production in the recent past (see Figure B-8). Approximately 5,500 acres are currently irrigated. The primary uses of OSMP agricultural land are livestock grazing and forage production, however a small number of acres are used for growing small grains. Grain crops currently being grown include wheat, corn, and barley. These crops are grown on 300 - 600 acres annually. Beef cattle and small grains have ~ , ~ ~ - - - long been standard products for / _ " Boulder County agricultural ~ ~ i~~-•x producers. However, horse hay has ~ ' ~ >:~;I become a significant commodity in ~ - the last two decades as rural ~'V ~ _ ~ residential home ownership has ~ ~ : • _ become more popular. Increasing ' f _ ~ 1•~'-==_ _ ~ ~ i numbers of homeowners are keeping .,.f~ ~ - V L ~i horses on acreages too small to meet ~ year-round forage needs creating a d year round demand for hay. ' ` - r'• Organic production for sale to local ~ .Iy~;• -`v'~ restaurants and at farmer's markets ,--t f';• ; , is a growing trend in the Boulder ` ~ _ i = ~ r Valley. OSMP lessees are involved j ~ - with organic beef production, but not 7~~rJ - _ the production of organic fruits or ~ ~ ~ ~ - ` r vegetables. Organic farming is a ~ ~ I r- / - ' land use on some OSMP _ ~ : , - °f _ =t, conservation easements. . Agricultural services represent a '}~;~';~~,.,,.1; ~ ~ ~r ~ j C`. ~ _ I r small percentage of farm/ranch ii.; /;'~~/f.;~~. _ _~(~1~ {I(~' 1 _ i I'' income for OSMP lessees. OSMP ' y ~J Ayrlc++lcar~ ConservaC/on Taryet ~ i:• iii. /i leases include a horse boarding j'"- ~ _ ~c,,.,F~~,t.~,;,,~,~m~.,;s~3~~~r.,i~ operation and a therapeutic riding j '"'`Gtlfic`0i' i - i~r~y~eu Raro~ facility. A Community Supported ~ r'i ~=.~,,va,~~ti^~arc,t~;m Agriculture (CSA) farm is I c t _ _~r~;' ''°`r`""-`'~°"~`''' an OSMP conservation easement. ~ ~ . ~ e Currently there are no agro-tourism - operations on OSMP, or seasonal attractions such as Halloween Figure B-8 Agricultural Areas and Land Uses in the Grassland pumpkin patches or corn mazes. Planning Area OSMP staff has not historically influenced the production choices of agricultura! users. Lessee's choices B-22 of specific agricultural commodities are influenced by local commodity markets and their ability to sell a product profitably. Ranch and farm operators have freedom to decide what to grow and to a large degree how to grow it. OSMP lease managers are involved in decisions about specific management practices (stocking rates, seasons of use, herbicide use, etc.j to ensure the sustainability of the land, protect public safety, and to minimize the need for special infrastructure specific to a particular crop or service. Because of the cost, complexity, liability and infrastructure associated with agricultural services; OSMP has focused on providing agricultural services either in short supply or not available from the private sector. The growing awareness of the scale of environmental impact resulting from global climate change is increasingly reflected in public policy. New markets are emerging for carbon credits. Grassland management provides opportunities for OSMP to both assist the city in meeting the objectives of the Council-approved Climate Action Plan and potentially receiving monetary payments for particular agricultural management practices through climate credit exchanges. In 1991 (most recent data available-cited in the Boulder County Comprehensive Plan-Online Resource), local commodity prices were identified as one of the major obstacles to farming in Boulder County. However, the growth in the horse hay market and the ability to market natural beef has improved local markets recently. Oil seed crops for biofuels and human consumption may be another opportunity for diversification by traditional agricultural users. Small scale organic production will also be a viable alternative in the future. As part of the same 1991 analysis, land prices and speculation by developers for agricultural land was identified as a threat to the future of agriculture in Boulder County. The protection of open spaces is one of several strategies in place to abate this threat. As early as 1986 Boulder's city charter identified two of the key attributes of agriculture-land and water. Without these two elements, OSMP would not be able to make a contribution to the continuation of agriculture in Boulder. The department has been very successful in securing both land and water in support of land conservation and has used agricultural as a land management tool. One measure of land suitability for agricultural production is the number of acres that is leased to farmers or ranchers. Currently OSMP leases approximately 17,600 acres of land for agricultural production. There are additional OSMP properties that are suitable for agricultural production, but for a variety of reasons are not leased. This includes small isolated parcels, and lands where other visitor use or natural resource values are incompatible with agricultural operations. OSMP's portfolio of water rights arises from the four major creek drainages in the Boulder Valley, springs and groundwater. These water rights are used to irrigate over 5,500 acres for hay and pasture production. This portfolio contains many senior water rights establishing a reliable source of irrigation in most years. Another key attribute for sustainability of agricultural operations is the availability of operators to lease open space agricultural properties. According to the 2002 Census of Agriculture (USDA 2004) the majority (88%) of agricultural operations in Boulder County were operated by a family or individual (rather than a corporation). OSMP is one of the largest agricultural landowners in Boulder County (the other is Boulder County Parks and Open Space)-yet we employ no staff to farm or ranch. We depend upon local farmers and ranchers to ensure the on-going agriculture production on nearly 18,000 acres of land. The availability of operators depends upon having competent, flexible individuals who are willing to agree with the city's lease requirements. Competency is typically assessed by learning about an operator's past experience farming or ranching successfully either on OSMP lands or elsewhere. In 8-23 addition, the OSMP Long Range Management Policies state that OSMP staff will perform a fiscal analysis of the lessee's ability to perform according to the terms and conditions of the lease. Flexibility is often a function of the size of the farmer or rancher's operation beyond lands leased from OSMP. Because OSMP has a variety of purposes, it may be necessary from time to time to manage for priorities other than agricultural production or efficiency. At these times, farmers or ranchers who have alternative lands to address their needs offer advantages over operators who are restricted to only lands they lease from OSMP-or even a single OSMP property. Operators with capacity to take on larger areas also reduce the number of leases that the department must keep track of, reducing administrative costs. Willingness to farm on OSMP lands is affected by the stresses associated with farming in an urbanizing area, and farming on lands open to public use. A 1985 Colorado State University -Boulder County Agricultural Survey revealed that the number one factor discouraging continued agriculture was not market economics but the stresses and impacts created from urban influences (Boulder County Comprehensive Plan-Online Resource). To date, willingness to lease open space properties has been measured by the response of operators to lease offerings (requests for proposals) or the number of people who contact OSMP during the course of the year interested in leasing land for agriculture. One measure that can be used to forecast long-term availability of lessees is the average age of farm operators. For Boulder County the average age is 56. This suggests that there are probably more farmers near the end of their farming careers than near the beginning. In 1967 the city of Boulder began the purchase of open space lands, many of them in the Grassland Planning Area. With few field staff and little on-the-ground management capacity, the city leased properties to (ocaf farmers and ranchers to address day to day management. Recognizing a long term responsibility to set management objectives, city-commissioned agricultural management plans were developed in 1975. These plans informed the city's leases with farmers to ensure long term sustainability of the land. As the open space staff grew and newly hired agricultural managers, rangers, wildlife and plant ecologists developed a better understanding of how agricultural practices were affecting biodiversity conservation agricultural was recognized as not only a charter purpose but also a tool to enhance the ecological values of the city's natural area. Agricultural operations on lands that are currently managed as open space have created novel ecosystems3 over the past century. Irrigation has been a major source of change to the landscape. Since natural precipitation alone cannot support agriculture in many settings in the planning area-especially the higher terraces, mesa sides and mesa tops, significant inputs of irrigation water are needed. This water, diverted from creeks supports not only agricultural production but a wide range of semi-native moist meadows and wetlands dominated by native species. A fairly common occurrence in irrigated pastures is the accumulation of "tail water" (irrigation water that drains from the lower ends of fields) in depressions where marshes and other wetlands are supported. Semi-native hayfields and pastures and the associated agricultural practices support wildlife not commonly found elsewhere on OSMP lands such as Bobolinks (Do/ichonyx oryzivorus) and Dickcissels (Spina americana), as well as species which are more widespread elsewhere on OSMP but still of conservation concern. These include the Grasshopper Sparrows (Ammodramus savannarum), Lark Sparrows (Chondestes grammacus), Savannah Sparrows (Passercu/us sandwichensis}, Northern Harriers 3 Ecosystems containing new combinations of species that arise through human action, environmental change, and the impacts of the deliberate and inadvertent introduction of species from other regions (Hobbs et al. 2006) B-24 (Circus cyaneus), and Swainson's Hawks (Buteo swainsonij. The federally threatened Prebie's Meadow Jumping Mouse is widespread on OSMP lands managed for agriculture. Irrigated pastures and the ditches that serve them support plant species of concern such as the federal threatened Ute-ladies'- tresses Orchid (Spiranthes diluvia/island the locally sensitive American Groundnut (Apios americana) and Showy Prairie Gentian (Eustoma grandif/orumj, OSMP staff has been working with lessees for several decades to operate in a manner consistent with the conservation of these species. in addition, OSMP lease managers, wildlife ecologists and plant ecologists work together on a regular basis to refine grazing plans to address the conservation needs of a wide range of common and rare species and natural communities. Agricultural management of OSMP has provided significant advantages for the conservation of native species. However there are ecological costs associated with the transformation of land into agricultural uses and agricultural practices can be incompatible with the protection of native biodiversity. Agricultural ?and uses on OSMP have been increasingly multifunctional. The Grassland Plan will more provide information about how agriculture and ecological conservation interact, and where OSMP's focus on one adversely or positively affects the other. 8-25 References Baker, W.L and S.M. Galatowitsch. 1985. The Boulder tallgrass prairies. M. Figgs and N. Lederer, Eds. Boulder County Nature Association No. 3. Bennett, B. and Breed, M. D. i 985. The nesting biology mating behavior and foraging ecology of Perdita opuntiae Hymenoptera Andrenidae. Journal of the Kansas Entomological SocietX 58(2): 185- 194 Bock, J.H. and C.E. Bock. 1998. Tallgrass prairie: remnants and relicts. Great Plains Research 8:213- 230. Center for Great Plains Studies. Botham, L.H. 1981. Geohydrology of the White Rocks. Unpublished report submitted to the City of Boulder Open Space (sic). 3 pp + attachments. Boulder County, 1997. Boulder County Comprehensive Plan. Agricultural Resources Element. Accessed 1 1 November 2006. http://www.co.boulder.co.us/lu/bccp/agriculture.htm Branson, F.A., R.F. Miller and I.S. McQueen. 1965. Plant communities and soil moisture relationships near Denver, Colorado. Buckner, D.L., ESCO Assoc. Inc. 1 994. Report of Findings: Nature and distribution of warm season grassland, Section 16, R70W, T2S, Jefferson County, CO. Prepared for Western Aggregates Inc. Bushnell, J.H. 1983. Letter to James Crain regarding collections of aquatic invertebrates in White Rocks ponds. 2 pp attachments. Carpenter, A. 1997. Eco?ogical studies of the rare plant Ph~saria bellii (Bell's twinpod) on City of Boulder Open Space Lands. Unpublished report submitted to the city of Boulder Open Space Dept. Clark, D.A., C. Crawford and W.F. Jennings. 2001. Draft Baseline Plant Survey of Whiterocks and Surrounding Area in Eastern Boulder County. Unpublished report prepared for the City of Boulder Open Space and Mountain Parks. 21 pp. Custer C. 1928. The Bee That Works in Stone; Perdita opuntiae Ckll. Ps~he. 35(2):67-84 Hanson, H.C. and E. Dahl. 1957. Some grassland communities in the mountain-front zone in northern Colorado. Vegetatio, 7:249-270. Hobbs, R.J., S. Arico, J. Aronson, J. S. Baron, P. Bridgewater, V. A. Cramer, P. R. Epstein, J. 1. Ewel, C. A. Klink, A. E. Lugo, D. Norton, D. Ojima, D. M. Richardson, E.W. Sanderson, F. Valladares, M. Vila, R. Zamora and M. Zobel. 2006. Novel ecosystems: theoretical and management aspects of the new ecological world order. Global Ecology and Biogeography. 15:1-7 Hoekstra, J.M., T.M. Boucher, T.H. Ricketts and C. Roberts. 2001. Confronting a biome crisis: global disparities of habitat loss and protection. Ecology Letters, (2005) 8: 23-29 Hoogland, J.L., ed. 2006. Conservation of the Black-tailed prairie dog .Washington, D.C. Johnson W.C., and S. K. Coilinge. 2004. Landscape effects on Black-tailed prairie dog colonies. Biological Conservation, 1 15:487-497. Livingston, R.B. 1952. Relict true prairie communities in Colorado. Ecology. 33(1):72-86. Kelso, S., N.W. Bower, K.E. Heckmann, P.M. Beardsley, and D.G. Greve. 2003. Geobotany of the 8-26 Niobrara chalk barrens in Colorado: a study of edaphic endemism. Western North American Naturalist 63(3). pp. 299-313. Knopf, F.L. 1985. Significance of riparian vegetation to breeding birds across an attitudinal cline. Pp. T 05-1 1 1 in Riparian ecosystems and their management: reconciling conflicting uses {R.R. Johnson, C.D. Zeibell, D.R. Patten, P.F. Ffolliot, and R.H. Hamre, tech. cords.) US Department of Agriculture, Forest Service General Technical Report RM-T 20. Kothera, L. 2006. Population genetics and incidence of hybridization in the rare Colorado endemic plant Physaria bellii. PhD dissertation, Biology Dept., Colorado State University.Livingston, R.B. 1952. Relict true prairie communities in central Colorado. Ecology, Vol. 33. No. 1. Kotliar, N.B., B. W. Baker, A. D. Whicker and G. Plumb. 1999. A critical review of assumptions about the prairie dog as a keystone species. Environmental Management 24 (2):177-192. Miller, B., C. Wemmer, D. Biggins, and R. Reading. 1990. A proposal to conserve black-footed ferrets and the prairie dog ecosystem. Environmental Management 14:763-769. Miller, B., G. Ceballos, and R. Reading. 1994. The prairie dog and biotic diversity. Conservation Biology 8(3):667-681. Moir, W. H. 1969. Steppe communities in the foothills of the Colorado Front Range and their relative productivities. American Midland Naturalist, 81:331-340. Netoff, D.I. 1971 Polygonal jointing in sandstone near Boulder Colorado. Mountain Geologist. 8:17-24. Prichard, D., H. Barrett, J. Cagney, R. Clark, J. Fogg, K. Gebhart, P.L. Hansen, B. Mitchell, and D. Tippy. 1993. Riparian Area Management: Process for Assessing Proper Functioning Condition. TR 1737-9 {Revised 1998). Bureau of Land Management,BLM/SC/ST-93/003+1737+REV95+REV98, Service Center, CO. 51 pp. Prichard, D., C. Bridges, R. Krapf, S. Leonard, and W. Hagenbuck. 1994. Riparian Area Management: Process for Assessing Proper Functioning Condition for Lentic Riparian-Wetland Areas. TR 1737-1 1. Bureau of Land Management, BLM/SC/ST-94/008+i 737, Service Center, CO. 37 pp. Ranker, T.A. S. K. Floyd, M. D. Windham, P.G. Trapp Ranker, 1994. Historical Biogeography of Asp/enium adiantum-nigrum {Aspleniaceae) in North America and Implications for Speciation Theory in Homosporous Pteridophytes American Journal of Botany, Vol. 81(6): 776-781 Sherriff, R.L. and T.T. Veblen. 2004. The historic Range of variability of fire in the lower montane zone of Boulder County: Past fire types and fire effects. Department of Geography, University of Colorado. Unpublished report submitted to city of Boulder Open Space and Mountain Parks Dept. Stoecker, R.E. 1972. Impacts of gravel mining upon wildlife at White Rocks. Unpublished report submitted to Flatiron Paving Company. 20 pp. United States Department of Agriculture (USDA). National Agricultural Statistics Service. 2004. 2002 Census of Aariculture: Colorado State and County Data. Volumel: Geographic Area Series. Part 6. AC- 02-A-6. Vestal, A.G. 1914. Prairie vegetation of a mountain-front area in Colorado. Botanical Gazette. 167:1574-1582. B-27 Weber, W.A. 1948. White Rocks. The Green Thumb October. pp. 6-8, S plates. Referenced in Johnston, B. C. 1980. Letter to 1im Crain regarding Asplenium andrewsii. Weber, W.A. 1983. Catalog of the vascular plants of the White Rocks Natural Area Boulder County, Colorado. Unpublished report. 22 pp. Wohl, E.E. 2001. Virtual Rivers: Lessons from the Mountain Rivers of the Colorado Front Range. Yale University Press. New Haven, CT. 210 pp. 6-28 City of Boulder Attachment B1: 1/3/2008 Open Space and Mountain Parks Grasslpnd Ecosystem Management Plan Nested Target Table (Draft) Common name Scientific Name ESA G-Rank S-Rank CDOW Boulder County BVCP OSMP Mixed rass Prairie Mosaic American badger Taxidea taxes taxes SC-2 American elk Cervus e/op/ws ne/soni SC-X Bobolink Do/ichonyx oryzivor•us GS S36 SC SC-2 Cross-line Skipper Po/ites origenes rhena GS S3 SC-2 Ferruginous Hawk Buteo regalis G4 S36,S4N SC SC SC-1 Golden Eagle Aqui/a chrysaetos SC SC-2 Grasshopper Sparrow Ammodramus savannarum SC SC-2 Lark Bunting Ca/amospiza melanocorys SC SC-2 Loggerlteod Shrike Lanius ludovicianus SC SC-2 Mottled Duskywing Eiynnis mania/is G3G4 S2S3 LC SC-2 Northern Harrier Circus cyaneus SC SC-2 Ottoe Skipper Hesperia ottoe G3G4 52 LC SC-1 Plains pocket gopher Geomys bursaries /utescens SC-3 Prairie Arogos Skipper Atrytone arogos Iowa G3 S2 LC SC-3 Prairie Tiger Beetle Cicinde/a nebraskana G4 S1? Savannah Sparrow Passercu/us sandwichensis SC SC-3 Short-eared Owl As/o f/ammeus SC LC SC-2 Short-horned lizard Phrynosoma doug/assii SC-3 Swainson's Hawk Buteo swainsoni SC SC-2 Beebalrn, Horsemint Monarda pectinata Sensitive Lilac penstemon Penstemon graci/is Sertsitivc Prairie dropseed Sporobo/us hererolepis Sensitive Silver-leaf scurf pea; SL Wild Alfalfa Fsara/idium rrgophy//um Sensitive Weatherby's ;pike-moss Selt~gir7ella u•eatheri~ionc. RP Sensitive Animals in black, plants in green type. Species shown with whi'e background, Natural Commurities shown with green. B-29 A key to abbreviations may be found on p. B-40 City of Boulder Attachment B1: t /3/2008 Open Space and Mountain Parks Grassland Ecosystem Management Plan Nested Target Table (Draft) Common Home Scientific Name ESA G-Rank S-Rank CDOW Boulder County BVCP OSMP Western Wheat HA Posco runr snrilhii HA NA NA Western Wheatgrass -Green Needle rass HV Pasco rum smithii - Nasse//a viridu/a HV G3G4 S2 Poscopyrum smithii -Bouteloua gracilis Western Wheat rass -Blue Grama HV HV GS S4 Hesperostipa tomato - Bouteloua gracilis Needle and Thread-Blue Grama HA HA NA NA Needle-and-Thread -Colorado Front Hesperostipa conrata Colorado Front Ran a HV Ran e HV G1G2 S1S2 SNC Schizachyrium scoparium -Bouteloua Little Bluestern -Sideoats Grama HA curfi endu/o HA NA NA Little Btuestem -Sideoats Gramo Schizachyrium scoparium - Bou1e/ova Western Great Plains HV curfi endu/a Western Great Plains HV G3 S1 Green Needle rass HA Nassel/a viridu/a HA NA NA Green Needlegrass HV Nossel% viridulo HV GU SNR Animals in black, plants in green type. Species shown with white background, Natural Communities shown with green. B-3O A key to abbreviations may be found on p. B-40 City of Boulder Attpchment B1: 1/3/2008 Open Space and Mountain Parks Grassland Ecosystem Management Plan Nested Target Table (Draft} Common name Scientific Name ESA G-Rank S-Rpnk CDOW Boulder County BVCP OSMP Xeric Tall rass Mosoic American elk Cervus e/aphus ne/soni SC-X Cross-line Skipper Polites origenes rhena GS S3 SC-2 Ferruginous Hawk Buteo regalis G4 S36,S4N SC SC SC-1 Golden Eagle Aqui/a chrysaetos SC SC-2 Grasshopper Sparrow Antmodramus savannarum SC SC-2 Lark Bunting Ca/amospiza melanocorys SC SC-2 Lark Sparrow Chondestes grammacus SC-X Northern Harrier Circus cyaneus SC SC-2 Ottoe Skipper Hesperia oboe G3G4 S2 LC SC-1 Prairie Aroyos Skipper Atrytone arogos Iowa G3 S2 LC SC-3 Prairie Regal Fritillary Speyeria ida/ia G3 S1 LC SC-1 Short-eared Owl Asio f/ammeus SC LC SC-2 Swainson's Hawk Buteo swainsoni SC SC-2 ball cactus Pediocactus sirnpsanii Sensitive Birdfoot violet, prairie violc9t Viola pedatir'ida GS S2 LC Dwarf leadplant, Dwarf indigo bush Amorpha nrna GS S2S:; RP LC Grassyslope sedgy Carex oreocharis G3 Sl Nr.rrow-leaved Milk~,~-eed Asc/epics stenophyl/a G4G5 S2 Porcupine grass Hespero>/ipa spartea Sensitive Prniric' dropseed S.vorobelus heterolepis Sensitive Silver-leaf scurf pea; St. b'?ild Alfalfa Pi01'alldlUrl7 C7GJOpltyl/!/A7 Sensitive Wecrth.=rby's s;Ji!cc-n;::~<_ Se~'c:rine!la t,-earirerUic~rtc.' RP $enSitivr Animals in olack, plants in green type. Speces shown with white background, Natural Corr.munites shown with green. B-31 A key to abbreviations may be found on o. B-40 City of Boulder Attachment B1: 1/3/2008 Open Space and Mountain Parks Grassland Ecosystem Management Plan Nested Target Table (Draft) Common name Scientific Name ESA G-Ronk S-Rank CDOW Boulder Count BVCP OSMP Xeric components of the Big Bluestem - jYellow Indian rass HA NA NA SNC Big-Bluestem -Little Bluesetem Western Andropogon gerardii - Schizachyrium Great Plains HV sco arium Western Great Plains HV G2? S2 SNC Big Bluestem -Prairie Dropseed Andropogon gerardii - Sporobo/us Western Great Plains HV hetero% is Western Foothills HV G2? S1S2 SNC Pinus onderosa Wooded Toll HA NA NA Tall rass Tree Savannah HV Xeric Toll rass Tree Savonnah HV NA NA Sensitive Ponderosa Pine /Mountain-mahogany / Big Bluestem Wooded Herbaceous Pinus ponderosa /Cercocarpus montanus Ve etation /Andro 0 on erardii Wooded HV G2 52? Soo weed Yucca Shrub Savonnah HA Yucca lauca Shrub HA NA NA Yucca /Big Bluestem Xeric Tallgrass Yucca g/auto /Andropogon gerardii Shrub Savannah Xeric Tall rass Shrub Savannah NA NA Sensitive Animals in black, plants in green type. Species shown ~~irh white background, Natural Communities shown with green. B-32 A key to abbreviations may be found on p. B-40 City of Boulder Attachment B1: 1 /3/2008 Open Space and Mountain Parks Grassland Ecosystem Management Pian Nested Target Table (Draft} Comman name Scientific Name ESA G-Rank S-Ronk CDOW Boulder County BVCP OSMP Plains Foothills Transitional Ri orlon American elk Cervus e/aphus ne/soni SC-X American Redstart Setophaga ruticil/a SC LC SC-2 Bald Eagle Ha/iaeetus /eucocepha/us G5 St B,S3N T LC SC-1 Black bear Ursus americanus amb/yceps SC-1 Black-crowned Night-Heron Nycticorax nycticorax SC SC-2 Brassy minnow Nybognathushankinsoni T SC-1 Brown Thrasher Toxostoma rufum SC SC-2 Common garter snake Thamnophis sirtalis parietalis GSs3 SC SC-2 Common shiner Luxilus cornutus T LC SC-1 Cylindrical pgpershell Anodontoides ferussacianus G5 S2 SC LC SC-2 Fringed myotis Myotis thysanodes thysanodes G4G5 S3 $C-2 Gray Catbird Dumetella carollnensis SC SC-3 Great Blue Heron Ardea herodias SC SC-2 Hops Azure Celestrina humulus G2G3 S2 LC SC-1 Lark Sparrow Chondestes grammacus SC-X Lazuli Bunting Passerina amoena SC-3 Lewis~s Woodpecker Melanerpes lewfs G4 S4 SC SC-2 Mottled Duskywing Erynnis mania/is G3G4 S2S3 LC SC-2 Mountain lion fe/isconco/orhippo/ester SC-1 Northern leopard frog Rana pipiens G5 S3 SC SC-1 Northern redbelly dace Phoxinus eos GS Sl E LC SC-1 Olive-sided Flycatcher Contopus cooperii SC SC-2 Plains topminnow Fun~1u/us sciadicus LC SC-2 Preble~s Meadow jumping mouse Zapus hudsonius preblei LT G5T2 S1 T LC SC-1 Snowy Egret Egretta thu/a G5 S2B Spiny softshell Apa/one spinifera hartwegi SC-3 Two-spotted Skipper Euphyes bimacula G4 S2 LC SC-2 Umbillicate Sprite Promenetus umbilicate!lus SC-2 Willow Flycatcher Empidonax trai//ii SC SC-2 Wood Duck Aix sponsa SC SC-3 Yellow Warbler Dendroica petechia SC-X Yellow-headed Blackbird Xanthocepha/us xanthocepha/us SC SC-2 Animals in black, plants in green type. Species shown with white bockground, Natural Communities shown with green. B-33 A key to abbreviations may be found on p. B-40 City of Boulder Attachment B1: 1 /3/2008 Open Space and Mountain Parks Grassland Ecosystem Management Plan Nested Target Table (Draft) Common Home Scientific Name ESA G-Ronk S-Rank CDOW Boulder Count BVCP OSMP At11EfiCCln Groundnut Apios arnericancr G5 S1 RP LC Car, ionflower Smilax lasioneuron Sensitive Chcaffweed Centunculus minirnus GS S 1 LC Colorcu!o butterfly plant Gavra neomexicona LT G3T22 Sl LC Oceanspray, Rock Spirea Holodiscus discolor Sensitive Ponclweed Potamogeton diversifolius GS Sl Ute lady's tresses Spiranthes diluvia/is LT G2 S2 RP LC Wild hops Humu/us /upu/us Sensitive Plains Ri arian Woodland Forest NA NA Narrowleaved Cottonwood / Bluestem Popu/us angustifolia~Sa/ix irrorata Willow Woodland Woodland G2 S2 Plains Cottonwood - (Peachleaf Willow) Popu/us de/toides - (Sa/ix omygda/oidesJ / Co ote Willow Woodland /Salix exi ua interior Woodland G3G4 53 Foothills Ri arian Shrubland Skunkbush Intermittently Flooded Rhus tri/obata Intermittently Flooded Shrubland Shrubland G2G3 S2 Western Snowberr Shrubland S m horicar os occidenta/is Shrubland G4G5 S3 Animals in black, plants in green type. Species shown with white background, Natural Communities shown with green. g-34 A key to abbreviations may be found on p. B-40 City of Boulder Attachment B1: 1 /3/2008 Open Space and Mountain Porks Grassland Ecosystem Management Plan Nested Target Table (Draft) Common name Scientific Name ESA G-Rank S-Rank CDOW Boulder County BVCP OSMP Wetlands American Bittern Bolaurus /entiginosus SC SC-1 American elk Cervus e/aphus ne/soni SC-X American White Pelican Pe/ecanus erythror/~ynchos G3 Sl B Black-necked Stilt Himantopus mexicanus GS S3B Bobolink Do/ichonyx oryzivorus GS S3B SC SC-2 Common garter snake Thamnophis sirtalis parieta/is GSs3 SC SC-2 Dickcissel Spiza americana SC-3 Eared Grebe Podiceps nigrico//is SC SC-2 Least Bittern /xobrychus exi/is SC SC-2 Northern Harrier Circus cyoneus SC SC-2 Northern leopard frog Rana pipiens GS S3 SC SC-1 Osprey Pandion ha/iaetus SC SC-2 Prairie Arogos Skipper Atrytone arogos iowa G3 S2 lC SC-3 Prairie Regal Fritillary Speyeria ida/ia G3 S1 LC SC-1 Sharp sprite Promenelus exacvous GS S2 LC SC-2 Short-eared Owl Asio f/ammeus SC LC SC-2 Two-spotted Skipper Eup/ryes bimacula G4 S2 LC SC-2 Wilson~s Phalarope Pha/aropus >rico/or GS S46,S4N Yellow-headed Blackbird Xanthocepha/us xanthocepha/us SC SC-2 Checker mallow Sida/cea neomexicana Sensitive Colorado butterfly plc:nt C-aura neomexicana LT G3T22 Sl LC Oceanspray, Rock Spirea Holoa'iscus discolor Sensitive Tvothr_t~p Rotala ramosior GS S1 LC Tuli;~ gentian, Showy prairie genticui ~ustoma grandiflorum RP Sensitive Ute lady~s tresses Spiranthes diluvirlis LT G2 S2 RP LC Wild hotx h'untulus /upu/us Sensitive Nebraska Sed e HV Carex nebrascensis HV G4 S3 Clustered Sed a HV Carex roe raci/is HV G3G4 S2 Ameican Manna rass HV Gl ceria rondis HV G2? S2 Mesic Tall rass Big Bluestem -Yellow Indiangrass Western Great Plains Herbaceous Andropogon gerardii - Sorghastrum Ve etation nutans Western Great Plains HV G2 S1S2 Prairie Cordgrass Western Herbaceous Ve etation S artina edinato Western HV G3? 53 nano s rn acK, p an s m green ype. Species shown with white beckground, Natural Communities shown with green. B-3S A key to abbreviations may be found on p. B-40 City of Boulder Attachment Bl: 1/3/2008 Open Space and Mountain Parks Grassland Ecosystem Management Plan Nested Target Table (Draft) Common name Scientific Name ESA G-Rank S-Rank CDOW Boulder County BVCP OSMP Animals in black, plants in green type. Species shown with white background, Natural Communities shown with green. B-36 A key to abbreviations may be found on p. B-40 City of Boulder Attachment Bl : 1 /3/2008 Open Space and Mountain Parks Grassland Ecosystem Management Plan Nested Target Table (Draft) Common Warne Sciantific Name E$A G-Rank S-Rank CDOW Boulder County BVCP OSMP Black-tailed Prairie Do and Associated Communi American badger Taxidea taxus taxus SC-2 Bald Eagle Ha/iaeetus /eucocepha/us G5 S I B,S3N T LC SC-7 Black-tailed prairie dog Cynomys /udovicianus /udovicianus G4 S3 SC LC SC-1 Burrowing Owl Athene cunicu/aria G4 S4B T SC LC SC-1 Ferruginous Hawk Buteo regalis G4 S3B,S4N SC SC SC-1 Golden Eagle Aquila chrysaetas SC SC-2 Proirie Tiger Beetle Cicinde/anebraskana G4 Sl? Shale Barrens 6cIL. r~,in~od Pl1v~_:;;r~ --Lli: v:' RP LC Indian Rice toss HA AchnaJherum h menoides HA NAB NA Achnatherum hymenoides Shale Barren Indian Rice rass Shale Barren HV " HV G2 S2 New Mexico Feather rass HA Hespervstipa neomexicana HA NA NA New Mexico Feather rass HV Hesperosti a neomexicana HV G3 S3 SNC White Rode Cliffs Barn Owl Tyto a/ba SC SC-3 Long-eared Owl Asio otus SC SC-2 Six-lined racerunner C-nemidophorus sex/ineatus viridis SC-3 Anter;cc:n Groundnut Ai:~ias aniericana GS Sl RP LC Beebalm ~1lorscrnint' Monrrdo pectu;aJa Sensi'ive Forktip Three-r•.vn Aristidr. basirameo GS S 1 RF LC S~~lecn:~;ort Aspior>%urn cdic~n!u,r.-nigrum, G` 51 RP LC Anirr,als in clack, plants 'r green type. Spec es snea:n with nvhite beckground, Natural Corr•niunit es snaan wlth green. 8-37 ;cey to abbreviations may be`ound an p. E-40 City of Boulder Attachmerrt B1: 1 /3/2008 Open Space and Mountain Parks Grassland Ecosystem Management Plan Nested Target Table (Draft} Common name Scientific Name ESA G-Rank S-Rank CDOW Boulder County BVCP OSMP A ricultural O erotions Bobolink Do/ichonyx oryzivorus GS S36 SC SC-2 Dickcissel Spiza americana SC-3 Grasshopper Sparrow Ammodramus savannarum SC SC-2 Lark Sparrow Chondestes grammacus SC-X Northern Harrier Circus cyoneus SC SC-2 Savannoh Sparrow Passercu/us sandwichensis SC SC-3 Swainson~s Hawk Buteo swainsoni SC SC-2 Tconc~up Rotaln rrmosior GS Sl LC American Groundnut Apics americans. G5 Sl RP LC Tulip gentian, Showy prairie gentian Eustema grandif/Drum RP Sensitive Wild hops Humu/us /upu/us Sensitive Ute lolly's tresses Spiranthes di/uviolis LT G2 S2 RP LC Semi-native Irri ated Meadows NA NA Sensitive Animals in black, plants in green type. Species shown with white background, Natural Communities shown with green. B-38 A key to abbreviations may be found on p. B-40 City of Boulder Attachment B2 r ~,sizccs Open Space and M,ounrain Parks Grassland Ecosystem Management Plan Draft Nested Target Table Extirpated Species Cornrnon name Scientific Name ESA G-Rank S-Rank CDOW Boulder County BVCP OSMP Black-tolled Prairie Do and Associoted Communi r r ~~I' -r _r.'c~-. L r~,- L_~n~~ ~ ~i',r:~-~ or,rr,,, r_,j-~1 c.1 E SC L: .iC.? I_._ r,,'r i Lc C~l Sl T tiC. Mountain 'Plover Chn~ad~in Creeks I~, i-. -:r is •:rd. LT E ~ C Mlxed ross Prairie Mosaic - ,I_ - - , - r ,~1 I - t' - Plains Foothills Transitional Ri orlon ,l v Shale Barrens _,...,ti..;.._~...._....:.,--~.....,~~:;:: Wetlands White Rode Cliffs - - Xeric Tall ross Mosaic ou; r - 1 _ .c„ LC / iL E SC Lr _ s B-3~ A key to abbreviatiors may be `o~nd cn p. B-40 Key to Abbreviations used in Attachments 81 and B2 ESA = US Endangered Species Act LE-Listed Endangered LT-Listed Threatened G-Rank: Global Rank S-Rank: Colorado Rank Nature5erve/lieritaae Program Imperilment Ranks 1 -Critically Imperiled 2- Imperiled 3- Rare or Uncommon 4-Widespread/Abundant 5-Secure CDOW=Status from Colorado Division of Wildlife Species of Concern List E-Endangered T-Threatened SC-Special Concern Boulder County =Boulder County and Boulder County Nature Association Rare Plants and Significant Natural Communities and Bird Species of Concern RP-Rare Plant SC-Special Concern SNC-Significant Natural Community BVCP =Plant and Animals Species of Local Concern in the Boulder Valle LC-Local Concern OSMP =Open Space and Mountain Parks Species of Concern SC-1 Special Concern Priority 1 (anima!) SC-2 Special Concern Priority 2 (animal} SC-3 Special Concern Priority 3 (animal} Sensitive Sensitive Plant Species B-40 Attachment C Preliminary Key Attributes and Indicators The Grassland Plan seeks to define objectives for conserving the plan's ecological targets and for managing agricultural operations on OSMP. By defining measurable objectives and taking measurements, OSMP will know how far we have to go and be able to measure progress. However, defining measurable objectives is especially challenging for ecological targets because of the inherent complexity and variability in natural systems. "Viability assessment" is a way of using the relevant principles of ecology (or in the case of agriculture both ecology and business) to identify the current status and the desired future condition of the planning targets. The process, developed for use with ecological targets by The Nature Conservancy, begins with the identification of "key attributes" for each target. A key attribute is an aspect of the target that if modified or removed would result in loss or significant degradation of the target over time. The tables that follow give some examples of the key attributes and indicators that are under development for the Grassland Plan. Mixed Grass Prairie Mosaic Xeric Tallgrass Mosaic (those indicators in bo/dita/ic address Xeric Tallgrass specifically) Shale Barrens (those indicators underlined address oniy Shale Barrens) Key Attribute Indicator Fire Regime years since last fire in a patch l ojo area with 5-io year fire return of target burned J Surrounding Land Use % of Surrounding Land Developed or Disturbed Intensity of human dominated land use within 100 m Functional Habitat Block size (Based on acceptable size range for selected Blocks grassland birds. Size derived from a landscape analysis, including external land use score and internal fragmentation analysis) Extent (areal of shale barrens Plant Composition Native species richness (number of native species) Relative cover by plant species that increase/decrease with grazing by native plant species by bare ground and litter Percent of area dominated by exotic plant species Rare p/ant pope/ation status (census or frequency/coversamp/ingJ Re/ative corer of rare bulterf/y host p/ant species Status of rare plant populations: Bell's twinpod (census or am lin Plant Structure Visual obstruction {height-density measure) Animal Composition Breeding bird species richness Partners in Flight Rank Index {migratory birds) Butterfly native species richness C-1 Wetlands 8~ Mesic Tallgrass Prairie Items shown in bo/ditalics are indicators for both wetlands and mesic tallgrass prairie; all other indicators are for wetlands alone. Ke Attribute Indicator Surrounding Land Use Land Use Score - % of surrounding {and developed or disturbed - intensity of human dominated land use within 100 m Hydrologic Regime Degree of alteration of hydrology Connectivity Road and Trail Density within 200 m Buffer Area Width of vegetated area surrounding wetland Connectivity Proximity to other wetlands or riparian areas Plant Composition Native species richness (number of native species) Relative cover by native p/ants by plant species that alter function or structure by litter and bare ground Floristic Quality Index Status of Ute Ladies'-tresses Orchid Plant Structure Saplings/seedling of native woody plants Animal Composition Presence of exotic species (bullfrogs, New Zealand Mudsnail) Bird species richness Native fish species richness Conservation (Partners in Flight) score for birds Native butterf/y species richness Native frog presense Fire Regime years since last fire in a patch 1 % area with 5-10 year fire return (for mesic tallgrass) % of target burned J Plains and Foothills Transitional Riparian Key Attribute Indicator Surrounding Land Use Land Use Score - % of surrounding land developed or disturbed - intensity of human dominated land use within 100 m Hydrologic Regime Departure from natural h drograph Buffer Area Width of vegetated area surrounding riparian area Connectivity Continuity of aquatic system Continuity of riparian vegetation Size Riparian area patch size Plant Composition Native species richness (number of native species) Relative cover -by plant species that increase decrease with grazing by plant species that alter function or structure -by bare ground and litter Floristic Quality Index C-2 Key Attribute Indicator Nutrient Regime Nutrient loading index Sedimentation Regime Sediment loading index Bank Stability Measures to be determined Woody regeneration Size/age class distribution of woody plants in riparian shrublands and forests Aquatic Habitat Fish Cover (instream habitat) Floodplain Morphology Alteration of natural floodplain Animal Composition Presence of exotic species (bullfrogs, New Zealand Mudsnail} Bird species richness Native fish species richness Conservation (Partners in Flight} score for birds Black-Tailed Prairie Doq and Associated Species Key Attribute Indicator Surrounding Land Use Land Use Score - % of surrounding land developed or disturbed - intensity of human dominated land use within 100 m - road density Colony Area Extent of colonies (area) Size of Complex Extent (area) occupied w/in habitat patch Prairie dog density # of prairie dogs acre Predator community # of species Commensal community # of species Patch Occupancy % of "GOOD" or "VERY GOOD" suitable habitat in patches occupied by prairie dogs Ecological Habitat % of Colonies in Good or Very Good suitable habitat Suitability Patch shape Corrected perimeter area ratio Aaricultural Operations Key Attribute Indicator Scale Acres available for agricultural production Productivity Irrigable land available for agricultural production Grassland condition Percent of grazed areas determined to be in good condition for forage production Availability of Summer Percent of summer grazing needs available in "grass bank" Grazing (generally a greater need for summer pasture than OSMP can provide because of our desire to limit timing and intensity) Availability of Water Percent of irrigable land with dependable water source. (Irrigation) (water available 4 years out of 5) Availability of Land Measure to be determined and Infrastructure C-3 Key Attribute Indicator Lands for Optimal Availability of land (acres) for market/operator driven Agricultural Production production choices. Availability of Measure to be determined Operators Time required to find qualified lessee or Number of qualified applicants for leases Animal Composition Hayfield Birds Conservation Value Score White Rocks Cliffs Key Attribute Indicator Plant Composition Floristic Quality Index of Grotto Vegetation Status of Rare Plants • Black Spleenwort ¦ Fork-tip Threeawn • Horsemint • American Groundnut Animal Composition Status of Animal Species of Concern • Six-lined Racerunner ¦ Barn Owl ¦ Long-eared Owl C-4 Attachment D Assessment of Target Viability: Grassland Ecosystem Management Plan Sample Viahility Table-Mixed Grass Prairie Mosaic i Conservation Current Indicator Curzent Desired Tar et Category Key Attribute Indicator Poor Fair Good very Good g Status Rating Rating 1 Mixed Grass Landscape Fire regime - Percent of target <25% 2s-50% 51-75% 70-100% Estimate that Prairie Context (timing, area 1.000 acreas Mosaic frequency, experiencing a out of 8.000 intensity, 5-10 yearfire (12.5'/0) acres rair Good extent) return burned in last 20 ears: 1 Mixed Grass Condition Vegetation Native Species <f0 io 60-87% &8-99% 100% HESCOM- Prairie Composition RELATIVE (HESCOM- (HESCOM- (N.ESCOM- (HESCOtv1- 80UGRA Mosaic COVER CHOGRA) CHOGRA) CNOGRA) CHOGRA) transects exhibit higher relative <33% (PASSPJIj 34-85% 86-99% 100% (PASSMI) cover of native (PASSMI) (PASSM;~ species than the PASSMI transects and are probably in acceptable Fair Gcod ~ i condition. A,Iso ~ ~ the HESCOM- E30UGRA ~ transects exhibit less variability of relative cover of native species. The PASSMI transec 1 -Mixed Grass Condition Vegetation Native species <5 (HESC0~4- 5-30 37-54 >54 (HESCOM- Species Prairie Composition RICHNESS CHOGRA) (HESCOM- (Nc'SCCf~i- CHOGRA) rchress is Mosaic CHOGRA) CNOGRA) depauperate. Fair Good <3 (PASSMI) >44 (PASSMI) 4.33 (PASSMI) ?4-44 (PASSMM;) D-1 Attachment U Assessment of Target Viability: Grassland Ecosystem Management Plan Sample Viability Table Vi[ixed Grass Prairie Mosaic I Conservation Category Key Attribute indicator Poor Fair Good Very Good Current Indicator Current Desired Target Status Rating Rating 1 Mixed Grass Condition 'Vegetation Percent Area >5% 3-5% 1-3% RAM species 3.88% of the Prairie Composition Dominated by not present cr target is Mosaic exotic species less than one mapped as tracked through percent of area being Fair Good RAM method dominated by dominated by "RAM species" RAM species. t Mixed Grass Condition Vegetation Relative Cover >40% 8.5-40% 2.5-8 ~i% <2.5°1° Prairie Composition Increaser Mosaic Species Fair Good 1 Mixed Grass Condition Vegetative Absolute Cover <5% o! >35°!° 5-10% or 26- 10-25% ? C-25% Prairie Structure Bare Ground (HESCCM- 35°/ (HESCCM- (HESCCPA- Mosaic CHOGRA) (HESCOM- CNOGRA) CHOGRA) CHOGRA) =air r=ecd <3% Cr >33% 3-10% 3-1C°.o (PASSMI} 11-33% (,pASSMI; (PASSh11) (PASSMI} 1 Mixed Grass Condition Vegetative Absolute Litter <10% or >60% 10-20°/, or 21-50% 21-50% Prairie Structure Cover >50% Mosaic ~ai~ Gcod D-2