Report May Be Cited As: Steuter Al, Jennifer S Hall and Mary Lammert Khoury
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gonserving2the2fiologil2hiversity of2the gentrl2wixedEqrss2ririe e2ypyvsy2hisqxih2py2gyxiesyx2egsyx el2teuter2222tennifer2F2rll2222wry2vmmert2uhoury CONSERVING THE BIOLOGICAL DIVERSITY OF THE CENTRAL MIXED-GRASS PRAIRIE A PORTFOLIO DESIGNED FOR CONSERVATION ACTION Al Steuter Jennifer S. Hall Mary Lammert Khoury Nebraska Field Office Great Plains Division Freshwater Initiative 1019 Leavenworth St, Suite 100 1402 Culver Road 8 S Michigan Ave, Suite 2301 Omaha NE 68102 Ann Arbor MI 48103 Chicago IL 60603 [email protected] [email protected] [email protected] This report may be cited as: Steuter Al, Jennifer S Hall and Mary Lammert Khoury. 2003. Conserving the biological diversity of the Central Mixed-Grass Prairie: A portfolio designed for conservation action. The Nature Conservancy, Nebraska Field Office, Omaha NE. To obtain additional copies of this report: Electronic copies can be downloaded at conserveonline.org Hard copies can be obtained by contacting the Nebraska Field Office at 402.342.0282 Front cover photograph: Nebraska Sandhills along the Niobrara River, Matt Bradley ACKNOWLEDGEMENTS The Central Mixed-Grass Prairie conservation plan is the product of the efforts of Conservancy and Natural Heritage Program staff, academic and agency reviewers supporting these staff, and the local conservation partners who we work and converse with on a regular basis. We extend our gratitude to those individuals who served in an official capacity as Sponsors, Core Team members, Technical Committee members, and Portfolio Design Group members (all are listed within the document). The plan benefited greatly from their previous experience with one or more neighboring regions. We especially wish to thank all those individuals who stayed with the effort over a longer than expected planning period. In addition, we would like to thank Hillary Loring (Kansas Biological Survey) and Gerry Steinauer (Nebraska Game and Parks and Prairie Plains Resources Institute) for their contributions to this planning effort. We hope that we have captured both the significant scientific details all of these individuals provided, as well as their spirit for effective conservation of the region’s biological diversity. Errors and omissions are strictly the responsibility of the authors. The aquatic portion of this conservation plan would not have happened without the support of Jonathan Higgins, Paula Gagnon, and Tom FitzHugh in the Chicago office of the Freshwater Initiative (FWI). Supporting these FWI staff through expert workshop and peer review were: Bob Angelo – Kansas Dept. Health/Environment Kristen Hase – Kansas Dept. Wildlife/Parks Debbie Baker – University of Kansas Ted LaGrange – Nebraska Game/Parks Ken Bazata – Nebraska Dept. of Env. Quality Brent Lathrop – TNC, Platte River Liz Bergey – Oklahoma Nat. Heritage Prog. Chris Mammoliti – Kansas Wildlife/Parks George Cunningham – Nebraska Wildlife Fed. Ed Peters – University of Nebraska Mark Eberly – Fort Hays State University Steve Schainost – Nebraska Game/Parks Keith Gido – Kansas State University Scott Sowa – Missouri Resource Assessment Christopher Guy – Kansas State University Ryan Waters – Kansas Dept. Wildlife/Parks Others providing significant expertise and review in support of this conservation plan include: Mike Bullerman – Prairie Plains Resources Institute Bruce Hoagland – Oklahoma Natural Heritage Mark Howery – Oklahoma Dept. Wildlife Conservation Jeff Huebschman – University of Nebraska, School of Biological Sciences Shannon Menard – NatureServe Randy Rodgers – Kansas Dept. Wildlife/Parks John Sidle – U.S. Forest Service EXECUTIVE SUMMARY The Central Mixed-Grass Prairie (CM-GP) region has long been known as a transition between the mesic tallgrass prairies to the east, and the arid shortgrass prairies to the west. The culture and land- use of the Central Mixed-Grass Prairie also has transitional qualities. A satellite view of the CM-GP reveals relatively large and distinct native landscapes remaining within a cropland matrix. In contrast, native grasslands become the landscape matrix to the west, while to the east a matrix of cropland is nearly exclusive. This Plan’s priorities, strategies, and actions associated with conserving biological diversity reflect the current human and ecological underpinnings of the CM-GP landscape. Importantly, we make any loss of size or increase in fragmentation of the most significant native landscapes unacceptable relative to achieving our conservation goals. The CM-GP region has three high quality native landscapes with compatible land-use histories distributed one each in the north, central, and south. These landscapes are regionally known as the Nebraska Sandhills, Kansas/Oklahoma Red Hills, and Oklahoma Granite Hills/Wichita Mountains, respectively. Numerous smaller and or lesser quality landscapes dominated with native vegetation occur throughout the region. These are the places where the primary ecological forces of climate, soils, weather, grazing, and fire still have the opportunity to interact to yield the dynamic spatial and temporal patterns required by the vast array of native plants, animals, and natural communities. They form the heart of the terrestrial conservation portfolio. Even in these areas, however, sound management by the predominately private landowners will need to recognize, and be fully vested in, the value of biological diversity. We know far less about the conservation needs of the aquatic ecological systems, aquatic communities, and aquatic species of the region. Their long-term conservation relies on a portfolio of sites which is much less intact, and much more threatened by the water demands and pollutants associated with modern socio-economic forces. The CM-GP biological assessment describes conservation targets, and goals for each, at multiple scales. Nine terrestrial ecological systems were identified as targets within which the species common to the CM-GP are assumed to be conserved. All 69 native plant communities within the region were selected as targets. Of these, only one is consider endemic to the CM-GP, while two are uncommon and found mainly in other regions. Most of the native plant communities are either widespread (34) in the CM-GP and common in other regions as well, or have a distribution mainly limited (32) to the CM-GP though occurring in several adjacent regions. At the fine-scale, all terrestrial species listed as endangered or threatened under the Endangered Species Act, as well as all species ranked critically imperiled, imperiled, or vulnerable by NatureServe and the Natural Heritage Program Network, are considered conservation targets within the region. Additional bird species targets were identified using a combination of established lists and expert knowledge. The resulting list of terrestrial species targets includes 6 mammals, 19 birds, 3 reptiles, 6 insects, and 13 plants. Conservation goals and viability assessment for terrestrial targets followed the guidelines set forth in Groves et. al. 2000a. The CM-GP was stratified into three planning units in order to consider the full range of ecological variation during the goal setting process. The large-scale and intense natural disturbance regimes, the generalized nature of the dominant native communities, and the resilience of the dominant native species argued for making size the over-riding consideration when assessing the viability ecological system targets. The goal for ecological systems was two per planning unit, while goals for natural communities and species were informed by guidelines established by other planning teams and modified based on expert knowledge of regional distribution, abundance, vulnerability, and threats. The judgement of an expert panel that there was a high likelihood that an occurrence would persist for 100 years under current conditions was used as a viability threshold. Strict viability assessment for most target occurrences was not possible during this planning effort due to a lack of scientific understanding of how to assess viability for a particular target and/or a lack of resources to apply viability assessment criteria when they existed. We hope this planning effort will initiate research into the development of viability criteria for the targets and will prompt inventory efforts in which to apply the criteria. Similar to the terrestrial targets, a coarse-filter approach was used to classify aquatic diversity at zoogeographic (3) and ecological drainage unit (9) levels based on lithology and landform. Smaller than the ecological drainage units, we recognized distinct aquatic assemblages of macrohabitats and species at a stream network scale as the aquatic ecological system. These systems are stream segments and small to medium sized lakes that are defined by unique combinations of co-occurring physical features, including size, elevation, gradient, connectivity, and upstream geology. Five size classes were defined a priori to distinguish headwater and creek systems, and small, medium, large, and extra large rivers. We used a Geographic Information System (GIS) and assigned a value for size, geology, gradient, and position in the drainage network to all streams in the region. Then, a multivariate clustering analysis (PC-ORD) was used to evaluate the patterns of stream and lake macro-habitat within these catchments. The clustering algorithm grouped catchments with similar macro-habitat components. These clusters of unique aquatic system types were used as surrogates of biological diversity, and each catchment as a