A Statewide Assessment of Wildlife Linkages Phase I Report
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LINKINLINKINGG COLCOLORADO'SORADO'S LLANDSCAPES:ANDSCAPES: AA STATEWIDESTATEWIDE ASSESSMENTASSESSMENT OFOF WILDLIFEWILDLIFE LINKALINKAGESGES PHASEPHASE II REPORTREPORT March 2005 © 2005 John Fielder In collaboration with: For additional information contact: Julia Kintsch, Program Director 1536 Wynkoop Suite 309 Denver, Colorado 80202 Tel: 720-946-9653 [email protected] www.RestoreTheRockies.org TABLE OF CONTENTS List of Maps List of Figures Acknowledgements Executive Summary .........................................................................................1 PART I: Introduction A. Project Description and Development ...................................................2 PART II: Methods A. Focal Species Approach.........................................................................5 B. Workshops ...........................................................................................10 Data Compilation and Linkage Prioritization................................15 C. Species Connectivity Modeling ...........................................................17 Modeling Approach .......................................................................17 Aquatic Fragmentation.........................................................................31 PART III: Workshop and Modeling Prioritization Results A. Summary of Workshop Results ...........................................................32 Results by Species Group ..............................................................48 B. Modeling Results .................................................................................97 Aquatic Fragmentation.................................................................101 C. Comparison of Workshop and Model Results...................................103 PART IV: Discussion A. High Priority Linkage Selection ........................................................113 B. Future Research ................................................................................124 C. Lessons Learned.................................................................................125 D. Phase II, Linking Colorado’s Landscapes .........................................127 REFERENCES ..............................................................................................129 APPENDICES A. Executive Committee members B. Focal species list and justification for selection C. Species expert consultants D. List of workshop participants E. Workshop dates, locations, and data collection forms F. Resource quality parameters for lynx, wolf and pronghorn G. Ecological Systems classification H. List of reviewers Attachment: CD-ROM (includes: full report, maps, GIS data, workshop data) Linking Colorado’s Landscapes, Phase I Report LIST OF MAPS Map 1: Vegetation..................................................................................................11 Map 2: Public Lands ..............................................................................................13 Map 3: Workshop-Identified Linkages..................................................................41 Map 4: Linkage Functionality................................................................................43 Map 5: Highly Threatened Linkages .....................................................................45 Map 6: Lynx...........................................................................................................51 Map 7: Black Bear .................................................................................................53 Map 8: Gray Wolf..................................................................................................55 Map 9: Mountain Lion...........................................................................................57 Map 10: Wolverine ................................................................................................59 Map 11: Mule Deer................................................................................................67 Map 12: Elk............................................................................................................69 Map 13: Pronghorn ................................................................................................71 Map 14: Bighorn Sheep .........................................................................................73 Map 15: Small Mammals.......................................................................................81 Map 16: Amphibians and Reptiles.........................................................................85 Map 17: Birds ........................................................................................................89 Map 18: Aquatic Species .......................................................................................93 Map 19: Example of a Connectivity Map for Lynx – High Scenario....................99 Map 20: Model Results for Lynx, Wolf and Pronghorn......................................101 Map 21: Aquatic Systems Fragmentation............................................................103 Map 22: Workshop and Model-Identified Linkages, Lynx .................................107 Map 23: Workshop and Model-Identified Linkages, Wolf .................................109 Map 24: Workshop and Model-Identified Linkages, Pronghorn.........................111 Map 25: Animal-Vehicle Collisions ....................................................................115 Map 26: High Priority Linkages ..........................................................................117 Linking Colorado’s Landscapes, Phase I Report LIST OF FIGURES Figure 2.1: Focal species..........................................................................................7 Figure 2.2: Patch structure quality as a function of distance from edge................22 Figure 2.3: Disturbance quality..............................................................................23 Figure 2.4: Flow chart of the inputs, major processes, and output from the defining habitat patches.........................................................25 Figure 2.5 Flowchart for movement step...............................................................26 Figure 2.6: Example of a landscape network (geonetwork) ..................................29 Figure 3.1: Percent of linkages with multiple focal species identified..................32 Figure 3.2: Number of linkages identified per species group................................34 Figure 3.3: Linkage functionality ..........................................................................42 Figure 3.4: Barriers to movement ..........................................................................47 Figure 3.5: Severity of impacts from barriers........................................................47 Figure 3.6: Severity of highway threat ..................................................................48 Linking Colorado’s Landscapes, Phase I Report ACKNOWLEDGEMENTS This project would not have been possible without the vision and encouragement of Edrie Vinson (Federal Highway Administration) and Chris Pague (The Nature Conservancy), both of whom were instrumental in its early development. The Executive Committee – Kevin Crooks, Chris Pague, Dave Theobald, Mike Vanderhoof, and Roland Wostl – likewise provided on-going support and input that served to define the project. Numerous biologists and wildlife experts from across the state contributed their time and expertise at the expert workshops and at many points throughout the project. Finaly, our reviewers were essential in providing feedback on the methodology as well as on several earlier drafts of this document. Thanks are therefore due to Dave Armstrong, Paul Beier, Anthony Clevenger, Kathy Daly, Jon Holst, Laurel Kagan-Wiley, Gary Miller, and Jean Smith. Cover photo of linkage at Douglas County Front courtesy of John Fielder. Linking Colorado’s Landscapes, Phase I Report Executive Summary In partnership with the Colorado Department of Transportation, the Federal Highway Administration, The Nature Conservancy, and Colorado State University, the Southern Rockies Ecosystem Project (SREP) launched Linking Colorado’s Landscapes in fall 2003. Habitat fragmentation is now recognized as one of the greatest threats to biodiversity and the decline of species worldwide (Ehrlich 1986; Wilcove et al. 1998) – a trend expected only to increase across the Southern Rockies (SREP 2004). Transportation infrastructure, in particular, is a significant cause of habitat fragmentation, with negative impacts on wildlife (e.g., Harris and Gallagher 1989; Maehr 1984; Reed et al.1996). The purpose of this work was to identify and prioritize wildlife linkages across the state of Colorado to promote safe passage for wildlife. This report documents the process used to define the locations of important wildlife linkages and to prioritize these areas for further assessment, and describes the decision-making process that led to the selection of high priority linkages. Linking Colorado’s Landscapes was conceived to focus conservation efforts on areas of the landscape that provide important connectivity functions for native wildlife. The objective was, therefore, to identify broad linkage zones that facilitate movement for Colorado’s diverse array of wildlife species and to prioritize amongst them for further study. To achieve this goal, we developed a science-based approach integrating local and regional expertise and computer modeling. While the scope of work required only