North Park Pronghorn Herd Management Plan
Total Page:16
File Type:pdf, Size:1020Kb
DRAFT NORTH PARK PRONGHORN HERD MANAGEMENT PLAN DATA ANALYSIS UNIT PH-3 GAME MANAGEMENT UNITS 6, 16, 17, 161, & 171 PREPARED FOR COLORADO PARKS AND WILDLIFE BY JEFF YOST THIS PLAN WAS APPROVED BY THE COLORADO PARKS AND WILDLIFE COMMISSION ON XXXXXX DRAFT PH – 3 HERD MANAGEMENT PLAN EXECUTIVE SUMMARY North Park Pronghorn Herd (DAU PH-3) GMUs: 6, 16, 17, 161, & 171 Posthunt Population: Previous Objective: 1,500–1,600 pronghorn; 2019 Estimate: 1,496 pronghorn. Preferred Alternative: 1,400–1,600 pronghorn Posthunt Sex Ratio (Bucks: 100 Does): Previous Objective: 30-40; Prehunt 2019 observed: 51.9; modeled: 35.3. Preferred Alternative: 30-40 bucks: 100 does 2500 2000 1500 1000 500 0 NUMBER OF PRONGHORNNUMBER OF 1995 2004 1996 1997 1998 1999 2000 2001 2002 2003 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 Population Objective Range Year PH-3 Population Estimate PH-3 modeled population estimate and objective range, 1995 – 2019. 350 300 250 200 150 100 50 0 NUMBER OF PRONGHORNNUMBER OF 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 YEAR Bucks Doe & Fawn Total Harvest PH-3 Harvest Estimates, 1995 - 2019. 100 90 80 70 60 50 40 30 20 10 BUCKS: 100 DOESBUCKS: 0 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 YEAR Sex Ratio Objective Range Modeled Posthunt Observed Prehunt PH-3 Observed Prehunt, Modeled Posthunt, and Sex Ratio Objective Range, 1995 - 2019. i DRAFT PH – 3 HERD MANAGEMENT PLAN Background Information Pronghorn DAU PH-3 is located in north-central Colorado and includes Game Management Units (GMUs) 6, 16, 17, 161, and 171. The area is commonly known as North Park and is comprised of nearly all of Jackson County. The Wyoming border is the northern boundary of the DAU. PH-3 encompasses 1,618 square miles and is a mix of public and private land. Cattle ranching and grass hay production have historically been, and continue to be, primary land uses in North Park. This high elevation, cold, semi-desert habitat has a strong agricultural base of irrigated hay meadows and cattle grazing. These conditions also provide productive wildlife habitat for big game, sage grouse, waterfowl and numerous nongame species. Timber harvest is also an important land use. Hunting and fishing provide significant revenue and jobs to the local economy. In recent years, oil and gas exploration and production have been increasing with potential to expand exponentially. The pronghorn population in North Park was very high in the late 1880’s but was completely eliminated by unregulated hunting by the 1930’s. The population was re-established by natural immigration from nearby herds in Wyoming in the 1950’s and limited harvest began in 1968. By the mid 1970’s, the population was estimated at approximately 500 animals and, by 2004, was roughly 1,500 pronghorn. The current modeled post hunt population is at the low end of the current objective of 1,500 to 1,600 pronghorn in the post-hunt population with a pre-season sex ratio of 51.9 bucks per 100 does. CPW manages the North Park pronghorn population for a quality hunt; not just for trophy class bucks but for limited doe hunting with minimal hunter crowding. Licenses are limited for all methods of take (archery, muzzle loading and rifle). In years when the pronghorn population is at or above objective licenses may need to be increased, to the point where some hunters feel crowded, in order to keep the population within the objective ranges. Significant Issues There are few significant issues with pronghorn in North Park. The herd is generally at a sustainable and tolerable size and there are very few conflicts. Access to good public land pronghorn hunting is available in all units in North Park and harvest success rates are very good for hunters on both public and private land. Management Alternatives Three post-hunt population objective ranges were considered: (1) decrease from the current objective to 1,200–1,400 pronghorn, (2) an objective of 1,400–1,600 pronghorn similar to the current objective of 1,500-1,600, (3) increase the objective to 1,600-1,800 pronghorn. Three post-hunt sex ratio objectives were considered: (1) 20-30 bucks:100 does to maximize recruitment, (2) 30-40 bucks:100 does which would allow good recruitment and trophy potential, or (3) 40-50 bucks:100 does to maximize trophy production. Through the DAU planning process and public input, a post hunt population of 1,400–1,600 pronghorn and a sex ratio of 30-40 bucks: 100 does were selected as future management objectives. This preferred population range represents a wider range than the current population objective. ii DRAFT PH – 3 HERD MANAGEMENT PLAN CONTENTS EXECUTIVE SUMMARY ..................................................................................... i Background Information.............................................................................. ii Significant Issues ...................................................................................... ii Management Alternatives ............................................................................ ii INTRODUCTION AND PURPOSE ......................................................................... 1 NORTH PARK PRONGHORN DATA ANALYSIS UNIT DESCRIPTION ................................... 3 Location ................................................................................................ 3 Physiography ........................................................................................... 3 Land Status ............................................................................................ 5 HABITAT RESOURCE AND CAPABILITIES ............................................................... 7 Habitat Distribution .................................................................................. 8 Habitat Condition and Capability ................................................................... 9 Conflicts with Agriculture ........................................................................... 9 HERD MANAGEMENT HISTORY, ISSUES AND STRATEGIES........................................... 10 Overview of Procedures to Estimate Population Size ........................................... 10 Post-hunt Population Size .......................................................................... 11 Pre-hunt Herd Composition ......................................................................... 11 Harvest and Licenses ................................................................................ 13 Past Management Strategies ....................................................................... 15 Current Issues ........................................................................................ 15 PUBLIC INVOLVEMENT .................................................................................. 16 PREFERRED ALTERNATIVES AND NEW OBJECTIVES ................................................. 17 LITERATURE CITED ................................................................................... XVIII APPENDIX I: POPULATION DYNAMICS, MAXIMUM SUSTAINED YIELD, AND DENSITY DEPENDENCE............................................................................................ XIX APPENDIX II: PUBLIC MEETINGS ANNOUNCEMENT ................................................ XXI APPENDIX III: PUBLIC SURVEY & RESULTS ......................................................... XXII APPENDIX IV: HPP COMMENT LETTER ............................................................. XXVI DRAFT PH – 3 HERD MANAGEMENT PLAN FIGURES FIGURE 1. CPW'S MANAGEMENT BY OBJECTIVE PROCESS TO MANAGE BIG GAME POPULATIONS BY DATA ANALYSIS UNIT. ..... 1 FIGURE 2. LOCATION OF DAU PH-3. ........................................................................................ 3 FIGURE 3. AVERAGE MONTHLY TEMPERATURE, WALDEN, CO 1981-2010. US CLIMATE DATA, 2015) ..................... 4 FIGURE 4. AVERAGE MONTHLY PRECIPITATION IN WALDEN, 1981-2010. US CLIMATE DATA, 2015) ....................... 4 FIGURE 5. LAND OWNERSHIP IN PH-3. ....................................................................................... 6 FIGURE 6. VEGETATION DISTRIBUTION IN PH-3. .............................................................................. 7 FIGURE 7. PRONGHORN RANGE IN PH-3. ..................................................................................... 8 FIGURE 8. MODELED POPULATION SIZE ESTIMATE AND OBJECTIVE IN PH-3 1995 - 2019. ................................. 11 FIGURE 9. OBSERVED PREHUNT FAWNS: 100 DOES & MODELED POSTHUNT POPULATION IN PH-3, 1995 - 2019. ........ 12 FIGURE 10. OBSERVED PREHUNT BUCKS: 100 DOES IN PH-3, 1995 - 2019. .............................................. 12 FIGURE 11. LICENSE NUMBERS BY METHOD OF TAKE IN PH-3, 1996 - 2020. .............................................. 13 FIGURE 12. MODELED POSTHUNT POPULATION ESTIMATE, HARVEST AND LICENSE NUMBERS IN PH-3, 1995 - 2019. ...... 14 FIGURE 13. PRONGHORN HARVEST IN PH-3, 1995 - 2019. ................................................................ 14 FIGURE 14. SIGMOID GROWTH CURVE. .....................................................................................XIX FIGURE 15. MAXIMUM SUSTAINED YIELD. ................................................................................... XX TABLES TABLE 1. LAND OWNERSHIP AND MANAGEMENT IN PH-3. .................................................................... 5 DRAFT PH – 3 HERD MANAGEMENT