Jeffrey M. Ver Steeg Colorado Parks and Wildlife. December 14, 2016

Transcription

1 Jeffrey M. Ver Steeg Colorado Parks and Wildlife December 14, 2016

2 If the proposals make sense, seem worth the financial investment and have the potential to inform future wildlife management If the two predator management proposals are consistent with the Mule Deer Strategy adopted by the Commission in 2014 If the predator plans fulfill the requirements of the Commission s policy

3 Not being asked to evaluate and approve the study designs

4 Commission s Mammalian Predator Management Policy (adopted in 1999 and revised in 2007) requires the preparation of a predator control plan that addresses 10 specific issues

5 Miramonte Gunnison sage-grouse in 2011 Desert bighorn sheep in Middle Dolores River in 2011 Rocky Mountain bighorn sheep SW of Castle Rock in 2013

6 CPW held 7 public meetings across the state to engage public re: mule deer declines Commission adopted Mule Deer Strategy in December 2014

7 Improve habitat Mitigate development impacts Reduce impacts of highways Reduce impacts of human recreation Regulate doe harvest Maintain strong population and disease monitoring programs

8 Strategy directs CPW to: Identify areas where predation may be limiting Conduct research where uncertainty hinders management

9 Piceance Study (3 years): Monitor fawn survival on two adjacent birthing areas over next 3 years Remove predators in treatment unit for 2 months in the spring of each year (during fawning) Estimate removals to be 1% of lion population and 2% of bear population Study site is within one of 4 lion units (out of 19 statewide) managed to minimize livestock conflicts

10 Arkansas Study (9 years): First 3 years reduce lion population in treatment unit and increase lion population in control unit Middle 3 years allow the lion treatment unit to recover to pre-research levels (or slightly above) and leave control unit static

11 Arkansas Study (9 years): Final 3 years reverse the first 3 years Reduce lion population in former control unit (D- 34) Maintain/increase lion population in former treatment unit (D-16) Net result, each unit has 6 years of low harvest and 3 years of high harvest

12 Arkansas Study (9 years): At the end of the 9 years, the total number of lions removed from the research area is likely to be the same as (or less than) would have been removed by hunting alone without the study

13 Arkansas proposal submitted September 2015 for feedback and scheduled for final action November 2015 Initially designed as a 5-yr Management Experiment (not a research project) Public asked for more time and requested at least one meeting in Denver Based on public feedback, CPW withdrew proposal and committed to revise and bring back in 2016 along with a second research proposal in the Piceance Basin

14 Modified Arkansas proposal from 5-yr management experiment to rigorous 9-yr research project and added Piceance project June Commission approved reduction in lion hunting quota for control unit in Arkansas project, pending final approval of predator control plan August 2016 Commission received an update on the status and timeline for considering the two predator control plans

15 CPW held 3 public meetings: August 15, 2016 in Salida August 16, 2016 in Rifle September 19, 2016 in Denver (as requested) Meetings requested by Human Society of United States: HSUS met with DNR September 12, 2016 HSUS met with CPW November 9, 2016

16 Carnivores/predators should not be hunted Bear/lion hunting in Colorado is trophy hunting and unacceptable Mountain lions are scarce and in decline Other factors explain mule deer decline habitat loss/fragmentation from: Energy and residential development Over-grazing by livestock Climate change, etc.

17 Hunting is responsible for mule deer decline Removing lions will cause social chaos and a trophic cascade Won t solve statewide mule deer decline Proposals are outside of Commission/CPW authority Scientific literature is clear and consistent predator control never works

18 It is illegal to trophy hunt in Colorado Doe licenses in Piceance reduced by 99% There are no legal flaws in the proposals Will follow Animal Welfare Act (and ACUC) as well has regulations pertaining to trapping Check traps daily Release non-target captures

19 Will relocate females with dependent young Literature on social chaos and trophic cascade scant, inconclusive and speculative (CPW will learn more through the study) Predator control not proposed solution to increasing mule deer throughout all of Colorado

20 Mountain lion population in West increasing last years Lions expanding into Midwest 61% Coloradans believe lions stable/increasing (only 22% feel lions in decline) 88% of Coloradans support research to learn more about mountain lions

21 Summarized by CPW, provided to Commission and on website Far from conclusive Relatively few large scale, long-term, experimentally robust studies Many study areas were habitat-limited (therefore, often expect predation to be compensatory) Most of better papers call for additional study

22 Authored by Tavis D. Forrester and Heiko U. Wittmer (both at Univ. of California) Published in Mammal Review in 2013 Reviewed 48 studies from previous 30 years Good overview of the state of the science

23 ... our conclusions predominantly relate to highdensity populations, since both predation and nutrition have different effects at different populations densities. The suppression of both fawn and adult survival simultaneously from predation and other mortality sources can lead to marked and sustained population declines.

24 Increasing wolf populations in Vancouver Island also caused a decline in a high-density black-tailed deer population, and the predator removal study that was conducted was successful in increasing deer populations. It is now acknowledged that both bottom-up [habitat/food limited] and top-down [predation] mechanisms simultaneously affect ungulate dynamics and often interact.

25 The relative contributions of predation, forage availability and weather to observed population changes remains unclear and controversial. Future research should be focused on... Predation was a more frequent, and malnutrition/disease a less frequent cause of mortality than expected for all fawn survival categories...

26 Results of predator control studies remain variable....two notable exceptions to the pattern of compensatory predation mortality were summer fawn mortality and predation in multi-predator, multi-prey systems.

27 ...the true effect of summer fawn predation on mule deer dynamics is currently hard to identify... The importance of mortality from predation, nutrition and weather depends on both mule deer age class and on the community of predator and prey species, but at this time there are not enough data to evaluate whether these interactions are driving dynamics and further investigation is needed.

28 ...the role of predation in multi-prey, multi -predator systems at varying deer population densities needs further investigation.

29 The role of predation in regulating ungulate populations is not yet well understood especially in areas where habitat is not limiting Those are the kinds of areas where we are proposing to conduct our investigations

30 Staff believes the two predator management plans comply with Commission s policy The plans are consistent with actions called for in the Mule Deer Strategy We ask the Commission to approve both proposals