FORAGING ECOLOGY, VIGILANCE OF COYOTES, - PowerPoint PPT Presentation

About This Presentation
Title:

FORAGING ECOLOGY, VIGILANCE OF COYOTES,

Description:

Foraging Ecology and Vigilance: ... In YNP, reduction of elk population: Allow vegetation to recover Increase population of competing herbivores On Isle Royale, ... – PowerPoint PPT presentation

Number of Views:274
Avg rating:3.0/5.0
Slides: 57
Provided by: JohnB461
Category:

less

Transcript and Presenter's Notes

Title: FORAGING ECOLOGY, VIGILANCE OF COYOTES,


1
FORAGING ECOLOGY, VIGILANCE OF COYOTES, AND
BEHAVIORAL CASCADES IN RESPONSE TO GRAY WOLF
REINTRODUCTION IN YELLOWSTONE NATIONAL PARK
T. Adam Switalski Post-Project Seminar December
11, 2001
2
Introduction
  • Species loss
  • Carnivores particularly at risk
  • Inherent rarity
  • Large habitat requirements
  • Competition with humans

3
Introduction
  • Extirpation of Keystone Predators leads to
  • Disturbed unstable systems
  • Increased numbers of prey and competing
    carnivores
  • Expanded range
  • Loss of anti-predatory behaviors
  • Vigilance
  • Avoidance
  • Ultimately, cascading effects

4
Wolf Range Past, Present, and Future
5
Introduction
  • Case study reintroduction of wolves in
    Yellowstone National Park
  • How are coyotes learning to coexist with wolves?
  • How are other species responding numerically and
    behaviorally?
  • What are the cascading effects?

6
Foraging Ecology and Vigilance of Coyotes in
Response to Wolf Reintroduction
  • Introduction
  • Study area
  • Methods
  • Results
  • Discussion

7
Coyote and Wolf Coexistence
  • No coexistence
  • Resource partitioning
  • Spatial avoidance
  • Temporal separation
  • Low degree of diet overlap
  • Different habitat use

8
Return of the Wolf to YNP
  • Historical coexistence
  • 1995, wolves translocated from Canada
  • Designated nonessential experimental population
  • Population increased quickly with highest
    fecundity recorded for species

9
Foraging Ecology and Vigilance Research Questions
10
Foraging Ecology and Vigilance Research Questions
  • Do coyotes exhibit different behavioral time
    budgets now as compared to before wolves were
    reintroduced into YNP?

11
Foraging Ecology and VigilanceResearch Questions
  • Do coyotes exhibit different behavioral time
    budgets now as compared to before wolves were
    reintroduced into YNP?
  • Do coyotes living between wolf packs (buffer
    zones) exhibit different behavioral time budgets
    than coyotes in high wolf use areas?

12
Foraging Ecology and Vigilance Research Questions
  • Now that wolves have become established in the
    Lamar Valley, do coyotes exhibit different
    behavioral time budgets when wolves are
    physically present as opposed to their absence?

13
Study Area Lamar Valley
14
(No Transcript)
15
(No Transcript)
16
Food Resources
17
Methods
  • Observations of coyotes and wolves from
    winter 1998 to summer 2000

18
Methods
  • Recorded
  • Wolf and coyote location
  • Type of behavior and time of day
  • Travel route
  • Location of behavior
  • Sex
  • Social status
  • Age class
  • Pack
  • Pack size

19
Coyote Behaviors
  • Rest (alert, sleep)
  • Travel
  • Hunting small mammals
  • Feeding on carcass
  • Vigilance
  • Howling
  • Other

20
Small Mammal Surveys
  • Captured during summer 1999 and 2000
  • 3 different sites for 2 sessions each year
  • Mini-grids trapped for 4 days 5 nights and
    checked twice daily
  • Once identified, the small mammals were
  • Toenail clipped
  • Weighed
  • Sexed
  • Released

21
Statistics
  • SAS
  • Factorial (split-plot) design
  • Analysis of variance using PROC MIXED
  • Snow depth was repeated measure
  • Sample unit was the individual coyote
  • Proportion of time
  • Each observation was given equal weight

22
Statistics
  • Variables analyzed included
  • Wolf activity
  • Wolf presence
  • Sex
  • Year

23
Results
  • From December 1997 to July 2000 we made
  • 1243 observations of coyotes
  • 1743 h of coyote activity budgets
  • 28 resident coyotes from 9 packs
  • 16 male and 12 females
  • 24 alphas and 4 betas

24
Lamar Valley Coyotes
  • For 60 years, coyotes thrived without wolves
  • Coyote population reduced 25 to 33 each winter
  • 23 observed coyote mortalities
  • Average pack size 3.2 (range 2.7-3.7)
  • Very low recruitment (predation and parvo)

25
Lamar Valley Wolves
  • Druid Peak and Rose Creek packs introduced into
    Lamar Valley in 1995 and 1996
  • Pack sizes
  • 7-8 adults in Druid Peak
  • 15-22 adults in Rose Creek
  • Druid Peak pack denned within study area
  • Wolf territories overlapped creating buffer
    zone

26
Coyote and Wolf Pack Territories Including Wolf
Buffer Zone
27
Mean Snow Depth
28
Coyote Behavioral Time Budgets Before and After
Reintroduction
29
Coyote Behavioral Time Budgets
30
Coyote Behavioral Time Budgets
31
Coyote Behavioral Time Budgets
32
Coyote Behavioral Time Budgets
33
Coyote Behavioral Time Budgets
34
Coyote Behavioral Time Budgets
35
Different Levels of Wolf Activity
36
Presence and Absence of Wolves
37
Discussion
  • In response to wolf reintroduction coyotes have
    adjusted their behavior
  • Spatially (buffer zone vs. non-buffer zone)
  • Temporally (present vs. absent)

38
How has coyote behavior changed?
  • Increase in the amount of time feeding on
    carcasses
  • Consistent with wolf recolonization in NW Montana
    (Arjo and Pletscher 1999)
  • Feeding on carcasses throughout the year
  • Contrasts Gese et al. (1996)
  • Decrease in travel

39
Energetic Benefits
  • Wild coyotes need 930 g of food daily (Bekoff and
    Wells 1986)
  • Coyote must consume the equivalent of
  • 27 mice
  • 11 microtines
  • 6 pocket gophers
  • 4 ground squirrels
  • or
  • Risking a few minutes feeding on a wolf-killed
    carcass

40
How is behavior different in the buffer zone?
  • Wolf buffer zones
  • Higher deer survivorship
  • Refuge for coyotes
  • In YNP, coyotes between Rose Creek and Druid Peak
    wolf packs have
  • Fewer agonistic interactions
  • Lower mortality rates
  • Different behaviors

41
How is behavior different in the buffer zone?
  • Coyote behavior in the buffer zone
  • Fed on carcasses less
  • Little wolf-killed carrion available
  • Rested more
  • Vigilant less
  • Less wary of predation by wolves

42
Is Behavior Different Wolf Presence?
  • When wolves were present
  • Fed on carcasses more
  • Wolf-killed carrion almost always present
  • Rested less
  • Vigilant more
  • More wary of predation by wolves
  • Most coyotes were killed while scavenging wolf
    kills

43
Coyote Behavior - Conclusion
  • Coyote population reduced
  • Surviving coyotes adjusted behavior
  • Coyotes benefit from wolf-killed carcasses
  • Increased feeding on carcasses
  • Increased costs
  • Increased vigilance
  • Decreased rest
  • Higher predation risk
  • Impact varies spatially and temporally

44
What is the big picture?
  • Reintroduction of large carnivores leads to
  • Numeric response
  • Behavioral response
  • Cascading effects

45
Numeric Response to Reintroductions
46
Numeric Response to Reintroductions
  • Contrary results in prey species
  • In NW MT, elk and deer populations decreased
  • No prey reduction in YNP, MN, and WI
  • Reduction of competing carnivores
  • Coyote population reduced in NW MT and YNP

47
Behavioral Response to Reintroduction
  • Minimize encounters
  • Adjust spatial and/or temporal use
  • Elk in National Elk Refuge dispersed
  • Coyotes in NW MT avoided wolves
  • Decrease success of attacking predator
  • Increased vigilance

48
Vigilance
  • Aids in
  • Detection of predators
  • Observation of conspecifics
  • Food acquisition
  • Prevention of kleptoparasitism

49
Environmental and Social Variables
  • Group size
  • Distance to refuge
  • Position in the herd
  • Body size
  • Age
  • Parenthood
  • Habitat type
  • Predation pressure
  • Ecotourism

50
Vigilance Conclusions
  • Increased risk of predation results in increase
    in vigilance
  • Increase in vigilance increases the animals
    safety, however decreases foraging
  • In GYE since wolf reintroduction
  • Elk, moose, and coyotes have increased their
    vigilance

51
Cascading Effects
  • In YNP, reduction of elk population
  • Allow vegetation to recover
  • Increase population of competing herbivores
  • On Isle Royale, increase in wolf population
    resulted in
  • Decrease of moose population
  • Recovery of balsam fir

52
Behavioral Cascades
  • IN YNP, No reduction of elk population, however
    behavior changes
  • Avoiding high wolf use areas
  • Aspen and willow recovery
  • Higher diversity of song birds
  • Increased number of spotted frogs
  • Recolonization of beaver

53
Behavioral Cascades
  • In YNP, decrease in coyote population and
    behavior changes
  • Increase of feeding on carcasses
  • Avoidance of high wolf use areas
  • Increase in small mammal density
  • Increase in the number of badgers, weasels, and
    foxes

54
Behavioral Cascades the Numeric and Behavioral
Dichotomy
  • Behavior changes may reduce fitness
  • Increased vigilance in elk may result in
  • Reduced fat content and lower body mass in
    females
  • Lower survival rates during the winter
  • Calves born with lower weights
  • Increased vigilance in coyotes may result in
  • Reduced survival of pups

55
Conclusion
  • Reintroduction of wolves has lead to
  • Reduction of prey populations???
  • Reduction of competing carnivore population
  • Change in behavior
  • Increase in anti-predatory behaviors (vigilance)
  • Change in space use
  • Ultimately, cascading effects may lead to an
    increase in biodiversity

56
Acknowledgements
  • Major Advisor John Bissonette
  • Eric Gese, Jim MacMahon, and Bill Adair
  • Susan Durham for statistical consultation
  • Yellowstone Ecosystem Research Center
  • Friends and family
Write a Comment
User Comments (0)
About PowerShow.com