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POPULATION-LEVEL EFFECTS OF PREDATION PowerPoint PPT Presentation


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POPULATION-LEVEL EFFECTS OF PREDATION. I. THE ROLE OF PREY DENSITY. A. Functional Response of Predators. I. THE ROLE OF PREY DENSITY. B. Numerical Response of Predators. I. THE ROLE OF PREY DENSITY. C. Total Response of Predators.

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POPULATION-LEVEL EFFECTS OF PREDATION

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POPULATION-LEVEL EFFECTS OF PREDATION


I. THE ROLE OF PREY DENSITY

A. Functional Response of Predators


I. THE ROLE OF PREY DENSITY

B. Numerical Response of Predators


I. THE ROLE OF PREY DENSITY

C. Total Response of Predators


II. DO MAMMALIAN PREDATORS REGULATE PREY POPULATIONS?

A. Predators of Waterfowl


II. DO MAMMALIAN PREDATORS REGULATE PREY POPULATIONS?

A. Predators of Waterfowl


II. DO MAMMALIAN PREDATORS REGULATE PREY POPULATIONS?


II. DO MAMMALIAN PREDATORS REGULATE PREY POPULATIONS?

B. Wolves and Ungulates

  • Declining caribou, moose, Dall sheep populations in Yukon

  • Experimental reduction of wolves over 5 years

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II. DO MAMMALIAN PREDATORS REGULATE PREY POPULATIONS?

B. Wolves and Ungulates

  • Declining caribou, moose, Dall sheep populations in Yukon

  • Experimental reduction of wolves over 5 yrs

  • Wolf predation was

    • reducing recruitment of caribou & moose calves

    • reducing adult survival of moose


II. DO MAMMALIAN PREDATORS REGULATE PREY POPULATIONS?

C. Weasels

  • and voles in western USA

  • and voles in Russian crop ricks


II. DO MAMMALIAN PREDATORS REGULATE PREY POPULATIONS?

D. Overview


III. INTERACTION OF PREDATION AND COMPETITION

A. Lynx and Hares

  • During peak hare year:


III. INTERACTION OF PREDATION AND COMPETITION

B. Wildebeest and Lions-Hyenas

1. Predation-sensitive food hypothesis (PSFH)

2. Predator regulation hypothesis (PRH)

3. Surplus prey hypothesis (SPH)


III. INTERACTION OF PREDATION AND COMPETITION


IV. INDIRECT EFFECTS OF PREDATORS ON PREY

  • Indirect effect:

    • Effect of one species on another is mediated through a third


IV. INDIRECT EFFECTS OF PREDATORS ON PREY

  • Example: Iberian lynx

    Egyptian mongoose

    European rabbit

  • Rabbits preyed upon: 5-10 fold increase in absence of lynx

  • Rabbit density: 2-4 fold lower in areas without lynx


V. THE CONCEPT OF COMPENSATORY EFFECTS

  • Compensatory Mortality

    • Substitution of mortality agents


V. THE CONCEPT OF COMPENSATORY EFFECTS

  • Compensatory Mortality

    • Substitution of mortality agents

    • Example: deer in predator-removal area


V. THE CONCEPT OF COMPENSATORY EFFECTS

  • Compensatory Mortality

    • Substitution of mortality agents

    • Example: woodchucks in Pennsylvania


V. THE CONCEPT OF COMPENSATORY EFFECTS

  • Other Types of Compensation

    • Example: woodchucks on a hunted site

      • increased survival of juveniles

      • reduced emigration of juveniles

      • increased fertility of yearling females


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