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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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i the role of prey density
I. THE ROLE OF PREY DENSITY

A. Functional Response of Predators

i the role of prey density3
I. THE ROLE OF PREY DENSITY

B. Numerical Response of Predators

i the role of prey density4
I. THE ROLE OF PREY DENSITY

C. Total Response of Predators

ii do mammalian predators regulate prey populations8
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 populations9
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 populations10
II. DO MAMMALIAN PREDATORS REGULATE PREY POPULATIONS?

C. Weasels

  • and voles in western USA
  • and voles in Russian crop ricks
iii interaction of predation and competition
III. INTERACTION OF PREDATION AND COMPETITION

A. Lynx and Hares

  • During peak hare year:
iii interaction of predation and competition13
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)

iv indirect effects of predators on prey
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 prey16
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
V. THE CONCEPT OF COMPENSATORY EFFECTS
  • Compensatory Mortality
    • Substitution of mortality agents
v the concept of compensatory effects18
V. THE CONCEPT OF COMPENSATORY EFFECTS
  • Compensatory Mortality
    • Substitution of mortality agents
    • Example: deer in predator-removal area
v the concept of compensatory effects19
V. THE CONCEPT OF COMPENSATORY EFFECTS
  • Compensatory Mortality
    • Substitution of mortality agents
    • Example: woodchucks in Pennsylvania
v the concept of compensatory effects20
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