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POPULATION-LEVEL EFFECTS OF PREDATION

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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  1. POPULATION-LEVEL EFFECTS OF PREDATION

  2. I. THE ROLE OF PREY DENSITY A. Functional Response of Predators

  3. I. THE ROLE OF PREY DENSITY B. Numerical Response of Predators

  4. I. THE ROLE OF PREY DENSITY C. Total Response of Predators

  5. II. DO MAMMALIAN PREDATORS REGULATE PREY POPULATIONS? A. Predators of Waterfowl

  6. II. DO MAMMALIAN PREDATORS REGULATE PREY POPULATIONS? A. Predators of Waterfowl

  7. II. DO MAMMALIAN PREDATORS REGULATE PREY POPULATIONS?

  8. 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 www.frankoberle.com Photo © Stephen Loring www.oklahoma.net

  9. 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

  10. II. DO MAMMALIAN PREDATORS REGULATE PREY POPULATIONS? C. Weasels • and voles in western USA • and voles in Russian crop ricks

  11. II. DO MAMMALIAN PREDATORS REGULATE PREY POPULATIONS? D. Overview

  12. III. INTERACTION OF PREDATION AND COMPETITION A. Lynx and Hares • During peak hare year:

  13. 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)

  14. III. INTERACTION OF PREDATION AND COMPETITION

  15. IV. INDIRECT EFFECTS OF PREDATORS ON PREY • Indirect effect: • Effect of one species on another is mediated through a third

  16. 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

  17. V. THE CONCEPT OF COMPENSATORY EFFECTS • Compensatory Mortality • Substitution of mortality agents

  18. V. THE CONCEPT OF COMPENSATORY EFFECTS • Compensatory Mortality • Substitution of mortality agents • Example: deer in predator-removal area

  19. V. THE CONCEPT OF COMPENSATORY EFFECTS • Compensatory Mortality • Substitution of mortality agents • Example: woodchucks in Pennsylvania

  20. 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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