D. Crowley, 2008 Predators & Prey LO: understand and identify adaptations of predator and prey.
PREDATION POPULATION-LEVEL EFFECTS OF PREDATION. I. THE ROLE OF PREY DENSITY A. Functional Response...
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Transcript of PREDATION POPULATION-LEVEL EFFECTS OF PREDATION. I. THE ROLE OF PREY DENSITY A. Functional Response...
POPULATION-LEVEL EFFECTS OF
PREDATIONPREDATION
I. THE ROLE OF PREY DENSITY
A. Functional Response of Predators
Deer Mice and Pine Sawflies
Coccoon Density (103/acre)
0 200 400 600 800 1000 1200
Co
cc
oo
ns
Op
en
ed
0
50
100
150
200
250
Type III
Source: Caughley and Sinclair (1994, Wildlife ecology and management)
I. THE ROLE OF PREY DENSITY
B. Numerical Response of Predators
Prey Density
Pre
da
tor
de
ns
ity Numerical Response Curve
I. THE ROLE OF PREY DENSITY
C. Total Response of Predators
Prey Density
Vit
al
Ra
te (
%)
K
A
B
Recruitment
Mortality (+)
Mortality (-)
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 II. DO MAMMALIAN PREDATORS REGULATE PREY POPULATIONS?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
Photo © Stephen Loring
www.frankoberle.com
www.oklahoma.net
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 II. DO MAMMALIAN PREDATORS REGULATE PREY POPULATIONS?REGULATE PREY POPULATIONS?
C. WeaselsC. Weasels– and voles in western USAand 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-Hyenas1. Predation-sensitive food hypothesis
(PSFH)
2. Predator regulation hypothesis (PRH)
3. Surplus prey hypothesis (SPH)
III. INTERACTION OF PREDATION AND COMPETITION
Prey Density
Vit
al R
ate
(%)
K
PRH
PSFH
Recruitment
SPH
Mortality
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