BIOTIC FACTORS AFFECTING POPULATIONS

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BIOTIC FACTORS AFFECTING POPULATIONS
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I. THE CONCEPT OF DENSITY DEPENDENCE

• Vital rates change as density changes

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I. THE CONCEPT OF DENSITY DEPENDENCE

• Vital rates change as density changes
• Evidence for density dependence

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II. LIMITATION AND REGULATION OF POPULATIONS

• Limiting factors
• any environmental factor quantifiably affecting
  population growth
• biotic and abiotic

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II. LIMITATION AND REGULATION OF POPULATIONS

• Limiting factors
• Regulating factors
• density-dependent factors (depress growth as N
  increases)
• biotic (competition, predation, disease)

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III. LOGISTIC MODEL OF POPULATION GROWTH
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III. LOGISTIC MODEL OF POPULATION GROWTH
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IV. INTRASPECIFIC COMPETITION

• A. Food As a Proximate Cause

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IV. INTRASPECIFIC COMPETITION

• Food supplementation experiments
• home-range size declined
• home-range overlap increased
• the breeding season was lengthened
• litter sizes increased in poor habitat
• population density increased 2-3 fold

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IV. INTRASPECIFIC COMPETITION

• A. Food As a Proximate Cause
• Limitation? Yes
• Regulation? No

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IV. INTRASPECIFIC COMPETITION

• A. Food As a Proximate Cause

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IV. INTRASPECIFIC COMPETITION

• A. Food As a Proximate Cause

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IV. INTRASPECIFIC COMPETITION

• A. Food As a Proximate Cause
• B. Space As a Proximate Cause

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IV. INTRASPECIFIC COMPETITION

• A. Food As a Proximate Cause
• B. Space As a Proximate Cause
• C. Effects of Competition on Vital Rates
• Dispersal rate

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IV. INTRASPECIFIC COMPETITION

• Dispersal rate
• lower survival rate of dispersers
• nondispersers survive better

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IV. INTRASPECIFIC COMPETITION

• C. Effects of Competition on Vital Rates
• Survival rate Juvenile mammals
• snowshoe hares

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IV. INTRASPECIFIC COMPETITION

• C. Effects of Competition on Vital Rates
• Survival rate Juvenile mammals

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IV. INTRASPECIFIC COMPETITION

• Survival rate Adult mammals

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IV. INTRASPECIFIC COMPETITION

• Fertility rate (Inversity)