week 08 - wildlife

Question 1

population, features, terms

Answer 1

group of conspecific individuals occupying a particular place @ a particular time w/ the potential to interbreed

• abundance
• density
• natality
• mortality
• emigration
• immigration
• geometric/exponential pop growth
  
  • dN/dt = rN
• logistic pop. growth (density dep.)
  
  • dN/dt = rN ( K-N / K ) … K = carrying capacity

Question 2

patterns of abundance

Answer 2

• annual: highs & lows w/in each year… birth pulse
• cyclic: regular patterns across multiple years
• irruptive: irregular, very large changes in abundance

Question 3

measuring the factors causing changes in populations requires….

Answer 3

• … individually marked animals
  
  • emigration difficult to distinguish from death
  • req’s periodic censusing
• intensive, long-term, expensive studies… but crucial
• PIT tag = passive internal transponder

Question 4

measuring abundance

Answer 4

• central to most wildlife investigations
• CMR most common
• Lincoln Index: two-sample index
  
  • assumes
    
    1. marked/unmarked captured w/o bias
    2. marked/unmarked have same mortality
    3. tags are not lost
  • N = ( M * n₁ ) / m₁
    
    • N = total population size,
    • M = # caught and marked in first sample
    • n₁ = # caught in second sample
    • m₁ = # caught with marks in second sample

Question 5

density

Answer 5

• # of individuals / area
• req’d for energy flow studies
• abolute abundance may be needed for T&E recovery
• hard to measure because you need both # of individuals & the area that each occupies
  
  • estimating area occupied is the hard part

Question 6

CPUE

Answer 6

• catch per unit effort
• a “good” index bears a consistent relationship to true abundance
• standardized approach is repeatable
• index is # of animals caught or observed per unit time
  
  • # caught / 100 traps
  • # / net hours
  • tracks / km
  • calls / km
  • # / person / hr
  • # / unit area searched

Question 7

a variety of census techniques…

Answer 7

• Pond Surveys
• Stream Surveys
• Terrestrial Searches
• Pitfall Trapping
• Pitfall Arrays
• Drift Fences
• Transect Census (fixed or variable width)
• Circular Plots (fixed or variable radius)
• Spot Mapping (singing male birds / territory disputes)
• Banding
• Removal or CMR trapping: small mammals
• Capture & radiotelemetry: large mammals
• Pellet plots
• Artifacts
• Tracking & Call Surveys
  *