Problems With Small Populations Flashcards
What are the four general causes of extinction in small populations?
Genetic losses, demographic variability and declines, environmental variability, and catastrophes
What is included in the landscape level of population dynamics?
Land use change, climate change, Succession, and disturbance
What is included in the population level of population dynamics?
Birth and death rates, immigration and emigration
What is included in the individual level of population genetics?
Feeding rates, growth rates, habitat selection, and predator avoidance
What are density independent factors?
Those that influence birth and death rates in a manner independent of population density
What are density dependent factors
Those that change with population density
What needs to happen for density dependent factors to regulate population growth?
Per capita mortality needs to increase, or per capita Natality needs to decrease (lower population size)
What factors affect mortality and natality?
Shortage of resources, increased predation/parasitism/disease, increased intensity of intraspecific social interactions, intense exploitation
What aspects of demographic uncertainty affect small populations?
Deviance from the ideal sex ratio, a decrease in reproductive success, or increased morality rates
How does environmental uncertainty affect small populations?
Can cause extinction due to a sudden increase of reproductive failure or individual mortality
What is critical for small populations?
New recruits
What is a metapopulation?
A population consisting of several subpopulations linked together by immigration and emigration
How are metapopulations maintained?
Dispersal from occupied patches and recolonization of empty ones
T/F the fate of an entire population may depend on whether the reproductive success of individuals in good habitats outweighs the lack of success by individuals in bad habitats
True
Population viability analysis
The use if quantitative methods ri predict the likely future status of a population or collection of populations of conservation concern
What do PVA models predict?
The total number of individuals in a population
What are count based pvas?
Abundance assessments conducted and calculated by counting individuals in a population
What are demographic pvas?
Abundance assessments conducted and calculated with consideration of survival, growth, and reproduction
The Allee effect
A biological phenomenon where a populations growth rate or individual fitness decreases at low population densities, and increases at large population densities
Where is sperm limitation documented?
In broadcasting, free spawning, Nx copulating taxa
What causes sperm limitation?
Shortage of males, large distances between sessile organisms, insufficient sperm production
In what type of spawning is the estimate of fertilization success nearly 100%
Free spawning due to self fertilization, high population densities, and filtration of dilite sperm out of the water
