Populations continued. Metapopulation Theory What is a metapopulation? Assumptions of the metapopulation theory Stochastic Perturbations & MVPs Sources of “uncertainty” MVP PVA. I. Metapopulation theory. What is a metapopulation? Populations are seldom independent
Huffaker’s mite experiment: examining predator-prey relationships-
Prey = six spotted mite, prey = Western predatory mite
Habitats = oranges, Nonhabitats = rubber balls
When prey sp. was forced to feed in oranges concentrated in large areas, they were exterminated, and predators died out… when oranges were widely dispersed, prey survived longer and the predator/prey populations followed predictable cycles
Also demonstrates the value of a heterogeneous environment in which predator and prey are widely dispersed
-population survival may be dependent upon a few key habitat patches
A. 4 Sources of “uncertainty” that can affect the size of a population:
The Heath Hen, and example of the stochastic effects-
C. PVA: population viability analysis
2). Add stochasticity to the model (Environmental, genetic, demographic stochasticity) – elements of variation, for a realistic approach
Eastern barred bandicoot, endangered Australian ground-dwelling marsupial
In 1989, only 150-300 individuals remained.
Leadbeater’s possum, Until recently, it was regarded as extinct, after disastrous fires throughout its range in 1939. However, in 1961 a small colony was rediscovered near Marysville, Victoria. As of 1996 it was confined to an area of about 3500 sq km (1350 sq mi) near the western limit of Victoria's Central Highlands.