Flashcards in Dispersal Deck (10):
Process by which species enter a local community from the surrounding area
What is alpha, beta and gamma diversity?
Alpha (α) diversity: number of species in a local community; avg. # of species in
Beta (β) diversity: species turnover among local communities (various formulas); effective # of
Gamma (γ) diversity: number of species across a broad region; regional sp. pool
Local vs regional species richness?
Greater regional influence
Greater local influence
-Local species richness increases with regional dispersal rate
Explain neutral model with dispersal.
-Fixed # of individuals in local communities
-Lottery model with local drift
100 species in regional pool
-Varying dispersal rates (m)
into 4 local communities
Turn over and species richness intersect
Whats turn over rate?
-Number of species reaches equilibrium, but species composition is continually turning over
-Equilibrium rate of immigration of extinction
Effect of dispersal- island mainland vs far islands
-Islands close to mainland have higher immigration than far islands
-Leads to higher species richness and turnover
How do large islands effect extinction?
-Large islands have lower extinction than small islands
-Leads to higher species richness and lower turnover
-Area effect produces well known relationship between size of an area (A) and the number of species (S) there