Lecture 13 - Gavin Flashcards
What are the two main extinction threats on islnads?
Habitat loss and Invasive species provide the largest threats to island species.
Disease may be a risk among some species too.
Why is the SxAR slope shallower on the mainland of equivalent size?
Likely because saturation will occur on islands, meaning there’s a ‘limit’ to species number.
What are species isolation relationships?
The theory on species number compared to how isolated the island is.
What is the equilibrium theory in regards to island communities?
A suggestion immigration and extinction are met at an ‘equilibrium’. E.g. A species gets wiped out but another immigrates in.
What did the Krakatoa natural ecological experiment show?
Immigration fast at first, then decreases as the island becomes more saturated.
Why do isolated islands have less immigration and more extinction?
As they’re unlikely to be reached by colonisers.
Meaning less immigration and individuals replacing species.
What did Simberloff and Wilson do?
They fumigated in Florida Keys
What did Florida keys experiment find?
They found less isolated islands were recolonised to normal levels faster than more isolated islands.
Why do larger islands have a steep species area relationship?
Because speciation occurs here, their speciation rates are 75%+ sometimes
