Biodiversity What is Biodiversity Short for biological diversity

Biodiversity • What is Biodiversity? – Short for “biological diversity” – Includes the diversity of … • • • genes species populations living communities ecosystems

Richness vs. Diversity

What affects biodiversity? • Area effects: species-area relationships • Climate effects: Temperate / tropical comparison – Compare Corcovado vs N. A.

Species : area relationships

Effect of habitat area • larger islands contain more species than smaller islands Reptiles & amphibians Log # of Bat species Bats Island size (Log km 2)

Effect of habitat isolation • isolated (distant) islands contain fewer species than nearby islands Lesser Antilles

Communities on Landscapes Island Biogeography Theory Area effect - Larger islands support higher S: • more habitats • lower extinction rates • (bigger population sizes) Isolation effect - Nearer islands support higher S: • Greater immigration / recolonization

Communities on Landscapes Island Biogeography Theory S Lowest As distance increases, S decreases; Mainland As size increases, S increases. S Highest

Island biogeography and species equilibrium Species differ in their dispersal capabilities and their susceptibility to extinction. I curve: species that disperse well arrive soon, poor dispersers show up later. E curve: more S = more competition (extinction)

Islands aren’t the only isolated habitats lakes and ponds mountaintops Forest patches