Factors Contributing to Biodiversity Biodiversity Why are there

Factors Contributing to Biodiversity

Biodiversity § Why are there more species in some places than others? ? ?

Factors which lead to higher biodiversity § Heterogeneity of Habitats: Variety of habitats = higher biodiversity § Chugach vs. ANWR

Isolation from/access to centers of dispersal § Islands and tips of peninsulas (Florida/Baja Mexico) have lower levels of biodiversity § Species Area Effect – The more area a given habitat has, the more species it will host

Distance from Equator § More than 50% of all species are found either in the tropical rainforest or in tropical reefs § Species diversity declines as one moves closer to the poles

Plant Productivity § Raise in Temp = raise in photosynthesis § Greater sun intensity = more photosynthesis § More rainfall = more growth § Lack of seasonality § Plant productivity leads to overall biodiversity

More food = more animals § Tropics = complex food web. § Fruit & flies > greater # of bats/rodents > greater overall # of spp.

Farther from equator = simpler food web § Grazers and predators get less return on energy expended § Fruit = high in energy § Grass = low in energy § Meat = high energy, but high energy expended

Diverse habitat = high biodiversity § Structurally complex habitats (more niches) = high biodiversity (rainforests, deserts) § Simple habitats (fewer niches) = low biodiversity (grasslands, marshes, tundra)