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  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  Islands and tips of peninsulas (Florida/Baja Mexico) have lower levels of biodiversity  Species Area Effect

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  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  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 (well, duh…)  Tropics = complex food web.  Fruit & flies > greater # of bats/rodents > greater overall # of spp.  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  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)  Structurally complex habitats (more niches) = high biodiversity (rainforests, deserts)  Simple habitats (fewer niches) = low biodiversity (grasslands, marshes, tundra)