Gavin Flashcards
species richness
number of species in an area/site; a balance of immigration and extinction
alpha diversity
the biodiversity within sites
gamma diversity
total biodiversity in the region
beta diversity
measures how different the samples are across the sites, or the turnover species
jaccard coefficient
a/ a+b+c
a = no. species found in both sites
b = no. species found in site 1 but not 2
c = no. species found in site 2 but not 1
if sites are nested
we can predict the identities of species absent in smaller sites
isolation and area
immigration rates increase with area
immigration rates decline with isolation
extinction rates decrease with area
extinction rates increase with isolation
defaunation in the florida keys
simberloff and wilson
macroecology
ecology, biogeography, paleobiology and micro/macro evolution come together
covers wide spatial and temporal scales
latitudinal diversity gradient
species richness increases closer to the equator
what determines species richness in a community on a global scale
climatic/ environmental factors - ecology
historical factors - evolution
climatic factors to species richness
productivity/energy
spatial and habitat heterogeneity
historical processes to species richness
tropical cradles to diversity
tropical museums of diversity
out of the tropics
net diversification
speciation rate - extinction rate
tropical cradles
tropics home to young, rapidly speciating lineages
tropical museums
tropics home to old, relictual species
out of the tropics
species that form in the tropics and move to extratopics
speciation peaks in the tropics
extinction rate declines in the tropics
most advantageous site size:
several small = better for maximum diversity if sites are complementary
single large site better for minimising negative impacts of edge effects
single large supports larger populations and allows longer term persistence
probability theory
if 2 events are independent of each other, then the probability of both occurring is the probability of one occurring multiplied by the probability of the other occurring
ideally, small separate sites need..
to be far enough apart that disturbances like fires impact each site independently
but close enough together to allow dispersal and recolonisation
