http://ctfs.si.edu/datasets/bci/ - PDF document

http://ctfs.si.edu/datasets/bci/

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Preston’s (1948) lognormal distribution for species abundance Species abundance distribution for moths collected in light traps at Rothamsted Field Station, UK http://web2 uwindsor ca/courses/biology/macisaac/55 437/lecture9 htm http://web2.uwindsor.ca/courses/biology/macisaac/55-437/lecture9.htm

From MacArthur & Wilson’s island biogeography to H bb ll’ U ifi d N Hubbell’s Unified Neutral Theory t l Th Island biogeography: Ecological equivalence among species No speciation No speciation Neutral theory: Ecological equivalence among individuals + “Zero-sum dynamics” + Speciation p

Neutral theory: Local community “Zero-sum dynamics”: Total number of individuals in the community is constant ( J ) community is constant ( J ) Probability that a ‘vacancy’ is filled by an individual of a certain species is proportional to the relative t i i i ti l t th l ti abundance of that species. In the long run, only one species survives! Close parallels with models of neutral drift in population Close parallels with models of neutral drift in population genetics.

Neutral theory: Metacommunity Hubbell: “The metacommunity is the evolutionary biogeographic unit in which species in the regional biogeographic unit in which species in the regional species pool spend their entire evolutionary lifetimes.” Local communities are embedded within, and receive immigrant individuals and species from, d i i i t i di id l d i f the metacommunity. Three key parameters: J M : number of individuals in the metacommunity  : speciation rate  : speciation rate m : migration rate from the metacommunity to the local community.

Species distribution curves in a local community d depend on: d J : number of individuals in the local community J : number of individuals in the local community m : migration rate from the metacommunity to the local community community  : “fundamental biodiversity number”  J m 

21 500 individuals of 225 species in a 50ha plot at BCI 21,500 individuals of 225 species in a 50ha plot at BCI. Volkov et al., Nature 2003

325 000 individuals of 325,000 individuals of 1175 tree species in a 52 ha plot in Borneo