|Precise estimates of modern biodiversity extinction rates|
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The Earth’s biodiversity has experienced 5 mass extinction events since the Cambrian. Extinction has kept pace with speciation, with >99% of all species that have ever existed now gone. Despite consensus that biodiversity has entered the 6th mass extinction, dubbed the Anthropocene because of human-driven changes, estimated extinction rates above background are highly imprecise. This arises partly because species richness is unknown for many taxa, and most extinctions go unnoticed. Without precise estimates of modern extinction rates, the urgency of the biodiversity crisis is not appreciated by society, and efforts to reduce biodiversity loss are weakened. We propose to collate existing information on the extent of meta-population extinctions of various Australian and global taxa. We will begin with Australian plants, mammals, birds & molluscs as 4 well-studied taxa within a single continent. Extinctions will be inferred from rates of observed meta-population extirpations. Given the good fossil evidence of pre-human extinctions in Australia, our inferred extinction rates will be compared to determine the modern inflation factor. We will also trawl the literature and update rates based on observed disappearances, correcting for unobserved extinctions using zero-inflated models. Using these empirical estimates, we will extend our range to global extinction rates based on state-of-the-art species-area relationships of species loss.
Slash-and-burn in the Amazon
Endangered white lemuroid possum from Mt Lewis, NQ
Bulldozer in Indonesian Borneo
Workshop 1 Report (4–8 July 2011)
The following is extracted for the ACEAS web site from the formal report for the group, and also from Corey’s blog ‘Conservation Bytes’ which has devoted two articles to the activities of this group. The latter one at the time of writing (August 2011) is titled ‘Life, death and Linnaeus’.
The first major achievement was the development of a spatial community simulation to examine various assumptions underlying species-area relationships. Fangliang He developed the code to simulate landscapes populated by many species following various abundance patterns and aggregation coefficients; Barry Brook developed the sampling code to construct SAR and endemic species-area relationships (EAR), incorporating aspects of extinction debt; and Corey Bradshaw developed a spatial habitat-destroying routine that simulates harvest patch distributions from completely random to highly clumped (based on the negative binomial distribution).
|Last Updated on Sunday, 08 February 2015 16:11|