The Proximate Causes of Extinction

摘要: The vast majority of contemporary extinctions can be viewed as anthropogenous in the sense that human activity greatly reduced population sizes and extinction would not likely have occurred now without activity. However, one still wish to know why small populations, even when protected from further interference, appear unusually prone extinction. Empirical data on last gasp such declining species are almost nonexistent but there is evidence four forces conspire put populations at increased risk: demographic stochasticity, genetic deterioration, social dysfunction, extrinsic forces. There presently no models accurately apportion threat among these available guidelines for indicating which especially risk very imprecise.