'Extinction-proof' population sizes cannot be predicted from species traits
Threatened species are characterized by declining and eventually small numbers of individuals. Once a population has been reduced below a certain level, its chances of recovery are slim. This size is commonly referred to as a 'minimum viable population', or MVP. But is there one size that fits all species, or are MVPs more idiosyncratic? Many have shown that the relative susceptibility of species to human-caused decline and extinction can be predicted by traits such as body size, ecological specialization, dispersal ability, fertility, and so on. However, a recent paper published in Ecology Letters by Brook, Traill and Bradshaw of Charles Darwin University in
Australia shows that this is not true for MVP. By modelling the long-term monitoring data of 1198 species they reveal a wide range of MVPs which are strongly linked to local environmental variability but unrelated to intrinsic ecological attributes. Any commonalities between species in MVP are swamped by the large-scale processes (e.g., habitat loss, over-exploitation) driving the global biodiversity crisis.
By John M. Grohol, Psy.D. on
21 Feb 2009
Published on PsychCentral.com. All rights reserved.
To know what you prefer instead of humbly saying Amen to what the world tells you you ought to prefer, is to have kept your soul alive.
~ Robert Louis Stevenson