The latest issue of Conservation Biology examines the viability of theSinai baton blue and the results of human population pressures. Thestudy predicts that in the absence of global warming, grazing, andplant collection (three activities directly linked to humans) theworld's smallest butterfly would persist for at least 200 years.
The population could withstand small increases in grazing intensitythat would decrease their climate, but not increases in temperature. Asthe level of global warming raises its impact, extinction rapidlyaccelerates. This implies "... that there may be an annual averagetemperature, specific to each endangered species, above whichextinction becomes much more likely," authors Martin Hoyle and MikeJames state. There is no such threshold of grazing pressure.
The authors mapped the entire global range of this butterfly andobtained data on the intensity of livestock grazing. The Sinai batonblue is one of only two endemic animals in St. Katherine'sProtectorate, one of Egypt's most recently designated protected areas.Based on the authors' model, the effect of global warming on the chanceof extinction does not depend on the future level of habitatdestruction due to this grazing; the growing number of families thatlive on the protectorate keep a small herd of goats and sheep thatgraze on the plants the butterflies thrive on. Global warming is thedeadly culprit.
"If the areas of habitat patches individually fallbelow certain prescribed levels, the butterfly is likely to goextinct,"the authors conclude.
This study is published in theAugust issue of Conservation Biology. Media wishing to receive a PDF ofthis article please contact [email protected]
Conservation Biology is a top-ranked journal in the fields of Ecologyand Environmental Science and has been called, "required reading forecologists throughout the world." It is published on behalf of theSociety for Conservation Biology.
Martin Hoyle is at the School of Biological and Chemical Sciences atthe University of Exeter, Hatherly Laboratories. He has performedresearch on metapopulation dynamics and has been published in numerousjournals.
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