The Durk Pearson & Sandy Shaw®
Life Extension NewsTM
Volume 17 No. 6 • July 2014


The Model Used in Predicting Biodiversity and Species Extinction for Government Policies Fails When Applied to Forest Fragments in Human-Dominated Ecosystems

We report very briefly here a VERY IMPORTANT paper from the 8 May 2014 Nature1 showing that the island biogeographic model that has been used for more than 30 years in estimating extinction rates (“a pillar of conservation science”1) does not provide the expected results for forest fragments in an agricultural or countryside human-dominated ecosystem. As the authors say, “Despite its known shortcomings, this theory [the island biogeographic model] persists as the basis for estimating extinction rates and making policy recommendations.”1

The authors analyze neotropical bat biodiversity, that the authors identify as a group acutely sensitive to tropical deforestation, in a true island habitat and in forest fragments embedded in human-created habitat (farmland). The two ecosystems were chosen for their similar ages, close geographic locations, and their evolutionarily homologous bat diversity.

The authors found that, in comparison with true islands, the forest fragments/farmland habitat supported more species with lower rates of local extinction. The authors said, “… we found that declines in bat species richness expected from island biogeography were almost never realized in countryside forest fragments.”

The authors conclude that their evidence supports the view that a “countryside biogeographic framework that is inclusive of human-made habitats and the opportunities it can afford to many species—given appropriate management of those habitats*—better represents how, at least, bat diversity is responding in the Anthropocene.”1

* The authors refer to problems in agricultural lands that included the use of “chemical inputs and practices that sterilize, structurally level, and standardize plots — homogenizing and decimating biodiversity.” We note that much of the homogenization of farmlands is the result of government subsidies to promote the production of certain crops, such as corn for ethanol, and especially the mandate to use that subsidized ethanol as an automobile fuel. Indeed, 40% of corn is now grown for that purpose. All that extra cropland devoted to corn is part of the increased uniformity of the crops grown in areas by agribusiness (crony capitalism) wanting to receive subsidies.

A Reality Check on the Endangered Species Act

One wonders how many of the “endangered” species listed by the EPA that forces private landowners to abide by innumerable costly rules and regulations are truly endangered or, if their estimated rate of extinction was derived from the island model as described in the paper. This information (how the agency determined whether a species should be listed) should be available by FOIA.


  1. Mendenhall, Karp, Meyer, et al. Predicting biodiversity change and averting collapse in agriculture landscapes. Nature. 509:213-7 (2014).

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