The need for geophysical conservation

How should we go about managing the conservation of biodiversity in the face of a changing climate?  Species by species?  Seems tedious.  And expensive to carry to completion.  Wouldn’t it be easier if we could determine what factors contribute to high species richness in a non-abstract way, find areas with those parameters, and start there, in terms of protection measures?  A new study in PLoS ONE by Drs Mark Anderson and Charles Ferree, both of The Nature Conservancy, is a step towards this.  The majority of conservation plans do not account for shifts in species distributions resulting from climate change; the authors posited that if some combination of large scale, geophysical variables, such as elevation or local geology, predicted species richness independently of climatic variables, then ecological reserves could be created that function to protect a large number of species in current and future climate scenarios.

Study area with overlaid geology classes (Anderson and Ferree 2010)

Using geology, elevation, species, and climate datasets for a section of the northeast US, combined with the Maritime Provinces of Canada, the researchers ran linear regressions in search of a model in which non-climatic factors predicted species richness, and did not show dependence on climate.  They found that the number of geology classes (like acidic shale or fine sediment), latitude, elevation range, and the amount of calcareous bedrock produced a non-climate dependent model with an R (sq) of 0.94—meaning that the model accounts for 94% of the variance in the species diversity among these states/provinces.

Anderson and Ferree 2010

That’s a stunningly significant statistical value, especially considering that this study concerns itself with an area that’s roughly twice the size of California.  When the 13,500 + species were split into their respect taxa, the model performed well.  During geographic analysis, 40% of rare species within this area were shown to be constrained within 1 geology class; 61% of rare species were constrained in two classes, further making the case of a species and geology class relationship.  In a further test, rare species were distributed non-randomly among geological classes—so some classes were associated with higher densities of rare species than others.  These results also show that habitat—in this case geophysical—heterogeneity may be more important than the size of the area surveyed (when no relationship exists between area and heterogeneity) in determining the number of species.

This study sets the stage for conservation approaches associated with geophysical settings, but also stresses scale is an issue—entire functioning ecosystems would need to be protected, not just bits of heterogeneous geology here and there.  However, this is a long-term strategy that may be successful in biodiversity conservation in a changing climate, and will not necessarily prevent specific species extinctions.  Species specific and geophysical conservation approaches could of course be combined, but the authors realistically expect that “inevitable tradeoffs” between these efforts in a period of rapid climate change should be expected.  Scale and connectivity between species’ geophysical environments are more important than before realized.

Images:  PLoS ONE makes figures and articles available under a Creative Commons attribution license.

Anderson, M., & Ferree, C. (2010). Conserving the Stage: Climate Change and the Geophysical Underpinnings of Species Diversity PLoS ONE, 5 (7) DOI: 10.1371/journal.pone.0011554


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