Loss of Diversity

Michael Rosenzweig’s article predicts our planet’s future loss of diversity. He argues that by decreasing the area available for wildlife, it not only decreases habitat, but also actually causes a decrease in the rate of speciation for all organisms. Essentially, his argument rests on how the size of a species range affects its rate of speciation. Although somewhat controversial, large range sizes are thought to have higher rates of speciation as well as lower rates of extinction, and Rosenzweig’s article looks at the other end of that equation. With habitats decreasing, range sizes must decrease as well and that in turn depresses the number of future new species. Eventually this leaves us with fewer and fewer species of life forms.

So where does this leave us? Rosenzweig acknowledges that due to the reality of human population needs large productive areas of landscape may not be able to be set aside solely for wildlife. He proposes a new paradigm of comprise he terms Reconciliation Ecology, which he describes as the modification of human habits and habitats to accommodate species diversity. His solutions often require complex relationships between government, business and the private sector. While, when possible, conservation of land for wildlife is often the best solution Reconciliation Ecology provides a new framework to increase habitat that is accessible to both humans and other species. Accordingly, this would provide larger habitat ranges for species, which, in turn, would cause a decrease in the loss of speciation.

Rosenzweig sees this as a win/win solution, which happens to be part of the title of one of his books on the topic. While some might argue, myself included, that it seems more like a win for us and a lose, although less of one, for wildlife. Many environmentalists, and others, want more and more lands set aside for pure conservation and see Reconciliation Ecology as a sell out. I can see their reasoning, however, I also think they may be missing an important point. The key word in his proposal is “compromise”. I believe he intended his idea would be a way that would take land that humans need for whatever purpose and try to make as many accommodations we can to allow it to be somewhat useful habitat. Those areas would most likely not be available for traditional conservation. That being said, I think the label sell out doesn’t quite fit, however, I’m not sure I would call it a win/win solution either.

Reference:

M. L. Rosenzweig (2001). Loss of speciation rate will impoverish future diversity Proceedings of the National Academy of Sciences, 98 (10), 5404-5410 DOI: 10.1073/pnas.101092798