Biodiversity? Not so much


Your article "McCain: T.R. or W?" contains this statement: "The San Pedro hosts the second-most biologically diverse array of mammals in the world, second only to the Costa Rican cloud forests" (HCN, 9/1/08). As far as I know, no scientists have ever claimed that the San Pedro River had biodiversity second only to Costa Rica. Apparently what happened is that someone read an approximately 40-year-old scientific paper and completely misunderstood it. People liked to think there was incredible biodiversity along the San Pedro and in time the misconception probably became more and more incorrect.

Unfortunately, the incorrect statement about biodiversity has become widely believed and even crops up on government Web pages that provide general information about the San Pedro River. The consensus of scientists working on biodiversity has for about two centuries been that the greatest mammal biodiversity is in the tropics. EPA graphics showing the number of mammal species per water district suggest that the San Pedro River area has the same mammal biodiversity as found throughout much of Arizona and New Mexico.

Dr. Gary Noonan
Sierra Vista, Arizona

RE: Biodiversity? Not Much
Scott Bailey, Twin Falls, Idaho
Scott Bailey, Twin Falls, Idaho
Oct 16, 2008 12:09 PM
I believe the writer was referring to biodiversity as in all life forms not just mammals as narrowly defined by the good Dr. You attempt to deny the reality by focusing on a single group of species, when biodiversity refers to all plants, animals, and other life forms.

It may not be the second most diverse place on the planet, but southern Arizona in general, and the San Pedro Conservation Area in particular, is an incredibly diverse and important area with respect to biodiversity (especially in the US). It is also at extreme risk of irreversable damage due to an ever increasing human population and unrestrained use of natural resources. Head in the sand attitudes and outright denial of the problem, as exhibited by the Dr., can only exacerbate the problem
Exaggerations do not help the cause
Oct 19, 2008 11:11 PM
There is no doubt that the biodiversity of southern Arizona is impressive. There is also no question that it is at risk because of climate change and other anthropogenic influences, but, like Dr. Noonan, I must take issue when these biodiversity "statistics" are incorrectly reported. Exaggerations and misstatements, whether intentional or not, always diminish the effectiveness of arguments for conversation. As a watershed, the San Pedro does not come close to being the 2nd-most bio-diverse place on earth. . .for any taxon, mammals or otherwise. But that doesn't mean the San Pedro doesn't deserve conservation. Clearly, the "head in the sand" problem you mention works both ways.