WILL OIL SPILL CAUSE EXTINCTIONS?

by Whit Gibbons

June 13, 2010

Q: With the current oil spill crisis in the Gulf, do you think the salt marsh snakes may be threatened? I know they are uncommon to begin with, and the Atlantic salt marsh snake is designated as threatened on the federal endangered species list. Is something being done to protect these animals? Protecting marine mammals and birds is obviously what most people view as important. But I hope the snakes don't get forgotten. I am concerned for their future.

A: The salt marsh snake is a harmless watersnake species that inhabits coastal regions from the Atlantic coast in Florida, through the Florida Keys, to Brownsville, Tex. Typically restricted to brackish waters, the snakes live in habitats that will be affected by the oil spill. Along the Atlantic coast the species is officially protected in Volusia, Brevard, and Indian River counties in Florida, including Merritt Island National Wildlife Refuge.

Many populations of salt marsh snakes will be in jeopardy not only because individual snakes will be dealing directly with the oil but also because much of their prey, which includes small brackish water and marine fish, may disappear in localized areas. Hopefully, some of the populations will be only minimally affected by the oil because they inhabit coastlines that are protected by barrier islands or by ocean currents. By the time the oil reaches the Atlantic side of Florida, if it does, it should be diluted enough so that the salt marsh snakes in that area will not be significantly impacted.

As is often the case with lower profile species such as most reptiles, amphibians, and invertebrates, the salt marsh snake per se is not likely to get any special attention with regard to its environmental welfare. It is unfortunate that the only way certain kinds of environmental protection can be achieved is through emotional appeal. People cringe at pictures of an egret, a brown pelican, or a baby manatee dying in an oil slick, and many will contribute to efforts to save such appealing animals.

But the far-reaching environmental devastation caused by the BP oil spill will affect virtually every species that relies on the coastal habitat, including species that cannot capture media attention. We must hope that the detrimental effects on the likable species are brought to everyone's attention and that the environmental solutions for the birds, mammals, and other charismatic megafauna will also be effective for the snakes through a form of trickle down environmental stewardship.

Q: Will any animals go extinct because of the Gulf oil spill?

A: I doubt if any vertebrate species will go extinct as a consequence of the appalling environmental disaster that has resulted from the BP oil rig explosion and continuous underwater release of oil. However, the focus should be on the populations of species that are affected rather than on the entire species. Some populations will definitely be eliminated by oil pollution, and the loss of individuals will be extensive.

No one knows exactly how many millions of gallons of oil will ultimately be released into the Gulf of Mexico and how much will reach the Atlantic. But the amounts estimated so far are staggering and will cause untold damage to coastal habitats, killing countless fish, birds, and marine invertebrates. Without question, millions of individual animals of numerous species will die. But all vertebrate species that inhabit the Louisiana Gulf Coast are found in other areas where the oil is unlikely to reach. So no wildlife species will be lost as a result of the spill.

Extinction, however, sometimes happens as a cumulative effect of negative impacts, including the gradual disappearance of local populations until too few are left to propagate successfully. As the geographic range of the species contracts, an environmental disaster, even a natural one such as a hurricane or unexpected cold spell, can be the death knell for a species.

And although no wildlife species is likely to go extinct as a direct result of the oil spill, jobs that depend on harvesting shrimp, oysters, and other shellfish in the Gulf Coast region may indeed disappear completely.

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