After reading an article in a recent issue of National Geographic magazine, I was intrigued enough to do a little more research on the subject of the Endangered Species Act. The article I was reading mentioned that the six largest of the Channel Islands (off the coast of southern California) have a population of foxes. These foxes are smaller than the grey fox found on the mainland, and are collectively known as island foxes. What caught my attention, however, is that each of the six islands' populations are considered to be different subspecies of the fox. Even though there is no difference between the foxes found, say, on Santa Rosa Island and those on San Nicolas Island, they are considered to be separate species (under the Endangered Species Act). I should point out, to be fair, that even if they were all counted as a single species, the island fox population is low enough to qualify for protection, but subspecies fragmentation (for lack of a better term) is one of the reasons that the ESA is such a mess.
An example is the Seaside Sparrow. In 1987, the last Dusky Seaside Sparrow died in captivity. No more seaside sparrows, right? Wrong. There are seven more seaside sparrow subspecies still alive, and their range is from New Hampshire to Texas (their winter range is from North Carolina to Texas). The scarcest of the seven subspecies is the Cape Sable Seaside Sparrow, with an estimated population of 3000. I cannot find a total census for all seven species (nor can I find a list of all seven species, for that matter), but if 3000 is the low-water mark, we are talking about at least 21000 birds, of which the only major difference is the color of their plumage (some are darkerduskierthan others).
There are those who claim that the extinction of a species will irreparably harm the ecosystem. This is true if one refers to the total elimination of a step in the food chain. However, a cottonmouth (snake) does not differentiate between a Cape Sable seaside sparrow and a Scott's seaside sparrow, and if one of the subspecies were to become extinct, (perhaps due to a natural disaster), it is likely that another subspecies would move in to fill the hole.
Some will argue that the extinction of any species might cause the loss of a cure for a disease (usually cancer or AIDS is mentioned). This would be an effective argument if we were talking about a biologically distinct organism. This is not the case. A study was done on genetic differences between the "Northern Spotted Owl", the "California Spotted Owl" and the "Mexican Spotted Owl", three recognized subspecies of the same bird, all of which are considered endangered. There is a break in the range between the first two and the third, but the Pit River in California is the official division between the "Northern" and "California" subspecies, even though it is known that the birds on either side freely cross from one range to the other (presumably, the bird changes species when it flies across the river). The genetic sequencing for the three were identical, with the differences in color and size likely due to variations in diet and climate. Nonetheless, the furor over the "Northern Spotted Owl" has severely hindered the timber industry, and, according to a Wall Street Journal report (I do not have a specific date), paper costs have risen 25% due to efforts to preserve the northern subspecies. This is why there are those who are fighting to rein in the ESA, but environmental groups, eager to prevent devlopment or economic activity, have used the courts (and the Department of the Interior) to tie everything up in litigation. The misguided effort to preserve all possible varations of a species at all costs is one of the reasons for a backlash against the environmental movement; instead of rationally choosing which fights are important, and which are window dressing, the environmentalists wage all-out war on every single issue, many of which needlessly alienate potential allies. A reform of the ESA, eliminating the subspecies fragmentation loophole, would go a long way in reducing the number of lawsuits. Incidentally, this will benefit the movement, because they will have fewer cases to litigate, and therefore will be able to devote more time and money to the cases that remain, many of which will be truly valid.