The War on the Sparrows

Perhaps the crowning example of general ignorance to ecology is the "Four Pests Campaign" initiated by Mao Zedong in 1958. An explanation of this requires some political background, however. Mao, having recently established his Communist government in China, had set about creating a series of reforms known as the Great Leap Forward. One of the chief goals of these was to increase Chinese farmers' grain production. To that end, he declared that sparrows, which ate grain, were to be exterminated.
Farmers took this very seriously--they banged pots and pans to scare sparrows away, destroyed their nests, and shot them on sight. On the surface, this seemed to work; it was not uncommon for crops to become quite successful once the birds were disposed of. However, it did not take long for the flaws to begin to show.
Most Chinese peasants, after all, were not well-versed in ornithology. To them, any small brown songbird was a "sparrow," and the techniques used to get rid of the sparrows affected other birds too. With the number of birds decreased, grain-eating insects experienced a population boom, thus contributing to the famine that would end up killing millions of starving Chinese. Mao's War on the Sparrows had backfired spectacularly.

Salt Marsh Cascades

Previously I discussed the importance of protecting species "low on the food chain" in order to maintain the high numbers of top predators and large herbivores from an ecological standpoint. However, ecosystem protection can work from other directions as well. In the salt marshes of Cape Cod, for example, overfishing of striped bass and blue crabs has led to a population explosion of herbivorous crabs and snails, which devour the marsh grass. With no predators to keep their numbers down, the herbivores' population increases beyond its natural limit. This has gotten to the point that scientists are considering artificially stocking the salt marshes with blue crabs and striped bass.
Removing predators can be just as problematic to an ecosystem as removing prey species, but unfortunately people such as fishermen who make a living by taking animals from the wild do not usually see the full ecological implications of what they do. In fact, many of the most popular food fish today--including tuna, salmon, seabass and swordfish--are top predators.

 In salt marshes like this one, ecosystems are in danger of collapsing due to the decline of top predators.

Umbrella Species

Earlier, I talked about how I consider it unproductive to protect single species instead of the entire ecosystems they inhabit. However, there may be a catch. Most of the creatures we think of when we think of endangered wildlife--the mega-mammals, large birds, and certain reptiles such as tortoises-- require very specific environments to survive. Any environmental preserve set aside for these creatures would, by default, also protect all other organisms living within it. For example, the Sundarban Tiger Reserve in India was created with the primary intent of protecting tigers. However, many other endangered species--some of which are even more threatened than tigers--also live in these reserves, and indirectly owe their continued existence to the efforts to preserve tigers.

This is why, rather than speaking of animals such as tigers as "charismatic megafauna", some ecologists prefer to call them "umbrella species." Like an umbrella, their presence provides a shield for all other species that occupy the same land they do. In my opinion it is acceptable to fund conservation efforts dedicated to these umbrella species, but only if the goal is to preserve them in the wild and thus maintain the ecosystem they live in. For there to be wild tigers, after all, there must first be Indian forests for them to live in, and the complete ecosystem that entails.

Where to draw the line?

As I mentioned before, ecosystems, not species, are the ideal scale at which environmental concern should be focused. However, this is not as easy as it sounds. While the idea of ecological preservation is to preserve all species in a given ecosystem, is there ever a point where this is impossible, or when a species should be allowed to go extinct for the greater good?
Consider the case of the Rocky Mountain Locust. The Rocky Mountain locust was once one of the most abundant insects in the world. They descended upon the crops of the pioneers in the American West in swarms of billions, devouring all vegetation in their path. Laura Ingalls Wilder, of Little House on The Prairie fame, described such an infestation in her book On The Banks Of Plum Creek. Yet by the beginning of the 20th century, the locusts had all but vanished. They were not intentionally exterminated--pesticides had not been invented yet--but rather their breeding grounds were destroyed when farmers plowed under them.
The loss of the Rocky Mountain Locust was not lamented. No one mourned for it, not the way they mourned for the herds of bison that once inhabited the Great Plains. Except for insect experts--of which there were few at the time-- no one remembered it as anything other than a pest.
Yet the demise of the locust had far-reaching consequences. The Eskimo Curlew, a migratory shorebird, depended on the locusts for food during its northward migrations. Deprived of their main prey and mercilessly pursued by hunters, the curlews declined heavily, and by 1963 they, too, were extinct.
The story of the Rocky Mountain Locust shows that no species is exempt from the attention of conservation. The extinction of anything will affect the ecosystem around it.