Exploitation

What is overexploitation? How does overexploitation affect the biodiversity of a region?How does hunting overexploit certain species? What are some examples of species that have been overexploited by hunting?

Exploitation occurs when a certain species are hunted or captured by humans than nature can replace over a given period of time, and it eventually leads to decreases in population. The population might reach a level to where the species is considered endangered and is no longer able to survive without protection by special laws and conservation activities.

The exploitation of a species directly affects the biological diversity of the earth and jeopardizes the survivability of other species that may rely on that exploited species for food. For example, where coyotes are excessively hunted, overpopulations of deer mice can appear. The mice, sometimes carrying the Hanta Virus, may then spread into human habitats and spread disease. In Pennsylvania, there is a white tailed deer overpopulation problem, which is largely occurring due to the fact that, years ago, deer's natural predators (cougars, wolves, coyotes) were popular game.

Hunting has been an important contributor to extinction of certain species. When railroads became popular, markets were developed, and hunters started to ship their catch to trade centers, making hunting a lucrative way to earn money. Hunters devised ways of killing large numbers animals. To hunt birds, for example, sulfur or fire suffocation, poisoned grains, shotgun blasts, netting, and decoys were all used, among other methods.

In the United States, there are several examples of species that were exploited for human gain. Passenger pigeons were once widely present, and flocks sometimes took three days to pass over a single spot. Once passenger pigeon hunting became popular, however, the decrease of the species was tremendous and amazingly fast. The last wild passenger pigeon was seen in 1989, and the last captive passenger pigeon passed away at the CincinnatiZoo in 1914. What is surprising is that hunters did not intentionally decimate the passenger pigeon population, as hunting the species lost its popularity years before its extinction. However, huge flocks had beenessential to the pigeon's survival, and when their populations became to small to maintain large breeding colonies, other factors like nesting failures, inbreeding, and deaths from predation led the species into extinction. Hunting had taken away the pigeon's natural lifestyle so much that they were unable to recover from their drastic population decrease.

The American Bison once numbered 30 to 40 million in population and covered the plains. Between 1870 and 1875, 2.5 million bison were killed annually, and by 1883, the last significant herd, with around 10,000 members, was done away with. By 1900, only 500 bison remained. It was saved from final extinction by protective legislation. Today, numbering 25,000, the American Bison exist only in parks and private herds.

Hunters can act as conservationists and keep a species' population in check so that it can coexist peacefully other animals and with humans, so it is certainly not necessarily or logical to prohibit hunting. However, it is necessary that hunters not exploit a species to the point where it cannot survive on its own.

http://library.thinkquest.org/25014/why/direct.hunting.html?tqskip1=1, http://www.cdli.ca/CITE/st_endangered.htm, http://ri.essortment.com/whatbiodiversit_rgzu.htm