Habitat
Habitat
A habitat designates the distinct, local environment where a particular species lives. Habitat has also been described simply as a place where a certain organism usually can be found. A shark's habitat is the ocean, and a trout's is a freshwater stream. Habitat requirements of the world's organisms vary widely and can be extremely different even for similar species. Habitat changes can affect the survival of a species.
The habitat where an organism lives is one in which that organism's particular requirements are met. Habitat has been described as the place where an organism can best do its job, or its biological "street address." A favorable habitat for any animal or plant means that this organism is able to get all the things is needs to live, and that it has a slight advantage over others. Habitats are usually described in terms of an outstanding geographical feature such as being mountainous, being a desert, or a being a grassland. However, the concept of habitat is dominated by the idea of a particular type of place. The place where an organism thrives can be anywhere, from the human gut where the bacterium Escherichia coli lives, to the soil an earthworm digs, to the rocky crevices a mountain goat leaps across. Habitats can be nearly any size, although when a habitat becomes especially large it is called a biome. The word "environment" is sometimes used in place of habitat, but environment usually suggests a larger area, while habitat suggests a more local area.
Within its habitat, every species eventually finds its niche or the particular role that fits it best. An organism's ecological niche is defined by many factors such as the food it lives on, who are its predators, what temperatures it tolerates, or how much water it needs to consume. While two species may live in the same habitat, they can never share the same niche. A niche is a smaller concept than habitat, since a niche is part of the larger habitat. That does not mean, however, that a niche is any less complex. An organism's niche is a highly complex set of activities, impacts, relationships, and roles that can be difficult to understand fully.
THOMAS EUGENE LOVEJOY
A leader in the emerging discipline of conservation biology, Thomas Love-joy (1941– ) conducted a unique twenty-year experiment to determine the best-sized habitat for conserving biological diversity (a broad term that includes all forms of life and the ecological systems in which they live). The goal of international conservation also has been fostered by his idea of a "debt-for-nature" swap in which a country's financial debt is partially forgiven if it carries out certain conservation measures.
Thomas Lovejoy was born in New York City into a life of wealth and privilege. While attending the Millbrook School in New York, Lovejoy was first made aware of the wonders of the natural world by that school's founder, Frank Trevor. The young Lovejoy was inspired to study field biology, especially birds, and became fascinated with biology and the natural world. After entering Yale University, he was able to study under the eminent English ecologist, George Evelyn Hutchinson. Lovejoy received his bachelor's degree in 1964. While in pursuit of his doctorate at Yale, Lovejoy was able to spend two years in Brazil as part of a Smithsonian Institution project. There he introduced the technique of bird-banding (tying bits of colored string on birds' legs in order to observe their behavior) to that country, and his doctoral thesis proved to be the first major long-term study of birds in the Amazon region. He was also able to study birds in Africa. In 1971 he received his Ph.D. from Yale University.
After serving the World Wildlife Fund for fourteen years, eventually becoming its vice president, Lovejoy joined the Smithsonian Institution in 1987. There he has been able to continue a long-term experiment that he had begun at the World Wildlife Fund. In 1978, Lovejoy initiated a twenty-year experiment (which has since been extended) to try and determine the best strategy for conserving biological diversity. Called the Minimum Critical Size of Ecosystems (MCSE) Project, its goal is to discover whether biological diversity is better favored by conserving a single large piece of land or by preserving a large number of smaller habitats. Although this was a serious issue that needed to be resolved scientifically, it seemed to be impossible to carry out until Lovejoy came up with an idea. Aware that Brazil had begun a program of developing the Amazon basin, Lovejoy also knew that that country allowed developers to clear only half of the rain forest and leave the remaining half untouched. Seeing that he had the raw materials for a large-scale experiment at hand, Lovejoy was able to get Brazil's support for his new idea. That idea consisted of twenty-four separate reserves, or habitats, that varied in size from 2.5 to 25,000 acres. After two decades of study, the project has yielded valuable results. One of the most interesting is called the "edge effect." This phenomenon occurs when the trees at the edge of the preserved habitat die off and the butterfly populations decline. This suggests that a reserve should always be made larger than is required to support its biological diversity, since there will always be an inevitable shrinkage of life-supporting land around the edges of the preserved habitat. Recent results further suggest that there may also be a loss of diversity deeper into the habitat than first thought.
Lovejoy is one of the first of a new wave of biologists who must combine their science with real-world concerns, such as politics, in order to advance their goals. If a scientist is studying biological diversity and seeks to preserve it, the realities of today's world are such that he or she can no longer remain in the laboratory or jungle and conduct research. Instead, if scientists want to preserve the subject of their study, like the world's essential biological diversity, they are being forced to become actively involved in the politics and economics of the twenty-first century. Lovejoy is a good example of a scientist who has become involved in politics and economics. He has done this through his "debt-for-nature" idea. Today, Lovejoy also is recognized as one of the most effective spokespersons on such issues as global warming and the loss of biological diversity.
Plant and animal habitats are often negatively impacted by humans. It is difficult for human populations to live near a species' habitat and not have an impact on it. Human impact can include climate change, acidification (from acid rain), reduction of wooded areas, lowering of water tables, and desertification (or the spread of a desert area). Such activities degrade, break up, and eventually destroy entire habitats. These human activities threaten the existence of other organisms. This can be particularly true for species that are highly specialized. An example is the giant panda that feeds only on a certain species of bamboo. Given the rate at which its habitat containing the bamboos species is being destroyed by human development, ecologists do not expect the giant panda to survive in the wild. As a result, giant pandas will eventually only be able to be found in zoos.