species+and+what+effects+an+increase+or+decline+of+them+would+do

Back  **Effects an Increase or Decrease may have on its Ecosystem**       An increase or decrease of a species (either human or naturally caused) may have many different effects on an ecosystem. The effects may be positive or negative, depending on the situation presented. In the rainforestthere is a great amount of diversity. An example of the effects of a decrease of a species on an ecosystem can be seen through a study done by the American Natural History Muesemon beetles in the Amazon Rainforests. The beetles have many niches in their environment, such as assisting plant pollination, and decomposing larger organisms. When the forests were cut into small sections (deforestation). The insects that normally inhabit the deep forest, had decreased in both abundance and number of species in the forest fragments. When populations become too small, individuals have difficulty finding mates. This may result in inbreeding, which may eventually lead to an even greater decrease in the population. The decrease of the beetles puts a gap in the food chain. This decrese in insects also creates a decrese of other species. In contrast to smaller forest fragments and forest edges, the interiors of large fragments often have fewer insects for small mammals, birds, and frogs( which do not travel to the forests' edges) to feed on. But, being food for other animals is not the only niche these bettles have. Thier major niche is decomposition. The study showed that the rate at which leaves break down on the forest floor is only one-third as fast as in undisturbed forests, becuase of the loss of insect diversity. The //amount// of insects has not decreased, but the species that was specifically adapted to decomposing the dead leaves has disapeared. Because of this slowed rate of decomposition, the nutrients in the dead leaves are not being recycled into the soil for living plants. [|Supertramp Beetles] An example of the effects of an increase of a species on an ecosystem can be seen by a study done at the University of Pittsburg on deer. Due to human factors, white-tailed deer populations have increased dramatically throughout many forests in North America in the past 50 years. This increase in deer populations negatively impacts plant populations through increased consumption, trampling, and soil compaction. In addition to reducing the number of plants, high amounts of deer also reduce the amount of plant diversity in the ecosystem. [|Deer]