Pennsylvania state animal White-tailed deer-paper代写

下面为大家整理的一篇优秀paper范文- Pennsylvania state animal White-tailed deer，供大家参考学习，这篇论文讨论了白尾鹿。白尾鹿是美国很常见的动物，它在很多不同气候的地方都能生存下去，是一种典型的食草动物。由于以前白尾鹿被很多州列为濒危动物，所以政府限制人们对它的狩猎和建立保护区。但随着白尾鹿的增长，如今生态系统已经满足不了数量剧增的白尾鹿了，而数量过多的白尾鹿也会导致一些流行病的传染。虽然如今科学技术非常发达，但人们也未找到彻底解决白尾鹿问题的方法。

White-tailed deer (Odocoileus virginianus) is 1.83-1.98 meters in length, 0.92 meters of shoulder height and 10-28 cm of tail length. Is has small ears and simple horns. It inhabits in thickets, desert, forest, tundra and swamps. It is typical herbivorous animals. Grass, young seedlings, twigs and bark are all its food. Once it has been alert to the surrounding environment or frightened, it will erect its tail, exposing the white hair to peer and jumping for pre-hedge, so it is called as white-tailed deer. This essay discusses the habitat and living style of white-tailed deer, as well as troubles it caused to America.

White-tailed deer has wide habitat range, from North Temperate Zone to subtropical zone. It can live in semi-arid environment and arid areas. White-tailed deer is a very adaptable species. almost all of the ecological types, including tropical rain forests, coniferous forests, deserts, mountains, grasslands, and even woodland and farmland, can meet its needs for survival. White-tailed deer can be found in Andes, low altitude areas, high latitude areas, transition zone of forest and grassland, bush, secondary forest, mixed pine oak forest, deciduous forest, equatorial rainforest, etc (Horsley et al., 2008). In the United States, it lives in broadleaf forest. In Canada, it lives in northern forest with cold climate. In Mexico, it lives on the arid slopes. It can be tough to survive under the hot and humid environment of Central and South America.

White-tailed deer is the most common deer species in America. Their shadows appear from tropical beachfront of Florida to coniferous forests at the junction of Canada. White-tailed deer is good at swimming. They have seasonal migration habits but do not like living in groups. They can swim across 6-14 kilometers of waters. When snowing or lack of food, there will be 4-5 white-tailed deer gathering around in the place with suitable habitat and rich food (Rooney and Waller, 2003). They eat a variety of foods, including moss, nuts, mushrooms, fruit fell to the ground, bark, twigs, grass, bushes, leaves, and so on (Joelle et al., 2006). White-tailed deer mates in November and December. A male white-tailed deer mates several female deer. After 196-210 days of gestation, 1-2 fawns (some time 3-4 fawns) will be born. Fawn will live with female deer for 1-2 years. Fawn fur is dark brown. The body is also dotted with white spots which are a natural camouflage. They hide in vegetations so that predators are difficult to find them.

In spring and summer, white-tailed deer puts on red-brown short-hair with beautiful and graceful posture. After into autumn, they begin to put on thick hair and the color becomes dull. Male white tail deer is 2 m in length and weighing up to 130 kg. Female deer is smaller with general body weight of not more than 90 kg. White tail deer distributing in warm regions in the south is small than the white-tailed deer living in northern America. This feature ecologically conforms to the law of one Bergmann: Northern individuals with bigger body will have small relative surface area (surface area and volume ratio) is, so the heat loss per unit of body weight is also small, which is in very favorable to maintain a constant body temperature in cold and long winter. In addition to size differences, there is a more significant difference between male and female deer that only the male deer will grow dendritic horns under normal conditions. Every year, white-tailed deer takes off the old horns and grow new horns. From late December to February in the next year, after male deer completed mating, old horns begin to fall off. It has to wait until March or April for the new horns gradually growing. If nutrition is good conditions, the new horns right corner will become bigger than before.

It is estimated that the United States has about 30 million white-tailed deer. Under optimum conditions, the number white-tailed deer will be doubled every two years. It is inconceivable that today's numerous white-tailed deer had slipped into the abyss of extinction more than a century ago. Because a lot of habitats have been transformed into farmland and towns, plus the prevailing hunting and not strong enforcement of hunting law, in the late 19th century, the number of white-tailed deer drastically reduced (Tilghman, 1989). By the last 1920s, white-tailed deer had been listed as endangered animals in many states. They once were extinct in the Midwest Indiana and Kansas. The situation caused widespread concern at the time. Initially, in order to protect white-tailed deer, the hunters provided funds and the state governments were responsible for developing protection laws. Then governments developed treaty to restrict hunting and established protected areas. They also controlled the natural enemies of white-tailed deer and re-introduced white-tailed deer in the region where the white-tailed deer had been extinct. These measures are quite successful. The number of white-tailed deer has a significant increase Plus the expansion of the suspended hunting area, as well as the declining number of US people participating in deer hunting since 1970s, the number of white-tailed deer rebounded to normal levels. It is seen as a typical case of large mammal management.

However, white-tailed deer has not slowed down the pace of growth since then. Biologists estimated that in the case of the ecological balance, each square kilometer of land can only support up to eight deer. But the reality is not optimistic. The highest density will squeeze more than 100 deer in one square kilometer of land, which brings the whole ecological environment with enormous pressure. Each year more than 12 million deer are born, such a lot of white-tailed deer is like an ecological bomb, bring problems (Nelson and Mech, 2011). Many insect-transmitted diseases spread with a large number of deer, including Lyme disease. Each white-tailed deer will eat half a ton of plants a year. A large number of deer make the plants in many parts overwhelmed. Plant species will be reduced by more than half within dozens of years.

Forest succession has also been greatly affected. Ecologists are worried that high-density deer may chew away hemlock seedlings in boreal forests of Canada (Russell et al., 2001). Because white-tailed deer like to eat their familiar native plants, but they do not eat alien plants, it contributes to the invasive plant expansion in the United States. Further, since numerous deer and the edible vegetations are often limited, hungry white-tailed deer often flock to farmland, nurseries and tree farms in groups (Schmitt et al., 1997). According to statistics 13 states in northeastern United States, this loss is nearly $ 250 million annually. Faced with this series of ecological problems, people come up with various ways to manage white-tailed deer. Michigan and Wisconsin recently successfully bring back the white-tailed deer's predators - wolves. However, the number of deer in these areas has not been significantly reduced. In fact, the relationship between white-tailed deer and their natural enemies is still poorly understood. Coyote with the similar body of dogs is seen as young deer killer, but in some parks in the Midwest, a large number of white-tailed deer and coyote live harmony. In addition, hunting white-tailed deer in a small area can quickly reduce the number, but it is difficult to promote this way to larger areas. It was also suggested to carry out deer sterilization. But even the deer with the surgery would still damage the environment.

With today so advanced science and technology, people have not been able to find solutions to the problems between white-tailed deer and the environment. There are still no pervasive programs for the conflict and contradiction. The game between people and white-tailed deer will continue. This is not only a challenge to management tools and techniques, but also the deep test to the relationship between man and nature.

References

Horsley, S. B., Stout, S. L. & Decalesta, D. S. 2008. White-tailed deer impact on the vegetation dynamics of a northern hardwood forest. Ecological Applications, 13, 98-118.

Joelle, T., Sauvé, D. G. & Cǒté, S. D. 2006. The Effects of Decreasing Winter Diet Quality on Foraging Behavior and Life‐History Traits of White‐Tailed Deer Fawns. Journal of Wildlife Management, 70, 1445-1454.

Nelson, M. E. & Mech, L. D. 2011. Twenty-year home-range dynamics of a white-tailed deer matriline. Canadian Journal of Zoology, 77, 1128-1135.

Rooney, T. P. & Waller, D. M. 2003. Direct and indirect effects of white-tailed deer in forest ecosystems ☆. Forest Ecology & Management, 181, 165–176.

Russell, F. L., Zippin, D. B. & Fowler, N. L. 2001. Effects of White-tailed Deer (Odocoileus virginianus) on Plants, Plant Populations and Communities: A Review. American Midland Naturalist, 146, 1-26.

Schmitt, S. M., Fitzgerald, S. D., Cooley, T. M., Bruning-Fann, C. S., Sullivan, L., ., Berry, D., ., Carlson, T., ., Minnis, R. B., Payeur, J. B. & Sikarskie, J., . 1997. Bovine tuberculosis in free-ranging white-tailed deer from Michigan. Journal of Wildlife Diseases, 33, 749-758.

Tilghman, N. G. 1989. Impacts of White-Tailed Deer on Forest Regeneration in Northwestern Pennsylvania. Journal of Wildlife Management, 53, 524-532.

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