Population Size – Essay Example

Nutria and the ecosystem of Louisiana Nutria (Myocastor coypus) is a large rodent of South American origin which was later introduced to other parts of the world considering the demand of its fur. Although they were extinct from the native lands due to over harvesting of fur, they multiplied unrestraint in secondly introduced lands due to gradual decline of the fur market including Louisiana. They eat plant foods and destruction of wetland vegetation in Louisiana by nutria was reported from 1950’s. Nutria is the main culprit for wetland vegetation loss in Louisiana which threatens the ecosystem.
There are four factors which affect the population size of a particular community.
Birth rate: Number of births occurs per 1000 persons in the society per year. High birth rates increase the population size rapidly while low numbers lead to slower growth or reduction of the population size.
Death rate is the number of deaths occurs per 1000 persons per year. Higher death rates lower the population growth and size.
Immigration is the number of people entering a country or particular community and it increase the population size.
Emigration   is leaving of native territory by the inhabitant and it lowers the population size.
For the nutria population in Louisiana first two factors involve significantly. Their birth rate is high. A female has a capacity to produce maximum about 40 offspring per year although the average is much lesser leading to a rapid population growth. However their death rate also as high as 80% within first year of life due to predators. In spite of their higher death rate they still grow alarmingly due to dramatic reduction in the fur harvesting. Further they are well adapted to the Louisiana environment.
Since this animal is nourished by any type of vegetation they will migrate to surrounding areas once the vegetation in Louisiana is destroyed.
References
1. Carter, Jacoby and Leonard, B. P. (2002). A Review of the Literature on the Worldwide Distribution, Spread of, and Efforts to Eradicate the Coypu (Myocastor coypus). Wildlife Society Bulletin, 30 ( 1) ; 162–175.
2. LeBlanc, Dwight, J. (1994). Prevention and Control of Wildlife Damage - Nutria. Animal and Plant Health Inspection Service.