Free Essay about Animals That Benefit from Human Activity: Nutria

Invasive species are capable of causing massive ecological disturbances as well as economic problems. They pose a threat that if not mitigated can be detrimental to biodiversity in areas such as Oklahoma (Maas-Hebner & Kathleen, 45). It is difficult to understand the some of these invasive species thus managing and controlling the problems they cause is sometimes an uphill task, especially with the changing climatic conditions that cause them to migrate. Invasive species compete for space and nutrients, prey upon native species, or disturb ecological balances in a number of ways. Normally, invasive species reproduce faster, reach, and attain their optimum sizes faster in these new habitats compared to their original habitats. Once an invasive species has established a considerable population, it becomes extremely difficult to get rid of. The Nutrias are some of the invasive species whose population has multiplied over the years hence become impossible to control.

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Nutria "is a semi-aquatic rodent with a voracious appetite and high reproductive potential, native to South America that has been introduced to wetland habitats worldwide since the early 1990's with the intent of farming in many cases."Its natural habitat is along rivers and lakes and in marshes and estuaries. Nutria looks similar to beavers, but is smaller and has a rat-like tail. On average, adults are relatively large (up to 7kg). Other characteristics include webbed hind feet, orange to yellow colored incisor teeth, and reddish brown fur (Witmer 28). Nutrias are adapted to an aquatic lifestyle but are capable of moving quickly whether on land or in water. They eat primarily aquatic vegetation, but will also consume terrestrial plants, with a special reference for monocotyledons. In its home range in South America, it has been documented to consume mollusks.

Nutrias typically live around 3 years but reproduce rapidly. Females can have two litters per year, ranging from 5-13 animals per litter. The average number per litter seems to be highly variable between locations. A rapid reproduction allowed nutrias to grow from an estimated Louisiana (Witmer 29). Given the high fecundity of nutrias, the chances that a small number of animals distributing to new habits will lead to infestation is high.

The population of nutrias spread as a result of human activities in the Great Plains. Nutrias were initially introduced in the United States in the 1930s in Louisiana, Michigan, New Mexico, Ohio, Oklahoma, Oregon, Utah, and Washington for their fur. The fur industry crashed during World War II due to decline in the price of fur pelts, and many defunct farms simply released the animal. Nutrias are currently thought to have stable or increasing populations in at least 15 states, although the number could be as high as 20 (Bekele & Bekele 39). Some states have reported small feral populations that were successfully eradicated; however, these populations may have already been limited by unfavorable habitat conditions. Other states have reported small feral populations that may have died off without eradication efforts. Nutrias have shown the ability to spread from state to state, with Maryland populations likely the source of populations in Delaware and populations in Louisiana using gulf waterways to establish populations in the Florida panhandle.

Nutrias have historically been valued for their fur, which has led to their spread as an invasive species through escapes from fur farms. It is evident that Nutrias mostly prefer their natural wild habitat. The animal is considered a pest or nuisance in many areas outside of its native range due to its feeding and burrowing habits. Additionally, nutrias are capable of rapid reproduction and are highly adaptive and capable of increasing their range into new habitats. Consequently, the detrimental effects of nutrias are of concern to stakeholders at multiple levels. This is evidence that nutrias are capable of destroying ecologically valuable wetland and marsh habitat, as well as creating economic costs through crop loss, damage to embankments and dams, and potential flooding.

The main factor for success in population establishment appears to be temperature, with nutrias unable to survive harsh winters. Consecutive days of frost have been shown to cause deaths in both adult and juvenile nutrias, and in harsher conditions, female nutrias have been known to abort litters. However, there is evidence that nutrias have a high level of behavioral flexibility (Guarnieri et. al., 19). Their ability as a tropical species to spread to temperate areas is indicative of this flexibility, and nutrias have spread to areas previously considered too cold for survival. Nutrias, in a pattern similar to many invasive animals, has been shown to mature earlier and reach larger body sizes. Such traits are an evolutionary response to the temperate conditions experienced in its new habitat.

Attempting to control an invasive species such as nutrias is typically expensive and sometimes futile. It requires an understanding of the extent and significance of the problem in order to understand if the species necessitates control, and if so, how control can be accomplished. Failure to understand the nature of nutrias may allow the species to gain a stronger hold and cause larger damages if action is not taken (Bekele & Bekele 43). On the other hand, resources could easily be wasted in an attempt to control a species in a manner that is ineffective or unnecessary. A large number of the nutrias species have made a habitat in states such as Louisiana and Maryland, and the states have instituted nutrias control programs after suffering great ecological damage to Nutrias infestation. Other states have not studied the effects or extent of nutrias infestation in their locality.

Nutrias are described as preferring stagnant fresh water but are also known to inhabit saltwater and brackish habitat. They preferentially eat aquatic and semi-aquatic vegetation in their habitats, such as reeds and sedges (Guarnieri et. al., 21). However, nutrias are capable of consuming a wide variety of vegetation and their diet in a given habitat is highly variable according to what is easily available, including crops adjacent to their habitat. Often, these are the losses most easily calculated as a result of nutrias infestation.

Nutrias cannot tolerate urbanization. Urbanization limits the availability of vegetation and wetlands. However, they multiply rampantly in areas with agriculture and polluted water. They have been described as abundant in holding ponds and drainage ditches, and some researchers have provided evidence that the animals thrive in highly polluted water systems, such as sewage lagoons near cattle ranches. This may be due to fertilizing effect of polluted water on emergent vegetation, which provides a dense food source for the rodent. For example, in Florida, enriched waters are often choked with exotic water hyacinth, which nutrias utilize heavily. However, nutrias are thought capable of infesting any wetland habitat, including those that are relatively undisturbed.

Nutrias have a variable home range. Studies in nutrias infested areas such as Oklahoma have shown that they remain within one general area throughout their lives, rarely traveling over 1200 yards from where they were released. Daily movements of nutrias are usually within 200 yards. Some nutrias, however, moved large distances: 18miles within 167 days, and 15 miles within 67 days. This means nutrias are perfectly capable of infesting new areas within a fairly short amount of time, although the majority of them may never leave the habitat of their birth. The degree to which nutrias spread into new habitats may be dependent on the quality and abundance of the resources in that habitat.

Nutrias have become a great threat to the native species within the Great Plains. They are considered voracious consumers of emergent vegetation. In one day, they can consume up to a quarter of their own weight. They also have a tendency to consume the base or stalk of plants, often uprooting the plant and allowing unconsumed portions to wash away. This means a population of nutria is capable of converting wetland or marsh habitat into open water within a relatively short amount of time hence living no vegetation for the consumption of the native species. Areas in which nutrias have significantly depleted vegetation are called "eat-outs". Additionally, the swimming channels created by nutrias to move through marshlands have a fragmenting effect and can accelerate the rates of loss (Jojola et al., 62). In some areas, these feeding habits have led to the loss of entire wetlands. Louisiana has attributed a loss of over 600,000 acres of coastal wetlands to nutrias invasion (Louisiana Fish and Wildlife). England, before beginning a control program, attributed major losses of reed swamp to the feeding habits of nutrias.

Areas in which wetlands are being restored and replanted are of particular concern. For example, wetland restoration in Italy has been slowed as nutrias expanded their range into the newly created habitat and depleted the vegetation. The disturbance caused by nutrias may favor the establishment of invasive plants through competitive exclusion, as native plants are unable to establish themselves under the pressure of herbivory (Sheffels et al., 151).

Nutria is additionally considered an agricultural pest which can affect crops adjacent to their habitats. Crop feeding is more prevalent in winter months, where nutrias have been known to feed up to 1.5 km away from their habitats ( Jojola et al., 67). Varieties of crops have been recorded as affected by nutrias, although alfalfa, sugarcane, and rice have been particularly affected. Additionally, they have been reported as destroying fruit and nut trees, and conifers. In some areas, such as Italy, damage by nutrias to crops has been calculated in the millions of dollars (Maas-Hebner & Kathleen 53).

Overall, there are a lot of unknown facts regarding nutrias, which reflect a greater lack of understanding of how invasive species behave in general. Researching nutria has a great benefit of adding to the scientific knowledge of how invasive species spread and impact ecosystems, and furthermore how they can be managed, controlled, or eradicated. The current status of nutria, although not entirely clear, may be optimal for eradication efforts, before this species pushes into new and highly sensitive areas, or population explodes. At a minimum, a public awareness campaign centralized reporting hotline, and thorough documentation is necessary next steps for informed policymaking.

Works Cited

Bekele, Frances, and Isaac Bekele. "Social and Environmental Impacts on Agricultural Development." (2017). Print.

Guarnieri, Giuseppe, Simonetta Fraschetti, Cesare Bogi, and Bella S. Galil. "A Hazardous Place to Live: Spatial and Temporal Patterns of Species Introduction in a Hot Spot of Biological Invasions." Biological Invasions. 19.8 (2017): 2277-2290. Print.

Jojola, Susan M, Gary W. Witmer, and Patrick W. Burke. "Evaluation of Attractants to Improve Trapping Success of Nutria on Louisiana Coastal Marsh." The Journal of Wildlife Management. 73.8 (2009): 1414-1419. Print.

Maas-Hebner, Kathleen G. "Rehabilitating Aquatic Ecosystems in Developed Areas." (2014). Print.

Sheffels, Trevor R, Mark D. Sytsma, Jacoby Carter, and Jimmy D. Taylor. "Efficacy of Plastic Mesh Tubes in Reducing Herbivory Damage by the Invasive Nutria (Myocastor Coypus) in an Urban Restoration Site." Northwest Science. 88.4 (2014): 269-279. Print.

Witmer, Gary W. "Perspectives on Existing and Potential New Alternatives to Anticoagulant Rodenticides and the Implications for Integrated Pest Management." (2018). Print.