Nutria - Overpopulation within the Ecosystems

Another issue that plagues the wetlands is the overpopulation of nutria. Nutria, also known as coypu, are semi-aquatic rodents that are not indigenous to in the United States. These rodents traditionally come from Argentina, Brazil, Chile, and other South American countries. Nutria were originally introduced to the United States in 1899 to California and can presently be found in 15 of the 50 states. In the early 1930s, the nutrias were imported from fur farms into the wetlands of Louisiana to be hunted in fur trades. The nutria were on the move when trappers moved them to Port Arthur, Texas and the Mississippi River area before a hurricane would disperse them further.

Nutria would aid in controlling the weeds in the wetlands through the late 1940s. They would be the primary consumers of water hyacinths that were throughout Louisiana. Their reproductive cycle being exponential helped with rapid population growth. The US Geological Survey discusses the reproductive cycle of the nutria in an article titled “Nutria, Eating Louisiana’s Coast”. The article stated that nutria reach sexual maturity at six months of age and has a gestation period of only 130 days. In a single year, adult nutria is capable of producing two litters in a year of four to five; however, they are capable of birthing up to 13 in a single litter. The baby nutria are also born fully furred with their eyes open.

The nutria population by the 1950s was above 20 million, and the nutria had destroyed natural levees. The nutria were destroying other agricultural areas were being destroyed, leading to their removal from list of protected wildlife near the end of the 1950s. Louisiana promoted fur as a natural resource because of their overabundance. From the early 1960s through the early 1980s, hunting the nutria and hurricanes and other severe weather would help aid in reducing their population. The fur trade went bad in the late 1980s so the only consumer of the nutria then would be the alligator. Damage could be seen in satellite imagery through the 1990s and in 2002, a program was put in place to reduce the numbers further.

Sources:

http://www.nwrc.usgs.gov/factshts/020-00.pdf

http://www.sciencedaily.com/releases/2008/03/080306094624.htm

http://www.nutria.com/site2.php

Disturbances on the Wetlands

One of the greatest debates going on about the coastal wetlands in Louisiana is whether or not the hurricanes, specifically Hurricane Katrina and Hurricane Rita in 2005, have impacted the land loss. Hurricanes are classified as disturbances. Disturbances, in scientific terms, can be defined as periodic and destructive events that cause change to an ecosystems and causes affects to the organisms within it either positively or negatively.

Obviously, hurricanes would affect the ecosystems of animals and vegetation in a negative way, not to mention humankind as well. However, there is a silver lining in what wetlands offer to such a destructive force. Wetlands traditionally can help be a buffer for hurricanes to damage onto the mainland. The vegetation of the wetlands helps spread rain and flood water on a more equal level. In an article published by Erin St. John she mentions the wetlands water capacity also can reduce erosion and lowers the heights of flooding, all of which have a deep impact on the destruction from hurricanes.

The problem with wetlands being destroyed is that helped in exacerbating the destruction from Hurricane Katrina and Hurricane Rita. Typically speaking, the damage from a hurricane comes in the form of large amounts of water flooding into the city. In an interview posted on MSNBC.com Sidney Coffee, executive assistant to the governor for coastal activities, states that “for every 2.7 miles of wetlands, storm surges are reduced by about one foot.” Hurricane Katrina and Hurricane Rita were both category five storms, the strongest classification of hurricanes.

While natural disturbances are a force that causes great destruction, the wetlands are also being eroded by the creation of man-made levees. Robert Morton explains this in his article “An Overview of Coastal Land Loss: With Emphasis on the Southeastern United States”:

Except for infrequent episodic deposition associated with hurricanes, marsh deposition rates are lowest in the summer and also in the spring. In Louisiana, low rates of sediment deposition are a result of flood control structures and levees on the Mississippi River and its distributaries. Before river control, spring floods annually delivered large volumes of suspended sediment across the delta plain helping maintain marsh elevations even on inactive delta lobes.

Man-made levees also can cause further damage when they are destroyed, as evident from Hurricane Katrina. When levees are destroyed the flood water that results can destroy both wetlands and the main land depending on the amount of water being held back by them. The wetlands are affected dramatically by disturbances, both natural and man-made ones. The affects of both can be devastating to humankind and other animals and organisms.

Sources:

http://www.helium.com/items/234937-how-wetlands-could-minimize-the-effect-of-hurricanes

http://www.msnbc.msn.com/id/9118570/ns/technology_and_science-science/

http://www.laseagrant.org/hurricane/archive/wetlands.htm

http://pubs.usgs.gov/of/2003/of03-337/wetland.html

Ecosystems Affected By Land Loss

Wetland loss affects not only the people of Louisiana and other states, but also the organisms living in its ecosystems. Ecosystems are communities of both living and non-living organisms that are interdependent of one another in an environment. The ecosystem has many uses for both animal and human usages, and the loss of such a valuable environment can be critical.

The wetlands are an open ecosystem, as in that it takes input from its surroundings as defined by Cunningham in Environmental Science A Global Concern. In Louisiana alone, migrating birds, such as the snow goose, the osprey, and herons utilize the environment. Fish and shellfish also use the wetlands as a place for nursing eggs. Other species that are a part of the wetland ecosystem include a plentiful number of endangered species. These species include the American bald eagle and according to the National Wildlife Federation, the Louisiana Black Bear and the green sea turtle are also endangered.

Animals are not the only part of the wetlands, plant life also comes in large quantities. Cattails, swamp roses, cypress trees, and some that are exclusive to Louisiana such as ruppia and cottonwood. These plants become important in protecting the people of Louisiana from severe weather situations. Wetlands absorb both water and the energy created by winds and waves. This prevents flooding by storing water and then releasing it slowly as well. These make wetlands highly resistant as an ecosystem is concerned.

Environmentalists want and need the coastal wetlands protected for many reasons. Louisiana currently loses approximately 24 square miles a year. The National Wildlife Foundation states that this is approximately the rate of a football field every 30 minutes, and Louisiana has lost already a land mass the size of Delaware. The wetlands provide a large part of Louisiana’s economy, from fishing to oil pipelines, losing these lands would provide disastrous for the people from the area that have already struggled post-Hurricane Katrina.