Sep
26
Filed Under (SW5, Uncategorized) by Josh McGrath on 26-09-2010

Starting in 1959, the American Bullfrog has been introdouced into most provinces in China, and because of its size and predatory nature, has been able to thrive off consuming the native species. The bullfrog has been known to eat a number of the native anurans, but to what extent has been hard to determine for scientists. Yanping Wang and his team from The Society for the Study of Amphibians and Reptiles, decided to try and determine which prey the bullfrogs preferred to determine the overall effect the bullfrog has. First, they tested which bullfrogs, larger or smaller and male or female, consumed most on a daily basis. Then they determined which of the four main sources of food the bullfrogs preferred and which size. The results of the experiment showed that the though the bullfrogs preferred the smaller species such as the Rana limnocharis but only because of the species generally smaller size compared to the other prey.

Journal of Herpetology. Volume 41, p. 514-520.(2007)

Sep
10
Filed Under (SW2) by Michael Di Nunzio on 10-09-2010

When World War II came to an end, the men and women of the Armed Forces stationed in China and Japan were finally able to return to the United States. Before mobilizing its troops, however, the military purchased a number of storage crates to facilitate the transport of equipment and supplies. The crates, made of Asian wood, were discarded at dumping grounds near Louisiana shortly after the troops arrived home. Unbeknownst to the returning veterans, the crates that once held their belongings were likely teaming with Formosan subterranean termites. Upon arriving in the United States, the invasive species began to slowly propagate. Despite the initial lag, by 1960 New Orleans was completely infested, and today citizens of the city complain of their overwhelming abundance. The invader’s success can be attributed to the extremely hospitable environment afforded by the southern United States. This region is characterized by a warm, humid climate which parallels that of the termites’ Asian homeland perfectly. Moreover, the invasive termites dwell both above and below ground, while species native to the larger New Orleans area are found solely below ground. Thus, the Formosan subterranean termite enjoyed limited competition as it wrought havoc across the South.

Today, citizens of New Orleans no longer wonder if they will be faced with termite infestation; they merely await the arrival of these pests, accepting their ensuing destruction as an inescapable fate. Because the termite problem in the south is so severe, researchers are forced to invest great amounts of time and energy in finding ways to control these pests. One of the most notable individuals working with Formosan subterranean termites is Dr. Claudia Riegel, senior entomologist for the city of New Orleans Mosquito and Termite Control Board. So prominent are these invaders, Riegel has given up hope of eradicating the termites and instead looks for methods to control their rapid proliferation. The most effective technique exploits the termites’ inherently social nature. Because the creatures are predisposed to share food sources with one another, Riegel can set a single poisoned bait trap and destroy an entire nest in the process.

While the strategy of baiting termites with contaminated food is an impressive feat of ingenuity, there are several perplexing questions that accompany this technique. One must wonder, for instance, the overall efficacy of this method. If it takes a prolonged amount of time for a termite nest to die from the poison found in the bait, the pests may be able to inflict significant damage before they are eliminated. Furthermore, does the number of nests destroyed by this time-consuming task actually have a significant effect of termite population numbers? If the answer is no, then taxpayers may be wasting their money on ineffectual termite control. Perhaps a more effective strategy would entail making termite traps a standard part of newly constructed houses, or installing these devices along the outsides of all wooden buildings. Finally, it may behoove etymologists to consider the introduction of yet another nonnative species in an attempt to control the termite population. While it is true that this method holds the potential for disaster, proper research can hedge the probability of misfortune, meaning there would be a very high benefits-to-risk ratio. If a more successful means of suppressing these invaders is not developed, it is depressing to think that New Orleans might soon lie in ruins.

Sep
09
Filed Under (SW2) by Cecile Diaz on 09-09-2010

Coptotermes formosanus, commonly referred to as the Formosan subterranean termite, is an invasive species native to China. The termite species was inadvertently introduced to the United States following World War II in the late 1940s. American troops packed up supplies in Tokyo Bay using crates from Chinese wood, and they were completely unbeknownst to the fact that these crates were infested and overrun by the Formosan termite. Upon arrival in the United States, the crates were discarded carelessly in the trash, allowing the troops of termites to easily infiltrate southern states’ homes and buildings.

(Image of Formosan termite’s distribution in the United States)

This species of termite found its ultimate feeding sites in Louisianan homes by the 1960s, where the local climate perfectly accommodates the termites’ preference for hot, humid weather. C. formosanus thrives specifically in New Orleans for two reasons: the sticky weather is comparable to its native China’s climate, as well as its unique capability to nest both below ground (where termites typically congregate) and above ground in trees. By nesting in trees, the termites remove themselves from the immediate threat of insecticides in the subbasements of houses, while termite exterminators are unable to exactly locate a termite nest’s exact headquarters because they could easily be an any tree within a block of the infested house.

Claudia Riegel and her team of experts have been struggling to eradicate this invasive species from the United States—a goal that Riegel knows is a long-shot and nearly impossible to achieve. First, her team is simply looking to control the termite infestation in New Orleans by attempting to control and manipulate the termites’ path of movement. Because it’s difficult to pinpoint the home nest of a termite mass, Riegel hopes to essentially intercept their trail of destruction by routinely checking the bait stations that are posted across the city for new infestations. When the team finds termites in a station, they remove the wood bait and deposit chemicals that the termites will carry back to the nest. In as little as three months, that Formosan colony’s nest could be poisoned and destroyed.

Because Riegel avoided biocontrol, or introducing a second non-native species to attempt to eradicate the termites, New Orleans will not have to worry about the negative effects a second species may have on the city and its native creatures. The team’s simple, methodical approach is primarily focused on the idea of containment, and then eventually future eradication. Her approach is commendable because it’s noninvasive to the people of New Orleans, as well as sustainable because these bait stations could easily be used for decades to come. Although containment measures have been in effect for years to reduce the populations of Formosan termites, the problem is hardly close to being solved. New Orleans residents reported sightings of the termites, despite the unusually cold 2009-2010 winter season, which apparently only delayed the termites’ annual summer appearance by about two weeks.

Sep
01
Filed Under (SW1) by Russell Buescher on 01-09-2010

The Northern Snakehead, or Channa argus is an exotic fish native to China and other parts of Asia. It is speculated that this breed of fish was introduced to the Chesapeake Bay area and other waterways along the East Coast through release from the fish market or pet aquariums. For ordinary fish, this would not be an overwhelming problem; they would probably succumb to their surroundings. But, the C. argus species is clearly dominant over all other fish. With its sharp teeth and growth up to 47 inches and 15 pounds, the Snakehead has been described as a “voracious top-level predator.” This means that it is at the top of the food chain in bays, ponds, and lakes, thus posing a serious threat to local fish populations. On top of this, the Northern Snakehead apparently has the ability to move short distances on land to other bodies of water.

The species was first caught in Crofton Pond, USA near Washington D.C. in 2002. Since the pond was in Maryland territory, the state government took action to poison the pond to prevent the uprising of this foreign fish. Even after this isolated incident, there have still been finds of the fish. 2 years later, in Wheaton Regional Park, Maryland, a very surprised fisherman landed a 19 inch Snakehead. The lake that it was caught in was soon drained. Still, another was caught in 2007 in Lake Wylie, North Carolina. I think that the Northern Snakehead is a serious threat to the water ecosystems of North America. More action should be taken in preventing them from entering our waters in the first place. Zoos, aquariums and wildlife agencies could buy overgrown fish from owners. Preventative measures are one possible solution to reducing Snakehead finds and protect indigenous ecosystems in the future.

image obtained from http://www.rivervalleynwc.com

Sep
01
Filed Under (SW1) by Shane Stone on 01-09-2010

The Chinese Mitten Crab first arrived on the shores of North America in 1965. One crab, found in Ontario,  resulted in widespread discussion throughout the country because no one wanted to see it spread. Unfortunately, it spread and they can be found in California, Maryland, New York, and most recently, New Jersey. In these states the crabs have caused many problems, i.e. clogging San Francisco’s water system, and now that New Jersey has become the next victim, fisherman have begun to panic. According to Gregory Ruiz “40 crabs have been caught, reported and confirmed in New Jersey alone, making that state ground zero right now for mitten crabs.” The state is trying to do whatever it can to contain the population, asking all residents to try and capture any specimen they encounter to prevent reproduction. New Jersey Division of Fish and Wildlife is trying to stop the spread now because the females can produce up to 1 million eggs per reproductive cycle, and that would not end well for New Jersey’s aquatic and marine ecosystems.

The urgency with which the state is trying to address the issue is completely rational. Hopefully New Jersey can manage the situation without it getting too out of hand. These crabs can cause serious issues to ecosystems because they are omnivores, and therefore prey on a multitude of organisms. Aside from the organisms, the crabs have destroyed the physical ecosystems in their previous homes when they burrowed into the walls of riverbanks, causing erosion. Despite Jew Jersey’s efforts, its plan is flawed because it relies so heavily on assistance from civilians. To many people the idea of seeing a live crab disturbs them, but to capture one is in a league of its own. Therefore, I believe that New Jersey should continue to encourage people, but try to unite with other states that have this problem so there can be a joint effort. Also, some people tend to work harder if there is some sort of incentive. Perhaps if a small reward were offered per crab, more people would try to catch them in hopes of profiting. In general, I just want this problem to be handled so that my home, New Jersey does not face any irreversible repercussions.