Journal of Great Lakes Research 35, 99-108 (2009).
Water Nutrient Management
In a recent article published in the Journal of Great Lakes Research, Bosch et al. (2009) presents a new direction for long-term control of the invasive species, Eurasian water milfoil (Myriopyllum spicatum), which is currently taking over lake ecosystems. Water milfoil out-competes native species by absorbing nutrients and forming thick mats on the water’s surface that block out sunlight to neighboring plants. Such canopies can take up to 80% of surface cover. Because water milfoil is nutrient dependent, and can absorb Phosphorous and Nitrogen by both root and shoot uptake, managing nearby watersheds proves to effectively decease biomass of the Eurasian water milfoil in this experiment’s project watersheds. Over a six-year period, annual surveys of plant biomass, species composition, and bed distribution were conducted. Observations of the regions before and after the experiment emphasize that the decrease in water milfoil was caused by the reduction of tributary nutrient loading attained in consequence of agricultural best management practices (BMPs), including manure injection. In combination with other management approaches, agricultural nutrient management can be used to control and eradicate this invasive specie.
The purple loosestrife have gotten out of control in the continental US, and are taking over and choking out native species and altering the habitats. Blossey et al. argues that the impacts of the purple loosestrife upon the environment are of great enough magnitude where it would be worth it to release another nonnative species, an insect, as a biocontrol method to attempt to reduce the population of the loosestrife and keep it under control. The loosestrife have risen in both number and extent to which they alter the habitat they live in, and though it might seem that they would only impact other competing native plant species, they also have become enough of a problem where they also are hurting animal species, especially specialized wetland birds. Though the introduction of other nonnative species may have unforeseen negative impacts, with so much potential in danger as a result of the loosestrife, the prospective benefits would outweigh the possible dangers.
Blossey, Bernd, Luke C. Skinner, and Janith Taylor. “Impact and Management of
Purple Loosestrife.” Biodiversity and Conservation 10 (2001): 1787 – 1807.
Web of Science. Web. 25 Sept. 2010.
The purple loosestrife is an aquatic invasive species that has infested almost all of the continental United States, and has become an especially huge problem because it outcompetes native wetland plants, many of which are endangered to begin with. It arrived in America via ship ballast water, and medicinal purposes. Without any natural predators, and incredible reproductive abilities, producing up to 2.7 million seeds on a mature plant in just one summer, it can quickly transform an aquatic habitat. Also, unless it turns out that it is a very localized and isolated case of purple loosestrife, there are presently no effective solutions to get rid of the plant. The only solutions that currently exist are either highly time consuming, such as removing the plant by hand, or incredibly expensive, like using herbicides.
I think that this invasive species sounds like a huge problem, and considering that it’s spread throughout the United States, I’m surprised that I had only ever heard of it through my environmental science classes and not through the media, because with the current state of wetlands in the country, more should be done about their preservation, given how high the percentage of endangered species are in wetlands. I was wondering though, is there some sort of way that fungus or blight could be utilized against this species? They have tried using insects, but it hasn’t completely worked.
Photo from here.
The first zebra mussel was discovered in the US twenty years ago. Scientists believe it was brought over by a Russian ship due to its tendency to “hitchhike” on the bottoms of boats. According to an article on Boston.com, preventative measures against the spread of zebra mussels began in 2005, but didn’t pose a problem until June 2009. Although Laurel Lake is the only impacted one in Massachusetts, zebra mussels infect the Great lakes as well as other lakes in Pennsylvania, New York, Connecticut, Vermont and other states.
WBZ News expressed concern over the new invaders for not only do they prevent people from swimming because of their sharp bodies, but they can also clog pipes, kill aquatic life, alter the ecosystem and foul water supplies. If they were to get into the pipe systems, the mussels could threaten millions of dollars of infrastructure damage. The fish are put in danger for each mussel can consume up to a gallon of water per day and filter out the zooplankton, a central part to a fish’s diet. Due to mussel’s ability to filter out and clean the water, aquatic plants beneficial to other species may emerge, and therefore drastically changing the ecosystem. Luckily the water supply remains out of danger for Laurel Lake is not the water supply for the region. To prevent the expensive and harmful effects of the invasive species, the government has focused on educating boat owners about properly cleaning boats exiting Laurel Lake.
Despite the continual problem of zebra mussels in Laurel Lake, it seems as if the preventative measures have been successful so far (no other Massachusetts lakes have been infected, only small tributaries surrounding Laurel Lake). Unlike the Eurasian watermilfoil, which can easily be spread simply by the felt on fly fisher’s shoes due to its relatively discreet appearance, the zebra mussels are much more detectable, and therefore are less likely to be transferred to another lake without notice.