By Travis Vatland
In the United States, there is an estimated 50,000 non-primitive species, with about 4,500 of those non- primitive species considered invasive. Some of the most notorious invasive animals in the United States include the Burmese python, emerald ash borer, zebra mussels, and the common carp. In Minnesota, some of the most common invasive species include earthworms, emerald ash borer, and zebra mussels.
All terrestrial earthworm species in Minnesota are non-native. Even before European colonization, the glaciers are believed to have killed of all terrestrial earthworms in Minnesota. So how did they get here? Colonial European settlers used to hold soil and rocks as ballast, which they would eventually get rid of to adjust the ship’s weight. Currently, terrestrial earthworms are mostly being spread in Minnesota because they are used as fishing bait. There are 15 non-native earthworm species currently living in Minnesota. But aren’t earthworms good? Well, for farmers and gardeners, terrestrial earthworms are can be very beneficial, creating tunnels to help with the movement of water and make nutrients more available to plants. However, terrestrial earthworms impede the natural growth of native plants in Minnesota’s forests. Terrestrial earthworms increase the impaction of forest soil, which in turn diminishes water infiltration. This increases surface water runoff and erosion in forests.
Next we will be taking looking at the zebra mussels and their impact in Minnesota’s bodies of water. Zebra mussels are native to Russia. Again, it is believed that zebra mussels got into the Great Lakes in the ballasts of European ships. Adults average ½-1½ inches. Female muscles can produce over 100,000 eggs per year. What environmental problems does it cause? One major problem with zebra mussels is that they increase the amount of algae growth in the Great Lakes. Zebra mussels are great filter feeders, thus greatly improve the water purity. This extra clarity in the water allows sunlight to penetrate the water easier, allowing algae to grow rapidly. Extra algae can have devastating effects on the environment and economy. Large amounts of algae can produce algae blooms, and these blooms release toxins into the water. One of these toxins has a direct effect on aquatic wildlife. With less fish diversity, businesses that profit off lakes and rivers will have major cuts in profit. Zebra mussels also attach to boat hulls and motors, which reduces productiveness.
Now for perhaps the most current talked about invasive species, the emerald ash borer (or EAB). The EAB is a species of beetle native to Asia. The EAB is believed to have arrived at the United States in wood products and cargo carried from Asia to the United States. The first discovery of EAB in the U.S. was in 2002 in Michigan. Since 2002, the EAB has been found in 31 states. So what do EAB impact? As their name indicates, emerald ash borers essentially feed on ash trees. It is, however, the larva that have the greatest impact because they burrow tunnels in the trees. As ash trees succumb to EAB infestation, they usually die within one to three years. As more trees become infested and eventually die, there will be many implications. Forests’ habitat will greatly change because of the lack of ash trees, making forests less diverse and allowing shrubs and grass to take over. This will have a significant effect on the many animals that rely on Minnesota’s forest lands. EAB also is a very costly animal because of the damage it can cause in communities and the money needed to remove infested trees.
In conclusion, the zebra mussel, terrestrial earthworms, and emerald ash borer pose the greatest threat currently to Minnesota’s natural environment. These invasive species not only affect the environment, but also communities all across Minnesota. Even though research is being conducted on how to manage these species, there is still a great need for communities across Minnesota to join and educate the public on how to stop these invasive animals.
References
DNR. (2018a). EAB. Retrieved at https://www.dnr.state.mn.us/invasives/terrestrialanimals/eab/index.html
DNR. (2018b). Earthworms. Retrieved at https://www.dnr.state.mn.us/invasives/terrestrialanimals/earthworms/index.html
DNR. (2018c). Zebra mussel. Retrieved at https://www.dnr.state.mn.us/invasives/aquaticanimals/zebramussel/index.html
Travis Vatland is a student at Mabel-Canton High School. He is one of seven area students participating in the Journal Writing Project, now in its 19th year.