How Do Beaver Dams Affect The Environment

There are many different species of organisms in the world. Some species, such as dominant species, are one example of having a large impact. They are species that are the most abundant in an area or have the most biomass, however, there are no definite reasons as to why they become the dominating species. Some debate that these species excel at competing for resources while others argue that they excel in avoiding predation. Yet, there are other species who provide a very large impact on its environment, often creating opportunities for other species to flourish; they are called keystone species and will be the main topic being discussed. Without keystone species, the ecosystem that revolves around that said species may perish. One example

Beaver dams are known to alter the riparian environment as the stream or river is converted into a pond or lake upon establishing a dam. This transformation from a lotic to a lentic environment drastically affects nearby plant and animal species as a beaver meadow is formed from the built up sediments trapped by the dam (Martell et al., 2006 and Rosell et al., 2005). Beavers follow a cycle where they create and abandon dams for long periods of time, which also affects the environment, however, dams are often left abandoned consequently due to food supplies running short. Generally, the dams are destroyed over time, yet, they are also left intact every now and then. Once they are destroyed, the lentic environment reverts back to a lotic environment and new trees are allowed to grow for the next beaver cycle (Martell et al., 2006). The study conducted by Martell et al. (2006) focuses on the changes in beaver dams and its effect on the riparian environment. Their hypothesis was that there would be an increase in dams in the area they are studying, foraging intensity will decrease as the distance from the water increases, and non-forest riparian areas will be greater at older dam sites (Martell et al., 2006). All of this was accomplished by taking aerial photos of the dam sites and the surrounding area while also physically going to that said area and

Various studies attest that beavers affect the geomorphology and water chemistry, buffering the water and allowing it to become nutrient rich for future plant growth (Hood & Bayley, 2008 and Rosell et al., 2005). Specifically, they questioned whether beavers can increase the area of wetlands and whether they can also bring this increase in wetlands during a drought. Aerial photos were used in Elk Park where they then created a mosaic to represent the wetlands found in the area. Data for temperature and precipitation, however, were collected by using the temperature of a nearby airport because of lack of accurate weather data at the time. Over time, they experienced two very dry years and used these two years as a source for testing whether beavers can mitigate the effects of climate. Coincidentally, one of the dry years, 1950, had no indications of beaver activity while the other year, 2002, had beaver activity. Comparing these two years along with the other data collected, Hood & Bayley (2008) found that wetlands contained 61% less water when there are no beavers and averaged at 3.9 ha. Wetlands with beavers, on the other hand, contained more water and had and average of 35.5 ha with ha being the unit of area of open water done in the study. From the data, beavers do in fact