Conclusions

State of Indian Lake

Our observations of the lake during the survey indicate that since all three significant points of current flow are in the northern half of the lake the areas affected are mostly in the southern half of the lake. This problem persists during the the 2015 survey. These observations conform to the suggestion that the lack of current flow to the southern end is one of the contributing factors in Indian Lake's weed overgrowth. This is likely because the lack of flow causes the water to become more stagnant and allow silt particulates to fall out of colloidal suspension to the lakebed. The southside of Sears Island also seems to be recieving problems because the lake is shallow, allowing plants to recieve sunlight and grow faster and spread easier. This in turn provides nutritious soil for plants such as Eurasian Milfoil to lay roots in. All of these problems are seen similarily in 2015. In 2004, the ESS Group performed a full survey of Indian Lake, which identified seven different species of plant. These plants were Eurasian watermilfoil, stonewort, pickerelweed, common reed, common grass, smartweed, and cattail. This survey identified much lower quantities of Eurasian milfoil and cattail when compared to the data collected from our survey. This survey has identified small pondweed as a much more prevalent species; in contrast small pondweed was not identified at all in 2004 [5]. In the last eleven years, Eurasian watermilfoil and small pondweed have spread to the extent that these plants were found in most regions of the lake shallower than seven feet. In 2015 the team noticed Eurasian milfoil has spread to northern parts of the lake, not just throuhgout the southern part of Sears Island like in 2013. Cattail and common reed have also seen significant growth along the lakes shorelines. Other plants that were identified in this survey were yellow pond lily and Poa spp. (common grass). The eutrophic nature of the lake creates a niche environment for the overgrowth of the naturally aggressive Eurasian Milfoil by accumulating phosphates and nitrates that are essential nutrients for plant growth.

State of Little Indian

The last plant survey conducted on Little Indian Lake was in 2011. The status of the lake five years ago is nearly identical as it is currently. There is still a large problem with small pond weed on the floor of the lake due to it being shallow enough throughout the entire Indian Lake to allow the weeds to grow. One change since 2011 is the amount of lilies growing in Little Indian. The majority of lilies were yellow lilies, however there were a few white lilies found. A major problem, similar to Indian Lake, is the growth of emergent plants on the shoreline of the lake. Little Indian is only about 4 feet deep, allowing sunlight to reach the bottom of the Lake everywhere. Another major issue that seems to also be of conceren is there is no flow of water through Little Indian.

Invasive and Agressive Plant Growth

The two plants identified that present the largest issue are Eurasian Milfoil (invasive) as well as small pondweed (native). Both plants exhibit aggressive growth patterns and present recreational as well as ecological problems that could have long term complications. One particularly concerning trait of Eurasian Milfoil is its ability to begin growing in the spring a few weeks before other plants allowing it extra time to grow and expand [14]. In 2004 small pondweed was not identified in Indian Lake and is now common. In eleven years it has gone through a large growth period and should be watched for further expansion. More specifically, in two years Eurasian milfoil has spread throughout the lake including the northwest corner where it was never previously recorded there.

Along the shoreline, cattail has also experienced aggressive growth over the last eleven years. Though usually considered invasive, there are two subspecies of common reed, one of which is native to the area and grows much less aggressively. In the last 11 years, common reed has shown little growth, which may suggest that the species present on Indian Lake is the native subspecies [15].


Developed as Part of a WPI Sponsored Project
In Affiliation with The Indian Lake Watershed Association
Worcester, MA 2013