For the fifth consecutive year, CAES IAPP surveyed Fence Rock Lake in Guilford, CT to track the invasive plant Brazilian waterweed (Egeria densa). The plant was first detected in 2009 and has since spread. In 2012, the western cove had several separate patches of Brazilian waterweed. This year, 2013, these patches have coalesced across nearly the entire cove. The large patch of Brazilian waterweed that was found in the southern portion of the lake in 2012 now reaches the southeast shoreline. The patch along the northwest shore has also increased since 2012 and extends along the entire northern shoreline, as well as reaching across the opening of the western cove. The increase in the coverage found the plant growing in deeper water than all previous years. Brazilian waterweed was found on 60 percent of the transect points this year, compared to only 40 percent in 2012.

The presence of the natives coontail (Ceratophyllum demersum), snailseed pondweed (Potamogeton bicupulatus), small pondweed (Potamogeton pusillus), and humped bladderwort (Utricularia gibba) have decreased from last year. The invasive minor naiad (Najas minor) was present in a few more patches than were found in 2012. While there are 17 native species present in the lake, Brazilian waterweed is the most dominant and it has been increasing in coverage each year.

Other Fence Rock Surveys: 2021, 2019, 2017, 2016, 2012, 2011, 2010, 2009