On July 21st we conducted a plant survey on the lake utilizing the PIRTRAM method. PIRTRAM (Point Intercept Rake Toss Relative Abundance Method) can be used to 1) relatively quantify the community composition, 2) investigate presence and absence of certain species, and 3) evaluate the extent of invasion when dealing with exotic plants.
The method calls for a metal double-sided rake to be thrown three times (in three different directions off either the stern or the bow) at predetermined points. These points can be selected randomly by the computer; however, as in this study, it is important to take previous studies and the depth into consideration when selecting site locations. Many rooted- submersed plants can grow at a range of depths depending on the light availability and sediment type. There have been plant surveys conducted by the NYSDEC in the past which influenced the selection of sites.
Two college students working with the Region 1 NYSDEC, Nick and Jordan, helped out with the survey. They were a huge help! Both threw rakes and I identified the plants that they "caught". Previous records show that the majority of the plant community is made of invasive plants, Hydrilla and Eurasian Watermilfoil. Not surprisingly, that is what we also found. The Hydrilla appeared to be just starting to grow; we found several dense patches of the plant, but most of the individual stalks were less than 6 inches tall. We did encounter some variety which included a naiad, filamentous algae, pondweed, and bladderwort species. The relative abundance methods used in this survey and by the NYSDEC can tell us how the plant community changes over the summer growing season.
The following weekend, I returned to the lake to collect water samples to continue the monitoring of nitrogen and phosphorus in the lake. We were joined by Sandra, a local resident who loves the lake and was walking around it taking in the sights. It was lovely having her aboard and help out with the monitoring protocol. We took a temperature, pH, and dissolved oxygen profile of the water column at the deep hole. The oxygen dropped significantly below 4 meters. After some technical difficulties, we collected water samples in 2 meter increments from the surface down to the bottom (around 16 meters). Secchi was 1.5 meters, the transparency decreased slightly since my last visit in June. We also collected zooplankton!
July was Lake Appreciation Month! Loved visiting and sampling during this month!
