Changes in aquatic communities resulting from interactions between climate change and invasive aquatic plants in the Adirondacks.
Thu, 02/09/2012 - 11:26
Abstract: Global climate change can act synergistically with invasive species leading to shifts in ecosystem structure and function. We assessed how a rise in water temperature influenced the potential competitive advantage of an invasive aquatic plant, Eurasian watermilfoil, (Myriophyllum spicatum) over a co-occurring native species northern watermilfoil (M. sibiricum). We also examined the interrelationship between water temperature, watermilfoil, and the aquatic ecosystem including periphyton growth and zooplankton abundance. The study was conducted using replicated mesocosms (3785-liter), with water heaters used to provide a range of temperatures. We found that increasing water temperature promoted the likely competitive advantage of the invasive species, M. spicatum: Survival of M. sibiricum plants was lower than that of M. spicatum across all temperature treatments with a mean survival rate of 24% and 96% respectively. M. sibiricum also showed significantly slower rates of plant growth (mean growth of 3.3 cm compared to 7.6 cm for M. spicatum) and reduced vigor compared to M. spicatum, with an average of less than half the number of growing meristems. Zooplankton densities averaged over 20 times higher in mesocosms with M. sibiricum compared to those with the invasive M. spicatum. Periphyton biomass was best explained by water temperature with an increase in growth in warmer water. Our study confirms that in the face of global climate change, the invasive M. spicatum will continue to exert dominance over its native counterpart. Our results also provide compelling evidence that the combined effects of climate change and invasive aquatic plants can dramatically alter aquatic ecosystems.
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Major: Environmental Sciences, Fisheries and Wildlife Science, Forestry, Natural Resources Management and Policy
File Attachments: Climate change and milfoil draft FINAL.doc