Human activities have moved thousands of species around the world, allowing them to establish populations in new places. These non-native species have large effects on biodiversity and ecosystems, cause enormous economic damage, and are one of the most important and least controlled of human impacts on the world's ecosystems. Scientists know that these effects can change through time, but the amount, timing, and nature of these changes are poorly known. This project will continue a long-term study of the changing impacts of the zebra mussel on the Hudson River ecosystem, an ecologically and economically important invasive species that first appeared in the Hudson River in 1991. This study will improve understanding of one of the world's most problematic invaders in aquatic ecosystems, and provide one of very few detailed studies of the long-term effects on a non-native species. The results of this research will continue to be used by government agencies that manage the Hudson River, and should inform management of non-native species in general. Findings will be disseminated by posting research data on open websites, continuing highly successful educational programs to provide data, lesson materials, and training to middle- and high-school teachers and students in the Hudson Valley and New York City school systems, and continuing an active program of public outreach.
The researchers will continue measuring population parameters (density, mortality rates and size structure) and filtration rates of zebra mussels, phytoplankton biomass, zooplankton density and species composition, bacteria production, water quality parameters (transparency and nutrient concentrations) and particulate and dissolved Carbon to answer the following questions: (1) How will the long-term changes in the zebra mussel population and its effects continue to develop? (2) Can these changes be explained by relationships between the size and characteristics of the zebra mussel population and the Hudson River ecosystem? (3) How does zebra mussel grazing interact with climate to shape properties of the Hudson River ecosystem? The researchers will use time series and regression models to explore zebra mussel population dynamics and the relationship between zebra mussel filtration rates and various components of the river food web. In addition they will analyze three interactions between zebra mussel invasion and climate: 1) effects of freshwater flow on zebra mussel grazing, 2) effects of water temperature and mussel grazing on phytoplankton biomass and 3) correlations between warm temperature and inter-annual variation in zebra mussel mortality. Five additional years of data will allow the researchers to document the remarkable changes that are now occurring in the Hudson River, and substantially increase the power of statistical models to describe these events.
