Gregory-Eaves Lab

Advancing our understanding of the structure and functioning of shallow lakes and littoral zones

 



Photo: Jennifer Barrow

Historically, freshwater biologists have focused on deep, open-water ecosystems; yet small, shallow water bodies dominate the landscape and are hotspots of biodiversity. Recent research on shallow lakes has identified nonlinear dynamics in water clarity associated with abrupt changes in macrophytes. However, these conclusions are based on the results from a limited number of lakes. To evaluate the prevalence of nonlinear dynamics in shallow lakes of eastern North America, my group has developed quantitative inference models that can be applied to sediment records with the goal of developing needed time series (Vermaire et al. 2011). Application of our models has shown that sediment core inferences were coherent with independently-collected historical data (Vermaire et al. 2013). Additionally, we have shown across ~40 Quebec lakes that the proportion of macrophyte-dominated lakes decreased from 80 to 43% over the past ~150 years (Vermaire et al. 2012). We would predict that these changes in macrophytes will substantially impact lake food webs as we have demonstrated that macrophyte abundance is a significant predictor of food chain length (Ziegler et al. 2015; Ziegler et al. in revision). More work is needed to develop continuous sediment core records and identify the prevalence of critical transitions – we are part of a working group trying to advance this issue. We are also now in the midst of conducting experimental pond research to better understand the mechanisms and food web dynamics associated with ecosystem degradation and recovery. Finally, we are conducting literature syntheses and field surveys of large reservoirs to generate a quantitative perspective of the ecological impact of reservoir creation and management (Turgeon et al. accepted; Elchyshyn et al. in revision). In particular, we are studying the effects of winter water-level drawdowns (a common practice associated with hydropower generation and flood control) on the littoral zone and ecosystem-wide interactions mediated through benthic-pelagic coupling.

Last update: Oct. 27, 2016