Long-term Lake Level Fluctuations in Wisconsin
I am working with a group of scientists from the University of Wisconsin, Wisconsin DNR, and USGS to link ground-water and climate to understand long-term lake level fluctuations in Wisconsin. Managing water quantity in Wisconsin has become challenging in recent years. The number of high capacity wells has grown rapidly, particularly in the Central Sands. Meanwhile, drought has plagued Northern Wisconsin for the past decade, with the lowest groundwater and lake levels since 1937. There is no question that climate and groundwater withdrawals impact surface waters, but the degree to which groundwater influences lake levels across the state is unknown. Hence, distinguishing the effects of groundwater withdrawal from climate influences on lake levels remains a challenge. This is in large part because the natural hydrologic regime of most lakes in the state is unknown. Similar to a stream, a lake’s hydrologic regime can be characterized in terms of the amplitude and frequency of changing water levels. Although this is a straightforward statistical exercise when data are available, water levels are not monitored on the majority of Wisconsin lakes. This project will develop models using groundwater and climate data to predict historical lake levels and characterize the hydrologic regime of seepage lakes in Wisconsin.
Macrosystems Biology Research in US Lakes Across Space and Time
I am part of an interdisciplinary group of researchers conducting research on cross-scale interactions (CSIs) at sub-regional to continental scales. A CSI exists where a driver at one scale, such as local land use, interacts with a driver at another scale, such as regional climate. These CSIs can lead to nonlinear and often unexpected relationships between drivers and responses.
We use lakes and their major nutrients (phosphorus, nitrogen, and organic carbon) as a model system because lakes are affected by many of the main classes of drivers postulated to be a part of CSIs (e.g., connectivity, land use, and climate), and because there is a wealth of existing data and knowledge from small-scale studies regarding possible mechanisms through which drivers could interact across scales.
We use lakes and their major nutrients (phosphorus, nitrogen, and organic carbon) as a model system because lakes are affected by many of the main classes of drivers postulated to be a part of CSIs (e.g., connectivity, land use, and climate), and because there is a wealth of existing data and knowledge from small-scale studies regarding possible mechanisms through which drivers could interact across scales.
North Temperate Lakes Long-Term Ecological Research Program
I am a Co-PI and Site Manager with the NTL-LTER program. NTL studies the ecology of lakes as one of a network of sites established by the National Science Foundation. We are interested in how geophysical setting, climate, and change land use and cover interact to shape lake charastics and dynamics over time (past, present, future).
Crystal Lake Perch Population Recovery
The introduction and establishment of invasive rainbow smelt in two NTL-LTER lakes has resulted in functional extirpations of formerly naturally reproducing populations of native yellow perch, walleye, and cisco. In 2011, a whole lake manipulation was initiated in Crystal Lake to destratify the lake and increase water column temperatures above the thermal limits of rainbow smelt in an effort to extripate them from the lake (Lawson et al. 2015). Although the mixing effort failed to extirpate rainbow smelt, continued NTL-LTER monitoring of the fish community in Crystal Lake suggests that the effort may have released the remnant native yellow perch population from former constraints imposed by rainbow smelt dominance. In 2017, we observed yellow perch relative abundances approaching levels observed prior to the introduction of rainbow smelt along with clear evidence of multiple age classes of yellow perch present in the lake.
We are studying the current yellow perch and rainbow smelt population, their age/size-structure, and foraging behavior since the mixing experiment. Results from these efforts are likely to provide insights into the factors that led to the potential competitive/predatory release of the native yellow perch population in Crystal Lake and be used to inform food web and species-interactions models. Additionally, these efforts will be critical for LTER and our understanding of the long-term fish community dynamics in Crystal Lake and how they may have unexpectedly changed as a result of the whole lake mixing manipulation.
We are studying the current yellow perch and rainbow smelt population, their age/size-structure, and foraging behavior since the mixing experiment. Results from these efforts are likely to provide insights into the factors that led to the potential competitive/predatory release of the native yellow perch population in Crystal Lake and be used to inform food web and species-interactions models. Additionally, these efforts will be critical for LTER and our understanding of the long-term fish community dynamics in Crystal Lake and how they may have unexpectedly changed as a result of the whole lake mixing manipulation.