I am an ecosystem scientist and limnologist who studies how disturbances and lake management drive changes in ecosystem function mediated by food webs. I seek to advance our adaptive management capabilities in the face of increasing disturbances driven by climate change. My research uses experimental ponds, natural experiments, food web modeling, and long-term data to address my research questions.

​Below is a brief overview of my current research! 

What are the drivers of bigheaded carps movement in the Upper Mississippi River? 

Bighead carp and silver carp, or bigheaded carps, are invasive species adversely affecting ecosystem health and the economies of communities along the Upper Mississippi River. Ongoing control methods include active removal and installed barriers or deterrents at the various locks and dams that characterize the upper Mississippi River. Modeling efforts to better understand the invasion front have so far relied on assuming movement rates across a population, yet only a few individuals with long distance movements can drive overall population dynamics. Through collaboration with Richie Erickson, Aaron Cupp, Andrea Fritts, and others we are using a large telemetry network to develop an individual based model for bigheaded carp movement.

How do successive species invasion impact the lower food web? 

Consequences of spiny water flea and zebra mussel invasion on the planktonic food web

​Invasive species have many well-known impacts on aquatic ecosystems that negatively impact native species and water quality. Spiny water flea negatively affect zooplankton and zooplanktivores and zebra mussels can filter large volumes of water severely reducing energy available for higher trophic levels. However, when multiple species invade an aquatic ecosystem, it is very difficult to predict the potential interactive effects. Through long-term data and small-scale experiments we are working to yield a deeper understanding of how invasive species affect nutrients, water quality, and the lower food web - including microbes! 

This research is ongoing in collaboration with Dr. Jake Vander Zanden and Dr. Trina McMahon with funding from the USGS. Read a three-part series on some of our work this past summer here! Part 1, Part 2, Part 3​

How do food webs mediate disturbances? 

Effects of food web structure on ecosystem resilience of shallow lakes to pulsed nutrient loading

Lakes are experiencing an increase in the frequency and intensity of disturbances due to global climate change. In particular, storms can deliver pulses of nutrients to lakes that may lead to large algal blooms. Lake food web structure may mediate lake resilience to algal blooms following a large storm. I use experimental ponds to investigate how different food web structures mediate ecosystem response to pulse disturbances. Check out our pre-print published on EarthArXiv
 
This research is ongoing in collaboration with Dr. Grace Wilkinson and Dr. Mike Weber with funding from the NSF-GRFP, Iowa DNR, and Iowa Water Center.  

Collaborations​

Impacts of sediment dredging in a large river ​
Sediment dredging can be an effective method to remove contaminated sediments, but doing so is a major disturbance within aquatic ecosystems. I investigate the response of macroinvertebrates and zooplankton to sediment dredging in the Fox River in Green Bay, Wisconsin over four years. This research is ongoing in collaboration with Dr. Carrie Kissman.

How do food web interactions drive ecosystem function?

Seasonal dynamics of zooplankton nutrient cycling in a hypereutrophic reservoir

Hypereutrophic ecosystems are characterized by an overabundance of inorganic nutrients that fuel algal blooms often dominated by toxic cyanobacteria. Recent evidence suggests that key consumers, such as zooplankton, may influence the transformation and flux of nutrients in hypereutrophic lakes. We found that zooplankton contribute to early summer phosphorus availability and influence phytoplankton size structure in a hypereutrophic reservoir​

 This research was in collaboration with Dr. Eric Moody and Dr. Grace Wilkinson with funding from the NSF-GRFP and Iowa DNR. Read more in our open-access paper published in the Journal of Plankton Research. The paper was recently selected for the Cushing Prize which honors the best paper by an under-30 scientist published in the journal that year!

​Collaborations

Eco-evolutionary dynamics in Daphnia 
​Zooplankton traits can vary with lake trophic state, particularly in hypereutrophic ecosystems. Increasing eutrophication of lakes can drive microevolution and alter consumer-resource dynamics. We found that Daphnia pulicaria may have adapted to hypereutrophic conditions by developing a more efficient metabolism and reducing their consumption rate of algae in hypereutrophic lakes. This research was led by Dr. Eric Moody in collaboration with Rachel Fleck, Dr. Punidan Jeyasingh, and Dr. Grace Wilkinson. See more in our publication in Freshwater Biology! ​



The effects of bigmouth buffalo density on shallow lakes
Bigmouth buffalo are large-bodied planktivores inhabiting shallow lakes and slow-moving rivers. However, we know very little about the food web and ecosystem-level effects of lowered bigmouth buffalo density following commercial harvest. We use experimental ponds to evaluate the effects of ambient and harvested bigmouth buffalo densities on algal and zooplankton biomass. This research is led by Dr. Grace Wilkinson and in collaboration with Elena Sandry, Martin Simonson, and Dr. Mike Weber. Read more in our pre-print on Earth ArXiv! 

How do long-term food web dynamics affect ecosystem function? 

Response of food web structure to biomanipulation in shallow lakes

Manipulating food webs by removing species that negatively affect ecosystems can be a powerful solution to water quality issues. Targeted harvests of the benthivore common carp and the planktivore bigmouth buffalo occurred in several Iowa Lakes over three years. By quantifying the sizes of macroinvertebrates, zooplankton, and fish within these lakes I am investigating the degree and magnitude of change in food web structure. Doing so will help inform lake managers of the efficacy of targeted harvest efforts and improve our understanding of how food webs respond to large removals of species. 

This research is ongoing in collaboration with Dr. Grace Wilkinson and Dr. Mike Weber with funding from the NSF-GRFP ​and Iowa DNR.

Long-term dynamics of biomass and energy flux in the Trout Lake pelagic food web

Climatic disturbances such as warming and changes in hydrologic regimes can drive changes in food web structure and alter ecosystem function. As food webs substantially drive the flow of energy and matter within lakes, they play a key role in mediating the effects of disturbances. Investigating biomass turnover and energy flux within food webs over time can inform how ecosystem functions are altered by compounding and interacting disturbances. I use a bioenergetics model to calculate energy flux and mathematical models to infer species interactions to describe changes over two decades in the well-studied pelagic food web of Trout Lake in northern Wisconsin. 

​This research is ongoing in collaboration with Dr. Grace Wilkinson, Dr. Jake Vander Zanden, and Ben Martin with funding from the NSF-GRFP ​and NTL-LTER.

Collaborations

Episodic zooplanktivory in largemouth bass
Largemouth bass are important keystone predators within lakes that feed on a diversity of prey items throughout their life history. However, largemouth bass generally shift exclusively to benthivory and piscivory after reaching 40 - 140 mm in length. Using a 25-year natural history record of largemouth bass diet in Paul Lake we observed at least one episode of zooplanktivory in 26% of individuals, and multiple events in 6% of individuals greater than 150 mm in length. These results demonstrate the individuality of largemouth bass foraging behavior and the variability of feeding interactions in food webs over time. This research was in collaboration with Dr. Jay Hodgson, Dr. Michele Guidone, and Dr. James Hodgson. Read more in our publication in the Journal of Freshwater Ecology