Freshwater food webs are among the most altered in the world. Nearly 40% of all freshwater fish in the United States are threatened or endangered. Losses of freshwater fish and other predators can drastically alter the functioning of freshwater ecosystems, but these effects may not be limited to the water.

We study how fish and other predators, like dragonflies, regulate links between water and land by reducing the emergence of aquatic insects. We do this experimentally by combining different kinds of predators in ponds and streams and measuring how ecosystems respond. See pic below for an example, along with some relevant publications.

Actual samples (chironomid midges) from cages with and without fish near the Missouri River. The presence of fish caused a 90% reduction in the number of emerging aquatic insects.
  • Warmbold, JW, and JS Wesner. 2018. Predator foraging strategy mediates the effects of predators on local and emigrating prey. Oikos 127: 579-589.
  • Henning, L. 2018. Direct and indirect effects of larval odonate predation. MS Thesis. University of South Dakota.
  • Wesner, JS. 2016Contrasting effects of fish predation on benthic versus emerging prey: a meta-analysis. Oecologia 180: 1205-1211. (abstract)
  • Wesner, JS. 2013. Fish predation alters benthic, but not emerging, insects across whole pools of an intermittent stream. Freshwater Science 32: 438-449. (pdf)
  • Wesner, JS. 2012. Predator diversity effects cascade across an ecosystem boundary. Oikos 121: 53-60. (abstract)
  • Wesner, JS. 2010. Aquatic predation alters a terrestrial prey subsidy. Ecology 91: 1435-1444. (pdf)