East African cichlid fishes:

African cichlid fishes are one of the world’s most remarkable examples of the evolution of biodiversity through a process known as adaptive radiation — the rapid formation of numerous ecologically divergent species. We use genomic tools to study fundamental questions about the evolution of biodiversity in East African cichlids. This work is currently supported by the National Science Foundation. Postdocs Chad Brock and Liz Mandeville, and PhD student Jimena Golcher-Benavides work on this project. We also continue to work together with with long-term collaborators at EAWAG in Ole Seehausen’s group. Our fish room allows us to bring a little bit of East Africa right to the University of Wyoming.

Linking genomics with environmental change:

Genomic data provide tremendous opportunity for studying population-level differences backwards in time, as well as spatial differences among current populations. We are using genomic data to study the origins and population biology of two groups of non-cichlid fishes in Lake Tanganyika: endemic relatives of the Nile Perch (Lates spp.) and the endemic clupeids  Stolothrissa and Limnothrissa. All of these fish are crucial components of the fishery in Lake Tanganyika that provides food to the millions of people living around Lake Tanganyika. Using genomics, we are looking for evidence of how their populations have fluctuated in size through time, when they originated in the 9-12 million year old lake, and how their current populations are structured spatially across this 600-km long ecosystem. This work has implications for understanding the causes of current population declines and informing management of the fishery, as well as generating foundational knowledge about the biology of these unique species. PhD student Jessica Rick leads the work on Lates, and has received funding from a number of sources to support her work. The work on the clupeids began as a project funded by The Nature Conservancy together with Pete McIntyre (University of Wisconsin), and now is a collaboration that includes Ole Seehausen and Bernhard Wehrli at EAWAG in Switzerland, funded by the Swiss National Science Foundation.

Evolutionary perspectives on ecological stoichiometry:

All organisms depend on nutrients in the environment to survive, and contribute nutrients to the environment during life and death. Organismal function can shift environmental nutrient balances, with important consequences for ecosystem functioning, and likewise nutrient availability in the environment can constrain and restrict what kinds of organisms can live in given environments. This interplay between organisms and the environment in studying the balance of nutrients underlies the theory of ecological stoichiometry. The Wagner Lab is part of a large multi-institute collaboration focused on Stoichiometric Traits of Organisms In their Chemical Habitats (STOICH), an project funded by NSF EPSCoR. In particular, or role in the project is to study have evolution interacts with ideas in ecological stoichiometry — how have stoichimetric traits in organisms evolved over macroevolutionary timescales, and how has this influenced organismal diversity and the functioning of ecosystems? How does this framework for the evolution of stoichiometric traits influence processes in community assembly? We will use datasets from a variety of taxa to address these questions. This project involves close collaboration with Amy Krist at the University of Wyoming and Eric Moody at Middlebury College, as well as other STOICH project investigators Jessica Corman, Hal Halvorson and others. Check out the STOICH project website for more information.

Wyoming biodiversity:

Yellowstone Cutthroat Trout

Rainbow trout (Oncorhynchus mykiss) have been widely introduced across the world, and in some locations hybridize with native trout. In the Wagner Lab, postdoc Liz Mandeville and MS student Will Rosenthal worked on this project together with Annika Walters (University of Wyoming) and Jason Burckhardt (Wyoming Game and Fish). We are studying hybridization between native Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) and rainbow trout in the North Fork Shoshone River drainage near Cody, Wyoming. This work is funded by the Wyoming Game and Fish Department.

In 2021, we started work on a large collaborative project to better understand range wide genetic diversity, connectivity, and history of the Yellowstone cutthroat trout. This work involves close collaboration with researchers in Idaho, Wyoming, and Montana, and has received funding from the Wyoming Game and Fish Department, the Western Native Trout Initiative, Jackson Hole One Fly, Jackson Hole Trout Unlimited, and the Greater Yellowstone Conservation Commission. PhD student Will Rosenthal leads the Wagner Lab work on this project.

Community Assembly in Alpine Lakes of the Wind River Range

The interactive effects of top down (fish) and bottom up (nutrients) controls on aquatic biodiversity are poorly understood, particularly in alpine lake environments. Alpine lakes are generally nutrient poor, young ecosystems that post-date the retreat of Pleistocene glaciers. To support a recreational fishery, fish, primarily salmonids, were introduced to hundreds of alpine lakes in Wyoming’s Wind River Range, starting in the nineteenth century and continuing in some places until today. Furthermore, a wind-driven phosphorus (P) gradient across the mountain range leads to variation in bottom-up nutrient supply to these ecosystems. Katie Wagner in collaboration with Annika Walters and Amy Krist  are using this natural and human-caused “experiment” to study the top-down and bottom-up controls on ecological community assembly in alpine lake ecosystems. This work is currently funded by the Biodiversity Institute at the University of Wyoming. We are enjoying a chance to do some local fieldwork!