Ranjan Muthukrishnan

Current Research

Ecosystems across the globe are facing a myriad of potential stressors including habitat fragmentation, nutrient loading, the translocation of exotic species, and shifting climate conditions. These global changes have the potential to dramatically restructure communities and ecosystems, disrupting their economic and social value to human society as well as the intrinsic value of those natural communities.

We study the dynamics of major shifts in ecological communities, particularly in the context of anthropogenic influences on natural systems, and the factors that make ecosystem more resilient to those stresses. Because ecological communities are fundamentally complex systems, to understand their dynamics we use a combination of observational studies, manipulative experiments, and theory development, which we synthesize through computational models of those systems. Integrating empirical and theoretical methods is the best way to make progress in understanding complex systems because it provides the opportunity to understand the network of interconnected processes that control real ecosystems and evaluate the emergent properties of systems as a whole.

We conduct research in a variety of systems from coral reefs to lakes, grasslands, and agroecosystems and on a variety of basic and applied questions. Some examples include studying the effects of various anthropogenic stresses on transitions between coral-dominated and algal-dominated reefs, the spread and impacts of an invasive seagrass (Halophila stipulacea) in the Caribbean and an invasive freshwater alga (Nitellopsis obtusa) in Midwestern lakes, and analyzing continental to global scale plant diversity data to understand macroscale drivers of community structure. We also collaborate with social scientists and regional, state, and tribal resource managers to design and implement community supported ecosystem management plans.

Selected Publications

• McCumber A., A. Sullivan, M.K. Houser, and R. Muthukrishnan (2023). Are lakes a public good or exclusive resource? Towards value-based management for aquatic invasive species. Environmental Science and Policy 139:130-138.
• Muthukrishnan R., K. Hayes, K. Bartowitz, M. Cattau, B. Harvey, Y. Lin, and C. Lunch. 2022 Utilizing NEON to evaluate tipping points across ecosystems in space and time. Ecosphere 13: e3989.
• Muthukrishnan R., L. Sullivan, A.K. Shaw, and J.D. Forester (2020). Plasticity in seed production alters the range of possible coexistence conditions in a competition-colonization trade-off. Ecology Letters 23:791-799.
• Muthukrishnan R., K. Chiquillo, C. Cross, P. Fong, T. Kelley, C. A. Toline, and D. Willette (2020). Little giants: A rapidly invading seagrass alters ecosystem functioning relative to native foundation species. Marine Biology 167:1-15.
• Muthukrishnan R. and D.J. Larkin (2020). Invasions and biotic homogenization in temperate aquatic plant communities. Global Ecology and Biogeography 29:656-667.
• Shoemaker L.G., L.L. Sullivan, I. Donohue, J.S. Cabral, R.J. Williams, M.M. Mayfield, J.M. Chase, C. Chu, W.S. Harpole, A. Huth, J. HilleRisLambers, A.R.M. James, N.J.B. Kraft, F. May, R. Muthukrishnan, S. Satterlee, F. Taubert, X. Wang, T. Wiegand, Q. Yang, and K.C. Abbott (2020). Integrating Stochasticity into Community Ecology. Ecology 101:e02922.
• Muthukrishnan R., N. Hansel-Welch, and D.J. Larkin (2018). Environmental filtering and competitive exclusion drive biodiversity-invasibility relationships in Minnesota lakes. Journal of Ecology 106:2058-2070.
• Muthukrishnan R., J.O. Lloyd-Smith and P. Fong (2016). Mechanisms of resilience: Strong positive feedbacks produce alternate stable states dynamics on a tropical reef. Journal of Ecology 104:1662-1672.