Joshua B. Grinath, Ph.D.
Visiting Assistant Professor
Community and Global Change Ecology
Office: Life Sciences 420 & 421
My research addresses broad questions about the processes that determine ecological community structure and ecosystem functioning. Specifically, I am interested in understanding how drivers of global change such as atmospheric pollution, climate change and species invasions, restructure communities and impact ecological dynamics from plants to predators. My work primarily occurs in grassland ecosystems that include plants and animals of conservation concern and that provide vital ecosystem services to humans. Using field experiments and modeling, I study systems that contain multiple types of species interactions, such as predation, mutualism, and ecosystem engineering. While many ecologists study ecological networks composed of single types of species interactions, for example food webs or mutualistic webs, most ecological systems are composed of multiple interaction types that must be considered together to fully understand the consequences of global change. Overall, my goal is to conduct research that is relevant to managing current and future environmental challenges and that can inform conservation efforts.
One of my primary research goals has been to understand how atmospheric nitrogen (N) deposition and the cascading effects of predators restructure a plant-arthropod community in a Colorado sagebrush steppe ecosystem. Through field experiments and network analysis, I discovered that ant-eating black bears indirectly benefit plants by suppressing an ant-herbivore mutualism, which should be considered in the management of bears. However, I also found that simulated low-level N deposition weakens this cascade of effects, which suggests that current widespread rates of N deposition have altered resource versus consumer control of ecological structure in other ecosystems as well. I have maintained this N manipulation for ten years now and plan to revisit the experiment to assess the long-term repercussions of low-level N deposition. This project provides a unique opportunity to not only assess the effects of chronic N deposition on plants, like most previous studies, but on animals and plant-animal interactions.
I have also conducted research on how an annual grassland community in California is structured by precipitation and a dominant, burrowing herbivore – the federally endangered giant kangaroo rat. I led studies on the ecosystem engineering effects of these rodents on soil properties (soil moisture and N dynamics) and plant-arthropod communities. Recently, I have used a combination of field experiments and herbarium records to study ‘cedar glade’ grassland responses to climate change, invasive insects, and restoration efforts.
My future research will focus on understanding how the combination of changes in N deposition and climate impact plant-animal communities and ecosystem functioning, particularly in sagebrush steppe. Plant growth is commonly limited by both N and water availability and responds synergistically to simultaneous changes in these resources. However, animal responses to these dynamics are poorly understood, as are the repercussions for ecosystem functioning.
Please see my personal website (jbgrinath.wordpress.com) for further details.
BIOL 1102 Biology II
BIOL 2209 General Ecology
BIOL 3316 Biometry Laboratory
2014 Ph.D. Ecology & Evolution, Florida State University, Tallahassee, FL
2004 B.S. Natural Resource Management & Applied Ecology, Cornell University, Ithaca, NY
My work is motivated by a deep desire to understand the impact that humans are having on the natural environment. Growing up in rural Maryland, I saw the woodlands and fields of my youth transform into housing developments, watched the growth of the nutrient-induced ‘dead zone’ within the Chesapeake Bay, and witnessed forests become infested with exotic pests. Determined to learn about the ecological consequences of such changes, I went to Cornell University to study Natural Resource Management and Applied Ecology. In 2004, I became a first-generation college graduate, with a B.S. degree and Distinction in Research based on my studies of the ecological repercussions of invasive water chestnut in New York waterways. I then went to work as a research assistant at the Rocky Mountain Biological Laboratory in Colorado, where I studied mutualistic interactions between ants and bugs in sagebrush meadows. Using the wealth of natural history knowledge that I gained in Colorado, I next attended graduate school at Florida State University to study the community-level effects of mutualistic interactions and how ecological dynamics are affected by nitrogen pollution, which was funded by a fellowship from the US Environmental Protection Agency. I graduated with my Ph.D. in 2014 and then held two postdoctoral positions (University of Colorado Boulder; Middle Tennessee State University) during which I studied how changes in climate impact ecological communities in California annual grasslands and cedar glade grasslands of Tennessee. I joined ISU’s biology faculty as a Visiting Assistant Professor in August, 2019 and am excited to continue research in the Intermountain West.
Please see my personal website (jbgrinath.wordpress.com) for my updated CV.
Grinath, J. B., L. Larios, L. R. Prugh, J. S. Brashares, & K. N. Suding. (2019) Environmental gradients determine the potential for ecosystem engineering effects. Oikos 128:994-1004. https://doi.org/10.1111/oik.05768
Griffith, K. A.*, & J. B. Grinath*. (2018) Interactive effects of precipitation and nitrogen enrichment on multi-trophic dynamics in plant-arthropod communities. PLoS ONE 13(8):e0201219. https://doi.org/10.1371/journal.pone.0201219
*These authors contributed equally to this work
Grinath, J. B. (2018) Short-term, low-level nitrogen deposition dampens a trophic cascade between bears and plants. Ecology and Evolution 8:11213-11223. https://doi.org/10.1002/ece3.4593
Grinath, J. B., N. Deguines, J. W. Chesnut, L. R. Prugh, J. S. Brashares, & K. N. Suding. (2018) Animals alter precipitation legacies: trophic and ecosystem engineering effects on plant community temporal dynamics. Journal of Ecology 106:1454-1469.
Prugh, L. R., N. Deguines, J. B. Grinath, K. N. Suding, W. T. Bean, R. Stafford, & J. S. Brashares. (2018) Ecological winners and losers of extreme drought in California. Nature Climate Change 8:819-824. https://doi.org/10.1038/s41558-018-0255-1
Grinath, J. B., B. D. Inouye, & N. Underwood. (2015) Bears benefit plants via a cascade with both antagonistic and mutualistic interactions. Ecology Letters 18:164-173