Ecosystem Services in Agricultural Landscapes
In 2014, the World Resources Institute Report (WRIR) stated that society must produce far more food, and quickly, while also reducing environmental impacts. Our lab is examining how prairie restoration on marginal lands of conventional farms can help address this issue at a local scale by providing ‘ecosystem services’. In collaboration with ALUS Canada, we are looking at the role of prairie strips in, 1) providing habitat for arthropods thus promoting diversity in agroecosystems, 2) serving as a soil carbon sink/storage, and 3) impeding nutrients from synthetic fertilizers (especially nitrogen and phosphorus) from leaching into ground and surface waters.
Global Drivers of Species Invasions
Evidence linking invasion to the suppression of native diversity is equivocal. Local studies often describe negative associations between native diversity and invasion via competition, while regional studies often report habitat-mediated positive associations (the ‘invasion paradox’). Using standardized multi-scale data from grasslands across the planet, this research tests how regional and local processes including human disturbances can be reconciled to explain the likely origins of the invasion paradox (a Nutrient Network project, https://nutnet.org).
Drivers of Fish Diversity
Species occurrence and diversity is regulated by a complex network of scale-dependent processes. Using a dataset comprised of fish species, lake characteristics, and isolation measures for hundreds of lakes in Ontario, Sweden, and Japan, we are working on teasing apart the relative importance of biotic and abiotic factors. We are also using a large dataset of aquatic monitoring data for rivers and streams in southern Ontario to examine similar questions.
Tropical Island Biogeography
MacArthur and Wilson’s classic model synthesizes a range of biogeographical processes to describe the regulation of diversity, but does not account for trophic interactions. We are testing how regional and local factors affect food web assembly in fragmented landscapes, focusing on insect-plant interactions in tallgrass prairie.
The Evolution of Spatial Pattern
Most populations are non-randomly distributed, reflecting interactions between stochastic and deterministic niche-based processes that operate at a range of spatial and temporal scales. Using multi-hectare assembly experiments, we are testing how trophic dynamics, stochastic priority effects, and species sorting drive the evolution of spatial pattern in plant communities.
This long-term study has determined that fire is critical for ecosystem function, but is highly destabilizing for populations of fire-dependent ground flora at local scales. Empirical data are being used to model the non-equilibrium dynamics of this system at local and regional spatial resolutions, illustrating ‘a tale of two stabilities’ defined by whether fire is present or continually suppressed (with Dr. Kevin McCann).
Rodent Plagues on Prairie Diversity
Small mammals influence diversity in many of the world’s grasslands by selecting against palatable plants – the community can become dominated by the plants they mostly avoid. We are exploring how global environmental changes relating to plant invasion, trophic collapse, eutrophication, and habitat fragmentation may be magnifying the intensity of these ‘rodent plagues’, and the implications for ecosystem function including primary production and soil carbon dynamics (Head PI: Stefan Schneider).
Rarity is associated with vulnerability to extinction, yet most of the world’s biological diversity is relatively uncommon in the systems where they occur. Rarity can be stabilized by a range of demographic processes that function within and across trophic levels, but many of these processes are being transformed by anthropogenic disturbances. This research explores whether stabilizing mechanisms persist despite disturbance or whether the likelihood of ‘extinction debts’ are increasing (with Drs. Ben Gilbert and Cort Griswold).
Field sampling locations