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Native grasslands are imperiled ecosystems. These ecosystems once hosted an enormous diversity of plants, animals, and microbes. The desire to conserve these species and ecosystems has inspired decades of attempts to restore grasslands, often by planting them in former agricultural land and reintroducing fire. However, these post-agricultural restored grasslands often (but not always) differ from untilled remnants in many ways: they lack characteristic species, they support less biodiversity, they differ in the relative abundances and spatial distributions of species, and they suffer from invasive and non-native species. In short, restoration goals (when they are clearly articulated) are not always met, and the outcomes of restoration are not always predictable. Confronting this contingency remains a major challenge for restoration practitioners and restoration ecologists.
With the goal of accurately predicting and shaping the outcomes of prairie restorations, we address issues such as the roles of soil microbial mutualists, genetic and species diversity, seedbanks, historical legacies, invasive species, and management strategies. For example, we are currently collaborating with Dr. Daniel Clemans at EMU to characterize the metagenomes of the soils of both restored and remnant prairies and develop a technique to encourage the growth of beneficial microbes in a "tea" that could be applied in a restoration setting. We are also collaborating with Dr. Jen Lau at Indiana University and Dr. Lars Brudvig at Michigan State University to examine how the genetic diversity of populations sown during restoration can influence ecological and evolutionary outcomes in prairie restorations at the Kellogg Biological Station. Throughout, we seek to enable land managers to assess when, and under what circumstances, they need to worry about particular forces that could determine the end product of their restoration efforts, and what strategies might be most effective in mitigating those destructive forces. |
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Plants engage in many types of mutualisms, including resource mutualisms where the plant exchanges carbon for nitrogen (in the case of legume-rhizobia mutualisms) or phosphorus (in plant-mycorrhizal mutualisms). However, these “mutualisms” can lose their value to plants, or even degrade to parasitism, where resources are abundant or where high-quality partners are absent.
Multi-mutualist effects occur when plants interact simultaneously with multiple partners, and these can be even more difficult to predict. In a new NSF-funded project, we are exploring multi-mutualist effects among prairie legumes, rhizobia, and mycorrhizal fungi to try to a) explain poor legume establishment in restored prairies, b) understand when and where these multi-mutualist effects could enhance establishment of which legumes, and c) produce strains of beneficial soil microbes for use by restoration practitioners. We are collaborating with Dr. Paul A Price at EMU, who is an expert in legume-rhizobium interactions, and Dr. Jonathan Bauer at Miami University in Ohio, who is an expert in plant-arbuscular mycorrhizal fungal interactions in restored and successional environments. |
Beta diversity, or spatial variation in the species that make up communities, is a key component of landscape diversity—one that we understand much more poorly than other measures of biodiversity. Beta diversity can develop when species map onto underlying environmental heterogeneity, so that we see different local communities in different microhabitats. However, beta diversity can also be caused by variation in dispersal, disturbances, drought, or larger landscape considerations such as the number of species in the region. In particular, the identity and abundance of dominant species might affect the development of beta diversity, a hypothesis we are testing in a restored prairie at the Legacy Land Conservancy's Johnson Preserve in Ann Arbor.
This variation in beta diversity and its drivers could also affect the way ecosystems function. Communities with higher beta diversity, or greater abundance of particular dominant species, might perform higher levels of ecosystem functions (such as decomposition, primary production, or N-fixation), and functioning might be more consistent through time. Furthermore, ecosystem multifunctionality (the simultaneous performance of many ecosystem functions) might depend on beta diversity because different species perform different functions and their spatial separation might enhance their ability to function. We are testing the relationships among dominant species, beta diversity, ecosystem function, stability, and multifunctionality in greenhouse mesocosms, our restored prairie at the Johnson Preserve, and a collaborative cross-site synthesis project (CORRE) spearheaded by Dr. Kim Komatsu at the Smithsonian Environmental Research Centre and Dr, Meghan Avolio at Johns Hopkins University. |