Research in the Fridley Lab at Syracuse University concerns the ecology of plant communities, including their organization, their distribution, and their control over ecosystem processes. Much of our work is performed in the context of species invasions and environmental change, using approaches that span from genetics and physiology to climatology, landscape ecology, and biogeography. 

Plant invasions in a global floristic context

The Syracuse Shrub Garden includes over 75 species of native and non-native forest understory shrubs, replicated in three blocks and covered with shade cloth over the growing season to simulate an understory environment. The collection is the basis of annual monitoring of growth phenology, leaf and root function, and pest and disease dynamics. The introduction and spread of plant species to areas distant from their native ranges is a complex biological process that gets to the heart of how plant communities are assembled. It is also a phenomenon of great public importance, given the economic and environmental ramifications of wholesale changes to ecosystems caused by aggressive invader species. We seek to understand properties of ecosystems that make them susceptible to invasion and properties of species that make them invasive.
A focus of this project is a large group of shade-tolerant, forest understory shrubs spreading throughout the Eastern Deciduous Forest of North America. Most of these species are native to East Asia but have close relatives in the Eastern U.S. flora, and our aim is to understand basic differences in the biology of these groups. We have established a common garden at Syracuse (above) that has provided material for a range of studies, including their phenology and ecophysiology.

Vegetation response to climate change

North-temperate ecosystems are expected to warm considerably over the coming century, which may force large shifts in the composition and functioning of terrestrial vegetation. The Fridley lab, with colleagues at the University of Sheffield (UK), directs one of the longest running manipulations of temperature and precipitation on a steep daleside in northern England. Established in 1992, the Buxton Climate Change Impacts Lab has demonstrated that some ecosystems may be relatively resistant to climate forcing. Current studies are focused on whether such resistance stems from 1) high fine-scale substrate heterogeneity, 2) dispersal limitation of potential invasive species, or 3) the capacity of existing populations to evolve quickly in response to new climate regimes. The Buxton Climate Change Impacts Lab, a long-term manipulation of temperature and rainfall in species-rich grassland in Derbyshire, UK. Support from the National Science Foundation has enabled over two decades of monitoring of how climate shifts will influence the diversity and productivity of grassland ecosystems, which account for a large portion of global agricultural production. Photo: A.P. Askew.

Biogeographic patterns of forest succession

One of six experimental locales of the Succession across Latitudinal Gradients Network (SLaGNET), adjacent to Hutcheson Memorial Forest in central New Jersey. Along with sister experiments in Syracuse, Millbrook (NY), Duke Forest (NC), Athens (GA), and Tallahassee (FL), this study involves growing 'northern' and 'southern' old field communities across a soil gradient. Once established, the communities are sown with early successional tree seeds to determine how fast trees can invade old fields.
Across the Eastern U.S., old fields of former crop and pasture lands revert to forests in a pattern of plant succession that has been well described for over a century. In a research collaboration with Justin Wright's lab at Duke University, we're exploring a novel biogeographic perspective in succession research that suggests the rate at which woody species colonize and dominate old fields decreases with latitude. With NSF support, we've established an experimental network of six research sites from Syracuse to northern Florida to identify whether faster rates of succession in the South are linked to a warmer climate, poorer soils, or differences in the competitive abilities of old-field herbaceous and pioneer woody species across latitudes.

Topographic drivers of montane vegetation dynamics

Great Smoky Mountains National Park in the Southern Appalachians has been a hotbed of ecological research for over half a century, in part due to its extreme topographic gradients that underlie what R.H. Whittaker called "the most complex vegetation in North America". In work now headed up by Mark Lesser in the lab, we are using decades of plant distribution data with our distributed ground-level meteorological network to address how topography interacts with regional climate to drive plant community dynamics. This involves monitoring of the vegetation (e.g., tree ring analyses) and environment (temperature, soil moisture, nutrient probes) across fine-scale spatial gradients.
The Carlos Campbell overlook in Great Smoky Mountains National Park, on a rainy day in April. Our work over the past decade has established the Great Smoky Mountain Temperature Network, a set of Ibutton sensors distributed throughout the Park that has since been expanded to include soil moisture and nutrient availability (PRS probes). Steep vegetation gradients appear to be strongly associated with extreme environmental heterogeneity, especially those associated with cove-to-ridge transitions.

Biodiversity dynamics: scale and function

Limestone grassland in Cressbrookdale, Derbyshire (UK), the basis for some of our work relating intra-specific genetic diversity to grassland community dynamics. 
We have long standing interests in the causes and consequences of plant diversity, using experimental and survey-based approaches. For example, past research using experimental microcosms has established links between the local genotypic diversity of limestone grassland species and rates of pasture productivity. Most of the plants of this community are obligate outbreeders that display considerable local variation, much of which has been shown to have a genetic basis. We have shown that such differences between individuals are an important driver of the overall biodiversity of this ecosystem.

We also have interests in the measurement and interpretation of survey-based plant diversity data. Patterns of biodiversity—such the number of species in a given area—are scale-dependent, meaning that their shape depends on the spatial grain and extent examined. As a consequence, many of the most well-studied patterns in ecology—such as species-area and species-time curves, species-abundance distributions, measures of beta diversity, diversity-environment relationships—all take on different functional forms when examined in small vs. large areas (or over small vs. long durations), and will thus defy generalization until researchers can account for scale sensitivity. We are particularly interested in how the distribution of plant diversity at ‘fine' scales (e.g., vegetation plots) reflects the distribution of diversity at much broader scales (such as a state or continent). Hyperdiverse longleaf pine savanna from the North Carolina coastal plain.