Welcome to the Fridley Lab at Syracuse University. Research in our lab concerns the ecology of plant communities — their organization, their distribution with respect to the environment, and their control over ecosystem processes. Current topics of active research include:

The dynamic geography of plant diversity: scaling diversity in space and time

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). Current research involves how to identify statistical constraints on diversity (e.g., at fine scales when diversity is constrained by a lack of individuals), and constructing a general theory of species-area curves based on statistical constraints, environmental variance, and dispersal processes.  
Hyperdiverse longleaf pine savanna from the NC coastal plain.

Related publications:

Fridley, J.D., Peet, R.K., van der Maarel, E., and Willems, J.H. 2006. Integration of local and regional species-area relationships from space-time species accumulation. The American Naturalist 168:133-143.

Fridley, J.D., Peet, R.K., White, P.S., and Wentworth, T.R. 2005. Connecting fine- and broad-scale species-area relationships of Southeastern U.S. flora. Ecology 86: 1172-1177.

Ecosystem consequences of plant diversity: from genes to species


Limestone grassland of Cressbrookdale, Derbyshire, UK. 		  Modern ecology has seen the study of biodiversity broadened from investigations of its causes (how ecosystem properties and local biota drive diversity) to consideration of biodiversity's consequences — e.g., are more diverse ecosystems more productive or more stable than similar but less diverse systems? The question has important implications for the management of both natural and managed plant communities, which in some circumstances are seeing rapid declines in biodiversity (due to eutrophication, for example) and in others at least temporary increases due to species invasions.

Much past research on ecosystem effects of plant diversity has been conducted at the species level, but there is increasing interest in the genetic level with the recognition that plant populations harbor surprising levels of genetically-derived phenotypic differences within small areas. With support from the National Science Foundation, experimental studies in our lab in collaboration with Phil Grime from the University of Sheffield (UK) are establishing links between the local genotypic diversity of eight species of limestone grassland and the long-term productivity of this pasture ecosystem. Two long-term experiments established in Sheffield in 2004 seek to understand how such levels of genetically-controlled polymorphisms are maintained in a small local area (all genotypes are derived from a 10 x 10 m quadrat), and the relative importance of species and genetic diversity in maintaining productivity in the face of spatial and temporal environmental heterogeneity.

Details of the Sheffield limestone grassland experiments are available online.

Related publications:

Fridley, J.D., Grime, J.P., and Bilton, M. Genetic identity of interspecific neighbours mediates plant responses to competition and environmental variation in a species-rich grassland. Journal of Ecology, in press.

Fridley , J.D. 2003. Diversity effects on productivity in different light and nutrient environments: an experiment with communities of annual plants. Journal of Ecology 91: 396-406.

Fridley , J.D. 2002. Resource availability dominates and alters the relationship between species diversity and ecosystem productivity in experimental plant communities. Oecologia 132: 271-277.

Fridley , J.D. 2001. The influence of species diversity on ecosystem productivity: how, where, and why? Oikos 93: 514-526.

Huston, M.A., Aarssen, L.W., Austin, M.P., Cade, B.S., Fridley , J.D., Garnier, E., Grime, J.P., Hodgson, J., Lauenroth, W.K., Thompson, K., Vandermeer, J.H., and Wardle, D.A. 2000. No consistent effect of plant diversity on productivity (Technical Comment). Science 289: 1255a.

Plant distributions and the environmental template: which factors, which scales?

Plants communities are composed of individuals endowed via natural selection to respond to cues from their immediate environment—cues that are controlled by climatic and geologic processes but modified by neighboring plants. Much of the history of plant ecology has been to understand which environmental cues plants respond to (such as temperature, root-available water and nutrients, and other indirect factors like salinity and soil pH), the extent to which different individuals and species vary in response to these cues, and how neighbors modify the distribution of such factors. In our era of rapid environmental change from global climate warming, pollution, eutrophication, fragmentation, and homogenization from invasive species, it is increasingly crucial to identify the key parameters influencing species distributions and thus how communities and ecosystems are expected to change over the coming decades. Unfortunately, only in rare circumstances are such parameters known in any detail; for the vast majority of plant species it remains unclear how populations will respond to changes in, e.g., temperature, water, and soil chemistry.

The Fridley lab has been involved in an ongoing study of vegetation-environment relationships of Great Smoky Mountains National Park (GSMNP). Building on decades of past vegetation research in the Smokies, we've assembled the first vegetation and environment databases for GSMNP, for the purposes of linking plant species distributions to environmental and historical factors (such as logging and settlement). A major part of this project has been the establishment of the Smokies Temperature Network, a 175+ datalogger array of ground-level temperature loggers deployed to construct high resolution (10m) maps of daily temperature for the >2000 sq. km park. Temperature maps will allow new analyses of species distributions with respect to current and potential future climates. With ongoing plant community surveys in various locales in GSMNP, we also seek to understand how plant communities are assembled at multiple scales with respect to the environment and biotic interactions.  
Northern hardwood forest along the Noland Divide Trail.

Related publications:

Fridley , J.D. High-resolution, large-extent mapping of ground-level temperature over complex terrain in the Great Smoky Mountains (NC, TN, USA). [In preparation]

Peet, R.K., Fridley , J.D., and Gramling, J.M. 2003. Variation in species richness and species pool size across a pH gradient in forests of the Southern Blue Ridge Mountains. Folia Geobotanica 38: 391-401.

Plant invasions: where and why do species invade?

Ongoing invasion of the grass Microstegium vimineum into NC piedmont forests.   The introduction and spread of plant species to areas distant from their native ranges is a fascinating, complex ecological 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 particularly aggressive invader species. We seek to understand properties of ecosystems that make them susceptible to invasion and properties of species that make them aggressive invaders. This is an area of research that is highly evolving, and by necessity we address invasion questions on scales ranging from small experimental studies to biogeographic surveys.

Related publications:

Fridley, J.D., Stachowicz, J.J., Naeem, S., Sax, D.F., Seabloom, E.W., Smith, M.D., Stohlgren, T.J., Tilman, D., and Von Holle, B. The invasion paradox: reconciling pattern and process in species invasions. Ecology, in press.

Fridley, J.D., Qian, H., White, P.S., and Palmer, M.W. 2006. Plant species invasions along the latitudinal gradient in the United States: comment. Ecology, in press.

Bruno, J.F., Fridley, J.D., Bromberg, K.D., and Bertness, M.D. 2005. Insights into biotic interactions from studies of species invasions. In: Sax, D.F., Gaines, S.D., and Stachowicz, J.J., eds. Exotic species, bane to conservation and boon to understanding: ecology, evolution, and biogeography. Sinauer, Sunderland , MA .

Fridley, J.D., Brown, R.L., and Bruno, J.F. 2004. Null models of exotic invasion and scale-dependent patterns of native and exotic species richness. Ecology 85: 3215-3222.

Brown, R.L. and Fridley, J.D. 2003. Control of plant species diversity and community invasibility by species immigration: seed richness versus seed density. Oikos 102: 15-24.