I am interested in behavior, ecological interactions, and how space mediates ecological andevolutionary dynamics. Much of my work occurs where these three themes converge, with a
focus on the conservation of terrestrial plants and mammals. Specifically, I am interested in how
plant-consumer interactions and predator-prey dynamics affect the prospects for long-term
conservation and restoration. To this end, I utilize theoretical, experimental, and observational
approaches: I develop theory to understand novel questions of spatial dynamics, I use a strong
experimental approach to evaluate existing ecological theory, and I use large-scale observational
data to inform conservation and management. I have two main research foci:
Research Focus 1. Spatial mediation of ecological interactions
Apparent competition, vertebrate consumers, and the composition of plant communities.
Invasive plants remain one of the most problematic ecological issues of our time, costing
billions, usurping habitat for native species, and altering ecosystem function. In collaboration
with other researchers, my lab has been evaluating an untested hypothesis of biological invasion:
that exotic species gain an advantage indirectly through their effect on native consumers (i.e.
apparent competition) rather than through direct competition with native species. I have been
particularly interested in understanding the implications of invader-mediated changes in
consumer behavior, such as how changes in consumer behavior can dictate the outcome of
invasions, change the rate of invasion, generate emergent Allee effects, and have implications for
Spatial controls on the conservation and restoration of flora and fauna in longleaf pine
ecosystems. Longleaf pine communities once stretched from Virginia to Texas and are one of
the most diverse ecosystems outside of the tropics; less than 3% remains today. I am part of a
mutli-university collaborative project to conduct a large-scale experimental examination of how
vertebrate consumers, competitors, and propagule limitation constrain the understory plant
communities in longleaf pine savannas. This experiment is replicated in three different states
(North Carolina, South Carolina, and Georgia) and embedded within a larger landscape context
that makes it possible to understand how historical influences (e.g. agriculture), contemporary
land-use practices, and spatial landscape configuration might mediate the ecological forces
affecting conservation and restoration (i.e. consumers, competitors, and propagule limitation).
Specifically, my role in this collaborative effort is to oversee implementation of experimental
treatments to disentangle consumer effects on understory plants.
Large-scale experimental evaluation of conservation corridors. Corridors are linear strips of
habitat that may be promising conservation tools. Yet, examination of corridor studies is often
hindered by the difficulty of performing an experiment at large spatial scales. In collaboration
with the corridor research group (see www.conservationcorridor.org), I am working to
understand whether conservation corridors are essential components of a viable conservation
program, using the first large-scale, replicated experiment designed to test corridor function.
Global variation in the strength of top-down and bottom-up control of grassland
communities. I am one of the 8 core participants and organizers of the Nutrient Network, a
unique examination of consumer- and resource-mediated dynamics in grassland dynamics using
the same experimental protocol across the world. Conceived by Dr. Eric Seabloom and Dr.
Elizabeth Borer at Oregon State University, the nutrient network consists of 60 participants and
45 participating institutions in 10 countries. As one of the core participants, my role in the
nutrient network is to spearhead the consumer-mediated portions of the experimental design, to
assist in the crafting of NSF proposals, and to implement additional experiments to understand
the role of consumers in affecting plant communities.
Research Focus 2. Individual behavior and the consequences of imperfect information
Conservation and anti-predator behavior. Evidence of the importance of anti-predator
behavior in promoting persistence is abundantly clear in island systems, where the introduction
of novel predators is cited as one of the most common causes of the extinction of insular prey. I
am interested in understanding how rapidly the evolution of anti-predator behavior can occur and
how rapidly predator-mediated shifts can propagate through the food web. Recently, I have also
been engaged in collaborative work to understand how changes in rodent populations on islands
can affect the prevalence of diseases that may also affect humans.
Understanding the pervasive and large-scale consequences of fear. Predators can impact
prey dynamics via consuming prey as well as by inducing changes in prey behavior and
morphology (i.e. non-consumptive effects). The consequences of non-consumptive effects can
rival or exceed those of consumptive effects, and may be much more far-reaching than often
thought. I am actively involved in developing theoretical, conceptual, and empirical approaches
to understanding how risk mediates spatial dynamics of a wide array of taxa, and how these nonconsumptive
effects my subsequently alter the potential for conservation and restoration. In
collaboration with Evan Preisser (Univ. Rhode Island), I am conducting a metaanalysis to
understand how body size alters the strength of non-consumptive effects.
Orrock, J. L., and R. J. Fletcher, Jr. In press. An island-wide predator manipulation reveals immediate and long-lasting matching of risk by prey.
Proceedings of the Royal Society B.
Haddad, N. M., L. A. Brudvig, E. I. Damschen, D. M. Evans, B. L. Johnson, D. J. Levey, J. L. Orrock, J. Resasco, L. L. Sullivan, J. J. Tewksbury, S. A. Wagner, and A. J. Weldon. In press. A review of the potential negative ecological effects of landscape corridors.
MacDougall, A. S., J. R. Bennett, J. L. Firn, Seabloom, E. S., E. T. Borer, E. M. Lind, J. L. Orrock, ....J. W. Morgan, and C. S. Stevens [22 authors total]. In press. Regional-scale factors most consistently explain plot-level diversity in invaded areas.
Global Ecology and Biogeography.
Veldman, J. W. P, L. A. Brudvig, E. I. Damschen, J. L. Orrock, W. B. Mattingly, and J. L. Walker. In press. Fire frequency, agricultural history, and the multivariate control of pine savanna understory plant diversity.
Journal of Vegetation Science.
Borer, E., T., E. S. Seabloom, D. Gruner, W. S. Harpole, H. Hillebrand, E. Lind, P. Adler, … J. L. Orrock, …, J.Wright, L. Yang [55 authors total]. 2014. Herbivores and nutrients control grassland plant diversity via light limitation.
Damschen, E. I., D. V. Baker P, G. Bohrer, R. Nathan, J. L. Orrock, J. R. Turner, L. A. Brudvig, N. M. Haddad, D. J. Levey, and J. J. Tewksbury. 2014. Models and experiments reveal wind-driven seed dispersal is affected by fragmentation and corridors.
Proceedings of the National Academy of Sciences USA 111:3484-3489.
Brudvig, L. A., J. L. Orrock, E. I. Damschen, C. Collins, P. G. Hahn, W. B. Mattingly, J. W. Veldman, and J. L. Walker. 2014. Land-use history and contemporary management inform an ecological reference model for longleaf pine woodland understory plant communities.
PLOS ONE 9:e86604.
Borer, E. T., W. S. Harpole, P. B. Adler, E. M. Lind, J. L. Orrock, E. W. Seabloom, and M. D. Smith. 2014. Finding generality in ecology: a model for globally-distributed experiments.
Methods in Ecology and Evolution 5:65-73.
Hahn, P. G. and J. L. Orrock. 2014. Effects of temperature on seed viability of six Ozark glade herb species and eastern red cedar (Juniperus virginiana).
American Midland Naturalist 171:147-152.
Orrock, J. L. 2013. Exposure of unwounded plants to chemical cues associated with herbivores leads to exposure-dependent changes in subsequent herbivore attack.
PLOS ONE 8:e79900.
Seabloom, E. S., E. T. Borer, Y. Buckley, E. Cleland, K. Davies, J. Firn, W. S. Harpole Y. Hautier, E. Lind, A. MacDougall,J. L. Orrock, S. M. Prober, P. Adler, T. M. Anderson..., J.Wright, and L. Yang [60 authors total]. 2013. Dominance by invasive species is the real embarrassment of riches: invasion in grassland ecosystems.
Global Change Biology 19:3677-3687.
Brudvig, L. A., E. Grman, C. Habeck, J. L. Orrock, and J. Ledvina. 2013. Strong legacy of agricultural land use on soils and understory plant communities in longleaf pine woodlands.
Forest Ecology and Management 310:944-955.
Mattingly, W. B. and J. L. Orrock. 2013. Historic land use influences contemporary establishment of invasive plant species.
Orrock, J. L., E. L. Preisser, J. H. Grabowski, and G. C. Trussell. 2013. The cost of safety for prey: refuges increase the impact of predation risk in aquatic systems.
Coyle, D. R., M. M. Murphy, S. M. Paskewitz, J. L. Orrock, X. Lee, R. J. Murphy, M. A. McGeehin, and K. F. Raffa. 2013. Belowground herbivory in red pine stands initiates a cascade that increases abundance of Lyme disease vectors.
Forest Ecology and Management 302:354-362.
Mattos, K. J., J. L. Orrock, and J. I. Watling. 2013. Rodent granivores generate context-specific seed removal in invaded and uninvaded habitats.
American Midland Naturalist 169:168-178.
O'Halloran, L. R., E. T. Borer, E. W. Seabloom, A. S. MacDougall, E. E. Cleland, R. L. McCulley, S. Hobbie, W. S. Harpole, N. M. DeCrappeo, C. Chu, J. D. Bakker, K. F. Davies, G. Du, J. Firn, N. Hagenah, K. S. Hofmockel, J. M. H. Knops, W. Li, B. A. Melbourne, J. W. Morgan, J. L. Orrock, S. M. Prober, and C. J. Stevens. 2013. Regional contingencies in the relationship between aboveground biomass and litter in the world's grasslands. PLoS ONE 8:e54988.