FSD 2010 - Levey

5th International Symposium-Workshop on Frugivores and Seed Dispersal (1985-2010)

Douglas J. Levey

Department of Biology
PO 118525
University of Florida
Gainesville, Florida 32611-8525

dlevey(at)ufl.edu

Website

Joshua J. Tewksbury

The Tewksbury Laboratory
University of Washington
548 Kincaid Hall
Box 351800
Seattle, WA 98115

tewksjj(a)u.washington.edu

Website

Activities

Douglas J. Levey: I’m interested in practically everything related to the evolutionary ecology of fruit-frugivore interactions. Recently, I’ve been focusing on the landscape ecology of fruit-eating birds – how the distribution of fruiting plants affects small and large scale movements of birds and how those movements affect the long-distance dispersal of seeds consumed by birds. Most of this work involves experiments and modeling; all of it involves inspiring collaborators. Nonetheless I’m getting restless, becoming more interested in doing less of what most of you probably consider “science.” I want to do a better job of communicating complex issues of ecology to the general public and pushing for change in the way we mentor students of all ages.

Joshua J. Tewksbury: I am a bit of a generalist, and so I think the best way to describe my interest is like this: I am interested in the context of diversity - the physical and biological environment in which individuals, populations and communities exist, and within that, I have always leaned toward interactions between species. In general, I see biological context as a defining feature of diversity (its creation and maintenance) and I think rigorous attempts to understand the details of that context will be critical if we are to have any hope of using evidence-based decision-making to manage natural communities. My research spans many traditional topics in ecology, evolution and conservation, from ecological and evolutionary studies of plant animal interactions (with particular interest in the relationships between fruiting plants and their consumers) to studies of global climate change impacts on physiology, ecology, and species interactions, to long-term studies of landscape fragmentation and connectivity. I favor experimental investigations of ecology and evolution and I am committed to a brand of natural science with ample space for natural history - the particulars of place - and for general theory that is empirically grounded in those particulars. The Ecology of Bird Loss Project

Abstract

Rethinking the benefits of vertebrate seed dispersal - escape, camouflage or pathogen removal?

Doug Levey¹, Josh Tewksbury²

¹ Biology, University of Florida, ² Biology, University of Washington

The primary benefit of vertebrate

dispersal is often considered to be “escape” – vertebrates move seeds away from the parent plants, where competition and high predation rates limit fitness. Yet vertebrate dispersal involves changes in seed location (escape) and changes in seed condition (seed handling). While these two benefits are often acknowledged, their relative benefits are rarely compared. Here we directly compare escape-related impacts to condition-related impacts in a shrub, Capsicum chacoense.

We found no evidence for escape-related benefits. In contrast, we found strong support for condition-related impacts: gut passage removed lipids from seeds, making them chemically camouflaged from ant seed predators. In addition, gut passage cleaned seeds of fungal pathogens; gut passage removed 30% of the fungal infection, resulting in a doubling in germination. Our results suggest that the benefits of animal seed dispersal may be far more diverse than previously appreciated.

Recent references - Levey - Tewksbury

Carlo, T. A., Tewksbury, J. J., Martinez del Rio, C. 2009. A new method to track seed dispersal and recruitment using 15N isotope enrichment. Ecology 90:3616-3525.

Clark, C. J., J. R. Poulsen, D. J. Levey, and C. W. Osenberg. 20078. Are plant populations seed limited? A meta-analysis and critique of seed addition experiments. American Naturalist 170:128-142.

Damschen, E. I., L. A. Brudvig, N. M. Haddad, D. J. Levey, J. L. Orrock, and J. J. Tewksbury. 2008. The movement ecology and dynamics of plant communities in fragmented landscapes. Proceedings of the National Academy of Sciences. 105:19078-19083.

McCoy, M.W., K. A. McCoy, and D. J. Levey. 2007. Teaching biodiversity to students in inner-city and under-resourced schools. American Biology Teacher 69:473-476.

Levey, D. J., J. J. Tewksbury, B. M. Bolker. 2008. Modeling long-distance seed dispersal in heterogeneous landscapes. Journal of Animal Ecology 96:599-608.

Tewksbury, J. J., R. B. Huey, and C. Deutsch. 2008. Climate Warming Puts the Heat on Tropical Ectotherms. Science 320:1296-129.

Tewksbury, J.J., Levey, D.J., Huizinga, M., Travaset, A. 2008 Ecology of a spice: Capsaicin in wild chilies mediates seed retention, dispersal, and germination. Ecology 89:107-117.

Tewksbury, J. J., K. M. Reagan, N. J. Machnicki, T. Carlo, D. C. Haak, A. L. Calderon-Peñaloza, and D. J. Levey. 2008. Evolutionary ecology of pungency in wild chilies. Proceedings of the National Academy of Sciences. 105:1180-11811.

Former FSD presentations

Levey, D.J. Methods of seed processing by birds and seed deposition patterns, pages 147-159. In: A. Estrada and T.H. Fleming (eds), Frugivores and Seed Dispersal. W. Junk Publishers, The Netherlands.

Denslow, J.S., T.C. Moermond and D.J. Levey. Spatial components of fruit display in understory trees and shrubs, pages 37-45. In: A. Estrada and T.H. Fleming (eds), Frugivores and Seed Dispersal. W. Junk Publishers, The Netherlands.

Moermond, T.C., J.S. Denslow, D.J. Levey and E. Santana-C. The influence of morphology on fruit choice in neotropical birds, pages 137-146. In: A. Estrada and T.H. Fleming (eds), Frugivores and Seed Dispersal. W. Junk Publishers, The Netherlands.

Byrne, M. and D. J. Levey. Removal of seeds from frugivore defecations by ants in a Costa Rican rain forest. Vegetatio 108:363-374

Levey, D. J., W. R. Silva, and M. Galetti. (eds) Seed dispersal and frugivory: Ecology, evolution, and conservation. CABI Publishing, Wallingford, UK.

Restrepo, C., S. Sargent, D. J. Levey, and D. M. Watson. The role of vertebrates in diversification of New World mistletoes. Pages 83-98. In: Levey, D. J., W. R. Silva, and M. Galetti. (eds) Seed dispersal and frugivory: Ecology, evolution, and conservation. CABI Publishing, Wallingford, UK.

Levey, D. J., J. J. Tewksbury, I. Izhaki, E. Tsahar, and D. C. Haak. Why fruit secondary compounds are of primary importance. Pages 37-58. In: A. Dennis, E. W. Schupp, R. J. Green, and D. W. Westcott (eds). Seed dispersal: theory and its application in a changing world. CAB International Publishing. Wallingford, U.K.

Bronstein, J.L, Izhaki, I., Nathan, R., Tewksbury, J., Speigel, O., and Lotan, A. 2007. Fleshy fruited plants and frugivores in desert ecosystems In: A. Dennis, R. Green, E. Schupp and D.Westcott, editors. Seed dispersal: Theory and its application in a changing world Wallingford, Oxfordshire, UK: CABI international.

Kwit, C., S. A. Turner, D. J. Levey, J. R. Poulsen, and C. J. Clark. Out of one shadow and into another: Causes and consequences of spatially contagious seed dispersal by frugivores. 2007. In: A. Dennis, E. W. Schupp, R. J. Green, and D. W. Westcott (eds). Seed dispersal: theory and its application in a changing world. CAB International Publishing. Wallingford, U.K.

FSD 2010 - Levey_Tewksbury