FSD 2010 - Steele

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

Michael A. Steele, Ph.D

H. Fenner Chair of Research Biology
Department of Biology
Wilkes University
Wilkes-Barre, PA 18766

Activities

My research focuses on ecological and evolutionary interactions between vertebrates and plants and the implications for conservation that follow from these associations. Within this general area, much of my interests center on the mutualism between the oaks (Quercus) and their seed predators and dispersers. I am particularly interested in how the physical and chemical characteristics of acorns influence the behavioral decisions of scatter hoarders and how these decisions in turn influence the dispersal, regeneration, and evolution of the oaks. My students, collaborators, and I are currently studying behavioral decisions by scatter-hoarding rodents and jays and their influence on seed fate under different conditions of mast abundance, predation risks, and landscape structure.

Abstract

The importance of multidisciplinary approaches for understanding the seed dispersal process: An example from the North American oaks.

by Michael A. Steele, Nate Lichti, Shealyn Marino, and Robert Swihart

Although a unified theory of seed dispersal has been slow to emerge, recent studies employing an integrative approach have greatly improved our understanding of this complicated but important ecological process. Here we review (1) a series of ecological, behavioral, and genetic approaches that have been used to understand oak dispersal in temperate forests of North America, (2) the consistencies and inconsistencies that result from these varied approaches, and (3) the additional approaches needed to resolve these inconsistencies. We report on a series of recent studies that show how secondary dispersal, cache memory, predator-prey interactions, and a retriever's advantage can all influence the seed dispersal process. By simulating predation of scatter-hoarding tree squirrels immediately after caching, we demonstrate that cache owners have a retrieval advantage over conspecifics even in a high-density population. We also show how habitat structure influences the placement of various seed types and how this influences spatial variation in cache pilferage. Our recent findings suggest that scatter hoarding is a dynamic process often controlled by the cache owner but also influenced by other ecological factors. We suggest that the close integration of genetic studies with behavioral and ecological experiments is vital for reconstructing the various mechanisms that contribute to the process of seed dispersal.

Recent Relevant Publications

Xia, Z., X. Gao, M. A. Steele, and Z. Zang. 2009. Frequency dependent selection by tree squirrels: adaptive escape of non-dormant white oaks. Behavioral Ecology 21: 169-175.

Steele, M. A, S. L. Halkins, P. D. Smallwood, T. McKenna, K. Mistopolus, and M. Beam. 2008. Cache protection strategies of a scatter-hoarding rodent: Do tree squirrels engage in behavioural deception? Animal Behaviour 75:705-714.

Steele, M. A. 2008. Evolutionary interactions between tree squirrels and trees: A review and synthesis. Current Science 95:871-876.

Steele, M. A., J. E. Carlson, P.D. Smallwood, A. B. McEuen, T. A. Contreras, and W. B. Terzaghi. 2007. Linking seed and seed shadows: A case study in the oaks (Quercus) In A. J. Dennis, E. W. Schupp, R. J. Green, D. A. Wescott (eds). Seed Dispersal: Theory and its Application in a Changing World. CAB International. Wallingford, UK.

Moore, J. E., A. B. McEuen, R. K. Swihart, T. A. Contreras, and M. A. Steele. 2007. Determinants of seed-removal distance by scatter-hoarding rodents in deciduous forests. Ecology 88:2529-2540.

Steele, M. A., S. Manierre, T. Genna, T. Contreras, P. D. Smallwood, and M. Pereira. 2006. The innate basis of food hoarding decisions in grey squirrels: evidence for behavioral adaptations to the oaks. Animal Behaviour 71:155-160.