OOS 44 - Examining Bottom-up and Top-Down Forces: Bringing together Aquatic and Terrestrial Perspectives

Thursday, August 11, 2011: 1:30 PM-5:00 PM
15, Austin Convention Center
Organizer: Torrance C. Hanley
Co-organizer: Kimberly J. La Pierre
Moderator: Torrance C. Hanley
The independent effects of bottom-up and top-down forces are well-understood in a wide variety of aquatic and terrestrial ecosystems. It is now necessary to examine how these often conflicting selection pressures interact, both in the laboratory and the field. The goal of this session is to bring together scientists studying the interaction of bottom-up and top-down forces in both aquatic and terrestrial ecosystems. In addition to examining the relative strength of these factors in aquatic and terrestrial communities, we aim to consider how (1) environmental gradients and (2) diversity at both the species and genotypic levels potentially impact the interaction of bottom-up and top-down forces. Our definitions of “bottom-up” and “top-down” are purposely broad to include a diverse group of studies and perspectives: bottom-up forces include nutrient and resource availability, and top-down forces include parasites, herbivores, and predators. In order to facilitate communication across these diverse fields, speakers in the session study a broad range of ecosystems, including salt marshes, rivers, lakes, grasslands, and arctic tundra, and employ a variety of observational, experimental, and theoretical approaches. The session is structured such that aquatic and terrestrial studies alternate to highlight similarities and differences between systems. The session will conclude with a unique talk considering the impacts of both aquatic and terrestrial top-down forces on a single plant as a suggestion for future research directions to consider the relative importance of bottom-up and top-down effects at the interface of aquatic and terrestrial ecosystems.
1:30 PM
Consumers as ecosystem engineers in freshwater ecosystems: Linking top-down and bottom-up forces
Alexander S. Flecker, Cornell University; Peter B. McIntyre, University of Wisconsin
2:10 PM
Culling the sick and the young:  How predators, resources, and stage structure interact to spread disease in hosts
Spencer R. Hall, Indiana University; Manja P. Holland, University of Michigan, Ann Arbor, MI; Carla E. Cáceres, University of Illinois at Urbana-Champaign
2:30 PM
Plant mediation of tritrophic interactions
Kailen A. Mooney, University of California, Irvine; Riley T. Pratt, University of California, Irvine; Victoria Hanna, University of California
2:50 PM
The interactive effects of bottom-up and top-down forces vary across a broad grassland productivity gradient
Kimberly J. La Pierre, UC Berkeley; Melinda D. Smith, Colorado State University
3:10 PM
3:40 PM
Comparing aquatic and terrestrial top-down forces on a single intertidal plant
Steven Pennings, University of Houston; Brian R. Silliman, University of Florida
4:00 PM
Ecology across boundaries: Reciprocal subsidies between aquatic and terrestrial ecosystems structure consumer-resource dynamics
Pia Bartels, Uppsala University; Julien Cucherousset, CNRS, UPS, ENFA; Kristin Steger, Uppsala University; Peter Eklöv, Uppsala University; Lars J. Tranvik, Uppsala University; Helmut Hillebrand, Carl von Ossietzky University of Oldenburg
4:20 PM
Keystones from the bottom up: Loss of rare species disproportionately impacts higher trophic levels
Matthew E. S. Bracken, Northeastern University; Natalie H. N. Low, Brown University
4:40 PM
Interaction cascades in anthropogenic glades: Adding habitat heterogeneity in an otherwise homogenous landscape across multiple spatial scales and trophic levels
Colin M. Donihue, University of Michigan; Robert M. Pringle, Princeton University; Johannes Foufopoulos, University of Michigan; Lauren E. McGeoch, University of California, Davis; Corinna Riginos, Teton Science Schools
See more of: Organized Oral Session
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Banner photo by Flickr user greg westfall.