Temporal pulses and spatial subsidies: Theoretical perspectives on commonalities, contrasts, and connections.
Holt, Robert1, 1 University of Florida, Gainesville, Florida, USA
ABSTRACT- The natural world is variable both in time and space, but relatively little ecological theory has been explicitly devoted to analyzing the consequences of both kinds of variability operating simultaneously. Flows between habitats are an intrinsic dimension of most food webs. Temporal variation in environmental conditions, including in productivity, is also ubiquitous. There are some similarities between temporal pulses in production, and spatial subsidies, but also important differences. For instance a buildup of generalist predators in a productive season can increase predation pressure in unproductive seasons; in like manner, productive habitat patches can sustain mobile generalist predators that can then impact unproductive habitats. But in the former temporal case, dynamics in the unproductive season may constrain predator impacts in the subsequent productive season; by contrast, spatial subsidies can be persistently asymmetric. In some circumstances, temporal variation can weaken the impact of spatial subsidies on local systems, but in others temporal variation greatly magnifies such impacts. Conversely, spatial flows can either buffer or magnify effects of temporal variation in production, depending on the detailed pattern and functional form of local interactions and movement rules. This talk will provide an overview of recent theoretical explorations of food web dynamics and species coexistence that explicitly deal with the interplay of temporal and spatial variability.
Key words: food webs, spatial subsidy, temporal pulses, community modules
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