Browsing by Subject "Metapopulation"
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Item The effect of dispersal behavior on stability in populations, communities, and ecosystems(2019-08-01) Deans, Robert Andrew; Gilbert, Lawrence E.; Leibold, Mathew A.; Jha, Shalene; Resetarits, William; Keitt, TimothyHabitat choice, when organisms move among habitat patches in a directed fashion based on environmental cues, is an underappreciated force in Ecology. Theoretical work suggests that such choice behavior might be a potent source of stability in populations, communities, and ecosystems. I tested the effects of dispersal behavior on stability with a series of mesocosm experiments at each of these scales. In populations of snails with stochastic disturbance, I found that movement among patches was density-dependent: snails tended to move away from high density and toward low density. These movements had dampening effect on oscillations in abundance, and they contributed to longer population persistence times relative to populations that were not connected by dispersal. A second experiment manipulated the colonization behavior of aquatic insects in order to see how this dispersal behavior affects the community response to a pulse of fish predation on the insect communities. While choice behavior exacerbated the effects of fish predation, reducing species richness beyond what was observed in communities with randomized colonization, choice resulted in faster recovery of communities relative to random colonization. A third experiment explored the effects of pulses of nutrient additions in mesocosms with developing aquatic insect communities. Presence of sediment had weak effects on stability, with small pulses of nutrients supporting more stable abundance values than ecosystems with no sediment. This stabilization effect was likely driven by habitat choice behavior, since the sediment input treatments affected organisms with active dispersal more than those with passive dispersal. Collectively, these experiments show that dispersal behavior is an important factor to consider when attempting to explain the spatial and temporal variation in ecosystems. Habitat choice behavior can have particularly significant effects on stability. Predicting how species respond to environmental change therefore requires knowledge of how they move.