Experimental biology of species range dynamics: drivers of survival and dispersal in range-core and range-edge invasive crayfish
Résumé
Projecting and managing the future response of invasive species to global change requires a mechanistic understanding of how climate and ecology jointly drive species demography and range dynamics. Here, we use mark-recapture in replicated outdoor mesocosms to examine how survival and dispersal, two key drivers of demography and range dynamics, respond to climate and ecology in the invasive red swamp crayfish (Procambarus clarkii) along an invasion gradient. We show that crayfish survival probability increased with (i) increasing body size at high (but not low) crayfish density and (ii) with warmer temperatures, and decreased (i) with increasing body condition and (ii) under higher crayfish density. Overland dispersal probability by crayfish increased with increasing (i) body-size, (ii) body condition and (iii) temperatures. In contrast, crayfish from range-edge and range-core habitats had similar survival and overland dispersal probabilities, suggesting no evolution of their range-expansion potential along the invasion gradient. Our results highlight that predicting species population dynamics and range shifts in a changing world requires accounting for the joint contributions of climate, body size and ecological interactions. In local P. clarkii populations, global warming will simultaneously promote both a numerical increase and a geographic-range expansion, especially in populations dominated by large-bodied individuals. In already-invaded ecosystems, we suggest that selective harvesting of large-bodied crayfish is a management strategy that could reduce a population’s range-expansion potential over both ecological and evolutionary time scales.
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