Marine range shifts and species introductions: comparative spread rates and community impacts
Sorte, C. J. B., Williams, S. L., & Carlton, J. T. (2010). Marine range shifts and species introductions: comparative spread rates and community impacts. Global Ecology and Biogeography, 19, 303-316. PDF.
Summary
Climatic warming has resulted in range shifts for species across latitudes, elevations, and depths as a response to increased environmental stress. As species move into new habitats there will be novel species interactions within the recipient communities. This phenomenon of novel range shifting species has been observed for many years in marine systems. But, it is unknown whether these range shifting natives tend to behave "invasively" with negative impacts on recipient communities similar to those observed from non-native species. Therefore, to determine how spread rates and community impacts compare between invasive and range shifting species, Sorte et al. (2010) conducted a meta-analysis of 73 marine species with reported range shifts. Of these range shifts, 75% were in a poleward direction, consistent with climate change expectations. Overall, range-shifting species had slower spread rates than non-native species, likely due to predator/competitor release or prey naivete associated with introduced species, although the community impacts for both were generally negative and of similar magnitudes. Incorporating species interactions into climate change projections will likely provide higher accuracy than distribution models alone. The ability to incorporate these data, however, is limited by the number of studies focusing on community level impacts, with effects reported for fewer than 10% of range-shifting species.
Take home points
Range shifts have the potential to affect community level processes. Spreading associated with range shifts occurred more slowly than those associated with introductions, but the effects of range shifts on marine communities is likely to be similar to those of introduced species.
Range shifts occur an order of magnitude faster in marine systems than in terrestrial systems, and marine communities may experience related climate change impacts more quickly.
Management implications
Native species shifting their ranges under climate change can have impacts of the same magnitude as those of non-native species invasions.
Important knowledge gaps to address include establishing baselines of existing ranges to track the occurrence and rate of shifts, as well as a greater focus on the community impacts of these species.
Keywords
Range Expansion; Meta-analysis; Aquatic Habitat; Risk Assessment