Meeting Abstract
Climate change is driving shifts in species distributions, and warming is accelerating over the 21st century. Impacts on individual species can escalate up to community and ecosystem levels, particularly when they involve strong interactors. In rocky shore systems, mussels are dominant foundation species that provide habitat and support diverse assemblages of associated species. The mussel guild in New Zealand is particularly diverse with four co-occurring species. By integrating comparative ecophysiology and population ecology approaches, we found that temperature appears to limit upper intertidal extents across low- and mid-intertidal species. Specifically, (i) lethal thermal limits coincided with temperatures experienced at upper tide-height limits, (ii) species with higher thermal tolerances occurred higher on the shore, and (iii) lethal tolerances were higher at a warmer site than cooler site. We uncovered differential vulnerability of species in the New Zealand mussel guild to climate warming. By year 2100, two species (Perna canaliculus and Aulacomya maoriana) are likely to experience temperatures exceeding their LT50 (temperature lethal to 50% of individuals) 4 to 24 times more often at their current maximum tide height. In contrast, Mytilus galloprovincialis is much less likely to experience temperatures exceeding its LT50 based on climate projections. These results suggest that intertidal ranges of Perna and Aulacomya are likely to contract, increasing dominance of the more tolerant Mytilus and decreasing overall habitat availability for associated organisms.
