No abstract

Aim Increasing sea‐surface temperatures (SST) have resulted in poleward range expansions of scleractinian corals and declines in their core ranges. These changes may provide management opportunities for the long‐term persistence of corals, but spatial prioritization rarely considers and anticipates these changes. We developed a spatio‐temporal conservation plan that accommodates future coral range expansions based on projections of future SST. Our spatial planning approach is particularly useful in places with limited information about species distributions. Our aims were to (1) identify areas that consistently remain important for conservation through time and (2) determine the differences between priorities for conservation that account for potential coral range expansions and those that ignore them. Location Japan. Methods We developed spatial planning approaches using predicted coral habitat distributions for current conditions, the near future and the distant future. Using the Marxan conservation planning software, we designed conservation plans for scenarios that incorporated different types of spatial and temporal connections. Spatial connections are physical connections between adjacent and nearby areas, whereas temporal connections connect planning areas throughout time. Results We found that protecting areas important for current and future coral habitat distributions is possible by prioritizing places that are consistently important through time. A spatially and temporally cohesive plan was accomplished with only a 14% increase in the overall reserve system costs, compared with reserve systems ignoring future coral habitat distributions. The attributes of priority areas (e.g. locations, outside boundary length and size) were substantially different when we varied the types of connections. Main conclusions This study demonstrated that areas with highest conservation priority now will not necessarily be optimal when planning for future change, such as coral range expansions. Furthermore, we showed that incorporating spatio‐temporal connections into spatial prioritization achieves objectives of simultaneously conserving corals in the current climate and facilitating their expansions as SST rises.

Abstract.Using results from four coupled global carbon cycle-climate models combined with in situ observations, we estimate the effects of future global warming and ocean acidification on potential habitats for tropical/subtropical and temperate coral communities in the seas around Japan. The suitability of coral habitats is classified on the basis of the currently observed regional ranges for temperature and saturation states with regard to aragonite ( arag ). We find that, under the "business as usual" SRES A2 scenario, coral habitats are projected to expand northward by several hundred kilometers by the end of this century. At the same time, coral habitats are projected to become sandwiched between regions where the frequency of coral bleaching will increase, and regions where arag will become too low to support sufficiently high calcification rates. As a result, the habitat suitable for tropical/subtropical corals around Japan may be reduced by half by the 2020s to 2030s, and is projected to disappear by the 2030s to 2040s. The habitat suitable for the temperate coral communities is also projected to decrease, although at a less pronounced rate, due to the higher tolerance of temperate corals for low arag . Our study has two important caveats: first, it does not consider the potential adaptation of the coral communities, which would permit them to colonize habitats that are outside their current range. Second, it also does not consider whether or not coral communities can migrate quickly enough to actually occupy newly emerging habitats. As such, our results serve as a baseline for the assessment of the future evolution of coral habitats, but the consideration of important biological and ecological factors and feedbacks will be required to make more accurate projections.