Spatio-temporal marine conservation planning to support high-latitude coral range expansion under climate change
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.
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.
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.
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.