Integrating environmental, evolutionary, and socioeconomic vulnerability to future-proof coastal conservation planning

Conservation of biodiversity remains a challenge as changing climate and other anthropogenic threats alter species distributions. Assessing vulnerability to future changes often takes solely a species- or environment-centred perspective, with few conservation plans integrating different vulnerability objectives, especially within a marine context. We evaluated conservation trade-offs associated with vulnerability measures reflecting a range of environmental, evolutionary, and socioeconomic objectives, based on contemporary and future timeframes. Using the South African coastline and three rocky shore invertebrates as a study system, we developed a framework to estimate cumulative biodiversity impacts across space and time. We compared conservation solutions obtained with the prioritizr decision support tool for individual scenarios to assess how priority areas differ between objectives and timeframes. We found that scenario solutions were more similar with a shared objective rather than timeframe. There were also no common priority areas selected across all scenarios, but most scenarios had overlapping solutions along the South African southwest coast. This study highlights the importance of integrating multiple vulnerability components, and how these are likely to have different trajectories into the future. Further, using a multi-objective approach increases the likelihood of capturing differences within objectives between now and the future, offering empirical evidence that multi-objective conservation plans can counteract uncertainties associated with future vulnerabilities.