Contingency planning for coral reefs in the Anthropocene; The potential of reef safe havens

Abstract

Reducing the global reliance on fossil fuels is essential to ensure the long-term survival of coral reefs, but until this happens, alternative tools are required to safeguard their future. One emerging tool is to locate areas where corals are surviving well despite the changing climate. Such locations include refuges, refugia, hotspots of resilience, bright spots, contemporary near-pristine reefs, and hope spots that are collectively named reef ‘safe havens' in this mini-review. Safe havens have intrinsic value for reefs through services such as environmental buffering, maintaining near-pristine reef conditions, or housing corals naturally adapted to future environmental conditions. Spatial and temporal variance in physicochemical conditions and exposure to stress however preclude certainty over the ubiquitous long-term capacity of reef safe havens to maintain protective service provision. To effectively integrate reef safe havens into proactive reef management and contingency planning for climate change scenarios, thus requires an understanding of their differences, potential values, and predispositions to stress. To this purpose, I provide a high-level review on the defining characteristics of different coral reef safe havens, how they are being utilised in proactive reef management and what risk and susceptibilities they inherently have. The mini-review concludes with an outline of the potential for reef safe haven habitats to support contingency planning of coral reefs under an uncertain future from intensifying climate change.

Heterotrophy in marine animal forests in an era of climate change

“…habitats where high geomorphic relief favours particularly strong currents and particle advection (Soetaert et al ., 2016) and which are not likely to be subject to aragonite undersaturation or hypoxia in the near future (Sweetman et al ., 2017). These refuges could be used strategically as natural sources of propagules within a network of interconnected marine protected areas (MPAs) taking into account their long‐term capacity given spatial and temporal variability and vulnerability (Camp, 2022). Further research is however needed on the full potential of such refuges in MAF conservation.…”

The trace metal economy of the coral holobiont: supplies, demands and exchanges

“…seabird‐derived nutrients leading to elevated coral growth rates; Savage, 2019), their interactive effects with human impacts can have a wide range of effects on coral physiology (Fabricius, 2005). However, the observation of ‘hope spots’ (contemporary near‐pristine reefs) within nearshore habitats with harsh conditions warrants further evaluation in relation to IME‐derived metal supplies, their contribution to the presence and distribution of these sites and the eco‐physiology of corals that persist in these environments (Fabricius et al ., 2004; Kenkel et al ., 2013; Brown et al ., 2015; Camp et al ., 2017; Thomas et al ., 2018; Camp, 2022).…”

“…Understanding the drivers of coral diversity will be enhanced by simultaneously evaluating patterns of local and regional metal biogeochemistry. Studies of coral reef ‘hope spots’ (see Camp, 2022), could allow us to uncover the role of metal seascapes in modulating the adaptive capacity of corals as well as identifying environmental conditions that sustain such refugia ( sensu Keppel et al ., 2012).…”

Diversification of refugia types needed to secure the future of coral reefs subject to climate change

“…For example, reef communities often show predictable changes and adaptation to stress across reef zones, along inshore to offshore gradients, from windward to leeward sides of islands, across archipelagos, across seasons, and along large ocean–basin geographic gradients (Asner et al., 2022; Camp et al., 2018; McClanahan, Darling, et al., 2020; McClanahan, Maina, et al., 2020; Selmoni et al., 2020). Therefore, coral reefs are expected to display a variety of responses, as exemplified in the diverse terminology and concepts used to describe outcomes of climate change (Camp, 2022; Kavousi & Keppel, 2018).…”

“…After evaluating the impacts of climate disturbances and the processes that influence thermally stressed corals, West and Salm (2003) recognized 3 major categories of refugia for reefs: avoidance, resistance, and recovery (Figures 1a & 2). Moreover, they and others recognize that this diversity of responses and associated locations creates a potential for strategic conservation science and interventions (Anthony et al., 2020; Camp, 2022; Chollett et al., 2022; Hoegh‐Guldberg, Kennedy, et al., 2018; McClanahan & Azali, 2021; McClanahan & Muthiga, 2017; Webster et al., 2017). Therefore, we reviewed the applied work that has evaluated progress toward promoting the diversified portfolio approach recommended to improve the chances for coral adaptation and persistence under rapidly warming ocean conditions.…”