Rewilding of Protected Areas Enhances Resilience of Marine Ecosystems to Extreme Climatic Events

E V Sheehan,A Rees,L A Holmes,A Cartwright,M J Attrill,B F R Davies

doi:10.3389/fmars.2021.671427

Abstract

Marine protected areas (MPAs) are employed as tools to manage human impacts, especially fishing pressure. By excluding the most destructive activities MPAs can rewild degraded areas of seabed habitat. The potential for MPAs to increase ecosystem resilience from storms is, however, not understood, nor how such events impact seabed habitats. Extreme storm disturbance impact was studied in Lyme Bay MPA, Southwest United Kingdom, where the 2008 exclusion of bottom-towed fishing from the whole site allowed recovery of degraded temperate reef assemblages to a more complex community. Severe storm impacts in 2013–2014 resulted in major damage to the seabed so that assemblages in the MPA were more similar to sites where fishing continued than at any point since the designation of the MPA; the communities were not dominated by species resistant to physical disturbance. Nevertheless, annual surveys since 2014 have demonstrated that the initial recovery of MPA assemblages was much quicker than that seen following the cessation of chronic towed fishing impact in 2008. Likewise, General Additive Mixed Effect Models (GAMMs) showed that inside the MPA increases in diversity metrics post-Storm were greater and more consistent over time than post-Bottom-Towed Fishing. As extreme events are likely to become more common with climate change, wave exposure observations indicated that 29% of coastal reef MPAs around the United Kingdom may be exposed to comparable wave climate extremes, and may be similarly impacted. This paper therefore provides an insight into the likely extent and magnitude of ecological responses of seabed ecosystems to future extreme disturbance events.

Highlights

Marine protected areas (MPAs) have been established worldwide in an effort to limit direct anthropogenic drivers of ecosystem change (UNEP-WCMC and IUCN, 2016)
While MPAs are aimed at managing direct anthropogenic disturbance on ecosystems at a local scale, these same ecosystems are subject to changes in patterns of global environmental drivers, whose influences are likely to be exacerbated under projections of climate change
It is likely that many other temperate reef systems within MPAs undergo natural shifts in abundance and diversity driven by extreme storm events (Figure 2)

Summary

Introduction

Marine protected areas (MPAs) have been established worldwide in an effort to limit direct anthropogenic drivers of ecosystem change (UNEP-WCMC and IUCN, 2016). Wave heights during extreme events have been observed to increase in recent decades (Young et al, 2011), potentially increasing the impacts of each extreme event With these anticipated shifts in wave forcing on coastlines and the seabed, it is important that the effects of extreme storm events on benthic assemblages are understood in order to inform long-term planning of conservation measures in the northeast Atlantic and beyond. Knowledge of the likely ecosystem responses to extreme storm events, and recovery timescales of impacted benthic habitats is key to ensure protection of sufficient habitat, species and genetic diversity to buffer against natural and anthropogenic disturbances, and provide a starting point for recovery

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