A Global Analysis of the Effectiveness of Marine Protected Areas in Preventing Coral Loss

Abstract

BackgroundA variety of human activities have led to the recent global decline of reef-building corals [1], [2]. The ecological, social, and economic value of coral reefs has made them an international conservation priority [2], [3]. The success of Marine Protected Areas (MPAs) in restoring fish populations [4] has led to optimism that they could also benefit corals by indirectly reducing threats like overfishing, which cause coral degradation and mortality [2], [5]. However, the general efficacy of MPAs in increasing coral reef resilience has never been tested.Methodology/Principal FindingsWe compiled a global database of 8534 live coral cover surveys from 1969–2006 to compare annual changes in coral cover inside 310 MPAs to unprotected areas. We found that on average, coral cover within MPAs remained constant, while coral cover on unprotected reefs declined. Although the short-term differences between unprotected and protected reefs are modest, they could be significant over the long-term if the effects are temporally consistent. Our results also suggest that older MPAs were generally more effective in preventing coral loss. Initially, coral cover continued to decrease after MPA establishment. Several years later, however, rates of coral cover decline slowed and then stabilized so that further losses stopped.Conclusions/SignificanceThese findings suggest that MPAs can be a useful tool not only for fisheries management, but also for maintaining coral cover. Furthermore, the benefits of MPAs appear to increase with the number of years since MPA establishment. Given the time needed to maximize MPA benefits, there should be increased emphasis on implementing new MPAs and strengthening the enforcement of existing MPAs.

Macroalgal terpenes function as allelopathic agents against reef corals

“…Recent analyses suggest that marine protected areas may promote local processes, such as herbivory and coral recruitment (39,40), that limit macroalgal proliferation and promote coral recovery, thereby bolstering coral resilience to large-scale disturbance (7,8,11,41,42). However, because several allelopathic macroalgae (e.g., Dictyota, Chlorodesmis, Galaxaura, Lobophora, Halimeda, Ochtodes) also contain toxins that deter some herbivores (43), developing effective marine reserves may require protecting a diverse herbivore guild that includes species that consume chemically defended macroalgae (18,33,43).…”

Monitoreo en aguas cercanas al área marina protegida en la costa de Granada, Caribe Oriental: cobertura bentónica y poblaciones de peces

“…Increased CO 2 levels in the atmosphere drive higher CO 2 levels in ocean water reducing pH that in turn hampers formation of the calcium carbonate skeletons of some coral species (Ries, Stanley & Hardie, 2006, Fine & Tchernov, 2007Riegl, Bruckner, Coles, Renaud & Dodge, 2009). Marine Protected Areas have the potential to offer some relief from the local stressors thereby increasing potential resilience of the coral community to impacts associated with climate change (Riegl et al, 2009;Selig & Bruno, 2010;Riegl et al, 2013). The purpose of this study is to monitor the coral reef community in Grenada's MPA as various management practices are implemented.…”

Demographics of bleaching in a major Caribbean reef-building coral:Montastraea annularis

“…MPAs have proven effective in decreasing biological stresses on corals, but their capacity to reduce physical stresses, such as elevated SST, appear to be limited (Mumby and Steneck 2008). A worldwide meta-analysis contrasting change in percent coral cover between MPAs and non protected areas concluded that MPAs were effective in preventing coral cover loss (Selig and Bruno 2010). However, the analysis of Selig and Bruno, (2010) also showed that coral cover decreased significantly after the 1998 mass bleaching event within MPAs in the Indo-Pacific region underscoring that MPAs offer little protection from rising SST related phenomena.…”

“…However, the recent increase in frequency of large-scale, mass coral bleaching events where entire regions are affected is understood to be related to global warming (Hoegh-Guldberg andBruno 2010, Lough andvan Oppen 2010). As a result, coral reefs around the planet have experienced significant live tissue cover decline (McClanahan et al 2002, West and Salm 2003, Hughes et al 2007, Selig and Bruno 2010). Yet, data on the demographic consequences of bleaching events on coral populations is mostly lacking.…”