Ecological limitations to the resilience of coral reefs 3

6 Abstract The decline of coral reefs has been broadly 7 attributed to human stressors being too strong and perva8 sive, whereas biological processes that may render coral 9 reefs fragile have been sparsely considered. Here we 10 review several ecological factors that can limit the ability 11 of coral reefs to withstand disturbance. These include: (1) 12 Many species lack the adaptive capacity to cope with the 13 unprecedented disturbances they currently face; (2) human 14 disturbances impact vulnerable life history stages, reducing 15 reproductive output and the supply of recruits essential for 16 recovery; (3) reefs can be vulnerable to the loss of few 17 species, as niche specialization or temporal and spatial 18 segregation makes each species unique (i.e., narrow eco19 logical redundancy); in addition, many foundation species 20 have similar sensitivity to disturbances, suggesting that 21 entire functions can be lost to single disturbances; and (4) 22 feedback loops and extinction vortices may stabilize 23 degraded states or accelerate collapses even if stressors are 24 removed. This review suggests that the degradation of coral 25 reefs is due to not only the severity of human stressors but 26 also the ‘‘fragility’’ of coral reefs. As such, appropriate 27 governance is essential to manage stressors while being 28 inclusive of ecological process and human uses across 29 transnational scales. This is a considerable but necessary 30 upgrade in current management if the integrity, and 31 delivery of goods and services, of coral reefs is to be 32 preserved. 3