Resilience of the marine animal forest: lessons from Maldivian coral reefs after the mass mortality of 1998.

Resilience is the ability of the ecosystem to recover after a perturbation. Assessing the resilience of marine ecosystems in the face of the increasing disturbance regime has become a major concern for their conservation. Among marine ecosystems, animal forests are expectedly little resilient. Their recovery may take long, increasing the risk of hysteresis and phase shift. Historical data series for most animal forests are virtually inexistent due to the challenging difficulty of the study of deep- and cold-water habitats. Tropical coral reefs, thriving in warm shallow waters, have undoubtedly been the best studied example of animal forest for a long time and may therefore provide ideas and concepts to be applied to the study of other animal forests. In this chapter, a historical data series on the coral reefs of the Maldives, which suffered mass mortality following the bleaching caused by the extreme El Niño - Southern Oscillation (ENSO) episode of 1998, is analyzed using an array of different descriptors to measure resilience. According to the specific descriptor considered, resilience varied between 4 and 16+ years, but full recovery may even be considered unachieved, as there are species that have not come back yet. The main take-home message from this Maldivian example is the need of adopting several distinct descriptors to assess the resilience of animal forests. Concentrating on the demography of the dominant species is not sufficient to get a reliable measure of whole ecosystem resilience.