Relative timescales of resistance and recovery control resilience in seagrass ecosystems

Ecosystem degradation is difficult and expensive to reverse. Regime change associated with degradation is important to avoid but hard to predict due to the inherent complexity of ecosystems, therefore enhancing resilience is a... [ view full abstract ]

Ecosystem degradation is difficult and expensive to reverse. Regime change associated with degradation is important to avoid but hard to predict due to the inherent complexity of ecosystems, therefore enhancing resilience is a key plank of ecosystem conservation. However this presents a paradox: ecosystems are complex, therefore we should aim to enhance resilience rather than predict trajectory, but it’s actually difficult to manage for resilience, because ecosystem complexity makes trajectory and hence resilience difficult to predict. We propose that seagrass degradation typically falls into one of three categories: 1) reversible (spontaneous recovery once the disturbance had passed), 2) hysteretic (threshold for recovery different from threshold for decline, and intervention is required for recovery to proceed), and 3) recalcitrant (conditions are unsuitable for recovery). Interactions between processes of different spatial and temporal scales determine which of these three trajectories is followed, because these cross-scale interactions affect both resistance to and recovery from disturbance. Comparing the timescales of seagrass resistance and recovery to timescales of disturbance duration and recurrence provides a useful framework to identify the ecological mechanisms controlling resilience. Resistance is particularly important for persistent species, while recoverability underpins resilience of colonising species. :