Response of seagrass indicators to shifts in environmental stressors: Aglobal review and management synthesis

Abstract

Although seagrass-based indicators are widely used to assess coastal ecosystem status, there is littleuniversality in their application. Matching the plethora of available indicators to specific managementobjectives requires a detailed knowledge of their species-specific sensitivities and their response timeto environmental stressors. We conducted an extensive survey of experimental studies to determine thesensitivity and response time of seagrass indicators to ecosystem degradation and recovery. We iden-tified seagrass size and indicator type (i.e. level of biological organization of the measure) as the mainfactors affecting indicator sensitivity and response time to degradation and recovery. While structuraland demographic parameters (e.g. shoot density, biomass) show a high and unspecific sensitivity, bio-chemical/physiological indicators present more stressor-specific responses and are the most sensitivedetecting early phases of environmental improvement. Based on these results we present a simple deci-sion tree to assist ecosystem managers to match adequate and reliable indicators to specific managementgoals.