Assessment of the conservation status of seagrass (Posidonia oceanica) meadows:: implications for monitoring strategy and the decision-making process

Posidonia oceanica (L.) Delile is a seagrass endemic to the Mediterranean Sea and constitutes meadows which are the basis of a highly diverse and productive ecosystem. However, the Posidonia ecosystem is threatened by anthropogenic perturbations. A simple index is developed to detect areas adversely affected by an industrial wastewater discharge. Using ordinal scaling four class intervals were established which indicated four different conservation states, and allowed the study area to be divided into four distinct zones. Such zonation is proposed as a means of improving the monitoring strategy for use as an early-warning and early control tool for conservation management of the meadows. (C) 2001 Elsevier Science Ltd. All rights reserved.