Crab induced salt marsh regeneration after the 1991 Gulf War oil spill

Abstract

The 1991 Gulf War led to the largest oil spill in human history. Over 770 km of coastline from southern Kuwait to Abu Ali Island (Saudi Arabia) were smothered with oil and tar, erasing most of the local plant and animal communities. Salt marshes were most severely hit of the different coastal ecosystem types along the Saudi Arabian coast and are far from being completely restored several years later. Repeated monitoring from 1993 until 2004 revealed that, out of several processes, the re-colonisation by crabs is the most important one regarding the restoration of salt marsh ecosystems. The occurrence of crabs (mainly Nasima dotilliformis) is concentrated along tidal channels from where they slowly advance into the adjacent oiled sediment. These results support the statements made by others in the mid 1990's (i.e. Höpner) that the intertidal fauna is clearly the first to re-colonize the oil affected salt marshes (several years before any plant species return). Therefore the idea of digging an artificial network of channels into the salt marshes in order to accelerate the slow process of re-colonisation in greater distance to the channels seems to be the most promising melioration effort.