What are the Consequences of Ecosystem Disruption on Acridid Diversity and Abundance?

Abstract

Since late 1950s, the water of the two tributaries of the Aral Sea, the Amu Darya and Syr Darya rivers, has been contaminated by agrochemicals and increasingly diverted for irrigation of cotton and rice monocultures. This resulted in the rapid desiccation of the Aral Sea which lost >50% of its area and >80% of its volume by 1999. The shoreline receded by > 100 km, and the exposed sea bottom became a source of toxic dust that feeds frequent dust storms and further contaminates the environment. The vast areas of the rivers’ deltas occupied by reeds shrunk by 70% losing a substantial part of their once abundant fauna. The desertification of the milieu led to the simplification of plant communities and the predominance of halophilous, weedy vegetation. Grasshopper communities have also changed accordingly, with mesic species being substituted by xeric forms, invading new habitats from the adjacent deserts. The once predominant Migratory Locust in the Aral Sea basin lost its economic importance to the Italian Locust. This species readily colonizes roadsides, fallows and weedy patches which constitute its most favorable breeding areas. As a result, some grasshopper species now demand continuous attention inflicting damage to cereal crops, and the Italian Locust became a permanent menace to the dwindling local agriculture, requiring extensive chemical treatments regularly. Recurrent insecticide interventions contribute to further deterioration of the ecological conditions in the Aral Sea basin.