Anthropogenic stressors are driving a steep decline of hemipteran diversity in dune ponds in north-eastern Algeria

Abstract

In arid North Africa, dune ponds qualify as hotspots of aquatic biodiversity, offering numerous sustainable ecosystem services. Despite mounting anthropogenic pressures that threaten their integrity, the overall consequences of these changes have yet to be documented and no strategy to mitigate potential impacts is being implemented. We monitored four dune ponds in northeast Algeria during five hydrological cycles spanning the period 1996–2013. The analysis revealed a steep decline in species richness (47%) and abundance (94%) over the study period. Remote sensing-based data indicated that marked human-induced changes in and around these dune ponds have over time led to a substantial expansion of built areas and cultivated plots and a reduction in both natural wet- and dry-land habitats. Fish predation by the introduced fish, Gambusia holbrooki, may have had both direct and indirect impacts on notonectids. We argue that aquatic hemipterans have undergone an alarming reduction driven by a combination of invasive species, human encroachment, agricultural runoffs, and possibly, climate change.