Do macroinvertebrate abundance and community structure depend on the quality of ponds located in peri-urban areas?
Contamination is one of the major threats to freshwater biodiversity. Compared to other aquatic ecosystems, peri-urban ponds are unique because they are embedded in human-dominated areas. However, it is poorly understood how different land uses such as urban or agricultural contribute multiple pollutants to ponds and thus affect pond biodiversity. In this work, 12 ponds located in a peri-urban area (Ile-de-France region, France) were monitored for 2 consecutive years in spring and fall. We surveyed macroinvertebrates and measured the physicochemical parameters and contaminants of different classes (trace elements, pharmaceuticals, pesticides and polycyclic aromatic hydrocarbons) in both water and sediment. The objective was twofold: (1) to explore local and regional macroinvertebrate spatiotemporal diversity and (2) to understand the effects of contaminants on community structure. We observed 236 macroinvertebrate morphotaxa, none of which were rare or sensitive to pollutants. Morphotaxa richness showed small differences between ponds but no difference between there was no effect of field campaign. There was no effect of ponds and field campaign on morphotaxa diversity and equitability. We did not observe a relationship between land use around the pond (agricultural, urban, or semi-natural) and diversity indices with the exception of the proportion of agricultural land in the vicinity of the pond on equitability. Regional beta diversity (between ponds) showed that differences in morphotaxa composition reflected species replacement more than differences in species richness; these were primarily due to the high abundance of pollutant-tolerant species in some of the ponds. The effects of environmental parameters on community structure were studied using partial redundancy analysis based on the presence-absence of morphotaxa, showing that community assemblages are shaped by sediment levels of pharmaceuticals, water conductivity and ammonium concentration. In conclusion, ponds in peri-urban areas are exposed to various human activities, with our results suggesting that this exposure leads to chronic and diverse contaminations that affect morphotaxa communities.