Benthic community response (primarily Chironomidae) to nutrient enrichment and alkalinization in shallow,soft water humic lakes

A comparison of the benthic fauna found in two shallow lakes in the New Jersey Pinelands (USA) illustrated the impact of elevated pH and nutrients caused by residential and agricultural disturbance on a naturally acidic, poorly buffered aquatic environment. Detailed community analysis suggested that change in community composition was a better indicator of response to disturbance than biological diversity indices. Chironomidae (insecta) were the predominant components of the benthic macroinvertebrate assemblage of both undisturbed Oswego Lake (low pH, low nutrients) and Nescochague Lake (fluctuating pH, elevated nutrients). The genera Procladius, Tribelos, and Pagastiella dominated Oswego Lake, where as Zalutschia zalutschicola, Procladius, Dicrotendipes, and Tanytarsus dominated Nescochague Lake. Glyptotendipes was a common and unique member of the Nescochague Lake assemblage. Cluster analysis indicated that the chemical differences between lakes were the most important community determinants, although, within each lake, depth and substrate affected the local communities. Oswego Lake exhibited a depauperate nonchironomid benthic fauna typical of low nutrient, acid lakes. In turn, Nescochague Lake exhibited an enriched nonchironomid fauna including mollusks and planaria which were not found in Oswego Lake.