Eutrophication of the Salt Valley Reservoirs, 1968?73 III. The macroinvertebrate community: Its development, composition, and change in response to eutrophication

Abstract

The macroinvertebrate communities of four flood control reservoirs in eastern Nebraska, differing in age and degree of eutrophy were investigated from Ekman grab samples. Generally, the longer a reservoir had been influenced by eutrophication the larger the standing crop in it. Chironomids, ceratopogonids. fingernail clams, and Hexagenia were important at various stages of eutrophication with Chironomus predominating in the most eutrophic reservoirs. Tubifex decreased with eutrophication as did Sphaerium simili while Sphaerium declive maintained its abundance and sometimes increased.The chironomids Chironomus, Coelotanypus, and Procladius, fingernail clams, and Tubifex were early colonizers in the newest reservoir and developed a total standing crop as large the first summer as in subsequent ones. However, its composition became more diverse with time. In one reservoir sampled yearround, the standing crop was largest in late fall or early winter and smallest during summer. The most accurate information on macro-invertebrate standing crops in lakes and reservoirs comes from data collected on a year-round basis.

Changes in benthic community composition in response to reservoir aging

“…Three permanent transects were established on Pawnee following those used by Hergenrader & Lessig (1980) . Three sampling sites were established on each of these transects (Fig .…”

“…Since results from this study were to be compared to findings obtained by Hergenrader & Lessig (1980) …”

“…Although there are some reports on benthic colonization of reservoirs immediately following first filling (Nursall, 1952 ;Burris 1954 ;Paterson & Fernando, 1969 ;Hergenrader & Lessig, 1980 ;Bass, 1992), there are no published accounts of changes in the composition of the benthos in response to reservoir aging . This may in part be due to a lack of studies on initial benthic composition of new reservoirs and the fact that many such impoundments have only recently exhibited signs of aging .…”

“…Kimmel & Groeger (1986) addressed the process of reservoir aging and some of the limnological changes associated with it, however no mention of benthic compositional changes were made . The objective of this study was to determine the composition of the benthos in Pawnee Reservoir, near Lincoln, NE, to compare these findings to earlier work on the reservoir by Hergenrader & Lessig (1980), and to assess the biological effects of reservoir aging on a major component of this aquatic ecosystem . …”

Insetos aquáticos do açude São José dos Cordeiros (semi-árido paraibano) com ênfase em Chironomidae

“…Mudanças nas variáveis físicas e químicas da água, associadas também a um aumento na quantidade de matéria orgânica suspensa na coluna d'água e nos sedimentos do fundo, produz um envelhecimento do reservatório e um conseqüente decréscimo na biomassa da comunidade bêntica (Hergenrader & Lessig, 1980;Dougherty & Morgan, 1991;Popp & Hoagland, 1995). Sendo que a presença de populações de Chironomus, segundo os autores, pode ser um bom indicador do enriquecimento orgânico do sedimento e de condições eutróficas no reservatório.…”