Chironomid Abundance Research Articles

Benthos of Lake Glubokoe

This paper presents the results of studies on the benthos of Lake Glubokoe in 1980 as compared to data for 1949 and 1950. The abundance of chironomids increased at medium depths, that of oligochaetes became higher along the entire depth and that of Chaoborus remained the same. The community of Sergentia was replaced by that of Chironomus.

Recolonisation of macrobenthic invertebrates in a Nigerian stream after pesticide treatment and associated disruption

Recolonisation of macrobenthic invertebrates in a tropical stream perturbed by pesticide treatment and associated human activities is discussed. The benthic community, dominated by Chironomidae, Baetidae and Naididae, was stable during the predisruption phase. The disruption severely reduced the standing crop and the diversity of macrobenthos. The recovery of the habitat was rapid. In spite of low diversity, high densities of invertebrates were recorded in the recolonisation phase. Naidids and chironomids were the most successful recolonisers while other groups recovered slowly. Most of the recolonising taxa occurred here during the pre-disruption phase and there were only a few new colonisers. The succession of recolonising taxa was distinct. The abundance of naidids and chironomids was extremely high in the initial stages of recolonisation and thereafter decreased rapidly.

Life history and abundance of the predaceous psammophilous mayfly Pseudiron centralis McDunnough (Ephemeroptera: Heptageniidae)

Aspects of the life history and abundance of Pseudiron centralis McDunnough were examined in the Sand River in east central Alberta. The population exhibited a univoltine summer life cycle, spending 9 to 10 months of the year in the egg stage. Eggs were large (0.33 × 0.41 mm; mean dry weight, 0.005 mg). Larvae were associated with three types of substrate in the river bed: shifting sand, marginal sand, and gravelly sand. Larvae were active epibenthic predators, feeding primarily on psammophilous chironomid larvae. Larval density was low (< 4 larvae/m2); however, larval mortality also appeared to be low. Stage III and IV larvae exhibited a random dispersion pattern. Annual production (instantaneous growth method) was estimated to be 28.70 and 11.24 mg∙m−2∙year−1 in 1980 and 1981, respectively. The relatively large size of first-instar larvae may allow them to cope with the dynamics of sandy substrates, or may be the minimum size that can effectively capture and consume chironomid larvae. Although chironomid abundance in sandy substrates remains high throughout the year, P. centralis larvae exploit this resource for only a short period.

Production and Ecology of Benthic Chironomid Larvae (Diptera) in Lake Hayes, New Zealand, a Warm‐monomictic Eutrophic Lake

AbstractThe distribution and abundance of larval chironomids in Lake Hayes were studied from December 1973 to March 1975. The mean annual production of the two dominant species, Chironomus zealandicus and Chironomus sp. a, was 29.2 g m−2 dry weight which is approximately 4.3 % of the average annual phytoplankton production in the lake. A high annual P/B ratio of 18.5 is consistent with the multivoltine life cycle of C. zealandicus. Larval chironomid production in the second summer when Anabaena blooms were absent was only one quarter of that in the first summer and is consistent with the hypothesis that the production of benthic chironomids in Lake Hayes is closely linked to that of the phytoplankton through the sedimentation of autochthonous organic matter.

Field experiments on interactions between vertebrate predators and larval midges (Diptera: Chironomidae) in the littoral zone of a reservoir.

A field experiment was designed to test a frequent assumption in the literature that vertebrate predators (in this case, fish and turtles) are capable of regulating the seasonal abundance and diversity of benthic communities in the littoral zone of lentic environments. Effects of thermal effluents from a nuclear reactor on predator-prey relationships were also examined. Benthic samples were removed after each of three, 3-month test periods from 36 predator exclusion cages (4m2) and 36 control plots located along a thermal gradient in Par Pond, an 1,100 ha freshwater reservoir in the southeastern United States.Results of our field experiments provide little evidence to suggest that either a single "keystone" species or vertebrate predators as a group were capable of regulating the abundance, diversity or productivity of chironomids in Par Pond. The relationship between predator treatment and community response (changes in density and species richness) was generally unaffected by either plot location or temperature fluctuations. When data from caged and control plots were pooled, however, both location and water temperature individually had significant impacts on the chironomid community. Alternative hypotheses are proposed to explain the lack of regulatory control of the benthic community by individual species or guilds of predators.

Macrobenthos of Simmons Bayou and an Adjoining Residential Canal

Species composition, abundance and seasonal variations of benthic macroinvertebrates in Simmons Bayou, Mississippi, and an adjoining deadend canal were investigated from July 1976 through June 1977. Cluster analysis of the data summed over five stations indicated four major time periods: July, August -November, Dccember-February, and March-June. Polychaetes and oligochaetes were most abundant in the winter and spring, amphipods in the summer, and chironomids in the spring. Temporal changes in abundance of polychaetes, oligochaetes, and chironomids appeared to reflect seasonal reproductive cycles. The peak in amphipod density correspondcd with dense growths of Ruppia maritima. Within the deadend canal, poor water quality and reduced infaunal densities appeared to be limitcd to the deeper water behind the sill.

A synoptic study of the limnology of Lake Thonotosassa, Florida

Limnological sampling of Lake Thonotosassa was initiated in 1970 to document current conditions following 15 years of artificial enrichment by organic wastes from primary treated sewage and citrus processing plants, and to provide base-level data for a long-term study of the rates of change following the installation of a secondary sewage treatment facility. Results from the first year of study indicated that the lake was in an advanced state of eutrophy. Inorganic nutrient levels were high; oxygen deficits occurred in the hypolimnion and at the mud-water interface; phytoplankton volumes were large and dominated by blue-green algae; primary productivity rates were comparable with those of grossly polluted lakes; small-bodied herbivores dominated the zooplankton; and benthic invertebrate populations were comprised of an overwhelming abundance of oligochaetes and chironomids. Construction of the new sewage treatment plant reduced the organic load and B. O. D. of the incoming waters and benthic diversity in the inlet subsequently increased. However, in the lake itself decreases in coliform bacteria concentrations were the only signs of immediate influence.

Characteristics of Yellow Perch Cannibalism in Oneida Lake and the Relation to First Year Survival

Abstract Because adult yellow perch were known to be cannibalistic in Oneida Lake, New York, this species was studied in 1965-71 to identify factors affecting the intensity of cannibalism and to evaluate the effect of cannibalism on the abundance of young perch. Adult perch changed their food habits in response to changes in the availability of different food items from June through September. Although young-of-the-year perch were most abundant in adult stomachs in August of most years, wide variations occurred in the annual intensity of cannibalism. Length and abundance of young perch, abundance of large chironomids and amphipods, and the size of the adult predator were identified as important factors for explaining variations in the frequency of occurrence of young perch in stomachs of adults. Correlations between the annual intensity of perch cannibalism and length and abundance of young perch imply that cannibalism operates as a compensatory or possibly an extrapensatory mortality process. The consump...