scholarly journals Impact of Methoxychlor on Selected Nontarget Organisms in a Riffle of the Souris River, Manitoba

1989 ◽  
Vol 46 (6) ◽  
pp. 1047-1061 ◽  
Author(s):  
Robert J. Sebastien ◽  
Reinhart A. Brust ◽  
David M. Rosenberg
Keyword(s):  
Aquatic Insect ◽  
Life Cycle Stage ◽  
Artificial Substrates ◽  
Invertebrate Drift ◽  
Insect Community ◽  
Catostomus Commersoni ◽  
Nontarget Organisms ◽  
Pesticide Treatment ◽  
Biological Variables ◽  
High Propensity

The insecticide methoxychlor was applied at 300 μg∙L−1 for 15 min to a riffie on the Souris River, located about 18 km downstream from Souris, Manitoba. Physical, chemical, and biological variables were measured and aquatic insect community structure was monitored using drift, emergence trap, and artificial substrate samplers. All taxa monitored, irrespective of functional feeding group, drifted catastrophically for 4–24 h immediately following methoxychlor addition. Different species demonstrated varying abilities to recoionize artificial substrates following treatment. Species having a high propensity to drift naturally, recolonized most rapidly. Taxa that required the longest period to recoionize following methoxychlor treatment were generally univoltine, had a low propensity to drift, and a limited ability to disperse as adults. Impact of methoxychlor was influenced by the prevalent life-cycle stage of some species at the time of treatment. Catostomus commersoni fry and juvenile Orconectes virilis were more sensitive to methoxychlor than previous research on mature individuals has indicated. Invertebrate drift appeared to be more sensitive to pesticide treatment than benthic invertebrates on artificial substrates. Species richness and total numbers of drift were significantly reduced for at least 33 d following treatment, whereas richness and numbers on artificial substrates were significantly lower for only 4 and 8 d, respectively.

Taxonomic sufficiency and effects of environmental and spatial drivers on aquatic insect community

2019 ◽  
Vol 107 ◽  
pp. 105624
Author(s):  
B.S. Godoy ◽  
A.P.J. Faria ◽  
L. Juen ◽  
L. Sara ◽  
L.G. Oliveira
Keyword(s):  
Aquatic Insect ◽  
Insect Community ◽  
Taxonomic Sufficiency

Spatial and seasonal variability of emergent aquatic insects and nearshore spiders in a subtropical estuary

2019 ◽  
Vol 70 (4) ◽  
pp. 541 ◽  
Author(s):  
Martha J. Zapata ◽  
S. Mažeika P. Sullivan
Keyword(s):  
Aquatic Insects ◽  
High Salinity ◽  
Aquatic Insect ◽  
Freshwater Ecosystems ◽  
Dispersal Ability ◽  
Insect Community ◽  
Insect Communities ◽  
Low Salinity ◽  
Subtropical Estuary ◽  
Adult Aquatic Insects

Variability in the density and distribution of adult aquatic insects is an important factor mediating aquatic-to-terrestrial nutritional subsidies in freshwater ecosystems, yet less is understood about insect-facilitated subsidy dynamics in estuaries. We surveyed emergent (i.e. adult) aquatic insects and nearshore orb-weaving spiders of the families Tetragnathidae and Araneidae in a subtropical estuary of Florida (USA). Emergent insect community composition varied seasonally and spatially; densities were lower at high- than low-salinity sites. At high-salinity sites, emergent insects exhibited lower dispersal ability and a higher prevalence of univoltinism than low- and mid-salinity assemblages. Orb-weaving spider density most strongly tracked emergent insect density rates at low- and mid-salinity sites. Tetragnatha body condition was 96% higher at high-salinity sites than at low-salinity sites. Our findings contribute to our understanding of aquatic insect communities in estuarine ecosystems and indicate that aquatic insects may provide important nutritional subsidies to riparian consumers despite their depressed abundance and diversity compared with freshwater ecosystems.

scholarly journals Effect of land use on the composition, diversity and abundance of insects drifting in neotropical streams

2015 ◽  
Vol 75 (4 suppl 1) ◽  
pp. 52-59 ◽  
Author(s):  
B. C. G. Gimenez ◽  
F. A. Lansac-Tôha ◽  
J. Higuti
Keyword(s):  
Land Use ◽  
Environmental Factors ◽  
Species Composition ◽  
Physiological Adaptation ◽  
Urban Stream ◽  
Invertebrate Drift ◽  
Insect Community ◽  
Generalist Species ◽  
Neotropical Streams ◽  
Wide Range

Abstract Streams may exhibit differences in community structure of invertebrate drift, which may be a reflex of variation in environmental factors, able to change in conditions of anthropogenic interventions. The aim of this study was to analyze the composition, diversity and abundance of insects drifting in two neotropical streams under different land use and to identify the environmental factors involved in determining such patterns. 54 taxa of aquatic insects were identified in urban and rural streams. The results indicated significant differences in species composition due to the replacement of specialist species by generalist species in the urban stream. Higher diversity of taxa was recorded in the rural stream, with high levels of dissolved oxygen and high water flow, which favored the occurrence of sensitive groups to environmental disturbances, such as Ephemeroptera, Plecoptera, Trichoptera and Coleoptera taxa, that living mainly in clean and well oxygenated waters. On the other hand, a higher density of insects drifting, especially Chironomidae, was observed in the urban stream, where high values of pH, electrical conductivity and nitrogen were observed. These larvae are able to explore a wide range of environmental conditions, owing to their great capacity for physiological adaptation. Despite observing the expected patterns, there were no significant differences between streams for the diversity and abundance of species. Thus, the species composition can be considered as the best predictor of impacts on the drifting insect community.

scholarly journals Usefulness of chironomids as a diversity index of aquatic insect community

2005 ◽  
Vol 56 (Supplement) ◽  
pp. 68
Author(s):  
K Kawai ◽  
S Aoki ◽  
H Imabayashi
Keyword(s):  
Diversity Index ◽  
Aquatic Insect ◽  
Insect Community

scholarly journals Intrinsic and extrinsic drivers of succession: effects of habitat age and season on an aquatic insect community

2014 ◽  
Vol 39 (3) ◽  
pp. 316-324 ◽  
Author(s):  
EBONY G. MURRELL ◽  
ANTHONY R. IVES ◽  
STEVEN A. JULIANO
Keyword(s):  
Aquatic Insect ◽  
Insect Community

How does the management of rice in natural ponds alter aquatic insect community functional structure?

2016 ◽  
Vol 67 (11) ◽  
pp. 1644 ◽  
Author(s):  
Marina S. Dalzochio ◽  
Renata Baldin ◽  
Cristina Stenert ◽  
Leonardo Maltchik
Keyword(s):  
Functional Divergence ◽  
Aquatic Insect ◽  
Functional Redundancy ◽  
Rice Fields ◽  
Functional Composition ◽  
Insect Community ◽  
Insect Communities ◽  
Conventional Agriculture ◽  
Organic Rice ◽  
Functional Richness

Changes to biodiversity have mainly been assessed using taxonomic diversity indices. Although these approaches contribute to our scientific understanding of species richness and composition patterns, trait-based metrics may be more useful for detecting responses to land-use change. We compared functional diversity of aquatic insect communities along a gradient of agricultural intensification. Our goal was to compare functional redundancy, functional richness, functional evenness and functional divergence among natural ponds, and organic and conventional rice fields. We recorded 15606 aquatic insects distributed across 61 genera. The highest functional redundancy and richness were observed in the natural ponds, followed by organic rice fields and conventional ones. The functional composition varied among natural ponds and rice fields, and differed between organic and conventional rice fields. Organic management favoured the establishment of some pond insect traits, such as predatory taxa, in rice agroecosystems. Our analysis suggests that the conversion of ponds to rice fields results in a shift to less specialised aquatic insect communities with altered functional composition groups. Nevertheless, this result should not be seen as a negative reflection on organic rice fields, because organic rice production affords a better compromise between agricultural production and ecosystem function than conventional agriculture.

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