Diversity Of Mayflies Research Articles

Preliminary survey of the mayflies (Ephemeroptera) and caddisflies (Trichoptera) of Big Bend Ranch State Park and Big Bend National Park

The mayfly (Insecta: Ephemeroptera) and caddisfly (Insecta: Trichoptera) fauna of Big Bend National Park and Big Bend Ranch State Park are reported based upon numerous records. For mayflies, sixteen species representing four families and twelve genera are reported. By comparison, thirty-five species of caddisflies were collected during this study representing seventeen genera and nine families. Although the Rio Grande supports the greatest diversity of mayflies (n=9) and caddisflies (n=14), numerous spring-fed creeks throughout the park also support a wide variety of species. A general lack of data on the distribution and abundance of invertebrates in Big Bend National and State Park is discussed, along with the importance of continuing this type of research.

Different sensitivity of mayflies (Insecta, Ephemeroptera) to ammonia, nitrite and nitrate: linkage between experimental and observational data

Complex toxic effects of ammonia, nitrite and nitrate to aquatic animals are not well investigated. In rivers of southwestern Siberia, Russia, elevated ammonia and nitrite concentrations corresponded to significant reduction in species diversity of mayflies. The objectives of the study were to evaluate the sensitivity of six mayfly species to the mixture of ammonia, nitrite and nitrate in acute laboratory tests and to compare the sensitivity found with results of the first river bioassessment in the region considered and with species saprobic indexes. The rank of the species sensitivity was: Baetis vernus < Potamanthus luteus < B. fuscatus=Cloeon bifidum < Ephemerella lenoki < Heptagenia sulphurea (p < 0.05). The experiments revealed variation in sensitivity among the species by a factor of 7.5. Comparison of the tests results and the available field data shows that species which exhibit higher tolerance in the tests inhabit comparatively greater amount of sites include contaminated places. Final conclusion is addressed in comparison of the results found with more spatially and temporally extensive observations. Saprobic indexes of the species and their acute tolerances (LC50s) tend to be positively correlated (r=0.93, p=0.02).

Among-taxon congruence in biodiversity patterns: can stream insect diversity be predicted using single taxonomic groups?

The utility of single taxonomic groups as indicators of biodiversity variation in other taxa has recently gained increasing attention, but such studies on stream organisms are lacking. We studied the diversity patterns of mayflies, stoneflies, caddisflies, and chironomid midges across 110 headwater streams in Finland. Specifically, we examined if species richness and assemblage composition showed similar variation among the taxonomic groups across environmental gradients and if a single taxon could be used as a predictor of diversity in the other groups. Species richness and composition in different taxa exhibited slightly different relationships to environmental gradients, leading to low degrees of concordance. The diversity of mayflies and chironomids showed strongest relationships with stream acidity and water colour, whereas stoneflies and caddisflies exhibited more complex correlations with geographical location and local environmental variables. The overall assemblage composition, however, exhibited significant among-taxon congruence, as shown by Mantel tests. However, even these correlations remained rather low, thus limiting their potential for conservation purposes. Overall, our results do not support the use of single taxonomic groups as indicators of insect biodiversity in headwater stream ecosystems. Alternative approaches for lotic biodiversity assessment (e.g., morphospecies, higher-taxon richness, and environmental diversity) should thus be examined in future studies.

Mayflies (Insecta: Ephemeroptera) and the assessment of ecological integrity : a methodological approach

Mayflies (Ephemeroptera) play an important role in almost all undisturbed freshwater communities and their larvae frequently form a considerable part of the material sampled during biomonitoring procedures. Mayfly taxa are widely accepted as bioindicators for water quality and form an integral part of standardized systems for the saprobic evaluation of running waters. Nevertheless, successful interpretation of data depends heavily on sampling strategies and the technical concepts adopted therein. The following paper discusses current problems affecting the correct assessment of mayfly community structure and proposes basic requirements to improve the meaningfulness of limnological routine sampling with regard to Ephemeroptera. The topics covered include: mayfly diversity in different types of freshwater communities in Europe; natural habitats and sampling sites / sampling strategies; life cycles and minimum sampling frequency; level of identification and interpretation of data.

Effects of differing inter-disturbance intervals on the diversity of mayflies recolonizing disturbed sites in a tropical stream

Field experiments to determine the effects of inter-disturbance intervals on the diversity of mayflies recolonizing disturbed subsites in the Naro Moru River, Kenya, were undertaken from June 1993 to January 1994. Stirring, shifting and relocation of streambed substrates by hand was used to delimit physical disturbance, which was also the act of sampling. Continuous disturbance had a distinct depressant effect on mayfly species diversity. No species diversity differences were observed between day and night (one-way ANOVA, p >0.05) at short inter-disturbance intervals of between 10 and 40 min. Medium/intermediate inter-disturbance intervals of between I and 10h had significant effect on species diversity (F (15, 132) = 5.25, p 0.05). The shorter the interval before the next disturbance, the greater was the species diversity decline. The short and long inter-disturbance intervals are important to stream ecosystems since they regulate species diversity in time and space. The increase and/or decrease in species diversity of the mayflies recolonizing the disturbed subsites, and the patterns thereof, may reflect mayfly mobility, especially in foraging for food and search for habitat and refuge.

Mayfly fauna (Ephemeroptera) and the biology of the species Potamanthus luteus (L.) in a warmed stretch of the Oslava River

Cooling waters of the Oslavany power station show a depressive effect on the species diversity of mayfly nymphs. Only seven of 35 taxons found in the study area occurred in all localities. In the warmed stretch of the river, the abundance and biomass of mayfly nymphs as well as the production of the most important speciesPotamanthus luteus decreased; a gradual regeneration of the disturbed mayfly population could be observed downstream. In Locality 5, situated 3.5 km downstream from the mouth of cooling waters, the species diversity, abundance, and biomass of mayflies were 69, 30, and 66 per cent, resp., of values found in Locality 1 with natural temperatures; the production ofPotamanthus luteus was 70 per cent of that found in Locality 1.