Aim Data and analyses of elevational gradients in diversity have been central to the development and evaluation of a range of general theories of biodiversity. Elevational diversity patterns have, however, been severely understudied for microbes, which often represent decomposer subsystems. Consequently, generalities in the patterns of elevational diversity across different trophic levels remain poorly understood. Our aim was to examine elevational gradients in the diversity of macroinvertebrates, diatoms and bacteria along a stony stream that covered a large elevational gradient. Location Laojun Mountain, Yunnan province, China. Methods The sampling scheme included 26 sites spaced at elevational intervals of 89 m from 1820 to 4050 m elevation along a stony stream. Macroinvertebrate and diatom richness were determined based on the morphology of the specimens. Taxonomic richness for bacteria was quantified using a molecular fingerprinting method. Over 50 environmental variables were measured at each site to quantify environmental variables that could correlate with the patterns of diversity. We used eigenvector‐based spatial filters with multiple regressions to account for spatial autocorrelation. Results The bacterial richness followed an unexpected monotonic increase with elevation. Diatoms decreased monotonically, and macroinvertebrate richness showed a clear unimodal pattern with elevation. The unimodal richness pattern for macroinvertebrates was best explained by the mid‐domain effect (r2 = 0.72). The diatom richness was best explained by the variation in nutrient supply, and the increase in bacterial richness with elevation may be related to an increased carbon supply. Main conclusions We found contrasting patterns in elevational diversity among the three studied multi‐trophic groups comprising unicellular and multicellular aquatic taxa. We also found that there may be fundamental differences in the mechanisms underlying these species diversity patterns.
Aim While ecologists have long been interested in diversity in mountain regions, elevational patterns in beta diversity are still rarely studied across different life forms ranging from micro‐ to macroorganisms. Also, it is not known whether the patterns in turnover among organism groups are affected by the degree to which the environment is modified by human activities. Location Laojun Mountain, Yunnan Province, China. Methods The beta diversity patterns of benthic microorganisms (i.e. diatoms and bacteria) and macroorganisms (i.e. macroinvertebrates) in a stony stream were simultaneously investigated between elevations of 1820 and 4050 m. Data were analysed by using a distance‐based approach and variation partitioning based on canonical redundancy analysis. Results Analyses of community dissimilarities between adjacent sampling sites showed comparable small‐scale beta diversity along the elevational gradient for the organism groups. However, bacteria clearly showed the lowest elevational turnover when analyses were conducted simultaneously for all pairwise sites. Variation partitioning indicated that species turnover was mostly related to environmental heterogeneity and spatial gradients including horizontal distance and elevation, while purely human impacts were shown to be less important. Main conclusions The elevational beta diversity at large scales was lower for bacteria than for eukaryotic microorganisms or macroorganisms, perhaps indicative of high dispersal ability and good adaptability of bacteria to harsh environmental conditions. However, the small‐scale beta diversity did not differ among the groups. Elevation was the major driver for the turnover of eukaryotic organisms, while the turnover of bacteria was correlated more with environmental variation.
This paper summarizes the history and current status of efforts to implement macroinvertebrate biomonitoring protocols for surface water pollution in China, Japan, South Korea, Malaysia, Mongolia, Russia (Far East), and Thailand. Impediments to biomonitoring in some of these countries include: (1) lack of knowledge about macroinvertebrate fauna and their tolerance values, especially during the aquatic, immature stages; (2) the scarcity of research programs and formal training opportunities for biomonitoring offered in universities; (3) the shortage of high‐quality microscopes and other necessary equipment; and (4) limited government understanding and support for biomonitoring, few skilled regulatory staff, and the persistence of old and unusable biomonitoring protocols. A recently established regional network, the Aquatic Entomological Society of East Asia (AESEA), and several major recent publications are helping to coordinate and promote science and technology in East Asia.
The jumping organ (furcula) is the most characteristic structure among collembolans, and it is of great taxonomical values at higher levels. The largest superfamily Entomobryoidea is traditionally classified into four families only by the morphology of the furcula. Actually, many taxa among these families are strikingly similar in morphology without considering furcula. The phylogeny of Entomobryoidea was reconstructed here based on mitochondrial and ribosomal fragments. This indicated that both Paronellidae and Cyphoderidae were ingroups within Entomobryidae with the former polyphyletic. Topology tests, which used the likelihood and Bayesian approaches, also rejected the traditional hypotheses relying on furcula morphology. Further ancestral state reconstructions have revealed that traditional taxonomical characters, i.e., furcula and body scales, had multiple independent origins in Entomobryoidea whereas tergal specialized chaetae (S-chaetae) exhibited strong phylogenetic signals. By integrating both molecular and morphological evidence, the results of this study drastically undermine the present classification of Entomobryoidea. Tergal S-chaetotaxic pattern in combination with other characters are more reasonable in taxonomy at suprageneric levels than convergent furcula. This study provides new insights of the jumping organ, which could be adaptively modified during evolution of Collembola.
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