Determining the macroinvertebrate community indicators and relevant environmental predictors of the Hun-Tai River Basin (Northeast China): A study based on community patterning

[EN] It is essential to understand the patterning of biota and environmental influencing factors for proper rehabilitation and management at the river basin scale. The Hun-Tai River Basin was extensively sampled four times for macroinvertebrate community and environmental variables during one year. Self-Organizing Maps (SOMs) were used to reveal the aggregation patterns of the 355 samples. Three community types (i.e., clusters) were found (at the family level) based on the community composition, which showed a clearly gradient by combining them with the representative environmental variables: minimally impacted source area, intermediately anthropogenic impacted sites, and highly anthropogenic impacted downstream area, respectively. This gradient was corroborated by the decreasing trends in density and diversity of macroinvertebrates. Distance from source, total phosphorus and water temperature were identified as the most important variables that distinguished the delineated communities. In addition, the sampling season, substrate type, pH and the percentage of grassland were also identified as relevant variables. These results demonstrated that macroinvertebrates communities are structured in a hierarchical manner where geographic and water quality prevail over temporal (season) and habitat (substrate type) features at the basin scale. In addition, it implied that the local-scale environment variables affected macroinvertebrates under the longitudinal gradient of the geographical and anthropogenic pressure. More than one family was identified as the indicator for each type of community. Abundance contributed significantly for distinguishing the indicators, while Baetidae with higher density indicated minimally and intermediately impacted area and lower density indicated highly impacted area. Therefore, we suggested the use of abundance data in community patterning and classification, especially in the identification of the indicator taxa. (C) 2018 Elsevier B.V. All rights reserved.This work was supported by the National Natural Science Foundation of China (51779275, 41501204, 51479219) and the IWHR Research & Development Support Program (WE0145B532017).Zhang, M.; Muñoz Mas, R.; Martinez-Capel, F.; Qu, X.; Zhang, H.; Peng, W.; Liu, X. (2018). Determining the macroinvertebrate community indicators and relevant environmental predictors of the Hun-Tai River Basin (Northeast China): A study based on community patterning. The Science of The Total Environment. 634:749-759. https://doi.org/10.1016/j.scitotenv.2018.04.021S74975963

Investigating the influence of habitat structure and hydraulics on tropical macroinvertebrate communities

[EN] The influences of habitat structure and hydraulics on tropical macroinvertebrate communities were investigated in two foothill rivers of the Udzungwa Mountains (United Republic of Tanzania) to assist future Environmental Flow Assessments (EFAs). Macroinvertebrate samples, hydraulic variables and habitat structure were collected at the microhabitat scale (n = 90). Macroinvertebrate communities were first delineated (i.e. clustered) through Poisson and negative binomial mixture models for count data in a semi-supervised mode by taking into account the sampled river. Then, genetically optimised Multi-Layer Perceptrons (MLPs) were used to identify the relationship of the most relevant variables with the delineated communities. Between the three delineated communities exclusively one community was shared between both rivers. The first and third communities presented similar values of richness (i.e. number of families) and diversity but the first was characterised by high abundance and was dominated by Baetidae (43.2%) while Hydropsychidae (36.3%) dominated the third community. The second community was dominated by Baetidae (33.4%), but it involved low abundance, richness and diversity samples and encompassed the microhabitats where no-macroinvertebrates were found. The performance of the MLP acknowledged the quality of the delineation and it indicated that the first community shows a clear affinity for microhabitats with aquatic vegetation and woody debris and the third for unshaded, fast flowing and shallow microhabitats on intermediate-sized substrate. Conversely, the second community occurred in deep and shaded microhabitats with low flow velocity and coarse substrate. We demonstrated that habitat structure and hydraulics are able to properly discriminate the macroinvertebrate communities, which, in turn, underlines their importance as drivers of community composition and abundance. Aquatic vegetation, woody debris, velocity and substrate index, followed by depth and shade, emerged as the most discriminant variables to understand macroinvertebrate communities in these tropical running waters. These results should enhance the implementation of ongoing and future EFA studies. (C) 2018 European Regional Centre for Ecohydrology of the Polish Academy of Sciences. Published by Elsevier B.V. All rights reserved.This study was financed by the United States Agency for International Development (USAID) as part of the Technical Assistance to Support the Development of Irrigation and Rural Roads Infrastructure Project (IRRIP2), implemented by CDM International Inc. J. Sanchez-Hernandez was supported by a postdoctoral grant from the Galician Plan for Research, Innovation, and Growth (Plan I2C, Xunta de Galicia).Muñoz Mas, R.; Sánchez-Hernández, J.; Mcclain, M.; Tamatamah, R.; Mukama, SC.; Martinez-Capel, F. (2019). Investigating the influence of habitat structure and hydraulics on tropical macroinvertebrate communities. Ecohydrology & Hydrobiology. 19(3):339-350. https://doi.org/10.1016/j.ecohyd.2018.07.005S33935019

The use of Artificial Neural Networks (ANNs) in aquatic ecology

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Dispersal Capabilities of Two Plecopteran Species and Macroinvertebrate Community from Four Watersheds in Northeast Ohio

This dissertation focused on the insect order Plecoptera, and hypothesized that Allocapnia recta populations would have lower genetic diversity than Leuctra tenuis between adjacent Chagrin and Grand Rivers due to wing structure and season of terrestrial adult emergence. Genetic variations within the 16s rRNA region of mtDNA in A. recta, a winter emerging adult with rudimentary wing structure, and L. tenuis, a summer emerging adult with fully developed wings, were compared and revealed significant genetic variability between A. recta samples from the two rivers (FST = 0.20) but not between L. tenuis samples (FST = 0.07). Further genetic variation investigation used A. recta, populations, within and between the Chagrin River and Grand River, hypothesized that differences in populations is a function of distance, and that greater distance leads to greater genetic variability. To strengthen the robustness of this work, samples were collected from two additional watersheds, the Rocky and Cuyahoga Rivers. Genetic variation of A. recta populations differed significantly across all four watersheds, especially between the Cuyahoga and Grand Rivers (G\u27ST = 1), Rarity of movement regardless of distance suggests that other factors have a more profound effect than previously thought - factors that include human influences. The unresolved genetic variation of A. recta and potential human influence resulted in a holistic examination of macroinvertebrate community structure and ecology within the four watersheds. Both legacy land use and anthropogenic disturbance effects on seasonal variation were examined and it was hypothesized that: (1) greatest species diversity and richness among stoneflies and other macroinvertebrates will occur during the summer months, when weather conditions in Ohio are more conducive. (2) The greatest species diversity and richness among stoneflies and other macroinvertebrates will occur where the landscape has been historically less disturbed. The results revealed inconsistencies in season

Dispersal Capabilities of Two Plecopteran Species and Macroinvertebrate Community from Four Watersheds in Northeast Ohio

This dissertation focused on the insect order Plecoptera, and hypothesized that Allocapnia recta populations would have lower genetic diversity than Leuctra tenuis between adjacent Chagrin and Grand Rivers due to wing structure and season of terrestrial adult emergence. Genetic variations within the 16s rRNA region of mtDNA in A. recta, a winter emerging adult with rudimentary wing structure, and L. tenuis, a summer emerging adult with fully developed wings, were compared and revealed significant genetic variability between A. recta samples from the two rivers (FST = 0.20) but not between L. tenuis samples (FST = 0.07). Further genetic variation investigation used A. recta, populations, within and between the Chagrin River and Grand River, hypothesized that differences in populations is a function of distance, and that greater distance leads to greater genetic variability. To strengthen the robustness of this work, samples were collected from two additional watersheds, the Rocky and Cuyahoga Rivers. Genetic variation of A. recta populations differed significantly across all four watersheds, especially between the Cuyahoga and Grand Rivers (G\u27ST = 1), Rarity of movement regardless of distance suggests that other factors have a more profound effect than previously thought - factors that include human influences. The unresolved genetic variation of A. recta and potential human influence resulted in a holistic examination of macroinvertebrate community structure and ecology within the four watersheds. Both legacy land use and anthropogenic disturbance effects on seasonal variation were examined and it was hypothesized that: (1) greatest species diversity and richness among stoneflies and other macroinvertebrates will occur during the summer months, when weather conditions in Ohio are more conducive. (2) The greatest species diversity and richness among stoneflies and other macroinvertebrates will occur where the landscape has been historically less disturbed. The results revealed inconsistencies in season

Dispersal Capabilities of Two Plecopteran Species and Macroinvertebrate Community from Four Watersheds in Northeast Ohio

This dissertation focused on the insect order Plecoptera, and hypothesized that Allocapnia recta populations would have lower genetic diversity than Leuctra tenuis between adjacent Chagrin and Grand Rivers due to wing structure and season of terrestrial adult emergence. Genetic variations within the 16s rRNA region of mtDNA in A. recta, a winter emerging adult with rudimentary wing structure, and L. tenuis, a summer emerging adult with fully developed wings, were compared and revealed significant genetic variability between A. recta samples from the two rivers (FST = 0.20) but not between L. tenuis samples (FST = 0.07). Further genetic variation investigation used A. recta, populations, within and between the Chagrin River and Grand River, hypothesized that differences in populations is a function of distance, and that greater distance leads to greater genetic variability. To strengthen the robustness of this work, samples were collected from two additional watersheds, the Rocky and Cuyahoga Rivers. Genetic variation of A. recta populations differed significantly across all four watersheds, especially between the Cuyahoga and Grand Rivers (G\u27ST = 1), Rarity of movement regardless of distance suggests that other factors have a more profound effect than previously thought - factors that include human influences. The unresolved genetic variation of A. recta and potential human influence resulted in a holistic examination of macroinvertebrate community structure and ecology within the four watersheds. Both legacy land use and anthropogenic disturbance effects on seasonal variation were examined and it was hypothesized that: (1) greatest species diversity and richness among stoneflies and other macroinvertebrates will occur during the summer months, when weather conditions in Ohio are more conducive. (2) The greatest species diversity and richness among stoneflies and other macroinvertebrates will occur where the landscape has been historically less disturbed. The results revealed inconsistencies in season

Characterising historic ecological conditions in lowland rivers: applying palaeoecological techniques to river restoration planning

It is widely recognized that anthropogenic activities have resulted in significant changes to the ecology and hydromorphology of riverine ecosystems globally. Across much of lowland England a number of riverine habitats and the flora and fauna inhabiting them, have been lost or disadvantaged by historic channel modifications. Many of the most significant modifications took place in the decades following World War II, in a drive to increase food security through improved land drainage and associated flood management. A better understanding of the geomorphological, hydrological and biodiversity elements that have been compromised or lost is required in order to characterise the benefits of planned measures to restore and reinstate channel form and function for EU WFD, Habitats Directive and other conservation designations (e.g. SSSI condition assessments). To generate this understanding in an environment where natural processes have been impacted over large spatial scales, an innovative palaeoecological approach is employed in this thesis that provides a window on historic riverine ecology and habitat conditions so that the contemporary channel and community inhabiting it can be gauged prior to the implementation of river restoration programmes. The analysis of historic archival material (maps, photographs, local authority and management records), and the detailed investigation of sedimentary records and sub-fossil insect remains (Trichoptera, Coleoptera and Gastropoda) associated with in-channel bars, weirs, bridges and palaeochannels is used in this thesis in order to achieve this. These records will provide data regarding changes to the aquatic macroinvertebrate community and instream hydromorphology within specific reaches/biotopes/habitats subjected to historical physical modification. The historic data (documents and palaeoenvironmental data) is analysed in parallel with contemporary data on instream habitats and faunal community composition to define benchmark conditions on three Site of Special Scientific Interest rivers. This approach enables a comparison between past and present channel hydromorphology and the instream faunal communities. The characterisation of benchmarks provides a baseline for future conservation and restoration policies within riverine ecosystems that can be used to help define pre-impacted or reference conditions. The research presented in this thesis has relevance to the conservation objectives of rivers with special designations (e.g. SSSI and Habitats Directive) for wildlife and to meeting the wider requirements of the Water Framework Directive