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

Abstract

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.

Recognition of Patterns of Benthic Diatom Assemblages within a River System to Aid Bioassessment

“…Hence, understanding biological patterns and their driving forces can aid in the identification of the stressors affecting them [1]. For a given river system, the assessment of changes in lotic assemblage structures/patterns and functions responding to stressors, namely bioassessments, could not only indicate the causes of degradation in the biological condition, but also guide proper watershed management practices [2][3][4]. Therefore, in recent decades, lotic bioassessments have been increasingly included as foundational components of watershed management plans [5,6].…”

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

“…Concerning to the macroinvertebrate composition, the most abundant family was Baetidae, which is globally distributed (Dallas, 2004;Mathooko and Mavuti, 1992), and thus it cannot be considered particularly indicative, although its low abundance has been stated to be indicative of impoverished ecological status (Elias et al, 2014;Shimba and Jonah, 2016;Zhang et al, 2018). Another widely distributed taxa, Diptera, was not abundant compared to the reference sites sampled in other studies focused on African systems (Dallas and Mosepele, 2007;Kasangaki et al, 2006;Mathooko and Mavuti, 1992).…”

Microbial community structure and functional properties in permanently and seasonally flooded areas in Poyang Lake

“…4). In the wet season, the re-flooding process in the emerged areas could cause the release of sedimentary nutrients 42 , and these nutrients might determine bacterial functional attributes 14,65,66 .…”

“…Poyang Lake shows typical interlacing changes among water and land due to the influence of water level fluctuations 14,15 . During the dry season, there is only a narrow and meandering channel in PYL due to the decrease in the water level 66,77,78 . With water drawdown, many inundated and emerged areas emerge in the dry seasons 15,34 .…”