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Referenztyp Zeitschriften
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Titel (primär) The key role of increased fine sediment loading in shaping macroinvertebrate communities along a multiple stressor gradient in a Eurasian steppe river (Kharaa River, Mongolia)
Autor Schäffer, M.; Hellmann, C.; Avlyush, S.; Borchardt, D.;
Journal / Serie International Review of Hydrobiology
Erscheinungsjahr 2020
Department ASAM;
Band/Volume 105
Heft 1-2
Sprache englisch;
POF III (gesamt) T32;
Supplements https://onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1002%2Firoh.201902007&file=iroh201902007-sup-0001-Table_and_Figure_captions_support_inf_new.docx
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Keywords anthropogenic impact; community metrics; continental climate; river bank erosion; steppe rivers
Abstract Aquatic communities across the Eurasian steppe face increasing anthropogenic pressures due to rapid population growth, catchment wide land‐use changes and climate change. The particular type, intensity, overlay and legacy of impacts along longitudinal gradients of Eurasian river networks provide a unique setting to investigate ecological responses in identifiable multiple stressor environments. We studied macroinvertebrate communities along the Kharaa River, Mongolia, which displays a distinct, downstream gradient of moderate nutrient enrichment, disturbed bank morphology, reduced riparian vegetation, elevated turbidity, increased fine sediment substrate proportions and fine sediment intrusion into the hyporheic zone. Within the encountered ranges of physical and chemical environmental factors (TP 0.02 ‐ 0.09 mg l‐1, TN 0.33 ‐ 0.96 mg l‐1, conductivity 167 ‐ 322 µS cm‐1, FNU 0.62 ‐ 5.43) and hyporheic fine sediment intrusion (0.9 ‐ 1.6 g DW l‐1 d‐1) population densities and biomass of macroinvertebrates were high (5313 ± 410 individuals m‐2 and 2656 ± 152 mg dry weight m‐2) and notably stable. In contrast, macroinvertebrate community structure showed strong and statistically significant negative linear relationships (Pearson's r) with turbidity, i.e. for taxa richness (r = ‐0.83), Shannon Index of Diversity (r = ‐0.89), Evenness (r = ‐0.86), relative abundance of EPT individuals (r = ‐0.93) and relative biomass of hard substrate colonisers (r = ‐0.86). Relative biomasses of fine substrate colonisers as well as Chironomidae and Oligochaeta (both r = 0.76) were positively correlated with mean turbidity values. In addition, the Proportion of Sediment‐sensitive Invertebrates (PSI) methodology was adjusted for local application and resulting index scores followed a similar pattern, with PSI also being significantly correlated (r = 0.66) with the relative abundance of EPT individuals, the latter being the most sensitive macroinvertebrate community index. We conclude that fine sediment load is the key factor for shaping macroinvertebrate community structure in the multi‐stressor setting of the Kharaa River followed by hydromorphological habitat complexity determined by shear stress, substrate and grain size distributions. We suggest that the implementation of effective regional management strategies aiming at the reduction of fine sediment pollution should be given the highest priority.
ID 22510
dauerhafte UFZ-Verlinkung https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=22510
Schäffer, M., Hellmann, C., Avlyush, S., Borchardt, D. (2020):
The key role of increased fine sediment loading in shaping macroinvertebrate communities along a multiple stressor gradient in a Eurasian steppe river (Kharaa River, Mongolia)
Int. Rev. Hydrobiol. 105 (1-2), 5 - 19