Abstract: We assessed the habitat suitability of macrobenthos in the upper and middle reaches of the Heihe River, with the dominant species Argyroneta aquaticaas the indicator species. Three indicator factors, including dissolved oxygen (DO), water temperature (WT), and sediment (SD), were selected from the habitat environmental factors. The habitat suitability curves of the three indicator factors were established, and the habitat suitability index (HSI) of A. aquatica at each site was calculated. The results showed that A. aquatica prefers pebble riverbeds, with the ranges of optimum dissolved oxygen (DO) concentration being 7.21-9.17 mg·L^-1, and the range of optimum water temperature (WT) being 17.25-22.10 ℃. The average HSI values in the upper and middle reaches of the Heihe River were 0.66 for the upper tributary, 0.63 for the upper mainstream, and 0.81 for the middle reaches. The upper tributary and upper mainstream reaches of Heihe River were under a suitable state, and the middle reaches were under the most suitable state for macrozoobenthos. Results of spatial variability analysis showed that human activities had little impact on the habitats of macrozoobenthos in the upper tributary and middle reaches of the Heihe River. Water temperature was the main factor restricting the habitat suitability of the upper tributary. The construction of cascade reservoir was an important factor affecting the habitat of macrozoobenthos in the upper reaches of Heihe River.

Key words: Heihe River, macrozoobenthos, habitat, suitability.