Effects of local, river-network and catchment factors on fish assemblages in the headwater streams of the Xin'an basin, China

Abstract

Identifying the spatial pattern of fish assemblages and the correlation between fish assemblages and environmental factors is basic for conserving and managing stream fishes. Based on data collected from 91 sampling segments within first-order through third-order streams of the Xin'an basin, China, we examined the spatial variation of fish assemblages in this area and related it to local, river-network and catchment factors. We found that fish species richness significantly increased from first-order to second-and third-order streams, but assemblage structures showed no among-stream variation. When the independent influence of the three categories of factors was considered, fish assemblages were significantly related to local habitat (e.g. wetted and substrate heterogeneity), tributary spatial position (e.g. confluence link and distance from mouth) and land use (e.g. agriculture and urbanization areas), respectively. However, when the effects of the these factors were considered jointly, local habitat and tributary spatial position were more important in influencing fish assemblages than land use. Our results suggest that fish assemblages in the headwater streams of the Xin'an basin were mainly determined by both local and spatial factors. The landscape data should be further refined in the future to provide more information for assessing how land use influence stream fishes.

Spatial and seasonal patterns of fish assemblages in mountain streams of the Ren River, southwest China

“…Similar findings were also observed in the lower Yangtze River, China (Li et al, 2012;Yan et al, 2010;Zhu et al, 2017). Yan et al (2010) observed that fish assemblages in the Puxi Stream were significantly different in spatial variation but not in temporal variation.…”

“…The present study showed fish assemblages in streams of the Ren River basin were structured by a combination of large-scale landscape factors (e.g., altitude and C-link) and local habitat features (e.g., channel width, water temperature, and depth), among which, landscape factors acted as the most important contributor in both wet and dry seasons. The importance of landscape position in structuring fish assemblages has been demonstrated by numerous studies (e.g., Fairchild et al, 1998;He et al, 2017;Li et al, 2012;Smith & Kraft, 2005;Zhu et al, 2017). With regard to landscapes therefore, streams should be regarded as connected networks with a definable "network geometry," rather than a linear hierarchy most represented by stream order (Benda et al, 2004;Smith & Kraft, 2005).…”

Fish Ecology of the Alto Madre de Dios River Basin (Peru): Notes on Electrofishing Surveys, Elevation, Palm Swamp and Headwater Fishes

“…The resulting graphics were also analogous when using both variables (Figure 3). Elevation and distance to mouth are widely used for multivariate analysis [55,56]. Nevertheless, they do not give environmental information, they are geographical variables and indicate spatial position.…”

An Integrative Framework to Control Nutrient Loss: Insights from Two Hilly Basins in China’s Yangtze River Delta

“…The dam, which was completed in 1959, lies southwest of Hangzhou, a beneficiary of the 845 mW of hydropower produced by the structure's generators and a major recipient of the lake's water for drinking as well [38]. The Xin'an River, which enters through the lake's northwestern arm, provides almost 70% of inflows [63], but more than 50 smaller waterways of at least 10 km in length also enter the lake [64].…”

“…Intensively managed tea plantations and orchards now occupy 4.5% and 2.3%, respectively, of the watershed, and greenhouses are also appearing. Most remaining cropland is northwest of the lake in Anhui Province, where agriculture is of small scale and dispersed in remote areas along minor streams [64]. Tea, on the other hand, is a growing factor for land use near the lake in Zhejiang Province, but it is only a minor activity in distant parts of the watershed [72,73].…”