Hydrologic connectivity driven natural stream fish assemblages in mountain streams in the Yangtze River basin: implications for stream fish conservation in monsoonal East Asia

Abstract

The East Asian monsoon and related seasonal rain belts are assumed to be significantly variable at intraseasonal, interannual, and interdecadal time scales, and largely determine the hydrology and ecological processes of the streams and rivers in this region. This study investigated the spatiotemporal variation in fish assemblages and the relative importance of local habitat and regional landscape variables in two protected streams in the middle Yangtze River basin. We hypothesized that the stream fish assemblages in this area are strongly influenced by the monsoon climate, and display a spatiotemporal variation in response to changes of stream flow regimes and physical habitats. The results show that species richness and abundance varied with both season and stream size. The distance to the downstream confluence site was the top important environmental factor, followed by altitude and downstream link. The results suggest that the fish assemblages within this protected watershed are mainly affected by regional landscape variables such as longitudinal position and stream position, but less by local habitat variables including water temperature and habitat types. The study highlights the importance of tributary connectivity and continuity to stream fish diversity in this area, indicating that restoration activities should preferentially recover the connectivity between upstream and downstream.Handling editor: M. Power

Pareuchiloglanis hupingshanensis, a new species of the glyptosternine catfish (Siluriformes: Sisoridae) from the middle Yangtze River, China

“…Recently, two new records of Schizothorax, S. prenanti Tchang and S. griseus Pellegrin, were reported from the Lishui River (He et al 2016). In addition, an endemic blind stone loach, Triptophysa xiangxiensis Yang Yuan & Liao, occurs in the adjacent drainage, upper Youshui River, another tributary of Lake Dongting .…”

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

“…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).…”

“…Osborne and Wiley ( 1992 ) observed D‐link explained the greatest portion of the variance in fish species richness and suggested downstream processes significantly influence the structure of fish assemblages. In addition, seasonal variations in environmental conditions caused by periodic flooding are expected to have significant impacts on stream fish assemblages (He et al., 2017 ; Ostrand & Wilde, 2002 ). Flooding can increase the diversity and availability of habitat structures and food resources and then lead to changes in fish assemblages between dry and wet seasons (Araújo et al., 2009 ).…”

“…In recent years, similar studies have been also conducted in China. However, nearly all these studies were concentrated in central and eastern regions (He et al., 2017 ; Li et al., 2012 ; Yan et al., 2010 ; Zhu et al., 2017 ). Southwest China contains a large number of streams and rivers and supports a diverse range of fishes, yet has received little attention.…”

“…Osborne and Wiley (1992) observed D-link explained the greatest portion of the variance in fish species richness and suggested downstream processes significantly influence the structure of fish assemblages. In addition, seasonal variations in environmental conditions caused by periodic flooding are expected to have significant impacts on stream fish assemblages (He et al, 2017;Ostrand & Wilde, 2002).…”