4.3 Implications for conservation
This study was the first to describe the spatial-temporal variation of
fish assemblages in mountain streams in the southwest China. Information
obtained from this study will enhance our understanding of the variation
in fish assemblages, and then help to develop strategies for future fish
diversity protection in such mountain streams. A total of 21 fish
species were collected during the sampling period. Among which, S.
macrolepis and S. prenanti have been considered as vulnerable.
These species used to be important commercial targets in Ren River
basin. However, compared to history records, their distribution range
has shrunk significantly, and their population size has declined
seriously (Zeng 1991). In addition, the miniaturization tendency of
these two species has become evident (Zeng 1991). The survive prospect
of S. prenanti is gloomier, as only three specimens of were
collected during our study period. Overfishing might be the main reason
responsible for this phenomenon (Zeng 1991). To protect these vulnerable
species, the local government should strengthen fishery management and
fight against illegal strictly. In addition, the present study indicated
that fish assemblages in streams of the Ren River basin were influenced
mainly by landscape factors, such as altitude and C-link. Specially,R . oxycephalus , a representative cold-water species, was
restricted to headwaters and small tributaries with higher elevation.
This species is an excellent bioindicator species low-temperature water
and a good model species for studying freshwater fish biogeographic,
because of their typically low dispersal ability and restriction to
small mountain habitats (Yu et al. 2014). Climate change and
anthropogenic interferences have seriously threatened this species (Yu
et al. 2014). Therefore, to maintain the stability of fish assemblage
structure in such stream ecosystems, human activities that will destroy
the naturality and connectivity of stream habitat, such as
deforestation, dredging and damming, should be forbidden strictly.
Acknowledgements This study was supported by the National
Natural Science Foundation of China (31400359), Natural Science
Foundation of Shanxi (2018JQ5121) and Sino BONāInland Water Fish
Diversity Observation Network. The authors are grateful to Lixia Shi,
Zhi Zhang, Liangxia Su, Nenghan Wang, Jian Zhang and Chunsen XU for
their help in filed samplings.