TY - JOUR
T1 - Assessing the natural and anthropogenic influences on basin-wide fish species richness
AU - Cheng, Su Ting
AU - Herricks, Edwin E.
AU - Tsai, Wen Ping
AU - Chang, Fi John
N1 - Funding Information:
This work was funded by the Ministry of Science and Technology, Taiwan , R.O.C. (Grant No. 104-2313-B-002-023-MY3 ). We are grateful to the Academia Sinica, Water Resources Agency of Ministry of Economic Affairs, and Environmental Protection Administration of Executive Yuan (Taiwan) for providing water quality and fish distribution data. We greatly thank Chia-Yu Lin and Chi-Jyun Yu for assistance with data management. We also sincerely thank Dr. Michael J. Wiley at the University of Michigan, Ann Arbor for his insights related to this work. Last, we are grateful to the editors and three anonymous reviewers for their constructive comments and suggestions that helped improve our manuscript.
Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2016/12/1
Y1 - 2016/12/1
N2 - Theory predicts that the number of fish species increases with river size in natural free-flowing rivers, but the relationship is lost under intensive exploitation of water resources associated with dams and/or landscape developments. In this paper, we aim to identify orthomorphic issues that disrupt theoretical species patterns based on a multi-year, basin-wide assessment in the Danshuei River Watershed of Taiwan. We hypothesize that multiple human-induced modifications fragment habitat areas leading to decreases of local fish species richness. We integrally relate natural and anthropogenic influences on fish species richness by a multiple linear regression model that is driven by a combination of factors including river network structure controls, water quality alterations of habitat, and disruption of channel connectivity with major discontinuities in habitat caused by dams. We found that stream order is a major forcing factor representing natural influence on fish species richness. In addition to stream order, we identified dams, dissolved oxygen deficiency (DO), and excessive total phosphorus (TP) as major anthropogenic influences on the richness of fish species. Our results showed that anthropogenic influences were operating at various spatial scales that inherently regulate the physical, chemical, and biological condition of fish habitats. Moreover, our probability-based risk assessment revealed causes of species richness reduction and opportunities for mitigation. Risks of species richness reduction caused by dams were determined by the position of dams and the contribution of tributaries in the drainage network. Risks associated with TP and DO were higher in human-activity-intensified downstream reaches. Our methodology provides a structural framework for assessing changes in basin-wide fish species richness under the mixed natural and human-modified river network and habitat conditions. Based on our analysis results, we recommend that a focus on landscape and riverine habitats and maintaining long-term monitoring programs are crucial for effective watershed management and river conservation plans.
AB - Theory predicts that the number of fish species increases with river size in natural free-flowing rivers, but the relationship is lost under intensive exploitation of water resources associated with dams and/or landscape developments. In this paper, we aim to identify orthomorphic issues that disrupt theoretical species patterns based on a multi-year, basin-wide assessment in the Danshuei River Watershed of Taiwan. We hypothesize that multiple human-induced modifications fragment habitat areas leading to decreases of local fish species richness. We integrally relate natural and anthropogenic influences on fish species richness by a multiple linear regression model that is driven by a combination of factors including river network structure controls, water quality alterations of habitat, and disruption of channel connectivity with major discontinuities in habitat caused by dams. We found that stream order is a major forcing factor representing natural influence on fish species richness. In addition to stream order, we identified dams, dissolved oxygen deficiency (DO), and excessive total phosphorus (TP) as major anthropogenic influences on the richness of fish species. Our results showed that anthropogenic influences were operating at various spatial scales that inherently regulate the physical, chemical, and biological condition of fish habitats. Moreover, our probability-based risk assessment revealed causes of species richness reduction and opportunities for mitigation. Risks of species richness reduction caused by dams were determined by the position of dams and the contribution of tributaries in the drainage network. Risks associated with TP and DO were higher in human-activity-intensified downstream reaches. Our methodology provides a structural framework for assessing changes in basin-wide fish species richness under the mixed natural and human-modified river network and habitat conditions. Based on our analysis results, we recommend that a focus on landscape and riverine habitats and maintaining long-term monitoring programs are crucial for effective watershed management and river conservation plans.
UR - http://www.scopus.com/inward/record.url?scp=84993953512&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84993953512&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2016.07.120
DO - 10.1016/j.scitotenv.2016.07.120
M3 - Article
C2 - 27592326
AN - SCOPUS:84993953512
SN - 0048-9697
VL - 572
SP - 825
EP - 836
JO - Science of the Total Environment
JF - Science of the Total Environment
ER -