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Keywords:

  • conservation planning;
  • ecosystem classification;
  • freshwater biodiversity;
  • Yangtze River

Summary

1. The Upper Yangtze River drains a catchment of c. 1 million km2 from its headwaters on the Tibetan Plateau to the city of Yichang below the Three Gorges Dam. The Upper Yangtze River Basin supports a diverse aquatic fauna, including 118 endemic fish species. The river basin has a long history of human use and environmental alteration and is further threatened by the demands of a large population and rapid economic development.

2. We identified a set of areas that, with adequate protection and/or management, might maintain the aquatic biodiversity and ecological processes representative of the basin. Methods were developed to address the scope and scale of conservation planning across the entire Upper Yangtze Basin in a short time-frame using available data. The analytical framework is a watershed hierarchy of five catchment size classes derived from a globally available hydrography dataset called HydroSHEDs. Catchments were assigned to ecosystem types according to catchment area and patterns of climate, catchment morphology, geology and sources of water. Catchments were also ranked by ecological condition using an index of cumulative anthropogenic impacts.

3. We defined conservation priorities as a combination of expert-designated focal areas that support endemic fish assemblages and habitat in good condition; sites selected with the conservation planning software MARXAN to meet representation targets for ecosystems and optimise ecological condition and longitudinal connectivity; and a set of rivers selected to provide refugia for fishes affected by a hydropower and flood control infrastructure development project.

4. Areas selected as conservation priorities include 3200 km (27% of total length) of large rivers, 9900 km (39% of total length) of small rivers and 30% of small stream catchments in the basin. To evaluate the degree to which the set of conservation priority areas supports threatened and endemic fishes, we conducted a gap analysis using survey records and historic range maps of 131 threatened and/or endemic fish species. The conservation priority areas contain survey records or portions of the known historic range of 116 (88%) of the 131 species we evaluated, with an average of 49% of the survey records and/or 26% of the known historic ranges of each species.