Using climatic-geomorphological surrogates to identify complete and incidental freshwater conservation gaps within large river basins in China

Freshwater wetlands play an important role in preserving global biodiversity and substantial ecosystem services, but they are exposed to higher pressures and threats and have received less attention in conservation planning in comparison to terrestrial ecosystems. Although a number of freshwater protected areas have been established in China, considerable freshwater conservation gaps still exist where ecologically valuable freshwater wetlands are vulnerable to anthropogenic threats, our study therefore explored systematic conservation planning specifically suited to freshwater ecosystems for the large river basins in China. A scheme of Climatic-geomorphological Classification of Freshwater Ecosystems (CGCFEs) was developed and employed as broad-scale surrogates based on their unique ecohydrological processes and biodiversity assemblages. A freshwater conservation assessment was conducted for each river basin using a complementaritybased planning framework (i.e., systematic conservation planning) and the prioritization software Marxan in consideration of the conservation targets of CGCFEs. Our research also demonstrated the need to introduce the concept of incidental gaps (IGs) in freshwater conservation planning, where the focal species and ecosystems have unintentionally been incorporated into a nature reserve with different conservation targets and thus created conservation gaps due to incidental and unfocused conservation efforts. The identified complete gaps (CGs) and IGs accounted for 10.56% and 8.66% of the total freshwater area respectively, implicating the need to enhance freshwater conservation efficacy by realigning existing conservation patterns to address these gaps. Our research provides a spatially explicit freshwater conservation strategy at the river basin and national scales and thus enables the central government and wetland resource managers to set ecologically meaningful spatial conservation priorities for freshwater ecosystems within those major large river basins. In addition, the methodology of using CGCFEs can be replicated for large-scale freshwater conservation planning elsewhere and promote freshwater conservation efficiency by capturing irreplaceable freshwater habitats.

Automated summary

Freshwater wetlands play a crucial role in preserving biodiversity and ecosystem services globally, yet conservation planning for these areas in China still faces gaps and challenges. By introducing the CGCFE scheme, a systematic conservation planning framework was applied to prioritize conservation efforts and address unintentional gaps, aiming to enhance freshwater conservation efficacy for major river basins in China.