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Integrated assessment of ecosystem health using multiple indicator species

Zhao, C., Shao, N., Yang, S., Ren, H., Ge, Y., Zhang, Z., Zhao, Y., Yin, X.
Ecological engineering 2019 v.130 pp. 157-168
aquatic communities, aquatic ecosystems, ecological restoration, ecosystem services, environmental health, fish, fish health, freshwater, health effects assessments, health status, humans, indicator species, phytoplankton, rivers, stakeholders, uncertainty, water management, zooplankton, China
Healthy river ecosystems can provide fundamental ecological services for human survival and social development. However, previous studies that have sought to assess river ecosystem health have primarily focused on individual biological communities rather than on all aquatic communities and have been based on a single-index assessment method, thereby leading to large uncertainties in the results. In this study, we developed a new framework for the integrated assessment of aquatic ecosystem health based on the principal communities of fish, zoobenthos, phytoplankton, and zooplankton in rivers. An index of biotic integrity was used to evaluate the health of fish and zoobenthos communities, and a diversity index was used to evaluate the health of zooplankton and phytoplankton communities. To integrate the health assessment results from these four communities, a quantile normalization method was developed, where uncertainties in assessments obtained using the diversity index were well compensated for by the assessments obtained using the biotic integrity index. The framework was then applied to a pilot city, which is being constructed as a civilized freshwater ecological city in China. The results were then compared with those previously obtained based on the single-community method. Using this new framework, we found that the aquatic ecosystem health changed regularly in space and over time. Large differences were detected among the assessments of the four individual communities based on the single-community method, with the health score determined using phytoplankton being the highest, followed by that of zoobenthos, zooplankton, and fish, which made it difficult to reach a definitive conclusion regarding aquatic health status. The integrated assessment framework presented in this study successfully overcame the narrow perspective of the single-community method, thereby reducing uncertainties in the assessments based only on a single diversity index, and instead provides a comprehensive view of the status of aquatic ecosystem health. Thus, this integrated framework could assist river managers and stakeholders in developing comprehensive strategies for ecological restoration and water resource management and could become a key research tool for the health assessment and rehabilitation of aquatic ecosystems globally.