Post-restoration monitoring of water quality and avifaunal diversity of Pashan Lake, Pune, India using a citizen science approach

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At a global scale, aquatic habitats within urban areas can be degraded by a multitude of stressors, and restoring these habitats is costly and challenging. Furthermore, post-restoration monitoring is rarely done or documented. Pashan Lake in Pune, India has been the site of an integrated restoration project since 2005, which was implemented after the lake suffered a decline in quality as a result of increased urbanization and changes in catchment land cover. These restoration efforts focused on improving the abiotic and biological integrity of the lake and included draining, extracting silt and construction debris, developing 2 islands for birds and the planting of indigenous tree species. To assess long-term restoration benefits on the biological and chemical status of the lake, volunteers from the local community and schools were trained to regularly assess water quality following globally recognized and standardized water testing methods suitable for citizen science. In parallel, bird populations around Pashan Lake were studied to identify relationships between species richness or abundance and water conditions. Measurements were made each month during the 18-mo period from December 2014 to June 2016. We found that species richness and abundance of birds around the lake increased following restoration and that nutrient concentrations (N-NO3 and P-PO4) decreased within the lake. Changes in avifauna diversity were most strongly associated with hydrological conditions related to water-level fluctuation and chemical conditions related to pH. Peak turbidity levels were observed during later winter and summer periods, which were weakly and positively correlated to wetland bird diversity. Citizen scientist assessments of lake ecosystems that combine water-quality tests, wetland bird surveys, and visual observations of environmental conditions provided important insights into the effectiveness of restoration activities in this urban ecosystem. Furthermore, citizen science increased advocacy in the local community.