Abrupt Ecological Shift and Recovery Trajectory of a Peri-Urban Lake in the Anthropocene: Insights From Paleoecology and Modeling Projection

Urban and peri-urban lakes are undergoing significant ecological deterioration in the fast-changing Anthropocene, leading to toxic algal proliferation jeopardizing ecosystem services and public health. Nevertheless, the ecological response of these lakes to anthropogenic disturbances, management interventions, and climate change remains inadequately understood. This study examined the dynamic trajectory of the algal community from Luoma Lake, a representative peri-urban lake in eastern China, from the 1900s to 2050, based on comprehensive paleoecological investigations and model projections. Phototrophic pigment analysis indicated an exponential increase in algal abundances since the early 2000s, coupled with an abrupt community shift toward eutrophic taxa driven by rapid urbanization, agricultural and fishery practices. Recent rate-based observations suggested a reversal in algal production and cyanobacterial proliferation due to management efforts, signaling an early ecological recovery. However, model projections under two representative climate scenarios (SSP1-2.6 and SSP5-8.5) suggested continued algal abundance growth and accelerated ecological response rates until 2050. This highlighted that the anticipated benefits of nutrient reductions may be diluted by climate warming, posing a significant challenge for future urban lake management. This study underscores the necessity of incorporating climate adaptation into rate-focused management strategies to mitigate adverse ecological impacts. Our findings provide valuable insights for policymakers and contribute to the broader understanding of urban lake ecosystem responses to combined anthropogenic and climatic stressors, offering new perspectives for effective lake restoration in the context of global climate change.