Abstract Paleolimnological studies provide valuable long-term records of environmental changes, crucial for assessing ecosystem services (ES) and understanding how aquatic ecosystems respond to various pressures. This study employs an integrated approach, combining paleolimnological, monitoring, and socioeconomic data to investigate changes in two interconnected reservoirs. Geochemical measurements related to eutrophication and metal contamination, along with monitoring data and official statistics, were used to identify the main drivers influencing the ES in these reservoirs. A stratigraphically constrained cluster analysis defined the primary paleoenvironmental zones. Standardized aggregated values for each ES were calculated. Redundancy Analysis was applied to investigate potential external drivers of these temporal changes, using demographic and economic data. The sediment profile revealed that significant changes were linked to eutrophication, characterized by increased nutrient levels, higher phytoplankton biomass (Chlorophyll-a and Pheophytin), and dominance of carotenoid pigments from Chlorophyceae and Cyanobacteria. Eutrophication intensified between the mid-1990s and early 2000s, leading to notable changes in ES by 2022, especially in support and regulation services. Although metal distribution did not adversely affect biological communities, it indicated increased anthropogenic activity. Provisioning services also faced challenges due to reduced reservoir flows, exacerbated by low precipitation and population growth. The impacts were more severe in the Jaguari than in the Jacareí reservoir, attributed to different land-use patterns. To mitigate these ES trade-offs, where enhancing one service diminishes another, investments in infrastructure and strategies to control diffuse pollution. Recommendations include land-use planning, wetland restoration, reforestation, and recovery of riparian vegetation to improve water security and address extreme drought effects.
Cardoso-Silva et al. (Fri,) studied this question.