The perception of the impacts of climate change in communities surrounding Lake Titicaca, Peru-Bolivia.

<ns3:p> Background Climate change is increasingly transforming socio-ecological systems in high-Andean regions, particularly in communities surrounding Lake Titicaca, where livelihoods depend heavily on climate-sensitive activities such as agriculture, fisheries, livestock, and tourism. Despite growing environmental pressures, limited evidence exists regarding how local populations and institutional actors perceive climate-related impacts and adaptive responses in this transboundary region. This study analyzes climate change perceptions, perceived impacts, and adaptation capacities in communities located in Puno Bay (Peru) and Cohana Bay (Bolivia). Methods A mixed-methods approach integrating quantitative and qualitative techniques was applied during fieldwork conducted in November 2024 and June 2025 in the communities of Quehuaya, Capachica, Guaqui, and Puno. Data collection included structured surveys administered to 62 community members and 26 institutional actors, semi-structured interviews, participatory workshops, and participatory mapping exercises. Descriptive statistics, chi-square tests, and Spearman correlations were used for exploratory quantitative analysis, while qualitative information was analyzed through thematic coding and socio-ecological interpretation. Results Findings revealed high levels of climate change awareness among community members (85.5%) and institutional actors (100%). Respondents identified reduced rainfall, increasing temperatures, hydrological variability, declining agricultural productivity, reduced fish availability, and tourism-related impacts as the principal perceived effects. Significant differences were identified regarding adaptation measures (χ <ns3:sup>2</ns3:sup> = 14.96, p &lt; 0.001) and institutional support (χ <ns3:sup>2</ns3:sup> = 18.32, p &lt; 0.001), evidencing structural inequalities in adaptive capacity. A moderate positive correlation (ρ = 0.36, p = 0.003) was observed between climate perception and reported impacts. Conclusions Climate change is widely recognized across Lake Titicaca communities; however, adaptive capacity remains uneven due to disparities in institutional support, resources, and technical knowledge. Strengthening multi-level governance, participatory adaptation strategies, and transboundary cooperation is essential for improving resilience in Andean socio-ecological systems. </ns3:p>