Vulnerability of Mnesarete williamsoni (Insecta: Zygoptera) to climate change and loss vegetation cover

Climate change and land-use alterations pose a significant threat to biodiversity, particularly for specialist species. The Amazonian damselfly Mnesarete williamsoni , a forest-dependent species with low dispersal capacity, serves as a suitable model to investigate these impacts due to its strong ecological association with well-preserved forest streams. This study aimed to model the potential distribution of M. williamsoni across three temporal scales: the Last Glacial Maximum (LGM), the present, and a future scenario (2041–2060), testing the hypothesis that climate change and habitat loss will drastically reduce its suitable niche. We employed an ensemble modelling approach that combined Maxent, Random Forest, and Support Vector Machine (SVM) algorithms. Models were calibrated with occurrence records and climatic variables for past, present, and future scenarios (CCSM4 model, RCP 8.5), projected across South America. Our models revealed fluctuations in suitability in habitat. During the LGM, suitable distribution was restricted, suggesting confinement to forest refugia. In the current scenario, a significant expansion of suitable habitat has been observed, mainly within the Belém Endemism Centre. However, future projections indicate a severe contraction, even greater than the restrictions observed during the glacial period, driven by climate change and loss of forest cover. The results highlight the vulnerability of M. williamsoni to anthropogenic disturbances. The projected future contraction emphasizes the urgent need for conservation actions aimed at preserving and restoring forest and riparian corridors in the Belém Center of Endemism. This study reinforces the value of specialist bioindicator species as tools to guide conservation policies and mitigate the impacts of global changes on Amazonian aquatic ecosystems.