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Spatiotemporal variation in the concentrations of mercury (Hg) and arsenic (As) in body feathers of Red-throated Ant-Tanager (Driophlox fuscicauda) and Clay-colored thrush (Turdus grayi) were evaluated. Body feathers were obtained from scientific collections (specimens collected from 1960 to 2011) in Mexico. Trace elements concentrations were determined by voltammetry through acid digestion. Red-throated Ant-Tanager presented higher concentrations of Hg (31.7 ± 23.7 μg/g) and As (7.58 ± 5.84 μg/g) than the Clay-colored thrush (Hg 1.04 ± 0.72 μg/g; As 1.68 ± 1.09 μg/g). In Quintana Roo, were identified three critical regions with Hg (54.4 ± 18.5 μg/g to 67.3 ± 4.5 μg/g) and one with As (15.16 ± 3.79 μg/g). In Red-throated Ant-Tanager there was an oscillatory pattern in Hg concentrations, with the peak in 1993 and As in 2007. In Clay-colored thrush there was also an oscillatory pattern in Hg with a peak in 1974, but in As was from 1960 to 1993 and then decreased. Factors intrinsic to each species such as trophic guild, eating habits, age, could have influenced the difference in the spatial and temporal concentrations obtained. These variations of Hg and As concentrations may be due to the enrichment of anthropogenic trace elements metals by atmospheric deposition., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Protected areas are of paramount relevance to conserving wildlife and ecosystem contributions to people. Yet, their conservation success is increasingly threatened by human activities including habitat loss, climate change, pollution, and species overexploitation. Thus, understanding the underlying and proximate drivers of anthropogenic threats is urgently needed to improve protected areas' effectiveness, especially in the biodiversity-rich tropics. We addressed this issue by analyzing expert-provided data on long-term biodiversity change (last three decades) over 14 biosphere reserves from the Mesoamerican Biodiversity Hotspot. Using multivariate analyses and structural equation modeling, we tested the influence of major socioeconomic drivers (demographic, economic, and political factors), spatial indicators of human activities (agriculture expansion and road extension), and forest landscape modifications (forest loss and isolation) as drivers of biodiversity change. We uncovered a significant proliferation of disturbance-tolerant guilds and the loss or decline of disturbance-sensitive guilds within reserves causing a "winner and loser" species replacement over time. Guild change was directly related to forest spatial changes promoted by the expansion of agriculture and roads within reserves. High human population density and low nonfarming occupation were identified as the main underlying drivers of biodiversity change. Our findings suggest that to mitigate anthropogenic threats to biodiversity within biosphere reserves, fostering human population well-being via sustainable, nonfarming livelihood opportunities around reserves is imperative., Competing Interests: Competing interests statement:The authors declare no competing interest.