| Abstrakt: |
Understanding the impact of mangrove vegetation and environmental conditions over rodents' occurrence allow to optimize conservation efforts, due to the fact these mammals are sensitive to extremely changing habitat conditions, such as changes in stand structure, floristic composition and flooding variations by daily tide. Using site-occupancy models, we aimed to assess the effect of mangrove species composition and stand structure together with flooding variations in rodent occupancy patterns in mangroves of Laguna de Cuyutlán, West-Central Mexico. We recorded two rodent species: Oryzomys couesi and Hodomys alleni, and one marsupial: Tlacuatzin canescens. Hodomys alleni is considered the first report for mangrove ecosystems. In total, we captured 41 individuals, 34 of O. couesi, six of H. alleni and one of T. canescens. Six models had substantial AIC weight (Akaike weight > 0.10; ΔAIC < 2), with Basal Area (BA) and Diameter at Breast Height (DBH) as important occurrence covariates. Adult tree and seedling density were important covariates when associated to floristic composition. Models including floristic composition, BA and DBH ranked high in explaining Oryzomys couesi occurrence. For Hodomy alleni, occupancy models suggest that tidal variation and BA have a significant impact on their occurrence probability as the Akaike weight and ΔAIC sustained (w > 0.13; ΔAIC < 2). Our results suggested that mangrove species composition, stand structure and daily tide significantly explained rodents' occupancy. Contrary to our expectations, rodents did not prefer higher floristic richness nor more mature mangrove forest stands. Our results also revealed the ability of O. couesi to change its patterns of occurrence associated to seasonal flooding conditions, but only in mangrove zones where water conditions rise and fall, suggesting an adaptation to daily tidal fluctuations. Variability in O. couesi occupancy patterns may reveal interesting implications on its plasticity to different environmental conditions in a climate change framework. [ABSTRACT FROM AUTHOR] |
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