Supporting Information to the paper Sousa J. B. D. et al. Effects of grazing on functional diversity along secondary succession in a tropical dry forest Applied Vegetation Science.

Question: Livestock production is among the main anthropogenic disturbances in seasonally dry tropical forests. However, their effects on plant functional composition in dry forests are poorly understood. Our goal was to analyze the variations in both functional composition and functional diversity of plant communities under goat grazing and fallow age scenarios in a tropical dry forest.Location: Brazilian dry forest (Caatinga) in Rio Grande do Norte State, northeastern Brazil.Methods: We measured the height, leaf area, and specific leaf area of all shrub-tree and herbaceous species along a gradient varying in stocking rate, years of grazing, and fallow age. Additionally, we quantified the foliar contents of nitrogen, phosphorus, and tannins in the tree shrub layer. We tested the effects of grazing and deforestation using linear mixed models. Results: Our findings suggest that the functional diversity of plant communities in the Caatinga is not altered when goat grazing and secondary succession are examined independently. However, a combined consideration of both factors have affected the functional diversity only in the herbaceous layer. Although grazing influenced specific traits in the shrub-tree layer, the overall functional diversity remained unaltered by grazing, succession, or their interaction.Conclusions: Grazing does not interfere with the natural succession process nor diminish the functional diversity of plant communities in the Caatinga. Therefore, with appropriate management, grazing can coexist with the conservation goals of the Caatinga.

研究问题：畜牧生产是季节性干旱热带森林的主要人为干扰因素之一，但目前学界对其在干旱森林中对植物功能组成的影响仍知之甚少。本研究旨在分析巴西干旱森林内，山羊放牧与休耕年限情景下植物群落的功能组成与功能多样性变化。研究区域：巴西东北部北里奥格兰德州境内的巴西干旱森林（Caatinga）。研究方法：本研究沿放牧载畜量、放牧年限及休耕年限的梯度，测定了所有灌乔木与草本物种的株高、叶面积及比叶面积；此外，还定量测定了灌乔木层的叶片氮、磷及单宁含量。本研究采用线性混合模型检验放牧与森林砍伐的影响效应。研究结果：本研究结果显示，当单独考察山羊放牧与次生演替时，卡廷加植被的植物群落功能多样性并未发生改变；但当同时考量这两个因素时，仅在草本层中观测到功能多样性受到影响。尽管放牧对灌乔木层的部分功能性状存在影响，但整体功能多样性并未因放牧、演替及其交互作用而发生变化。研究结论：山羊放牧既不会干扰卡廷加植被的自然演替过程，也不会降低其植物群落的功能多样性。因此，通过合理的管理措施，放牧可与卡廷加植被的保护目标共存。