Shrub encroachment in semi-arid rangelands is a phenomenon associated with changes in floristic composition, loss of diversity and ecosystem degradation, enhanced by inappropriate grazing practices. However, the outcome depends on the species' identity and the management carried out. The objective of this study was to evaluate shrub species dynamics and their effect on plant community composition in a Monte rangeland of Argentina, under conservative grazing management at two different working scales. During two years, ground-based vegetation and soil cover measurements were performed in patches with and without shrubs using Daubenmire and Canfield's methods. Herbaceous and woody species recorded were classified according to their functional traits and forage value. Specific richness, Shannon's diversity index and Pielou's evenness were calculated. At a larger-scale evaluation, Sentinel-2A satellite images from year 2016–2022 were classified into three cover classes to evaluate the shrub encroachment process. Although an increase in shrub presence was observed over the years at both scales no effect was found on the diversity and specific composition, nor on the occurrence of forage species. Shrub presence promotes the coexistence of species with different functional traits and creates favorable conditions for soil protection and the establishment of desirable species for livestock purposes.

中文翻译：

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阿根廷布宜诺斯艾利斯西南部半干旱牧场的灌木侵占不会影响植物多样性和组成

半干旱牧场的灌木侵占是一种与植物区系组成变化、多样性丧失和生态系统退化有关的现象，不适当的放牧做法加剧了这种现象。然而，结果取决于物种的特性和所进行的管理。本研究的目的是评估阿根廷蒙特牧场在两种不同工作规模的保守放牧管理下的灌木物种动态及其对植物群落组成的影响。在两年的时间里，使用 Daubenmire 和 Canfield 的方法对有或没有灌木的斑块进行了地面植被和土壤覆盖测量。记录的草本和木本物种根据其功能特征和饲料价值进行分类。计算了具体丰富度、Shannon多样性指数和Pielou均匀度。在更大规模的评估中，2016年至2022年的Sentinel-2A卫星图像被分为三个覆盖类别，以评估灌木丛侵蚀过程。尽管多年来在这两个尺度上都观察到灌木存在的增加，但没有发现对多样性和特定组成以及饲料物种的出现有影响。灌木的存在促进了具有不同功能性状的物种的共存，并为土壤保护和建立畜牧业所需物种创造了有利的条件。