Goats at high densities are known to degrade vegetation in arid environments around the world. Their role as potential dispersers of seeds of native and exotic plant species, however, still remains uncertain. This study assesses whether goats, through endozoochorous seed dispersal, may potentially change the plant assemblage of seasonally dry tropical forests. We used seedling emergence as a method to analyze which plant species germinated from goat feces and thus may be dispersed by goats after passing through their intestinal tract. Seedling emergence data were analyzed with respect to the plot vegetation, water availability (permanent, temporary and no water courses), and altitude (as an indicator of anthropogenic pressure). We identified 18 species belonging to 14 families. Feces from the plots near permanent water with the largest anthropogenic pressure were characterized by the highest number of germinated plants. The most common plant species by far found in the experiment was the exotic Prosopis juliflora. This high abundance of P. juliflora seedlings shows that non-native grazers facilitate the spread of exotic plant species in threatened dry forest habitats. We therefore conclude that free-roaming goats may play an important ecological role in changing plant species assemblages of even remote areas.

众所周知，高密度的山羊会导致世界各地干旱环境中的植被退化。然而，它们作为本地和外来植物物种种子的潜在分散剂的作用仍然不确定。这项研究评估了山羊是否通过食道内的种子传播可能会改变季节性干燥热带森林的植物组成。我们使用幼苗出苗作为一种方法来分析哪些植物物种从山羊粪便中萌发，因此可能在山羊通过肠道后被山羊驱散。针对地块植被，水的可利用量（永久，临时和无水流）和海拔高度（作为人为压力的指标）对幼苗出苗数据进行了分析。我们确定了14个科的18种。来自人为压力最大的永久水附近地块的粪便具有发芽植物数量最多的特征。迄今为止，在实验中发现的最常见的植物物种是外来物种桃花Prosopis juliflora。P. juliflora幼苗的高丰度表明，非本地放牧者促进了外来植物物种在受威胁的干旱森林生境中的传播。因此，我们得出的结论是，即使在偏远地区，自由漫游的山羊也可能在改变植物种类组合中发挥重要的生态作用。