Effects of large mammalian herbivores on woody vegetation tend to be heterogeneous in space and time, but the factors that drive such heterogeneity are poorly understood. We examined the influence of fine‐scale habitat heterogeneity on the distribution and browsing effects of two of the largest African terrestrial mammals, the elephant and giraffe. We conducted this study within a 120‐ha (500 x 2,400 m) ForestGEO long‐term vegetation monitoring plot located at Mpala Research Center, Kenya. The plot traverses three distinct topographic habitats (“plateau,” “steep slopes,” and “valley”) with contrasting elevation, slope, soil properties, and vegetation composition. To quantify browsing damage, we focused on Acacia mellifera, a palatable tree species that occurs across the three habitat categories. Overall tree density, species richness, and diversity were highest on the steep slopes and lowest on the plateau. Acacia mellifera trees were tallest and had the lowest number of stems per tree on the steep slopes. Both elephant and giraffe avoided the steep slopes, and their activity was higher during the wet season than during the dry season. Browsing damage on Acacia mellifera was lowest on the steep slopes. Elephant browsing damage was highest in the valley, whereas giraffe browsing damage was highest on the plateau. Our findings suggest that fine‐scale habitat heterogeneity is an important factor in predicting the distribution of large herbivores and their effects on vegetation and may interact with other drivers such as edaphic variations to influence local variation in vegetation structure and composition.

中文翻译：

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细微的栖息地异质性影响大象和长颈鹿的浏览损害

大型食草动物对木本植物的影响在空间和时间上往往是异质的，但是导致这种异质性的因素却鲜为人知。我们研究了细微的栖息地异质性对非洲最大的两种陆地哺乳动物（大象和长颈鹿）的分布和浏览效果的影响。我们在肯尼亚Mpala研究中心的120公顷（500 x 2,400 m）ForestGEO长期植被监测区中进行了这项研究。该地块横越了三个截然不同的地形生境（“高原”，“陡坡”和“谷”），它们的海拔，坡度，土壤特性和植被组成形成鲜明对比。为了量化浏览损害，我们重点研究了相思树，一种可口的树种，分布在三个栖息地类别中。总体树木密度，物种丰富度和多样性在陡坡上最高，而在高原上最低。在陡坡上，相思树最高，每棵树的茎数最少。大象和长颈鹿都避开了陡峭的斜坡，在雨季，它们的活动要比旱季高。浏览对金合欢的伤害在陡峭的斜坡上最低。大象的浏览伤害在山谷中最高，而长颈鹿的浏览伤害在高原上最高。我们的研究结果表明，细微的栖息地异质性是预测大型草食动物的分布及其对植被影响的重要因素，并且可能与其他驱动因素（如前生变化）相互作用，从而影响植被结构和成分的局部变化。