Data from: Foraging impacts of Asian megafauna on tropical rainforest structure and biodiversity

Megaherbivores are known to influence the structure, composition, and diversity of vegetation. In Central Africa, forest elephants act as ecological filters by breaking tree saplings and stripping them of foliage. Much less is known about impacts of megafauna on Southeast Asian rain forests. Here, we ask whether herbivory by Asian megafauna has impacts analogous to those of African forest elephants. To answer this, we studied forest (1) structure, (2) composition, (3) diversity, and (4) tree scars in Belum and Krau, two protected areas of Peninsular Malaysia, and compared the results with those obtained in African forests. Elephants are abundant in Belum but have been absent in Krau since 1993. We found that stem density and diversity, especially of tree saplings, were higher in Krau than in Belum. Palms and other monocots were also more abundant in Krau. In Belum, however, small monocots (<1 m tall) were very abundant but larger ones (>1 m tall) were virtually absent, suggesting size-selective removal. The frequency of stem-break scars was equal at Belum and Krau but less than in Central Africa and greater than in the Peruvian Amazon where tapirs are the only megafauna. Pigs and tapirs could also contribute to the high frequency of tree scars recorded in Malaysian forests. Forest-dwelling elephants in Asia seem to have a reduced impact on tree saplings compared to African forest elephants, but a very strong impact on monocots.

巨型植食动物（Megaherbivores）已知会影响植被的结构、组成与多样性。在中非地区，森林象（forest elephants）通过折断树苗并剥去其叶片，扮演着生态过滤器的角色。目前学界对巨型动物群对东南亚热带雨林的影响却知之甚少。本研究旨在探讨亚洲巨型动物群的植食作用，是否与非洲森林象具有相似的生态影响。为解答这一问题，我们对马来半岛两处保护区——贝卢姆（Belum）与克劳（Krau）的森林展开研究，分析了（1）森林结构、（2）植被组成、（3）物种多样性，以及（4）树木伤痕情况，并将研究结果与非洲森林的相关数据进行对比。贝卢姆境内大象种群数量充足，而克劳自1993年起便无大象栖息。研究发现，克劳的茎干密度与物种多样性（尤其是树苗的相关指标）均高于贝卢姆；棕榈类与其他单子叶植物（monocots）在克劳的丰度也更高。但在贝卢姆，小型单子叶植物（株高<1米）数量极多，而大型个体（株高>1米）却几乎绝迹，这表明存在按体型选择性移除的现象。两地的茎断裂伤痕出现频率相当，但均低于中非地区，却高于以貘（tapirs）为唯一巨型动物群的秘鲁亚马逊地区。野猪与貘或许也对马来西亚森林中较高的树木伤痕频率存在贡献。相较于非洲森林象，亚洲栖息的森林象对树苗的影响似乎有所减弱，但对单子叶植物却具有极强的调控作用。