Doctoral Dissertation Improvement: Diet, Ranging Patterns and Social Behavior of Lar Gibbons at Huai Kha Khaeng, Thailand: Exploring the Limits of Flexibility

在Thad Bartlett博士的指导下，Lydia Overbaugh将在泰国怀康野生动物保护区(HKK)探索濒危白手长臂猿的行为灵活性程度。生活在香港的白手长臂猿生活在一个在许多方面都是独一无二的环境中。首先，这片森林比其他白手长臂猿研究地点要干燥得多，降雨量不到其他地方的一半，使这片森林成为白手长臂猿范围内的生态极端。其次，森林是东南亚最大的连续保护区的一部分，这减少了人为压力，同时保持了基本完好的大型哺乳动物群落(包括大象、老虎、8种昼夜活动的灵长类动物、两只豹和两只金丝雀)。最后，香港长臂猿生活在一种镶嵌景观中，包括季节性干燥的常绿、丘陵常绿、落叶和落叶龙脑果林类型。这为研究白手长臂猿如何在其活动范围的极端和不同的栖息地对生态差异做出反应提供了一个独特的机会。为了确定栖息地质量如何影响长臂猿的行为和生态，我们将在12个月的时间里研究6个长臂猿社会群体的取食和活动行为，以检验以下预测：第一，常绿森林中的长臂猿将(I)活动范围更小，每天旅行更少，(Ii)花费更少的时间觅食，(Iii)拥有更高质量的食物；第二，这些差异是由果树密度所表明的家乡质量差异的结果。目前人类进化的假说倾向于增加人的行为和饮食灵活性，以解释我们血统的成功。通过研究远亲类人猿物种的灵活性程度，我们可以更好地评估灵活性是人类独有的创新这一断言。正如许多长臂猿研究人员所描述的那样，长臂猿依赖于常绿森林，这项研究将展示白手长臂猿如何应对生态边缘栖息地。此外，长臂猿主要是一夫一妻制，但在一些种群中记录到了显著的一夫多妻制和一夫多妻制，这些发生与生态差异有关，例如季节和地理资源的可获得性。因此，这个项目将增加我们对栖息地质量在维持白手长臂猿社会一夫一妻制方面的作用的理解。拟议的项目将有助于研究生培训，增加妇女参与科学研究，同时促进一个为少数群体服务的机构。此外，建立一个新的现场将提供培训泰国现场助理和指导美国本科生的机会。这项拟议的研究最切实的影响是它对灵长类保护的适用性。通过更好地了解在不同生态条件下和在该物种的生态极端情况下行为的灵活性程度，该项目将为白手长臂猿的保护政策提供信息。在缺乏其他更严重濒危长臂猿物种的全面知识的情况下，这些知识也可以暂时用于保护目的。

Under the guidance of Dr. Thad Bartlett, Lydia Overbaugh will explore the degree of behavioral flexibility in the endangered white-handed gibbon in the Huai Kha Khaeng Wildlife Sanctuary (HKK), Thailand. White-handed gibbons living at HKK inhabit an environment that is unique in many ways. First, the forest is considerably drier than other white-handed gibbon study sites, receiving less than half the amount of rainfall than elsewhere, making this forest the ecological extreme of the range of white-handed gibbons. Second, the forest is part of the largest continuous protected area in Southeast Asia, which has led to the reduction in anthropogenic stresses while maintaining a largely intact large mammal community (including elephant, tiger, 8 diurnal primates, two leopards and two canids). Finally, gibbons at HKK inhabit a mosaic landscape, including seasonally dry evergreen, hill evergreen, mixed deciduous and deciduous dipterocarp forest types. This presents a unique opportunity to examine how white-handed gibbons respond to ecological differences at the extreme of their range and in a diversity of habitats. To determine how habitat quality impacts gibbon behavior and ecology, the feeding and ranging behavior of 6 gibbon social groups will be studied over a period of 12 months to test the following predicitions: first, that gibbons in evergreen forest will (i) have smaller home ranges and travel less per day, (ii) spend less time foraging, and (iii) have a higher quality diet; and second, that these differences are a result of differences in home range quality as indicated by the density of fruiting trees.Current hypotheses in human evolution favor an increase in the behavioral and dietary flexibility of Homo as an explanation for the success of our lineage. By examining the degree of flexibility present in a more distantly related ape species, we can better evaluate the assertion that flexibility is a uniquely human innovation. As many gibbon researchers have described gibbons as being dependent upon evergreen forest, this study will demonstrate the ways in which white-handed gibbons cope with ecologically marginal habitats. Furthermore, gibbons are primarily monogamous, but significant rates of polyandry and polygyny have been recorded for some populations and these occurrences have been linked to ecological differences such as seasonal and geographic resource availability. This project will therefore increase our understanding of the role of habitat quality in the maintenance of social monogamy in white-handed gibbons.The proposed project will assist in graduate student training and increase the participation of women in scientific research while promoting a minority-serving institution. Additionally, the establishment of a new field site will provide opportunities for training Thai field assistants and instructing US undergraduate students. The most tangible impact of the proposed research is its applicability to primate conservation. By better understanding the degree of behavioral flexibility under distinct ecological conditions and at this species' ecological extreme, this project will inform conservation policies for white-handed gibbons. This knowledge can also provisionally be used for conservation purposes in the absence of comprehensive knowledge of other more critically endangered gibbon species.