Data from: Inter-group variability in seed dispersal by white-handed gibbons in mosaic forest

Seed dispersers, like white-handed gibbons (Hylobates lar), can display wide inter-group variability in response to distribution and abundance of resources in their habitat. In different home ranges, they can modify their movement patterns along with the shape and scale of seed shadow produced. However, the effect of inter-group variability on the destination of dispersed seeds is still poorly explained. In this study, we evaluate how seed dispersal patterns of this arboreal territorial frugivore varies between two neighboring groups, one inhabiting high quality evergreen forest and one inhabiting low quality mosaic forest. We predicted a difference in seed dispersal distance between the two groups (longer in the poor quality forest). We hypothesized that this difference would be explained by differences in home range size, daily path length, and ranging tortuosity. After six months data collection, the evergreen group had a smaller home range (12.4ha) than the mosaic group (20.9ha), significantly longer daily path lengths (1507m vs 1114m respectively) and greater tortuosity (39.1 vs 16.1 respectively). Using gut passage times and displacement rates, we estimated the median seed dispersal distance as 163 m for the evergreen group (high quality forest) and of 116 m for the mosaic group (low quality forest). This contradiction with our initial prediction can be explained in term of social context, resource distribution, and habitat quality. Our results indicate that gibbons are dispersers of seeds between habitats and that dispersal distances provided by gibbons are influenced by a range of factors, including habitat and social context.

种子传播者（如白掌长臂猿（Hylobates lar））会因栖息地内资源的分布与丰度差异，表现出显著的种群间变异。在不同的家域（home range）中，它们不仅会调整自身的运动模式，还会改变所产生的种子扩散阴影（seed shadow）的形态与规模。然而，种群间变异对种子传播目的地的影响机制仍未得到充分阐释。本研究针对这一树栖领域性食果动物，探究其两个相邻种群的种子传播模式差异：一个种群栖息于高质量常绿阔叶林，另一个则栖息于低质量镶嵌林。我们预测两个种群的种子传播距离存在差异——低质量栖息地种群的传播距离更长。我们假设该差异可通过家域面积、日行进路径长度以及活动路径曲折度（ranging tortuosity）的差异得到解释。历经六个月的数据收集后，我们发现栖息于常绿阔叶林的种群家域面积（12.4公顷）小于镶嵌林种群（20.9公顷），但其日行进路径长度（分别为1507米与1114米）与活动路径曲折度（分别为39.1与16.1）均显著更高。结合肠道滞留时间与移动速率数据，我们估算得到：栖息于高质量常绿林的种群的种子传播中位数距离为163米，而镶嵌林种群的该数值为116米。这一与初始预测相悖的结果，可从社会背景、资源分布与栖息地质量三个方面得到解释。本研究结果表明，长臂猿可实现跨生境的种子传播，且其传播的种子距离受多种因素影响，包括栖息地特征与社会背景。