Fluctuations of population density in Bornean orangutans (Pongo pygmaeus morio) related to fruit availability in the Danum Valley, Sabah, Malaysia: a 10-year record including two mast fruitings and three other peak fruitings

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• 作者：Tomoko Kanamori ; Noko Kuze ; Henry Bernard ; Titol Peter Malim ; Shiro Kohshima
• 关键词：Orangutans ; Population estimate ; Marked nest count ; Seasonal movement
• 刊名：Primates
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：58
• 期：1
• 页码：225-235
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Zoology; Animal Ecology; Behavioral Sciences; Evolutionary Biology;
• 出版者：Springer Japan
• ISSN：1610-7365
• 卷排序：58

文摘

We investigated the population density of Bornean orangutans (Pongo pygmaeus morio) and fruit availability for 10 years (2005–2014), in primary lowland dipterocarp forests in the Danum Valley, Sabah, Malaysia. During the research period, two mast fruitings and three other peak fruiting events of different scales occurred in the study area. The orangutan population density, estimated every 2 months by the marked nest count method, changed between 0.3 and 4.4 ind/km2 and the mean population density was 1.3 ind/km2 ± SE 0.1 (n = 56). The population density increased markedly during mast and peak fruiting periods. A significant positive correlation was observed between the population density and fruit availability in the study period (Spearman, R = 0.3, P < 0.01, n = 56). During non-fruiting periods, however, no significant correlation was observed between them. These results suggest that the spatial difference in fruit availability during mast and peak fruiting periods was larger than during non-fruiting periods, and many orangutans temporarily moved to the study site from the surrounding areas seeking fruit.