Predictors of Colobus Abundance: How Populations Respond to Stress

生态学中的一个基本问题是调节动物种群密度的决定因素。 随着需要为濒危或受威胁物种制定知情的管理计划，了解动物丰度的决定因素的重要性日益增加。 就灵长类动物而言，这些问题至关重要，因为灵长类动物占据的热带森林正在经历快速的人为改造。 然而，理解和预测决定灵长类动物丰度的因素被证明是极其困难的。 对森林灵长类动物的大量研究表明，不同地点之间的密度存在很大的差异，但很少有直接的测试来解释这种差异。 值得注意的例外是食叶灵长类动物的研究，其中可用叶的蛋白质/纤维比已被用来预测食叶灵长类动物的生物量。 在之前的国家科学基金会中，科林·查普曼（Colin Chapman）证明了这种关系适用于小的空间尺度，他能够预测乌干达基巴莱国家公园内邻近的colobine猴子种群的生物量。 他还展示了高蛋白质与纤维比例的食物的饮食选择，并测试了两个替代假设（colobines是能量有限或受特定矿物质的可用性限制）。 然而，找到单一因素解释复杂的生物现象，如决定colobine丰度，是不太可能的。 相反，最近的长期研究强调了多因素解释的重要性。 因此，目前的项目将探讨营养和寄生作用协同影响疣猴种群动态的可能性。 将采取两种办法。 首先，在1995年以来监测的森林片断系统中，该项目将测试人口变化的规模是否是优质食物供应和寄生虫感染水平变化的函数。 为了部分评估采用第二种方法时所做的假设，从粪便样本中分离出的应激激素水平将与种群变化的幅度相关。 其次，使用稳定的人口的长期观察，应激期的程度，如粪便材料中皮质醇代谢物的水平所指示的，对应于食物短缺和/或寄生虫感染增加的时期将被评估。 这项研究的广泛影响是多方面的。 例如，这些信息将有助于为世界各地的食叶灵长类动物制定明智的管理计划。 供资还将促进在基巴莱的长期监测，建设马凯雷雷大学生物野外站的基础设施，促进乌干达学生的培训和保护（已确定2名学生），在佛罗里达大学进行研究生和本科生培训，并通过协助制作自然电影（特别是与英国广播公司合作）向公众传播这一信息。

A fundamental issue in ecology is determining factors that regulate the density of animal populations. The importance of understanding determinants of animal abundance has increased with the need to develop informed management plans for endangered or threatened species. With respect to primates, these issues are critical because tropical forests occupied by primates are undergoing rapid anthropogenic transformation. However, understanding and predicting factors that determine primate abundance has proven extremely difficult. Numerous studies of forest primates have revealed a high degree of inter-site variation in density, but there are few direct tests of general hypotheses proposed to account for this variation. Notable exceptions are studies of folivorous primates, where the protein/fiber ratio of available leaves has been used to predict folivorous primate biomass. In a previous NSF, Colin Chapman showed that this relationship applied to small spatial scales, and he was able to predict the biomass of neighboring populations of colobine monkeys inside Kibale National Park, Uganda. He also demonstrated diet selection for foods with high protein to fiber ratios and tested two alternative hypotheses (colobines are energy limited or restricted by the availability of particular minerals). However, finding single factor explanations for complex biological phenomena, like determinants of colobine abundance, is unlikely. Rather, recent long-term studies have highlighted the importance of multifactoral explanations. As a result, this current project will explore the possibility that nutrition and parasitism operate synergistically to influence colobus population dynamics. Two approaches will be taken. First, in a system of forest fragments monitored since 1995, this project will test if the size of population change is a function of changes in the availability of quality foods and the level of parasitic infections. To partially evaluate assumptions made when taking the second approach, levels of stress hormones, isolated from fecal samples, will be relate to the magnitude of population change. Secondly, using long-term observation of a stable population, the degree to which periods of stress, as indexed by levels of cortisol metabolites in fecal material, correspond to periods of food scarcity and/or increased parasite infections will be assessed. The broader impacts of this study are many. For example, this information will be useful in construction of informed management plans for folivorous primates around the world. Funding will also facilitate long-term monitoring in Kibale, building the infrastructure of Makerere University Biological Field Station, promoting Ugandan student training and conservation (2 students have been identified), graduate and undergraduate training at the University of Florida, and dissemination of this information to the public by assisting the development of nature films (particularly with the BBC).