Range utilization slopes as a measure of central tendency and intergroup overlap in primates

Animals that occupy stable home ranges tend to unevenly exploit different areas in their efforts to find fitness-limiting resources, while also reducing the risks of intergroup conflict. Most analyses of these extrinsic forces identify their effects on movement paths and home range geometry, but not on the interaction of these responses or how movements might be centrally constrained as a result of competition with neighbors. The range utilization slope is a measure of central tendency and consists of space use plotted against distance from the center of the range. Slopes tend to be linear, concave-up, or concave-down, and are predicted to change as a function of feeding competition from neighbors. To test this prediction and determine the spatio-temporal scales over which the central tendency might vary, we calculated utilization slopes and an index of range overlap for grey-cheeked mangabeys (Lophocebus albigena), blue monkeys (Cercopithecus mitis), and red-tailed monkeys (C. ascanius..., Members of the Ngogo Monkey Project intermittently collected observational data on monkey groups from January 2008 through August 2016 at the Ngogo research station (0°29' N 30°25' E) in Kibale National Park (0°13-41' N 30°19-32' E), Uganda. Monkey groups were followed from dawn until dusk for 5–14 consecutive days per month. In 2008–2009, 3–4 red-tailed monkey groups were followed simultaneously for 1 week each month, and alternated with week-long follows of 3–6 grey-cheeked mangabey groups. In 2012–2015, pairs or trios of red-tailed monkey groups were observed for 1–2 weeks each month for periods of (mean ± SD) 4.9 ± 1.1 months (N = 7 periods), with 11–17 months between successive periods in which a group was followed. The blue monkey groups were followed monthly from Aug 2015 through Aug 2016. The field team recorded the centroid position of the majority of group members every 30 min using a 50 x 50 m gridded map of the trail system and by pacing to the nearest trails (2008–2015), or..., We used STATA v12.1 to analyze the data, but the files can also be opened with Microsoft Excel or R.占据稳定家域（home range）的动物，在搜寻限制其适合度的资源时，往往会不均匀地利用不同区域，同时也能降低群体间冲突的风险。现有针对这些外在压力的多数研究，仅揭示了其对动物移动路径与家域几何形态（home range geometry）的影响，却未探讨这些响应之间的相互作用，以及邻群竞争如何导致移动行为受到核心约束。家域利用斜率（range utilization slope）是一种集中趋势（central tendency）测度指标，其定义为以距家域中心的距离为横轴、空间利用（space use）强度为纵轴绘制的曲线。该斜率通常呈现线性、上凹或下凹三种形态，且理论上会随邻群间取食竞争的变化而改变。 为验证该理论预测，并明确集中趋势发生变化的时空尺度，我们对灰颊白眉猴（grey-cheeked mangabey, *Lophocebus albigena*）、青猴（blue monkey, *Cercopithecus mitis*）以及红尾猴（red-tailed monkey, *C. ascanius*）的家域利用斜率与家域重叠指数（range overlap index）进行了计算。 恩戈戈猴类项目（Ngogo Monkey Project）的研究团队于2008年1月至2016年8月期间，在乌干达基巴莱国家公园（Kibale National Park，0°13′-41′ N 30°19′-32′ E）内的恩戈戈研究站（Ngogo research station，0°29′ N 30°25′ E）断续收集猴群的观测数据。 研究团队每月会从黎明到黄昏连续追踪猴群5至14天。2008至2009年，团队每月同时追踪3至4群红尾猴，时长为1周，随后轮换追踪3至6群灰颊白眉猴，同样为期1周。2012至2015年，团队每月对1至2群红尾猴集群（成对或3只组群）开展为期1至2周的观测，每个观测周期时长为（平均值±标准差）4.9±1.1个月（N=7个周期），相邻两个追踪周期的间隔为11至17个月。青猴群则于2015年8月至2016年8月期间每月接受追踪。 2008至2015年，野外团队每30分钟便利用覆盖步道系统的50×50米网格地图，通过步测至最近步道的方式记录猴群多数个体的质心位置（centroid position）；2015年及之后的记录方式未在文本中详述。 本研究使用STATA v12.1进行数据分析，数据文件也可使用Microsoft Excel或R语言打开。