Biology subjects

Glotfelty, E.

Publications and source records attributed to Glotfelty, E..

2 recordsLinked to original sources

bioRxiv2023

Predictors of Population Estimates in a Critically Endangered Species of Black-and-White Colobus Monkeys

Population monitoring can help us determine population status and trajectory, but it is important to assess what factors may influence the number of individuals counted. In this study we conducted a complete count of the Critically Endangered Colobus vellerosus in the forests attached to the Boabeng and Fiema communities in central Ghana. We used 157 repeated counts of the same groups, including both good and unreliable counts to assess what factors predict the number of counted individuals in each group. The number of counted individuals increased with proxies for observation condition, observer experience, and habituation. We therefore recommend observer training and careful planning to increase the chances of having good observation. Then, we used the good counts to calculate the population size and group compositions. The obtained maximum number was 393 individuals in 25 groups. There were no significant differences in group sizes or immature to adult female ratios between groups occupying the older growth forest and groups in other forest types. Although there was still a relatively high immature to adult female ratio indicating that the population size may still increase, it does not appear to grow as rapidly as it used to, based on comparisons with previous population counts. Based on these findings, we recommend priority areas to promote conservation success.

zoology↗

bioRxiv2023

When population growth intensifies intergroup competition, female colobus monkeys free-ride less

In many social species, intergroup aggression is a cooperative activity that produces public goods such as a safe and stable social environment and a home range containing the resources required to survive and reproduce. In this study, we investigate temporal variation in intergroup aggression in a growing population of colobus monkeys to ask a novel question: "Who stepped-up to produce these public goods when the competitive landscape changed?". Both whole-group encounters and male incursions occurred more frequently as the population grew. Males and females were both more likely to participate in whole-group encounters when monopolizable food resources were available, indicating both sexes engaged in food defence. However, only females increasingly did so over time, suggesting that when intergroup competition intensified, it was females who increasingly invested in home range defence. Females were also more active in male incursions at high population densities, suggesting they also worked harder to maintain a safe and stable social environment over time. This is not to say that males were chronic free-riders when it came to maintaining public goods. Males consistently participated in the majority of intergroup interactions throughout the study period, indicating they may have lacked the capacity to invest more time and effort.

animal behavior and cognition↗