A meta‐analysis of anthropogenic impacts on physiological stress in wild primates

Abstract

As humanity continues to alter the environment extensively, comprehending the effect of anthropogenic disturbances on the health, survival, and fitness of wildlife is a crucial question for conservation science. Many primate populations occupy suboptimal habitats prone to diverse anthropogenic disturbances that may be sources of acute and chronic stress. Quantification of glucocorticoid (GC) concentrations has repeatedly been used to explore the impact of disturbances on physiological stress. Although it is still debated, prolonged elevation of GC levels may impair reproduction, growth, and immune system activity of individuals. We quantified the effect of anthropogenic disturbances on physiological stress in primates with a global meta‐analysis based on data from 26 articles, covering 24 distinct species in 13 different countries. Anthropogenic disturbances were classified into 6 distinct categories: habitat loss, habitat degradation, ongoing logging, hunting, tourism, and other human activities. We calculated effect sizes (Hedges’ g) with the standardized mean difference in GC concentrations between primates affected by human activity and their undisturbed conspecifics. We ran random‐effects models and subgroup analyses to estimate the overall effect as well as a cumulative effect size for each disturbance category. Overall, primates inhabiting sites subject to anthropogenic disturbances exhibited significantly higher GC levels (g = 0.60; 95% CI: 0.28–0.93). Habitat loss and hunting were overall associated with increased GC concentrations, whereas the cumulative effects of the other disturbances were not statistically significant. Biologically, high GC levels may increase fitness by enabling individuals to overcome the challenges linked to anthropogenic disturbances. However, primates in disturbed environments may have sustained elevated GC levels. To strengthen future research, it is necessary to control confounding factors systematically (e.g., diet, reproductive status, predatory pressure, and resource availability) and improve understanding of the link between GC levels and the health, fitness, and survival of animals.

The influence of seasonality, anthropogenic disturbances, and cyclonic activity on the behavior of northern sportive lemurs (Lepilemur septentrionalis) at Montagne des Français, Madagascar

“…In the case of felled logs or cut tree trunk remains, the vernacular species name was recorded. We recognize that various anthropogenic disturbances may have different levels of impact on NSLs as shown in other studies (Kaisin et al, 2020), however, for this study, all disturbances were weighted equally.…”

“…In the case of felled logs or cut tree trunk remains, the vernacular species name was recorded. We recognize that various anthropogenic disturbances may have different levels of impact on NSLs as shown in other studies (Kaisin et al, 2020), however, for this study, all disturbances were weighted equally. elsewhere (Dinsmore et al, 2018); however, it is important to note that the anthropogenic disturbances analyzed in this study could be distinguished from those caused by the cyclone, as felled trees appeared distinct from those uprooted or snapped as a result of the cyclone.…”

Social support correlates with glucocorticoid concentrations in wild African elephant orphans

“…Extended research is also needed to investigate whether there are long-term fitness effects associated with our findings in non-natal orphans. Importantly, we cannot equate altered GC concentrations with reduced fitness 57,58 ; non-natal orphans in this study survived the duration of sampling, despite orphans having a lower survival probability in general 25 .…”

Effect of disturbances and habitat fragmentation on an arboreal habitat specialist mammal using GPS telemetry: a case of the red panda

“…Most of the available studies on responses of arboreal mammals to habitat fragmentation and disturbances are based on sign surveys, e.g. marsupials (Youngentob et al 2013 ; Lindenmayer et al 2021 ), primates (Almeida-Rocha et al 2017 ; Kaisin et al 2021 ) and tropical mammals (Whitworth et al 2019 ). Further, GPS telemetry coupled with camera trapping has not yet been applied in studying how arboreal mammals are adapting in human-dominated landscapes.…”