2023 - Full Presentation Schedule
The effects of human disturbances on mammal diel activity: Does trophic level matter?
Abstract
Globally, humans are the most successful predators of terrestrial mammals. Although human exploitation affects all trophic levels, it is more intense for large predators than for mesopredators or herbivores. To avoid the threat posed by humans, mammals may avoid habitats with high human disturbances, but they may also temporally avoid humans by changing their diel activity patterns.
We investigated the effect of human disturbance on the diel activity of mammals of different trophic levels. We hypothesized mammals would be more nocturnal in open habitats because they are more visible to humans. We also hypothesized that mammals would be more nocturnal in sites with human disturbance, but the disturbance would affect large predators the most, herbivores the least, and have an intermediate impact on mesopredators.
We tested our hypotheses by deploying camera traps at sites across Upstate South Carolina. Each camera was classified by habitat type based on canopy cover and human-disturbance level based on the frequency of images of human activity. Each picture was labeled with species and time of day. We compared the proportion of nocturnal observations at cameras with different disturbance levels and at cameras in different habitats.
As hypothesized, we found more nocturnal observations at cameras in more open habitats for all trophic levels. However, we found that while both large predators and herbivores were more nocturnal in areas with higher human disturbance, mesopredators were more diurnal. Our results suggest that when they are more visible to humans, mammals will be more nocturnal.
However, members of different trophic levels show different responses to human disturbance. Although large predators and herbivores temporally avoid humans, mesopredators are more tolerant of human disturbances.
The effects of human disturbances on mammal diel activity: Does trophic level matter?
CLC Ballroom - Biology/Ecology
Globally, humans are the most successful predators of terrestrial mammals. Although human exploitation affects all trophic levels, it is more intense for large predators than for mesopredators or herbivores. To avoid the threat posed by humans, mammals may avoid habitats with high human disturbances, but they may also temporally avoid humans by changing their diel activity patterns.
We investigated the effect of human disturbance on the diel activity of mammals of different trophic levels. We hypothesized mammals would be more nocturnal in open habitats because they are more visible to humans. We also hypothesized that mammals would be more nocturnal in sites with human disturbance, but the disturbance would affect large predators the most, herbivores the least, and have an intermediate impact on mesopredators.
We tested our hypotheses by deploying camera traps at sites across Upstate South Carolina. Each camera was classified by habitat type based on canopy cover and human-disturbance level based on the frequency of images of human activity. Each picture was labeled with species and time of day. We compared the proportion of nocturnal observations at cameras with different disturbance levels and at cameras in different habitats.
As hypothesized, we found more nocturnal observations at cameras in more open habitats for all trophic levels. However, we found that while both large predators and herbivores were more nocturnal in areas with higher human disturbance, mesopredators were more diurnal. Our results suggest that when they are more visible to humans, mammals will be more nocturnal.
However, members of different trophic levels show different responses to human disturbance. Although large predators and herbivores temporally avoid humans, mesopredators are more tolerant of human disturbances.