Predictors of group formation by mammals in Upstate South Carolina
Document Type
Event
Abstract
Mammals may form groups to access resources, care for offspring, avoid predation, or in response to human disturbance. We hypothesized that both predation and human disturbance at the local and the landscape scale would drive mammal group formation in Upstate South Carolina. Consequently, we expected groups would be more common in vulnerable prey species than they would be in species with lower predation risk. We also predicted mammals would be more likely to form groups in open habitats where they are visible to predators. Finally, because human disturbance has been observed to have a similar effect on mammals as predation, we predicted that groups would be more common when either local temporary human disturbance (THDLocal) or lasting landscape-level human disturbance (LHDLandscape) is high. To test these hypotheses, we collected data at 4 sites, using 19 camera stations positioned in forest, edge, and open habitats and capturing varying levels of THDLocal. The photos captured were labeled by species and number of individuals. We quantified THDLocal for each camera station and used QGIS to quantify LHDLandscape for each site. We used a Fisher’s exact test to analyze the data collected from the images within each category (predation risk, habitat openness, THDLocal, LHDLandscape). Groups were most frequently formed in mammals with the highest predation risk (p< .0001), but mammals with medium to low predation risk were not significantly different in their group formation. Group formation was most common in open habitats and least common in forested habitats (p< .0001). Group formation was highest when both THDLocal and LHDLandscape were high (p< .0001). Because groups are formed most often in prey species and in open habitats, our results support the hypothesis that mammals form groups in response to the threat of predation. Our results also show that human disturbance increases group formation at the landscape and local scale.
Predictors of group formation by mammals in Upstate South Carolina
Breakout Session A: Ecological Sciences
CLC BallroomMammals may form groups to access resources, care for offspring, avoid predation, or in response to human disturbance. We hypothesized that both predation and human disturbance at the local and the landscape scale would drive mammal group formation in Upstate South Carolina. Consequently, we expected groups would be more common in vulnerable prey species than they would be in species with lower predation risk. We also predicted mammals would be more likely to form groups in open habitats where they are visible to predators. Finally, because human disturbance has been observed to have a similar effect on mammals as predation, we predicted that groups would be more common when either local temporary human disturbance (THDLocal) or lasting landscape-level human disturbance (LHDLandscape) is high. To test these hypotheses, we collected data at 4 sites, using 19 camera stations positioned in forest, edge, and open habitats and capturing varying levels of THDLocal. The photos captured were labeled by species and number of individuals. We quantified THDLocal for each camera station and used QGIS to quantify LHDLandscape for each site. We used a Fisher’s exact test to analyze the data collected from the images within each category (predation risk, habitat openness, THDLocal, LHDLandscape). Groups were most frequently formed in mammals with the highest predation risk (p< .0001), but mammals with medium to low predation risk were not significantly different in their group formation. Group formation was most common in open habitats and least common in forested habitats (p< .0001). Group formation was highest when both THDLocal and LHDLandscape were high (p< .0001). Because groups are formed most often in prey species and in open habitats, our results support the hypothesis that mammals form groups in response to the threat of predation. Our results also show that human disturbance increases group formation at the landscape and local scale.