Top carnivores increase their kill rates on prey as a response to human-induced fear

Abstract

The fear induced by predators on their prey is well known to cause behavioural adjustments by prey that can ripple through food webs. Little is known, however, about the analogous impacts of humans as perceived top predators on the foraging behaviour of carnivores. Here, we investigate the influence of human-induced fear on puma foraging behaviour using location and prey consumption data from 30 tagged individuals living along a gradient of human development. We observed strong behavioural responses by female pumas to human development, whereby their fidelity to kill sites and overall consumption time of prey declined with increasing housing density by 36 and 42%, respectively. Females responded to this decline in prey consumption time by increasing the number of deer they killed in high housing density areas by 36% over what they killed in areas with little residential development. The loss of food from declines in prey consumption time paired with increases in energetic costs associated with killing more prey may have consequences for puma populations, particularly with regard to reproductive success. In addition, greater carcass availability is likely to alter community dynamics by augmenting food resources for scavengers. In light of the extensive and growing impact of habitat modification, our study emphasizes that knowledge of the indirect effects of human activity on animal behaviour is a necessary component in understanding anthropogenic impacts on community dynamics and food web function.

Mesopredator spatial and temporal responses to large predators and human development in the Santa Cruz Mountains of California

“…Raccoon detections only exhibited a negative relationship with coyote activity at sites without pumas. While both pumas and coyotes will kill raccoons, raccoons are a frequent prey species of pumas in California (Allen et al, 2015b;Smith et al, 2015) and may consequently respond more strongly to pumas than coyotes.…”

Paws without claws? Ecological effects of large carnivores in anthropogenic landscapes

“…Humans have the potential to exclude predators (and their impact) from certain habitats or parts of the landscape [51]. However, as discussed above, predators can also profit from higher prey densities in more densely populated areas [10,87] or the predation rate might increase because of higher disturbance at kill sites [53]. The presence of humans can therefore either decrease or increase large carnivore impact on prey populations through effects on carnivore behaviour, but we currently have poor understanding of what drives the variation in these effects.…”

“…Finally, we need to develop a better understanding of how human hunters and carnivores change their functional responses in relation to each other's presence or to human activity in general. Preliminary data suggest that both hunters [35] and carnivores [53] do respond, but the effects of these altered functional responses on more complex trophic cascades have been largely unexplored in research and wildlife management to date.…”

“…They might be so in some cases [52], but the opposite may also occur. Smith et al [53] showed that female pumas (Puma concolor) left kills more frequently and spent less time on kills as human housing density increased. To compensate for this reduced prey consumption time, pumas in high-housing-density areas increased the number of deer they killed compared with kill rates in areas with little residential development.…”

Feline Immunodeficiency Virus Cross-Species Transmission: Implications for Emergence of New Lentiviral Infections

“…To determine the lower limit of quantitation (LLOQ), PLV standards (diluted in TE buffer) were tested on multiple days to determine the lowest concentration that could consistently be quantified. Standard concentrations tested were 10 2 to 10 7 plasmid copies/well (10-fold dilutions), as well as values below this range (10,20,40,50,60, and 80 copies/well). The LLOQ was determined to be 10 2 copies/well, equivalent to 17,000 RNA copies/ml plasma.…”