Activity Patterns Of Carnivores Research Articles

Effects of vehicle-passing frequency on forest roads on the activity patterns of carnivores

In this study, we evaluated the effect and extent of linear human disturbance caused by vehicle traffic on forest roads on animal activity time. Our research focused on four sympatric carnivores (red fox, Vulpes vulpes; raccoon dog, Nyctereutes procyonoides; Japanese marten, Martes melampus; and Asiatic black bear, Ursus thibetanus) living in the forest region of northeastern Japan. From August to November 2019, we obtained data on the activity time for each species from nine infrared-triggered cameras installed along two types of unpaved forest roads with different vehicle frequencies (high or low) and subsequently assessed the effect of vehicle-passing frequencies on activity using kernel density estimation and chi-square test. Red foxes and raccoon dogs were nocturnal on all forest roads; however, their nighttime activities were significantly greater on the forest road with a high vehicle-passing frequency than on the road with a low vehicle-passing frequency. Japanese martens showed a nocturnal pattern on all forest roads, and there was no significant difference in the proportion of nighttime activities between the forest roads. Asiatic black bears were highly active during the daytime on forest roads with a low vehicle-passing frequency, but were highly nocturnal on forest roads with a high vehicle-passing frequency. Our results suggest that human disturbance influences the ratio of daytime to nighttime activity in carnivores; however, the extent and magnitude of this effect are limited. This finding indicates that the spatial scale of effects of human disturbance on the activity of each animal species should be assessed before habitat management programs are implemented.

Small-scale alterations in carnivore activity patterns close to motorways

The effects of roads on the fauna of their surroundings, negative ones for most species, have been widely studied over recent decades. Nevertheless, little is known of changes in the activity patterns of carnivores near roads, which determine what impacts that they may experience. An intensive 2-year study of the carnivore community around a 5-km stretch of Spanish motorway has been carried out in order to clarify this situation. The carnivore activity patterns at three distances from the motorway (0, 500 and 1000 m) were assessed by means of three complementary sampling methods (scat transects, hair traps and camera traps) and by both whole-community analyses (redundancy analysis) and species-specific analyses (generalised linear mixed models, occupancy models). The results show an intense use of the motorway proximities by the carnivore community, with the road possibly acting as an artificial home-range boundary, as well as differential interspecies responses to the presence of the infrastructure. Thus, foxes, stone martens, weasels and genets made more intensive use of the motorway vicinity whereas badgers and cats were indifferent or slightly favoured more distant zones. Knowledge of this alteration in activity patterns near a motorway is important for understanding both the direct effects (e.g. roadkills) and indirect effects (e.g. predation cascades) that roads may trigger in ecosystems, and it may have relevant implications for the design and effectiveness of mitigation measures.