Invisible Barriers in Human Dominated Landscapes
Landscape modification is one of the leading causes of wildlife depletion or extinction. Changes in any given landscape may influence species behavior, temporal and spatial patterns and densities. The spatial and seasonal responses of wildlife in human dominated landscapes have been greatly studies, however, little is known about the effects of landscape modification on species circadian activity and to what extent are circadian rhythms dynamic to allow species to adapt to newly introduced anthropogenic pressures. These questions have occupied my mind during my PhD. Luckily my group member, Roi Maor, who uses phylogenetic methods to reconstruct the evolution of activity patterns in mammals, teamed up with me to explore questions that are extremely relevant for wildlife conservation. We used camera traps to measure the activity of five mammal species along a disturbance gradient in an agricultural-natural mosaic landscape designated as a national ecological corridor. Results of this work were published in 2018. Wildlife diurnal activity was minimal around towns, where humans were active during the day. Nevertheless, predator activity increased near towns and at other sites of high disturbance. Although attracted to highly disturbed areas, predators avoided humans temporally by restricting activity to night-time, whereas prey activity relative to less disturbed areas was negligible. We conclude that perceived threat from humans during daytime combined with elevated nocturnal predation risk exclude prey species from large areas of an agricultural region designated as ecological corridor. Human activity may have triggered a cascading effect mediated by predators’ diel activity shifts, which reduced landscape permeability to prey. Our study underlines the need to consider wildlife diel activity patterns for conservation and environmental management planning.
Conceptual figure to illustrate predator and prey circadian response to human activity