Quantifying wildlife-livestock interactions and their spatio-temporal patterns: Is regular grid camera trapping a suitable approach?

Abstract

Camera trapping use has increased significantly in ecological studies in recent decades due to its ability to register information about cryptic and/or elusive species and, more recently, due to its ability to derive population parameters, such as population abundance or density. For these latter applications, camera traps set in a regular grid pattern (CT-RG) are required to obtain representative information of the study area. The present work aims to assess the usefulness of the information collected through CT-RG to study interspecific interactions between animals, in terms of frequency of interaction and their spatiotemporal pattern. The results from CT-RG were compared with those obtained from GPS collars. For this latter methodology, 31 individuals were monitored with GPS-GSM collars (9 red deer [Cervus elaphus], 7 fallow deer [Dama dama], 6 wild boar [Sus scrofa] and 9 cows). The results showed that all the types of interactions recorded by GPS devices were also recorded by CT-RG. However, the relative frequency of each type of interspecific interaction was not precisely estimated using CT-RG. Nor did we observe an overlap between methodologies in the temporality of the interactions. These results are possibly due to most of the interactions tending to occur at aggregation points, which cannot be sufficiently represented by a regular grid. Finally, the spatial pattern obtained from CT-RG correlated with those obtained with GPS collars. Nowadays, camera trapping is being established as an affordable and effective tool to study different population parameters and, therefore, a huge amount of area is monitored with these devices using regular grids. Our results suggest that the information obtained through CT-RG can also be used to study the patterns of interaction between species.