Movement and habitat use of a vulnerable Neotropical ungulate in agricultural landscapes

Background/Question/Methods

Agricultural landscapes are becoming increasingly more pervasive throughout the Tropical world. Some ungulate species continue to persist in those landscapes. Changes in their movements and habitat use due to changes in landscape configuration are expected, and important to be quantified, as they should affect population persistence, and have cascade effects on vegetation regeneration. Yet, those changes are still poorly documented. In the present study, we address this issue by monitoring a vulnerable Neotropical ungulate (white-lipped peccary, Tayassu pecari, hereafter WLP) in an agricultural landscape of Central Brazil. WLP is the sole Neotropical forest ungulate that lives in large herds, with unique top-down effects on forest regeneration. WLP is disappearing from large tracts of continuous forest, but persist in some agricultural landscapes. Since 2013, we have tracked eight adults from five distinct herds using GPS-tracking technology (number of days varying from 76 to 190 per animal). Our main goal is to quantify patterns of movement and habitat use of each herd and how those variables correlate with natural factors (season, topography, proximity to rivers, and habitat type) as well as anthropogenic ones (percentage of natural cover, structural and functional connectivity, mean patch size, variation in patch size, and number of patches). 

Results/Conclusions

Preliminary home range estimates range from 1000-2300 ha (Movement-based Kernel Density - 95%), and average distance between consecutive locations (6-hours interval) ranges from 326 to 1,133 meters.  Both measures seem to positively correlate with percentage of habitat cover and to negatively correlate with topography. Habitat use is highly correlated with presence of natural cover and number and spatial configuration of areas of high use differ between animals. Animals in landscapes with higher percentage of natural cover and with more connectivity between natural patches, have more, and more dispersed, areas of high use. Overall, our preliminary results indicate that the animals respond to changes in landscape configuration by restricting their movements, areas more intensely used, and overall home range, in landscapes where percent cover and connectivity between natural vegetation are lower. To refine our analyses, we will further explore habitat use by analyzing two distinct elements (residence time and frequency of revisits). We will identify whether areas of high use are more directly explained by residence time or frequency of revisits. We will also further explore movement patterns, by correlating distances between consecutive locations with angles, and by correlating those with landscape features, through step-selection functions.