Space use by giant anteaters (Myrmecophaga tridactyla) in a protected area within human‐modified landscape

Abstract

Spatial ecology data are essential for conservation purposes, especially when extinction risk is influenced by anthropogenic actions. Space use can reveal how individuals use the habitat, how they organize in space, and which components are key resources for the species. We evaluated the space use and multiscale habitat selection of giant anteaters ( Myrmecophaga tridactyla ), a vulnerable Neotropical mammal, in a Cerrado site within a human‐modified landscape in southeastern Brazil. We used GPS transmitters to track eight anteaters in the wild. With the resulting dataset, we estimated home range and core‐area sizes and then used two overlap indexes. We assessed habitat selection by compositional analysis and analyzed events of spatio‐temporal proximity. The average Brownian bridge kernel estimate of home range size was 3.41 km 2 (0.92–7.9). Regarding home range establishment, five individuals showed resident behavior. Males ( n = 4) had larger home ranges and were more active than females ( n = 4). Despite the spatial overlap of home range (above 40% in four dyads), maximum temporal space sharing was 18%. Giant anteaters were found in proximity. Habitat selection favored savanna, and exotic timber plantation was always avoided. Roads and built‐up areas were selected secondarily at the landscape level. The selection of anthropogenic sites denotes behavioral plasticity regarding modified habitats. However, the high selectivity for savanna, at all levels, demonstrates a high dependence on natural habitats, which provide the necessary resources for the species. The recurrent proximity of male–to‐female anteaters may indicate reproductive behavior, which is essential for maintaining this isolated population.

Sexual, allometric and forest cover effects on giant anteaters’ movement ecology

“…Once home range crossing time indicates the timescale of autocorrelation in position, our results show that, on average, a two-days interval between consecutive relocations is necessary to consider them spatially independent [ 63 ]. However, previous studies using GPS devices have adopted monitoring regimes much shorter than that and unconsidered the spatial autocorrelation of data [ 30 , 42 ], probably leading to underestimating results. This is an important factor explaining why our estimates of daily distance moved, and home range size were, in average, bigger than those provided by recent studies [ 30 , 42 ], once AKDEc incorporates and controls for the autocorrelation in both location and velocity [ 63 ].…”

“…However, previous studies using GPS devices have adopted monitoring regimes much shorter than that and unconsidered the spatial autocorrelation of data [ 30 , 42 ], probably leading to underestimating results. This is an important factor explaining why our estimates of daily distance moved, and home range size were, in average, bigger than those provided by recent studies [ 30 , 42 ], once AKDEc incorporates and controls for the autocorrelation in both location and velocity [ 63 ]. Other possible explanations to this discrepancy can be related to the intrinsic characteristics of monitored individuals and the environmental characteristics associated with the site and period of monitoring.…”

“…Once we saw the anteaters, we captured them using dip nets, dart-guns, or a blowpipe. Anteaters were immobilized and sedated following the protocol described by [ 42 ] in Santa Barbara Ecological Station and following the protocol described by [ 57 ] in Baía das Pedras Ranch. Each captured individual was sexed, weighted, and equipped with a global positioning system (GPS) harness during anesthesia.…”

“…Despite the efforts to understand giant anteaters’ movement ecology, previous estimates of their home range size have ignored the intrinsic autocorrelation of high-resolution movement data and have not been based on movement models, probably generating underestimated results [ 24 , 30 ]. While some studies showed no evidence of sexual effects on their movement [ 36 , 40 ], other ones showed males presenting longer daily activity time [ 41 , 42 ] and using larger areas than females [ 42 ]. Because of their sexual size dimorphism [ 36 ], the possible influence of body mass on movement needs to be considered when assessing sexual effects.…”

“…Because of their sexual size dimorphism [ 36 ], the possible influence of body mass on movement needs to be considered when assessing sexual effects. Besides, although we know that giant anteaters select forests to set their home ranges and allocate time within it [ 42 ], we still ignore if the proportion of forest cover within home ranges influences their movement patterns and spatial requirements. Here we used a continuous-time movement model to offer reliable estimates of giant anteaters’ movement patterns (specifically home range crossing-time, daily distance moved and directionality) and home range size.…”