Plasticity in the timing of activity in the Red-rumped Agouti, Dasyprocta leporina (Mammalia: Rodentia), in the Atlantic Forest of southeastern Brazil

Abstract

Timing of activity is a consequence of adaptations to daily and seasonal changes in the environment and examining these patterns is important to better understand the temporal niches of the species. Here we examine temporal activity in the Red-rumped Agouti (Dasyprocta leporina) in two fragments of Atlantic Forest and those factors that influence the circadian rhythm in the study areas. Camera traps were used to gather data in two protected areas (one montane and other coastal) in the state of Espírito Santo, southeastern Brazil. A total of 49 photos were taken in the mountains and 152 in the coastal area. Activity patterns were diurnal and bimodal, and animals were active for 14-15 hours each day. Activity peaked in the morning soon after sunrise and then before and during dusk. Activity patterns were different in the two study areas (W = 6.77, p = 0.034). There was a longer peak in the morning in the coastal area, and a higher peak in the evening in the mountains, where activity starts later and becomes less intense earlier. The difference between activity patterns in the two locations suggests plasticity in agouti behavior. Because the two study areas are at about the same latitude, we suggest that the behavioral plasticity is due to different temperature regimes associated with a local effect of altitude and topography of the terrain on the incidence of solar rays inside the forest. The influence of other factors is also discussed. In addition to a better understanding of the temporal niche of the Red-rumped Agouti, the behavior patterns we describe here can be useful to optimize strategies for D. leporina conservation in southeastern Brazil once the species is more susceptible to poaching at times when animals are most active.

Activity Pattern of Brocket Deer (Genus Mazama) in the Atlantic Forest: Does Sampling Design Affect the Patterns?

“…Percentages were used so that any differences related to the absolute number of records did not affect the visual comparison of the activity patterns recorded. The activity peak was defined when the percentage of captures in any given hour was 50% greater than the hour with the greatest percent of captures [23].…”

“…From the comparison of the results of previous studies performed with M. americana and M. gouazoubira, we observe that there are peculiarities in the activity time for the same species of brocket deer between sites (intraspecific variations), and the differences are related to the hours of more intense activity and occasional periods of inactivity. These variations may be attributed to differences in the photoperiod between the sampled sites, which varies with latitude [5]; local effect of altitude associated with topography on the incidence of solar rays inside the vegetation at each study area [23]; differences in the ambient temperature between regions [6,23]; local variations in the response to competition between Mazama spp. [15]; the size of the studied remnants [6]; or changes in the activity pattern in response to the presence of hunters [6].…”