Differential habitat use by two sympatric brocket deer species (<i>Mazama americana</i>and <i>M. gouazoubira</i>) in a seasonal Chiquitano forest of Bolivia

Abstract

A study of habitat use of two sympatric brocket deer species was conducted by recording dung and tracks along 40 km trails cleared through four vegetation types in the chaco-cerrado border of Santa Cruz Department, Bolivia. Deer signs of each species were characterized and discriminated by size and shape and counted for each habitat (transitional chaco forest, chiquitano riverine forest, chiquitano moist piedmont forest and cerrado open woodland) by walking 180-km in the wet season and 90-km in the dry season. The four habitats showed differences in vegetation structure and plant composition (canopy height and cover, horizontal visibility, and fruit resources) as well as frequency of signs for each brocket deer species. Although red brocket signs were less abundant than gray brocket signs, for both species and in every habitat we found consistently more tracks than dung in the wet season, and more dung than tracks in the dry season. Dung and track counts indicated that gray brockets were common and widespread in the four habitats, while reds occurred mostly in piedmont and riverine forest. Daily activity hours recorded by camera trapping showed that red brockets were active mostly from sunset until sunrise (6 pm to 6 am: 87% of 32 events) and gray brockets mostly in the morning (5 am to 10 am: 66% of 87 events). Patterns of habitat use and daily activity suggest that these sympatric deer species segregate in space and time. A comparative study of their diet, plus more behavioral data from sympatric and allopatric situations are needed to better understand the way in which deer may partition resources.