Fire management, dry fruits availability, and the abundance of a macaw species in central Brazilian savannas

In Cerrado, the savanna ecosystem that dominates central Brazil, fire management consists in the maintenance of “aceiros” - bands of vegetation usually measuring <100m  in width. “Aceiros” are burned annually in the early dry season (May) with the intention of creating a barrier to the spread of fires that might occur later in the year. This study aimed to examine the effect of fire management on the Blue-and-yellow Macaw at Emas National Park, Brazil. This species feeds on seeds of cashew-apple plants, shrubs that grow on the lower strata of woodland savannas in Cerrado. Macaws and cashew-apple plants had their abundances estimated in September and October 2006. Twelve study sites were selected: “aceiros” made at woodland savannas (n=6) and woodland savannas (n=6). At each study site, one transect (1kmx40m) was set to the counting of macaws and five transects (100mx20m) set to estimate the cover of cashew-apple plants. No macaws were recorded in woodlands, while 108 macaws were recorded at “aceiros” (after 36 transect samples). Most groups of macaws were feeding on seeds of cashew-apple plants. The cover of cashew-apple plants was substantially higher at aceiros than at native woodlands. These results suggest that fire management of woodland savannas provides suitable feeding sites for Blue-and-yellow Macaws. This might occur due to two reasons: 1) high availability of cashew-apple fruits at “aceiros”; 2) the herb strata (specially the 2m tall “capim flecha” grass) are burned prior to the fruiting season of cashew-apple plants, thus favoring the landing and take over of macaws.