No abstract

The preference of grazing herbivores to feed on grass regrowth following savanna fires rather than on unburnt grass swards is widely recognised. However, there is little information on which factors govern patterns of resource selection within burnt areas. In this study, we attempted to disentangle the effects of different habitat and grass sward characteristics on the utilisation of post-fire regrowth by nine species of ungulates in a fire-dominated woodland savanna in north Cameroon. We used resource-selection functions based on logistic regression. Overall, the resource-selection functions identified the time elapsed since burning as the most influential parameter in determining probability of use by ungulates, as most species strongly selected swards that were recently burned. This pattern might be related to nutrient levels in the grass sward. In addition, most species selected areas with high grass cover and avoided grass swards with high amounts of dead stem material. This is likely to increase bite mass and, hence, intake rates. The avoidance of high tree cover by some species may suggest selection for open areas with good visibility and, hence, reduced risk of predation. Body mass seemed to have no effect on differential selection of post-fire regrowth, irrespective of feeding style.

Abstract:We studied the effects of savanna fires on the structure of local ungulate communities in a West African woodland savanna. The distribution of 11 ungulate species over 9−15 burned sites (the number of which increased as burning activity continued during the dry season) and 7−13 unburned sites was compared with a variety of null models or randomized 'virtual communities'. Five different parameters of community structure were examined: body mass distribution, co-occurrence patterns, species richness, species density and guild dominance. Overall, ungulate species were not randomly distributed over burned and unburned sites. The regular spacing of body masses in the set of species recorded on burned and unburned sites indicated competition, since species similar in body mass are more likely to compete than species of different size. However, co-occurrence patterns on burned sites were random, indicating absence of competition at fine spatial scales due to differential habitat use within the burned landscape. Although the attractiveness of the regrowth on burned sites resulted in higher numbers of ungulates compared with unburned sites, species richness was not different. Grazers were the dominant guild on burned sites, but there were no differences in species richness or species density between grazers and browsers on unburned sites.

No abstract

SummaryMonitoring of nests of the Visayan Tarictic Hornbill Penelopides panini panini on the Philippine island of Panay revealed thus far undescribed information on the breeding biology of this species. Females occupied nest holes in March-April, after which two or three eggs are laid. Although cooperative breeding is suspected for the genus, at two nests no helpers were recorded. Nest-concealment behaviour was observed in the adult male. After a nestling period of 55-58 days, the adult female and one juvenile left the nest simultaneously. Immature birds resemble their respective sex. Nest site characteristics of 24 nests of the Tarictic Hornbill and two of the Writhed-billed Hornbill Aceros waldeni, respectively, were recorded on Mt Balabag, Panay Mountain Range. Tarictic Hornbill nests were situated in living as well as dead trees, at an average height of 11 m. Cavity compass direction was uniformly distributed around the circle. Nests are aggregated within the habitat, with a mean nearest-neighbour distance of 190 m. Writhed-billed Hornbills may require larger trees for nesting than Tarictic Hornbills. Nest density was calculated to be around three Tarictic Hornbill nests and 0.2-0.3 Writhed-billed Hornbill nests per square kilometre. Given a total amount of suitable hornbill habitat on Panay of 225-450 km 2 , about 750-1,000 Tarictic Hornbill breeding pairs and 60-100 Writhed-billed Hornbill breeding pairs may remain on Panay.