Comparison of fruit tree richness and abundance as an indicator of food resource availability for the endangered Tauraco bannermani in Mount Oku and Mount Mbam, Western Highlands of Cameroon

Abstract

The Endangered Bannerman’s Turaco, Tauraco bannermani, is an arboreal montane forest bird, endemic to the Bamenda Highlands and currently facing several threats including selective extraction of trees, some of which are fruit trees on which the bird is known to feed. This study assessed the abundance and species richness of fruit trees known to provide food resources to the Bannerman’s Turaco as a factor contributing to the variation in the population size of the bird between Mt Oku and Mt Mbam. 45 plots where systematically established at each site using the point transect method targeting suitable habitats of Bannerman’s Turaco. In each plot, we identified and recorded all fruit trees known to provide food resources to Bannerman’s Turaco. Diameter at breast height and height of each fruit tree were measured. Data was analysed using Chi-square tests at threshold probability of 5%. Results obtained indicated that fruit trees were significantly more abundant in Mt Oku (n = 531) compared with Mt Mbam (n = 154) (Chisq = 207.49, df = 1 and p = 0.0002). Mt Oku also had a significantly higher fruit tree biomass (Chisq = 5701, df = 1 and p < 0.0002). Similar results were obtained when we controlled for altitude between sites. Of the eight fruit tree species known to provide food resources to Bannerman’s Turaco, we recorded seven at Mt Oku (Allophylus bullatus, Ficus sp, Maesa lanceolata, Podocarpus latifolius, Prunus africana, Schefflera abyssinica and Schefflera mannii) and five at Mt Mbam (Allophylus bullatus, Ficus sp, Prunus africana, Schefflera abyssinica and Schefflera mannii). These findings suggest that the significantly higher abundance and biomass of fruit trees contribute to explain the higher population size of Bannerman’s Turaco in Mt Oku compared with Mt Mbam. Hence, conservation efforts to protect this endangered bird should take into consideration the protection of fruit trees on which it feeds.

Keywords: Bannerman’s Turaco, Frugivores, Fruit trees, Montane forest, IBAs