The Djibouti francolin and juniper forest in Djibouti: the need for both ecosystem and species-specific conservation

摘要

The majority of Galliformes are ground dwelling, many live in forests, and c. 25% are on the IUCN Red List. The Djibouti francolin Francolinus ochropectus is a Critically Endangered galliform endemic to only two areas of relict Juniperus procera forest in Djibouti. This study assessed population status and habitat condition in the species' stronghold in the Foret du Day during the post-breeding season. Line transect distance sampling was used to survey the francolin, recording visual encounters and calls. Canopy and understorey vegetation were sampled across the study area at 150-m intervals using 400-m2 quadrats. Interviews were conducted in all adjacent villages to obtain information about francolin sightings, forest use and capacity for community-based conservation. Distance was used to generate francolin population density estimates. A geographical information system and generalized linear modelling were used to determine predictors of francolin presence and juniper condition. The Distance model estimated francolin density to be 38-94 km~(-2) Within the Foret du Day this is equivalent to a population of 285-705 individuals. The presence of juveniles in the samples suggests that the effective population size may be lower and therefore, although this is the first estimate of Djibouti francolin density using standard survey methodology, it should be interpreted cautiously. Juniper condition in the Foret du Day is poor. The healthiest forest is 50% dead. Francolins are more abundant where tree cover is high. This cover now mostly consists of Buxus hilde-brandtii, which appears to have mostly replaced the original juniper. In areas of high tree cover, grazing intensity is significantly negatively correlated with francolin presence. Anthropogenic influences on juniper health andrnfrancolin decline are mediated through the large number of cows grazing in the forest. We recommend an ecosystem approach to conservation of the forest, with additional species-specific protection measures for the francolin and juniper.