Central Africa's Albertine Rift region is a biodiversity hotspot consisting of a system of highlands that spans six countries. Recent studies demonstrated that the population of sooty bush-shrikes occupying the region's mid-elevation forests was a distinct species, and new research from The Condor: Ornithological Applications reveals that this recently discovered species may already be endangered due to pressure from agricultural development.
The recently identified mid-elevation species has been dubbed Willard's Sooty Boubou, as opposed to the previously recognised high-elevation species, Mountain Sooty Boubou. Fabio Berzaghi and his colleagues used museum records and bird survey records to analyse the ecological niche occupied by each species, and their results confirm that there is very little overlap between the ranges of the two. Willard's Sooty Boubou is found at approximately 1,200–1,900 metres and Mountain Sooty Boubou at 1,800–3,800 meters. In Burundi, Rwanda, and Uganda, 70 per cent of the potential for Willard's Sooty Boubou lies outside of protected areas and has been converted to agriculture, and the numbers for the Democratic Republic of Congo are only slightly better.
Willard's Sooty Boubou has been recognised as a full species for less than a decade, yet already faces the realistic threat of extinction (Josh Engel).
Willard's Sooty Boubou joins several other imperiled bird species that depend on the region's mid-elevation forests, which have been largely overlooked by conservation efforts. "The Albertine Rift is a crossroads of amazing biodiversity, dramatic and diverse landscapes, and heartbreaking social and political unrest. It goes from glaciers to volcanoes to plateaus to lakes, with a succession of vegetation types from high-elevation cloud forests to lowland tropical forests," explained Berzaghi. "It is home to gorillas and forest elephants as well as a high number of endemic animal and plant species. Unfortunately, much of the region has gone through never-ending conflicts, with very negative consequences for both humans and biodiversity, and conservation involving local populations is paramount."
Rauri Bowie, an expert on African birds who was not involved in the study, added: "This paper provides additional data in support of the recognition of Willard's Sooty Boubou as a species distinct from Mountain Sooty Boubou. Clarification of the niche that Willard's Sooty Boubou occupies, that of mid-elevation forests, distinct from the higher-elevation Mountain Sooty Boubou, is important, because these habitats are among the most heavily impacted in Africa from agriculture.
"Conservation agencies have an opportunity to move beyond taxonomic debate and use the models derived from this species to improve conservation outcomes for not only this species, but also a broad set of mid-elevation Albertine Rift endemic vertebrates through protection of mid-elevation forests that have received relatively little protection in comparison to high-elevation montane habitats."
Berzaghi, F, Engel, J E, Plumptre, A J, Mugabe, H, Kujirakwinja, D, Ayebare, S, and Bates, J M. 2018. Comparative niche modeling of two bush-shrikes (Laniarius) and the conservation of mid-elevation Afromontane forests of the Albertine Rift. The Condor 120(4):803-814. DOI: https://doi.org/10.1650/CONDOR-18-28.1.