|Aim Detailed knowledge of species distributions, endemism patterns and
threats is critical to site prioritization and conservation planning. However,
data from biodiversity inventories are still limited, especially for tropical forests,
and even well recognized hotspots remain understudied. We provide an example
of how updated knowledge on species occurrence from strategically directed
biodiversity surveys can change knowledge on perceived biodiversity importance,
and facilitate understanding diversity patterns and the delivery of conservation
Location Eastern Arc Mountains (EAM), Kenya and Tanzania.
Methods We surveyed amphibians, reptiles, birds and mammals during 2005–
2009, targeting mountain blocks that had been poorly surveyed or unsurveyed
by the early Noughties. We combined new and old data to produce a database
of species presence by mountain block spanning four decades of research. Species
richness is regressed against survey effort, funding, ecological and human
disturbance factors to analyse the best predictors of vertebrate richness across
mountain blocks. Similarity among species assemblages among blocks is
analysed using dissimilarity analysis.
Results New surveys raised the number of endemic and regional endemic vertebrates
by 24% (from 170 to 211 species), including 27 new species of which
23 are amphibians and reptiles. Vertebrate richness is best explained by forest
area, but rainfall is also important, especially for amphibians and reptiles. Forest
elevational range is important for mammals and for block-endemic birds.
Funding explains 19% of the variation in total species richness, while survey
effort generally explains < 10% of variance. Cluster analysis shows that species
assemblages are partitioned by geographical proximity among mountain blocks.
Main conclusions The biological value of the EAM has been underestimated,
and strategic surveys are important even in well-recognized hotspots. The
exceptional and global importance of these mountains for endemic vertebrates
is highlighted, supporting the development of a network of Nature Reserves
and the proposed inclusion within UNESCO’s natural World Heritage Sites.|