Ecological regions aggregate habitats with similar
biophysical characteristics within well-defined boundaries,
providing spatially consistent platforms for
monitoring, managing and forecasting the health
of interrelated ecosystems. A major obstacle to
the implementation of this approach is imprecise
and inconsistent boundary placement. For globally
important mountain regions such as the Eastern Arc
(Tanzania and Kenya), where qualitative definitions
of biophysical affinity are well established, rulebased
methods for landform classification provide
a straightforward solution to ambiguities in region
extent. The method presented in this paper
encompasses the majority of both contemporary
and estimated preclearance forest cover within
strict topographical limits. Many of the species
here tentatively considered ‘near-endemic’ could be
reclassified as strictly endemic according to the
derived boundaries. LandScan and census data show
population density inside the ecoregion to be higher
than in rural lowlands, and lowland settlement to be
most probable within 30 km. This definition should
help to align landscape scale conservation strategies in
the Eastern Arc and promote new research in areas
of predicted, but as yet undocumented, biological
importance. Similar methods could work well in other
regions where mountain extent is poorly resolved.
Spatial data accompany the online version of this
article