Abstract:
Information on the response of herpetofauna to different land uses is limited though important
for land-use planning to support conservation in human-modified landscapes. Though
transformation is dogmatically associated with extinction, species respond idiosyncratically to
land-use change, and persistence of species in habitat fragments may depend on careful
management of the human-modified matrix. We sampled herpetofauna over a vegetation-type
gradient representative of regional land uses (old-growth forest, degraded forest, acacia
woodland (i.e. new-growth forest), eucalyptus plantation, and sugar cane cultivation) in the
forest belt skirting the southeastern coast of Africa, part of a biodiversity hotspot hosting many
endemic herpetofaunal species in a highly transformed landscape. We categorized species into trait-derived functional groups, and assessed abundance and richness of groups and compared
community metrics along the gradient. We further assessed the capacity of environmental
variables to predict richness and abundance. Overall, old-growth forest harbored the highest
richness and abundance, and frogs and reptiles responded similarly to the gradient. Richness was
low in cultivation and, surprisingly, in degraded forest but substantial in acacia woodland and
plantation. Composition differed between natural vegetation types (forest, degraded forest) and
anthropogenic types (plantation, cultivation), while acacia woodland grouped with the latter for
frogs and the former for reptiles. Functional group richness eroded along the gradient, a pattern
driven by sensitivity of fossorial/ground-dependent frogs (F2) and reptiles (R2) and vegetationdwelling
frogs (F4) to habitat change. Variables describing temperature, cover, and soil were
good predictors of frog abundance, particularly of functional groups, but not for reptiles.
Conserving forest and preventing degradation is important for forest herpetofaunal conservation,
restoration and plantations have intermediate value, and cultivation is least beneficial. Our study
demonstrates the utility of function-related assessments, beyond traditional metrics alone, for
understanding community responses to transformation. Particularly, fossorial/ground-dependent
frogs and reptiles and vegetation-dwelling frogs should be closely monitored.
