Local and landscape characteristics shape amphibian communities across production landscapes in the Western Ghats

Global tropical forests have been modified and fragmented by commodity
agroforests, leading to significant alterations in ecological communities.
Nevertheless, these production landscapes offer secondary habitats that
support and sustain local biodiversity. In this study, we assess community
level and species-specific responses of amphibians to land management in
areca, coffee and rubber, three of the largest commodity
agroforests in the Western Ghats. A total of 106 agroforests across a
30,000 km2 landscape were surveyed for amphibians using a
combination of visual and auditory encounter surveys. We used a Bayesian
multi-species occupancy modeling framework to examine patterns of species
richness, beta diversity, dominance structure and individual species
occupancies. The influence of biogeographic variables such as elevation
and latitude as well as microhabitat availability of streams, ponds and
unpaved plantation roads were tested on amphibian species
occupancy.  Coffee agroforests had the highest species richness
and lowest dominance when compared to areca and rubber. Beta diversity was
highest in areca for within agroforest measures. Compared across
agroforests, coffee had highest beta diversity with areca and rubber. Both
elevation and latitude showed an overall positive association with
amphibian occupancy although species-specific responses varied
considerably.  Microhabitat availability was one of the strongest
predictors of amphibian occupancy, with mean community response being
positive with presence of water bodies and roads. Pond presence increased
species richness per site by 37% (species-specific responses in occupancy
ranged from -2.7% to 327%). Stream presence alone did not change
species richness but species-specific response ranged from -59%
to 273%). Presence of plantation roads also increased species richness by
21.5% (species-specific response range -82% to 656%). Being
unpaved with little vehicular traffic, plantation roads seem to provide
additional habitats for amphibians. Presence of all three microhabitats at
a site increased species richness by 75%. Our study highlights the
importance of land management strategies that maintain diverse native
canopy and freshwater bodies and other microhabitats in sustaining
amphibian fauna. Market driven land-use change from coffee to
other agroforest types will have detrimental effects on amphibian
communities and their long-term sustainability in the Western Ghats.