Large expanses of tropical rainforest have been converted into agricultural landscapes cultivated by smallholder farmers. This is also the case in north-eastern Madagascar; a region that retains a significant proportions of forest cover despite shifting hill rice cultivation and vanilla agroforestry. The region is also a global hotspot for herpetofauna diversity, but how this diversity is affected by land-use change remains largely unknown. Using a space-for-time study design to uncover land-use effects, we compared species diversity and community composition in seven prevalent land uses: unburned (old-growth forest, forest fragment, and forest-derived vanilla agroforest) and burned (fallow-derived vanilla agroforest, woody fallow, herbaceous fallow) land-use types, and rice paddy. We conducted six comprehensives, time-standardized searches across at least ten replicates of each land-use type and applied genetic barcoding to confirm species identification. We documented an outstanding diversity of endemic herpetofauna (119 species): amphibian species richness at the plot level was highest in old-growth forest and significantly lower in all other land-use types. Plot-level reptile species richness was significantly higher in the unburned land-use types than burned land-use types. For both amphibians and reptiles, the less-disturbed land-use types showed more uneven communities and particularly in old-growth forest, the species composition differed significantly from all other land-use types. Amphibians showed a higher level of forest dependency compared to reptiles (38% versus 28% of species exclusively occurred in old-growth forest). Our analyses thus revealed that the two groups respond differently to land-use change: we found less pronounced losses of reptile species richness especially in unburned agricultural habitats, suggesting that reptiles are less susceptible to land-use change than amphibians. Overall, old-growth forest harboured a unique diversity, but some species also thrived in agroforestry systems, especially if these were forest-derived. This highlights the importance of conserving old-growth forests and non-burned land-use types within the agricultural landscape.
Differential responses of amphibians and reptiles to land‐use change in the biodiversity hotspot of north‐eastern Madagascar