Data from: Land-use intensification increases richness of native and exotic herbaceous plants, but not endemics, in Malagasy vanilla landscapes

Aim: North‐eastern Madagascar is a hotspot of plant diversity, but vanilla
and rice farming are driving land‐use change, including slash‐and‐burn
management. It still remains unknown how land‐use change and land‐use
history affect richness and composition of endemic, native and exotic
herbaceous plant species. Location: North‐eastern Madagascar. Methods: We
assessed herbaceous plants along a land‐use intensification gradient
ranging from unburned land‐use types (i.e. old‐growth forest, forest
fragment and forest‐derived vanilla agroforest) to burned land‐use types
(i.e. fallow‐derived vanilla agroforest, woody fallow and herbaceous
fallow) and rice paddy. We compared land‐use types and analysed the
effects of land‐use history, canopy closure and landscape forest cover on
species richness. Additionally, we analysed species compositional changes
across land‐use types. Results: Across 80 plots, we found 355 plant
species (180 native non‐endemics, 57 exotics, 60 endemics and 58 species
of unknown origin). Native and exotic species richness increased with
increasing land‐use intensity, whereas endemics decreased. Unburned
land‐use types had higher endemic species richness
(4.28 ± 0.37 [mean ± SE]) than burned
ones (2.4 ± 0.21). Exotic and native species richness,
but not endemics, decreased with increasing canopy closure. Increasing
landscape forest cover reduced exotic, but not native or endemic richness.
Species composition of old‐growth forests was unique compared to all other
land uses and forest‐derived, not fallow‐derived vanilla agroforests, had
a similar endemic species composition to forest fragments. Main
Conclusions: Our results indicate that old‐growth forests and forest
fragments are indispensable for maintaining endemic herbaceous plants. We
further show that the land‐use history of agroforests should be considered
in conservation policy. In forest‐derived vanilla agroforests, management
incentives are needed to halt loss of canopy closure, thereby maintaining
or even enhancing endemics. In conclusion, considering species origin
(endemic, native and exotic) and composition is essential for the
identification of suitable management practices to avoid irreversible
species loss.