Role of species richness and human-impacts in resisting invasive species in tropical forests

The biotic resistance hypothesis suggests that biodiversity rich areas should be resistant to biological invasions. Globally, conservationists use this hypothesis to protect diverse ecosystems. However, supporting data are often contradictory, possibly due to several confounding factors. Complexity in inferences increase in the tropics, which are sparsely studied.

We hypothesize that human impacts, forest type and climate would modulate the relationship between native and invasive plant richness. To understand these interacting and varying effects of native richness and human disturbance on plant invasions, we sampled 354 grids of 25 km2 with equal representation of protected areas and multi-use areas to record abundance of native and non-native plants from 34 protected areas across five forest types in tropical India. We used linear mixed effect models to investigate occurrence and abundance of invasive plants with respect to varying native richness, human impacts, forest types and ...