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 ...生物抗性假说（biotic resistance hypothesis）提出，生物多样性丰富的区域应具备抵御生物入侵的能力。全球范围内，保护工作者常依托该假说开展多样生态系统的保护工作。然而，支撑该假说的实证数据往往存在矛盾，这可能源于多种混杂因素的干扰。在研究较为匮乏的热带地区，相关推论的复杂程度进一步提升。 本研究提出假设：人类活动影响、森林类型与气候会调控本地与入侵植物物种丰富度之间的关联。为厘清本地物种丰富度与人类干扰对植物入侵的交互且可变的影响机制，我们在印度热带区域的5种森林类型、34个保护地中，布设了354个面积为25平方千米的样方，且保障保护地与多用途区域的占比均等，以此记录本地与外来植物的多度。我们采用线性混合效应模型（linear mixed effect models），针对不同梯度的本地物种丰富度、人类活动影响、森林类型以及……探究入侵植物的发生与多度情况。