Tropical rainforest conversion and land-use intensification reduce understory plant phylogenetic diversity

1. Conversion of rainforest into agricultural land affects multiple facets of tropical plant diversity. While the effects of tropical land use change and intensification on species diversity are comparatively well studied, the effects on phylogenetic diversity and structure of plant communities are largely unknown. Furthermore, it is not clear how the loss of native species and addition of alien species collectively affect phylogenetic diversity and structure. 2. We investigated the phylogenetic diversity and structure of understorey plants; a diverse and ecologically important, yet poorly studied group. We studied four prominent land use systems (tropical lowland rainforest, jungle rubber agroforest, rubber plantations and oil palm plantations) in the lowlands of Sumatra (Indonesia), a region experiencing dramatic land use changes. 3. Across the four systems, we investigated differences in four metrics of phylogenetic community structure (phylogenetic diversity, mean pairwise distance,...1. 热带雨林转为农地会对热带植物多样性的多个维度产生影响。尽管学界对热带土地利用变化与集约化程度加剧对物种多样性的影响已有较为充分的研究，但针对植物群落系统发育多样性（phylogenetic diversity）与群落结构的影响却在很大程度上尚不明确。此外，本土物种丧失与外来物种引入二者共同如何作用于系统发育多样性与群落结构，目前仍不清晰。 2. 本研究聚焦林下植物——一类物种丰富且具备重要生态功能，但尚未得到充分探究的类群——的系统发育多样性与群落结构。我们以正经历剧烈土地利用变化的印度尼西亚苏门答腊低地地区为研究区域，选取四类典型土地利用系统：热带低地雨林、橡胶农林复合系统、橡胶园与油棕园。 3. 我们针对这四类系统，探究了植物群落系统发育结构的四项量化指标差异：系统发育多样性、平均成对距离（mean pairwise distance）……