Data from: Passive restoration of sub-tropical grassland after abandonment of cultivation

Passive restoration of grasslands after the abandonment of cultivation may be a viable restoration option where seed sources from remnant grasslands are available, and if the risk of deflected succession is low. Passive restoration of subtropical grassland in Queensland, Australia was evaluated along a chronosequence of abandoned cultivation (fallow) paddocks. Plant communities in fallow paddocks were compared with nearby remnant grassland. On average, species richness recovers after 60 years of abandonment and floristic composition shows affinities with nearby remnant grassland (Bray-Curtis ˜ 0·6). The risk of deflected succession, such as dominance by exotic grasses, has apparently been low in this ecosystem. Annual grasses and forbs are rapid colonizers of the abandoned fields, and richness of perennial forbs exhibits near-linear recovery. Perennial grasses are relatively slow to establish but all except two species have statistically insignificant differences in abundance between remnant grassland and fallow fields after 20 years. The perennial grasses that recover most rapidly in fallow paddocks have disseminules that are adorned with appendages for wind dispersal including the most important dominant grass, Dichanthium sericeum. The perennial grasses that are slowest to recover are probably less effective dispersers. Synthesis and applications. Passive restoration of grasslands after the abandonment of cultivation can be a viable contribution to grassland conservation where there is an adequate matrix of remnant grasslands in the vicinity of fallows, perennial exotic species do not monopolize fallows and the dominant native grasses are well dispersed.弃耕后草地的被动修复（passive restoration），在具备残存草地（remnant grasslands）种子源且偏转演替（deflected succession）风险较低的场景下，是一种切实可行的修复途径。本研究针对澳大利亚昆士兰州的亚热带草地（subtropical grassland），沿弃耕牧场（fallow paddocks）的时间序列样地（chronosequence）梯度开展了被动修复效果评估，并将休耕地的植物群落与周边残存草地进行了对比。 平均而言，弃耕60年后物种丰富度即可恢复，且植物区系组成（floristic composition）与周边残存草地具有较高相似性（布赖斯-柯蒂斯相似度指数（Bray-Curtis）约为0.6）。该生态系统中，以外来草本植物（exotic grasses）占优为代表的偏转演替风险显然较低。 一年生草本植物（annual grasses）与非禾本科草本植物（forbs）是弃耕地的快速定植者，多年生非禾本科草本植物（perennial forbs）的丰富度则呈现近乎线性的恢复趋势。 多年生草本的定植速度相对较慢，但在弃耕20年后，除两个物种外，其余多年生草本的种群丰度在残存草地与休耕地之间均无统计学显著性差异。 在休耕地恢复最快的多年生草本，其传播体（disseminules）带有适于风力传播的附属结构，其中包括该生态系统最关键的优势草本Dichanthium sericeum。 恢复速度最慢的多年生草本，其传播效率普遍偏低。 总结与应用：若休耕地周边存在足够规模的残存草地景观基质（matrix），且多年生外来物种未对休耕地形成垄断，同时本土优势草本具备良好的传播能力，则弃耕后草地的被动修复可有效助力草地保护工作。