Data from: Measuring the success of reforestation for restoring biodiversity and ecosystem functioning

Effective assessment of the success of ecological restoration projects is critical in justifying the use of restoration in natural resource management as well as improving best practice. One of the main goals of ecological restoration is the recovery of ecosystem function, yet most researchers assume that increasing species and or functional diversity equates with restoration of ecosystem function, rather than empirically demonstrating these mechanistic relationships. In this study we assess how dung beetle species diversity, community composition, functional diversity and ecological functions vary along a restoration chronosequence and compare restored areas with reference (rainforest) and degraded (pasture) systems. We also directly investigate the dung beetle diversity – ecosystem functioning relationship in the context of ecological rainforest restoration by testing the predictive power of traditional taxonomic indices and functional diversity metrics for functionality. Species richness, abundance, biomass and functional richness all increased with restoration age, with the oldest restoration sites being most similar to rainforest; whereas functional evenness and functional divergence decreased with restoration age. Community composition in the restored areas was clearly progressing towards the rainforest sites and deviating from the pasture sites with increasing restoration age. Secondary seed dispersal rates increased with restoration age, but there was only a weak positive relationship between dung removal and soil excavation and restoration age. Biodiversity metrics explained 47–74% of the variation in functions mediated by dung beetles; however, functional trait-based indices provided greater explanatory power of functionality than traditional species-based metrics. Synthesis and applications. Our results provide empirical evidence on the potential of tropical forest restoration to mitigate biodiversity losses, recovering not only faunal species diversity, but also functional diversity and ecosystem functions in a relatively short period of time. We also demonstrate that functional trait-based metrics are better predictors of functionality than traditional species-based metrics but that the relationship between restoration age, diversity and ecosystem functioning is not straightforward and depends on the functions, traits and metrics used.对生态修复项目成效开展精准评估，是论证生态修复在自然资源管理中应用合理性、并优化最佳实践路径的核心前提。生态修复的核心目标之一在于恢复生态系统功能，但当前绝大多数研究者仅默认物种多样性或功能多样性的提升等同于生态系统功能的修复，却未通过实证手段验证二者间的机制性关联。 本研究围绕恢复时间序列（restoration chronosequence），探究蜣螂（dung beetle）物种多样性、群落组成、功能多样性及生态功能的变化规律，并将修复样地与参照（雨林）及退化（牧场）生态系统进行对比分析。同时，本研究针对雨林生态修复场景，通过检验传统分类学指数与功能多样性指标对生态功能的预测能力，直接探究蜣螂多样性与生态系统功能间的关联机制。 研究结果显示：物种丰富度、个体多度、生物量与功能丰富度均随修复年限增加而上升，修复年限最长的样地与雨林生态系统最为相似；而功能均匀度与功能分歧度则随修复年限增加而下降。修复样地的群落组成随修复年限增加，逐渐向雨林样地靠拢，同时愈发偏离牧场样地。 次生种子传播速率随修复年限增加而提升，但粪粒移除与土壤挖掘这两项蜣螂介导的生态功能与修复年限仅存在微弱的正相关关系。生物多样性指标可解释蜣螂调控的生态功能47%~74%的变异；但基于功能性状的指数相较于传统物种维度的指标，对生态功能具有更强的解释力。 研究综合与应用：本研究结果为热带森林修复在缓解生物多样性丧失方面的潜力提供了实证依据——修复不仅可在相对较短的时间内恢复动物物种多样性，同时还可恢复功能多样性与生态系统功能。本研究同时证实，基于功能性状的指标相较于传统物种维度的指标，可更精准地预测生态功能；但修复年限、多样性与生态系统功能间的关联并非简单线性，而是取决于所选取的功能类型、性状种类与指标体系。