Data_Sheet_1_Assisted restoration interventions drive functional recovery of tropical wet forest tree communities.docx

Choosing appropriate forest restoration interventions is challenging. Natural regeneration can rapidly facilitate forest recovery in many situations. However, barriers such as dispersal limitation and competition with non-native species can require assisted restoration approaches to facilitate plant community recovery. We used a study that has directly compared the outcomes of tropical wet forest restoration interventions across 11 replicate sites in southern Costa Rica. Within this framework, we examined the functional recovery trajectories of recruiting tree sapling communities across a gradient of restoration interventions including low (natural regeneration), intermediate (applied nucleation), and high (plantation) initial resource-investment, which we compared to remnant reference forest. We collated leaf and stem functional traits for tree species that comprised the bulk of recruiting saplings, then determined how community-weighted trait means and functional diversity metrics changed over a decade across treatments. Results show that assisted restoration approaches (applied nucleation, plantation) sped the development of more functionally diverse tree communities, more than tripling the functional richness (FRic) of recruiting communities when compared to natural regeneration. However, functional dispersion (i.e., the trait range of dominant species) was equivalent across interventions, and between 28 and 44% lower than remnant forest, indicating that increases in FRic under assisted restoration were driven by species recruiting in low abundances (

选取适宜的森林恢复干预措施是一项极具挑战性的任务。在诸多情形下，自然更新能够迅速促进森林的复苏。然而，诸如扩散限制与外来物种竞争等障碍可能需要辅助的恢复方法以促进植物群落的恢复。本研究直接对比了在哥斯达黎加南部的11个重复样地中实施的雨林恢复干预措施的效果。在此框架下，我们探讨了在包括低（自然更新）、中（应用核化）和高（人工种植）初始资源投入在内的恢复干预梯度上，招募树苗群落的功能恢复轨迹，并将其与残存参照森林进行对比。我们收集了构成大量招募树苗的树种叶片和茎部功能性状，然后确定了社区加权性状平均值和功能多样性指标在十年间在各处理中的变化。结果显示，辅助恢复方法（应用核化、人工种植）加速了更功能多样性的树群落的形成，与自然更新相比，招募群落的功能丰富度（FRic）增加了超过三倍。然而，功能扩散（即优势种群的性状范围）在各干预措施间以及与残存森林之间并无显著差异，且分别低28%至44%，表明在辅助恢复下FRic的增加是由低丰度物种的招募所驱动。