Data from: Phylogenetic diversity is maintained despite richness losses over time in restored tallgrass prairie plant communities

Ecosystem restoration is an important tool for mitigating biodiversity loss and recovering critical ecosystem services to humanity, but restoration rarely takes into account the evolutionary attributes of the community being restored. Phylogenetic diversity (PD) represents a potentially valuable measure of restoration success because it can correlate with functional trait diversity that drives ecosystem function. However, PD patterns in restored communities are rarely assessed. We surveyed plant communities in restored tallgrass prairies 2–19 years old and calculated two PD measures, SESMNTD and SESMPD, of the communities and seed mixture applied to sites. We also identified high-threat exotic species present in each site to determine if PD of the seed mixture applied was related to resistance against invasion. We show that PD in North American tallgrass prairie restorations, as measured by both SESMNTD and SESMPD, is maintained over time even as richness declines. Neither the resulting community PD nor invasion by high-threat exotic species were affected by PD of the seed mixture used in site restoration. Thus simply maximizing PD of seed mixtures without considering the particular component species is unlikely to help achieve restoration goals. Synthesis and applications. These results suggest that species losses over time are not biased toward species with or without close relatives in the community. If phylogenetic diversity (PD) reflects functional trait diversity in communities, then local declines in species richness may not necessarily mean the loss of ecosystem function in restoration projects. However, PD of restored communities may be limited by low establishment rates for most species. Conservation practitioners should consider PD with careful planning to maintain overall community diversity and potentially maximize ecosystem function and services in restorations. This perspective will require a deeper understanding of the relationships between phylogenetic relatedness and traits associated with competition and fitness.

生态系统修复（ecosystem restoration）是缓解生物多样性丧失、恢复为人类提供的关键生态系统服务的重要手段，但修复工作极少考虑待修复群落的进化属性。系统发育多样性（phylogenetic diversity, PD）是衡量修复成效的潜在有价值指标，因为它可与驱动生态系统功能的功能性状多样性相关联。然而，修复群落的系统发育多样性模式极少被评估。我们对2至19年生的修复性高草草原植物群落开展了调查，并计算了两类系统发育多样性指标：群落及样地播种所用种子组合的标准化效应量平均最近分类单元距离（SESMNTD）和标准化效应量平均成对分类单元距离（SESMPD）。我们还识别了每个样地中的高威胁外来物种，以探究播种种子组合的系统发育多样性是否与抗入侵性相关。研究结果显示，以SESMNTD和SESMPD衡量的北美高草草原修复群落的系统发育多样性，随时间推移得以维持，尽管物种丰富度有所下降。最终群落的系统发育多样性，以及高威胁外来物种的入侵情况，均不受修复所用种子组合的系统发育多样性的影响。因此，仅最大化种子组合的系统发育多样性，而不考虑具体组成物种，不太可能助力实现修复目标。综合与应用。上述结果表明，随时间推移发生的物种丧失，并不会偏向于群落中亲缘关系较近或较远的物种。如果系统发育多样性（PD）能够反映群落的功能性状多样性，那么修复项目中物种丰富度的局部下降，未必意味着生态系统功能的丧失。不过，修复群落的系统发育多样性可能会受到多数物种定植率偏低的限制。保护实践者在开展修复工作时，应审慎考量系统发育多样性，以维持群落整体多样性，并潜在最大化生态系统功能与服务。这一认知需要我们更深入地理解系统发育亲缘关系与竞争、适合度相关性状之间的关联。