Data from: Restored tallgrass prairies have reduced phylogenetic diversity compared with remnants

Ecological restoration is critical for mitigating habitat loss and providing ecosystem services. However, restorations often have lower diversity than remnant, reference sites. Phylogenetic diversity is an important component of biodiversity and ecosystem function that has only recently been used to evaluate restoration outcomes. To move towards prediction in the restoration of biodiversity, it is necessary to understand how phylogenetic diversity of restorations compares with that of reference sites, and where deficits are found, to evaluate factors constraining phylogenetic diversity.

We quantified plant taxonomic and phylogenetic diversity in eastern tallgrass prairie, one of the most endangered ecosystems on earth. We measured diversity at large (site) and small (plot) scales in 19 restored prairies and compared patterns with those from 41 remnant prairies. To evaluate how environmental conditions and management actions influence outcomes, we tested the effects of soil properties and seed mix composition on diversity of restorations.

Restored prairies were less phylogenetically diverse than remnants at both spatial scales. On the other hand, the total species richness of remnant and restored prairies did not significantly differ, but remnants had higher native richness. Restored communities were taxonomically and phylogenetically distinct from remnants.

Soil properties (moisture and pH) influenced phylogenetic diversity and composition. There were positive relationships between the taxonomic and phylogenetic diversity of seed mixes and resulting diversity of planted assemblages (excluding volunteer species). Species in seed mixes were more closely related than expected by chance, and several clades found in remnant prairies were missing from seed mixes.

Synthesis and applications. Restored tallgrass prairies had lower phylogenetic diversity than remnant prairies, which may contribute to the widely observed phenomenon of restorations not being functionally equivalent to reference sites. It is encouraging for restoration efforts that seed mix phylogenetic diversity predicted phylogenetic diversity of planted assemblages. This indicates that designing phylogenetically diverse seed mixes for restoration is beneficial. In addition, clades found in reference sites that are missing from restoration seed mixes could be added to new or existing restorations to reduce gaps in phylogenetic diversity. Further work on the effects of management on phylogenetic diversity is needed to advance restoration of biodiversity.

生态修复对于减缓生境丧失、供给生态系统服务至关重要。然而，修复生境的生物多样性往往低于残存参照样地。系统发育多样性（Phylogenetic Diversity）是生物多样性与生态系统功能的重要组成部分，直至近年才被用于评估修复成效。若要实现生物多样性修复的可预测性，我们有必要明晰修复生境的系统发育多样性与参照样地的差异，并在发现多样性不足时，剖析制约系统发育多样性的因素。

本研究针对全球最濒危的生态系统之一——东部高草草原，量化了其中植物的分类学多样性与系统发育多样性。我们在19个修复草原的大尺度（样地整体）与小尺度（样方）两个层面开展多样性测定，并将结果与41处残存草原的测定模式进行对比。为探究环境条件与管理措施对修复成效的影响，我们检验了土壤性状与种子混合配方组成对修复样地多样性的作用。

在两个空间尺度下，修复草原的系统发育多样性均低于残存草原。另一方面，残存草原与修复草原的总物种丰富度并无显著差异，但残存草原的本土物种丰富度更高。修复群落与残存群落在分类学及系统发育层面均存在显著差异。

土壤性状（含水量与pH值）会影响系统发育多样性与群落组成。种子混合配方的分类学与系统发育多样性，与最终定植群落（不含自然侵入物种）的多样性呈正相关关系。种子混合配方中的物种亲缘关系比随机预期更为紧密，且残存草原中存在的多个演化支在种子混合配方中缺失。

总结与应用：修复高草草原的系统发育多样性低于残存草原，这或许可以解释学界广泛观测到的现象——修复生境无法在功能层面与参照样地等效。令人振奋的是，种子混合配方的系统发育多样性可以预测定植群落的系统发育多样性，这对修复工作而言是积极信号。这表明，为修复项目设计具有高系统发育多样性的种子混合配方是有益的。此外，可以将参照样地中缺失于修复种子混合配方的演化支添加至新修复或已修复的生境中，以缩小系统发育多样性的差距。未来仍需开展更多关于管理措施对系统发育多样性影响的研究，以推动生物多样性修复工作的发展。