One reason restoration often fails is a lack of native plant establishment. Establishment failure can occur due to a lack of dispersal into the site, inappropriate abiotic conditions for plant survival, or biotic interactions that reduce germination rates or seedling survival. Understanding what is limiting establishment is critical for restoration success. Unfortunately, there has been little synthetic work to identify which restoration practices (e.g., direct seeding, weeding, irrigation) are most likely to improve plant establishment. Here we used a meta-analytical approach to determine what practices are most likely to enhance establishment success in grassland communities in California. We explored the impact of these practices on whole communities as well as on different functional groups (grass and forb). We categorized techniques by the constraint they addressed (dispersal, abiotic, or biotic) to determine which restoration practices are more likely to improve plant establishment. We found that addressing the dispersal filter is the best way to improve plant establishment regardless of the functional group. This suggests that most native plants targeted in restoration are seed limited. While we were able to identify restoration techniques that improve plant establishment, our synthesis revealed that there were insufficient numbers of studies and a lack of uniformity between treatments that hampered efforts to make broad conclusions. If we can expand research to more ecosystems, and use standardized treatments within each ecosystem, the restoration community could synthesize research more efficiently, which would inform our ultimate goal of increasing the success of restoration.

中文翻译：

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通过荟萃分析确定有效的恢复方法，以最大限度地提高加利福尼亚草原的植物数量

恢复经常失败的原因之一是缺乏本地植物建立。建立失败可能是由于缺乏扩散到现场、不适合植物生存的非生物条件或降低发芽率或幼苗存活率的生物相互作用。了解限制建立的因素对于恢复成功至关重要。不幸的是，几乎没有综合工作来确定哪些恢复实践（例如，直播、除草、灌溉）最有可能改善植物定植。在这里，我们使用元分析方法来确定哪些做法最有可能提高加利福尼亚草原社区的建立成功。我们探讨了这些做法对整个社区以及不同功能群体（草和森林）的影响。我们根据技术所解决的限制（扩散、非生物或生物）对技术进行分类，以确定哪些恢复实践更有可能改善植物的建立。我们发现无论功能组如何，解决分散过滤器都是改善植物建立的最佳方法。这表明大多数以恢复为目标的本地植物种子有限。虽然我们能够确定改善植物建立的恢复技术，但我们的综合表明，研究数量不足，处理之间缺乏统一性，阻碍了得出广泛结论的努力。如果我们可以将研究扩展到更多的生态系统，并在每个生态系统内使用标准化的处理方法，那么恢复社区就可以更有效地综合研究，