Data from: Where and how to restore in a changing world: a demographic-based assessment of resilience

Managers are increasingly looking to apply concepts of resilience to better anticipate and understand conservation and restoration in a changing environment.

In this study, we explore how information on demography (recruitment, growth and survival) and competitive effects in different environments and with different starting species abundances can be used to better understand resilience. We use observational and experimental data to better understand dynamics between native Stipa pulchra and exotic Avena barbata and fatua, grasses characteristic of native and invaded grasslands in California, at three different levels of nitrogen (N) representative of a range of pollution via atmospheric deposition. A modelling framework that incorporates this information on demography and competition allows us to forecast dynamics over time.

Our results showed that resilience of native grasslands depends on N inputs, where natural recovery should be possible at low N levels whereas native persistence would be difficult at high N levels. Hysteresis was evident at moderate N levels, where the starting conditions mattered.

Synthesis and applications. The resilience of both invaded and native grasslands is influenced by nitrogen inputs. Our modelling approach gives direction about how best to allocate limited management resources as baselines shift: where natural recovery is possible, where best to allocate active restoration efforts, and where native remnants may be most vulnerable.

生态管理者正日益寻求应用恢复力（Resilience）相关概念，以在变化的环境中更好地预判与开展生态保护与修复工作。
本研究探讨了种群统计学（补充、生长与存活）相关信息，以及不同环境下、不同初始物种多度下的竞争效应，如何用于深化对恢复力的理解。本研究利用观测与实验数据，解析了加州原生草原与入侵草原的代表性草本植物——原生美花针茅（Stipa pulchra）以及外来物种细茎燕麦（Avena barbata）与野燕麦（Avena fatua）——在三种不同氮（N）水平下的种群动态，该三种氮水平对应大气沉降污染的不同梯度。本研究构建的整合种群统计学与竞争关系信息的建模框架，可用于预测种群动态随时间的变化。
研究结果表明，原生草原的恢复力取决于氮输入水平：低氮条件下可实现自然恢复，而高氮条件下原生草原难以维持种群存续。在中等氮水平下存在明显的滞后效应，且初始条件对系统动态具有显著影响。
研究结论与应用展望：入侵草原与原生草原的恢复力均受氮输入的影响。本研究提出的建模方法可为基线条件变化下的有限管理资源分配提供指导，具体包括可实现自然恢复的区域、最优主动修复投入区域，以及原生草原残存斑块最易受威胁的区域。