Stipa Seedling SurvivorshipStipa pulchra seedling survivorship and stem counts of Stipa seedlings and adults and Avena adults across two community types (Stipa pulchra or Avena fatua), three Nitrogen treatments (low, ambient, and high), and three light treatments (low, ambient, and high) within study conducted at the University of California South Coast Research and Extension Center.JPE_stipa data.csvStipa adult survivorshipThe number of Stipa pulchra adults at each sampling point and the proportion of adults that survived across seven blocks of paired grazed and ungrazed plots over two years at the Vasco Caves Regional ParkJPE_Vasco_Stipa_adult_survival.csvStipa adult fecundityReproductive data for Stipa pulchra at Vasco Caves Regional Park. These data include total number of individuals within a plot, whether a given individual reproduced and the number of culms per plant if it did. These data span multiple years and grazed treatments.JPE_Vasco_Stipa.csvStipa pulchra recruitment dataRecruitment data for Stipa pulchra across three nitrogen treatments at the Irvine Ranch Natural LandmarkJAE_stipa germination data.csvData to assess Avena seed productionAvena fatua stem counts and per capita seed production data, as well as Stipa pulchra seedling and adult stem counts across two community types (Stipa pulchra or Avena fatua), three Nitrogen treatments (low, ambient, and high), and three light treatments (low, ambient, and high) within study conducted at the University of California South Coast Research and Extension Center.JPE_Avena data.csvAvena recruitmentGermination and recruitment stem data for Avena barbata across a density and precipitation experiment conducted at the University of California Sierra Foothills Research and Extension Center.JPE_Avena recruitment.csv

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.