Data from: Long-term and year-to-year stability and its drivers in a Mediterranean grassland [Software]

indicescom.R: calculation of richness, synchrony and stability indices at the community level. functionalindicescom.R: calculation of functional composition (Community Weighted Mean) and diversity (Rao) for the five traits studied (plant height, Leaf Dry Matter Content, Specific Leaf Area, Leaf Area, Seed Mass), at the community level. spstabilityindices.R: calculation of stability indices at the species level. models_boxplots.R: R script for multiple linear regression models analysing the relationship between richness, synchrony or stability values and the approach used (long-term or year-to-year), treatment (control or fertilized) and the interaction between approach and treatment. models_stability_communitylevel.R: R script for simple and multiple linear regression models analysing the drivers of long-term and year-to-year community stability. SEMs.R: R script for Piecewise Structural Equation Models analysing the relationships between long-term and year-to-year community stability and their drivers. models_stability_splevel.R: R script for simple and multiple linear regression models analysing the relationship between long-term and year-to-year species stability and functional traits. spstability.R: R script for Pearson's correlations and paired t-tests analysing the effects of treatment and long-term trends on species stability.

Understanding the mechanisms underlying community stability has become an urgent need in order to protect ecosystems from global change and resulting biodiversity loss. While community stability can be influenced by richness, synchrony in annual fluctuations of species, species stability and functional traits, the relative contributions of these drivers to stability are still unclear. In semi-natural grasslands, land-use changes such as fertilization might affect stability by decreasing richness and influencing year-to-year fluctuations. In addition, they can promote long-term directional trends, shifting community composition and influencing grassland maintenance. Thus, it is important to consider how species and community stability vary year-to-year but also in the long term. Using a 14-year vegetation time series of a species-rich semi-natural Mediterranean grassland, we studied the relative importance of richness, synchrony, species stability and functional traits on community stability. To assess land-use change effects on stability, we applied a fertilization treatment. To distinguish stability patterns produced by year-to-year fluctuations from those caused by long-term trends, we compared the results obtained using a detrending approach from those without detrending. Stability is influenced by richness, synchrony and functional traits. Fertilization decreases species and community stability by promoting long-term trends in species composition, favouring competitive species and decreasing richness. Studying stability at the community and species level, and accounting for the effect of trends is essential to understand stability and its drivers more comprehensively.

Fundación Caja Navarra Crossref Funder Registry ID: http://dx.doi.org/10.13039/501100006671 Award Number: Ref. 10833 (Programa "Tú Eliges, Tú Decides")

Universidad de Navarra Crossref Funder Registry ID: http://dx.doi.org/10.13039/501100004435 Award Number: Project "Biodiversity Data Analytics and Environmental Quality"

Universidad de Navarra Crossref Funder Registry ID: http://dx.doi.org/10.13039/501100004435 Award Number: Project "Red de Observatorios de la Biodiversidad de Navarra (ROBIN)"

Departamento de Educación, Gobierno de Navarra Crossref Funder Registry ID: http://dx.doi.org/10.13039/501100003425 Award Number: Ayudas predoctorales para la realización de programas de doctorado de interés para Navarra; Plan de Formación y de I+D 2018

Ministerio de Ciencia, Innovación y Universidades Crossref Funder Registry ID: http://dx.doi.org/10.13039/100014440 Award Number: Ref. RTI2018-096884-B-C31 (Project FORMAL)

Czech Academy of Sciences Crossref Funder Registry ID: http://dx.doi.org/10.13039/501100004240 Award Number: No. RVO 67985939

Peer reviewed