DOI: 10.5061/dryad.6djh9w11k
title: Data from: Water the odds? Spring rainfall and emergence-related seed traits drive plant recruitment

description: Recruitment of new individuals from seed is a critical component of plant
 community assembly and reassembly, especially in the context of ecosystem
 disturbance and recovery. While frameworks typically aim to predict how
 communities will be filtered on the basis of traits influencing
 established plant responses to the environment, assembly from seed is more
 complex: the responses of seeds (affected by dormancy and germination
 function) and establishing plants (affected by root and leaf function) can
 both influence outcomes within a single growing season. This creates a
 potential role for a more diverse set seed and seedling traits, and for
 environmental variability on shorter timescales (e.g., seasonal versus
 annual dynamics), than are typically considered. We followed thousands of
 individual seeds comprising eleven herbaceous grassland species through
 the first growing season, seeking to uncover critical environmental
 (precipitation amount and timing) and trait-based filters on seedling
 emergence and survival in assembling communities. We saw the biggest
 recruitment limitation when seeds failed to emerge, driven independently
 by a dry spring and interspecific variation in seed mass (positive effect)
 and seed dormancy (negative effect). Seedling survival rates were higher
 than emergence, with weaker predictive roles for traits like seedling root
 mass allocation (positive effect) and seed mass (positive under spring
 drought), and lesser impacts of summer rainfall on soil moisture and
 survival. Interestingly, most trait relationships were not conditional on
 rainfall, suggesting water-independent mechanisms of their respective
 advantages. Although recruitment is a complex process, our findings
 suggest that trait-based assembly frameworks can be a useful way to
 anticipate outcomes, particularly if dynamic early-stage conditions (e.g.,
 spring rainfall) and attributes (e.g., seed dormancy) receive greater
 attention. Given the importance of recruitment for community turnover in
 the context of global change and land management efforts, this is an area
 ripe for continued expansion in trait-based and applied ecology.
description: We collected seed emergence and recruitment data from a set of 17
 native and exotic herbaceous species sown into a common garden experiment
 in Boulder, CO, USA. We manipulated rainfall as part of the experiment to
 understand how recruitment patterns differed under ambient conditions
 (control) and relatively dry or wet conditions in the spring or summer.
 Seeds were sown in late winter and montiored on an individual basis weekly
 through late summer. Our data reflect the germination/emergence success,
 survivorship, and successful recruitment for each planted seed, as well as
 the timing of these events. We used different types of mixed models to
 relate recruitment outcomes to rainfall treatment, and also explored
 whether species-level functional traits held predictive power (including
 seed mass, dormancy, and seedling root traits). Please
 see the published article and supporting information for further details
 (Larson et al. Water the odds? Spring rainfall and emergence-related seed
 traits drive plant recruitment. Oikos)
description: There are several CSV files containing data related to the
 implementation of the rainfall treatment, impacts of the rainfall
 treatment on soil moisture, the summary and temporal responses of
 individual seeds, and species-level traits. Please see the metadata file
 (metadata_Larson_Ebinger_Suding_2021.csv) for a description of each
 spreadsheet and variables within. Missing values are generally denoted
 with NA. Code for analyses reported in the manuscript
 is available upon request from the authors.