DOI: 10.5061/dryad.12jm63z3x
title: Exotic success following disturbance explained by weak native resilience and ruderal exotic bias

description: Disturbance is a primary driver of exotic plant invasions, but why
 disturbance commonly favors exotics over natives is unresolved. To address
 this question, we conducted the first biogeographic study of disturbance
 across multiple plant species. We experimentally disturbed grasslands and
 added seeds of 34 plant species to plots in their native range and in two
 introduced ranges that differed in invasibility (susceptibility to
 invasion) to evaluate recruitment while examining potential influences of
 resource availability, native community recovery from disturbance
 (resilience), and life-history traits in local species pools. Species
 pools in the native (donor) range were more strongly skewed toward ruderal
 taxa than species pools in the introduced ranges. This bias in the donor
 pool was exacerbated by introduction filters that further selected for
 ruderal traits, strongly skewing exotic species pools in the introduced
 ranges toward ruderals. Sown species, which reflected these trait
 patterns, benefited from disturbance universally, but their disturbance
 response was 10-fold greater in the more invasible introduced range. This
 result was not explained by nutrient availability, which responded
 similarly to disturbance across ranges. Nor was it driven by background
 propagule pressure, which was minimal. Rather, the exaggerated disturbance
 effect in the more invasible introduced range appeared to be driven by
 weak recovery of the native plant community that allowed ruderal-biased
 exotics to proliferate. Overall, disturbance appeared to favored exotics
 because they were much more likely than natives to be ruderal. However,
 this trait bias only corresponded with an invader advantage in the more
 invasible range where weak community resilience was linked to
 slow-growing, stress-tolerant natives that failed to rapidly recover space
 and resources. In contrast, in the less invasible introduced range, highly
 competitive native perennials quickly filled the disturbance gap,
 demonstrating high community resilience that appeared to limit invader
 recruitment.  Synthesis. Biogeographic influences on local
 species pools can facilitate invader success following disturbance, but
 final invasion outcomes are conditioned by native community
 resilience. 
description: These data were collected in experimental plots using parallel
 methods in each of three regions representing either the native range
 (Turkey) or the introduced range (La Pampa, Argentina and Montana, USA) of
 34 focal plant species. Treatments were seed addition of focal species
 (added or not) crossed with disturbance (disturbed or not). Plots were
 read in the first growing season after treatment for recruitment (number
 of seedlings per focal species) and for evaluation of community responses
 to disturbance (cover per species, including non-focal taxa, and species
 richness). Community responses to disturbance were assessed again in the
 second post-treatment year.  See publication for sampling
 details.   Components of the dataset are:
 RAW RECRUITMENT DATA - recruitment by individual focal species
 for both seeded and unseeded plots in the first growing season after
 treatment. PLOT LEVEL RECRUITMENT  DATA - Recruitment
 across focal species plus background community measures (non-focal
 species) for both seeded and unseeded plots in the first growing season
 after treatment. COMMUNITY RESPONSE DATA - Community
 measures (including both focal and non-focal taxa) in unseeded plots prior
 to disturbance and in the first two post-treatment years.
description: The datafiles are Excel spreadsheets. Each includes a README tab
 that describes each data field/variable.