DOI: 10.5061/dryad.b1v2c
title: Data from: Biotic resistance to tropical ornamental invasion

description: We examined invasive, casual (found occasionally outside cultivation) and
 non-invasive (found only in cultivation) species to investigate the role
 of species traits and two forms of biotic resistance (plant neighbours and
 herbivores) in limiting invasion in Hawaiian lowlands. Seeds of 21 species
 of common woody ornamentals from three plant families (Acanthaceae,
 Apocynaceae, Bignoniaceae) that are non-invasive, casual or invasive in
 Hawai'i were outplanted at two field sites. We measured germination
 of seeds and growth and survival of seedlings for one year in plots with
 and without neighbours from the naturally-assembled community. The
 presence of neighbours reduced survival in some species, mostly
 non-invasive or casual species and completely excluded two non-invasive
 species from community plots. Damage from the existing community of
 herbivores was correlated with lower survival in the Acanthaceae and
 Bignoniaceae, but not the Apocynaceae. Non-invasive and casual species had
 lower survival and growth rates than invasive species and lower
 photosynthetic rates in the presence of neighbours than invasive species.
 Non-invasives without neighbours also had lower specific leaf area than
 invasives and casuals. We found evidence for barriers to invasion in some
 non-invasive and casual species, including low growth rate, low survival,
 or low survival in the presence of neighbours. By contrast, five of the
 six invasives flowered and three began setting fruit within the duration
 of the experiment, as did one of the casual species. Synthesis: Our
 research demonstrates biotic resistance, presumably as a result of
 competition. Neighbouring plants reduced survival and growth for most
 species. For non-invasive species with low survival and growth even
 without competition from neighbouring plants, this resulted in complete
 exclusion from community plots or such low growth rates that exclusion
 over longer time frames was likely. We also provide evidence for
 traits-based barriers to invasion in non-invasive and casual species.
 However, no single barrier to invasion was shared across all non-invasive
 and casual species.
description: Germination, survival
 and traits of tropical ornamentals in the fieldThese data show the
 germination, survival, and traits from 21 species of introduced tropical
 ornamental plants in Hawai'i. Plant species were drawn from three
 taxonomic families and classed as invasive, casual or non-invasive. Seeds
 were planted at two sites (wet or seasonally dry) in 10 blocks per site in
 plots with or without neighbours. Seedlings were monitored for one year to
 track germination and survival. After one year, leaf traits were measured
 on any remaining plants and plants were harvested to measure biomass.
 Canopy cover and richness and biomass of the plant community in plots with
 neighbours are also included.Field_Seedling_Data.csvGermination of tropical ornamentals in germination chambersThese data show the results of controlled germination trials of 21 species of introduced tropical ornamental plants in Hawai'i. Plant species were drawn from three taxonomic families and classed as invasive, casual or non-invasive. Germination trials were conducted in two germination chambers in petri dishes of damp sand, with two dishes (specified by location on upper or lower rack) per species per chamber. Germination trials were conducted simultaneously with experimental plantings at two field sites and germination chamber settings mimicked light and temperature regimes of the two sites.Lab_Germination_Data.csvPlant community composition in field plots with neighboursThese data show the plant community composition of plots at two sites (wet or seasonally dry) in 10 blocks per site in plots with neighbours. All plots were cleared of vegetation and planted with seeds of 21 species of introduced tropical ornamental plants in Hawai'i. Subsequently, the plant community was allowed to regenerate in plots with neighbours. In these plots, plant community was measured by visually estimating the percent cover of all species within two 1 m x 1 m quadrats (excluding experimentally planted species). Data were collected at the end of the experiment when experimentally planted species were harvested. Sites and blocks are the same as those recorded in Field_Seedling_Data.csv (Data 1).Plant_Community_Data.csv