Data from: Biotic resistance to tropical ornamental invasion

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.本研究针对入侵种、逸生种（仅在栽培环境外偶有发现）与非入侵种（仅见于栽培环境）开展调查，旨在探究物种性状与两种生物抗性（biotic resistance，植物邻体（plant neighbours）与植食动物（herbivores））在限制夏威夷低地植物入侵过程中的作用。我们选取了隶属于爵床科（Acanthaceae）、夹竹桃科（Apocynaceae）、紫葳科（Bignoniaceae）3个植物科的21种常见木本观赏植物种子，这些物种在夏威夷可分为非入侵、逸生或入侵三类，随后将其移栽至两个野外样地中。我们在包含自然组装群落邻体与去除邻体的样地中，连续一年监测了种子萌发、幼苗生长与幼苗存活情况。邻体的存在会降低部分物种的幼苗存活率，这类物种多为非入侵种或逸生种，且有2种非入侵种完全被自然群落邻体样地排除。现有植食动物群落造成的取食损伤与爵床科、紫葳科物种的较低存活率显著相关，但这一关联并未见于夹竹桃科。非入侵种与逸生种的存活率、生长速率均低于入侵种，且在存在邻体时的光合速率也低于入侵种。去除邻体的非入侵种的比叶面积（specific leaf area）也低于入侵种与逸生种。我们在部分非入侵种与逸生种中发现了入侵阻碍的相关证据，包括生长速率低下、存活率低下，或是存在邻体时存活率低下。与之形成对比的是，6种入侵种中有5种在实验周期内开花，其中3种开始结实；1种逸生种也出现了同样的繁殖进程。综合讨论：本研究证实了生物抗性的存在，其成因推测为植物间的竞争作用。邻体植物会降低多数物种的存活率与生长速率。对于即使在无邻体竞争的情况下仍表现出低存活率与低生长速率的非入侵种而言，邻体的存在会使其完全被自然群落样地排除，或是生长速率极低，从而在更长的时间尺度上大概率被排除。我们还为非入侵种与逸生种中基于性状的入侵阻碍提供了证据。但并未存在一种能覆盖所有非入侵种与逸生种的通用入侵阻碍机制。