While introduced plants often have restricted distributions at high elevations, their impacts may be more extensive if they compete for native pollinators, potentially reducing pollinator services to native biotically pollinated plants. Conversely, introduced biotically pollinated plants might facilitate improved pollinator services to native plants by supporting higher pollinator densities and extending the flowering season. We examined weekly pollinator visitation to native and introduced plants, at five elevations over two flowering seasons on The Remarkables range, south-central South Island, New Zealand. In this area, introduced plants dominate the vegetation at lower elevations but are restricted to disturbed areas above treeline. We tested whether pollinator visitation rates and quantities of introduced pollen on insects or transferred to native flowers differed with elevation and community context, or with the local abundance of introduced flowers regardless of elevation. Introduced biotically pollinated plants produced more flowers and flowered later than most native species and were extensively utilised by native solitary bees. Weekly visitation rates to native flowers were higher in the first half of the flowering season than the second half, and were positively correlated with visitation rates to co-occurring introduced flowers. Introduced flower abundance did not affect visitation to native flowers but did significantly predict the occurrence of introduced pollen on native insects and stigmas of native flowers. Pollen contamination was also higher in the latter part of the flowering season. While an increase in introduced flowers at high elevations may benefit native pollinators by increasing the quantity and duration of floral resources available, the heavy use of introduced flowers by native bees will lead to at least localised stigma contamination, particularly for late flowering species. However, more information is required on foraging ranges of native pollinators and pollen limitation in native species to understand the consequences of introduced species expansion into alpine areas.

中文翻译：

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在山地-高山环境中引进的植物是否对本地传粉媒介服务构成威胁？

尽管引进的植物在高海拔地区的分布通常受到限制，但如果它们争夺本地授粉媒介，其影响可能会更大，从而可能减少传粉媒介对本地生物授粉植物的服务。相反，引入的经过生物授粉的植物可能会通过支持更高的传粉媒介密度和延长花期来促进对本地植物的传粉媒介服务。我们在新西兰南岛中南部的The Remarkables山脉中，在两个开花季节的五个海拔高度上，调查了授粉媒介每周对本地和引进植物的探访情况。在该地区，引入的植物在较低海拔的植被中占主导地位，但仅限于林线以上的受干扰地区。我们测试了传粉者访问率和昆虫上或转移到本地花上的引入花粉的量是否随海拔和群落环境或引入的花的局部丰度而与海拔无关。引入生物授粉的植物比大多数本地物种产生更多的花和更晚的开花，并被本地的单独蜜蜂广泛利用。在开花季节的前半周，对本地花的每周探访率高于下半年，并且与同时出现的引入花的探望率呈正相关。引入的花丰度不会影响对原生花的造访，但可以显着预测在原生昆虫和原生花柱头上引入花粉的发生。花粉期后期花粉污染也较高。虽然通过增加可用花卉资源的数量和持续时间，高海拔地区引进的花卉增加可能使本地授粉者受益，但本地蜜蜂大量使用引进的花卉将至少导致局部的柱头污染，特别是对于晚开花的物种。但是，需要更多有关本地传粉媒介觅食范围和本地物种花粉限制的信息，以了解引入物种扩展到高山地区的后果。本地蜜蜂大量使用引入的花朵将至少导致局部的柱头污染，特别是对于晚开花的物种。但是，需要更多有关本地传粉媒介觅食范围和本地物种花粉限制的信息，以了解引入物种扩展到高山地区的后果。本地蜜蜂大量使用引入的花朵将至少导致局部的柱头污染，特别是对于晚开花的物种。但是，需要更多有关本地传粉媒介觅食范围和本地物种花粉限制的信息，以了解引入物种扩展到高山地区的后果。