College of Horticulture and Forestry Sciences/Hubei Engineering Technology Research Center for Forestry Information, Huazhong Agricultural University, Wuhan 430070, China.
College of Informatics, Huazhong Agricultural University, Wuhan 430070, China.
Sci Total Environ. 2019 Mar 20;657:1568-1577. doi: 10.1016/j.scitotenv.2018.12.099. Epub 2018 Dec 12.
A worth noticing pattern in current invasive biology is the clonal ability of many of the world's worst invasive plants. Selective placement of ramets (i.e. foraging behavior) can intensify ramet performance and allocation, and place more ramets in the more favorable microhabitats, which can maximum utilize resource and share risk in heterogeneous environments. Still little is known about whether invasive alien and native clonal plants differ in the selective placement patterns of ramets in invasive clonal plants or not. We used five congeneric pairs of naturally co-occurring invasive alien and native clonal plant species in China. In a glasshouse, we grew all species in pots under a homogeneous and three heterogeneous conditions (i.e. light, soil nutrients or water) subjected to resource-high or -low patches. All biomass parameters and number of ramets significantly increased in resource-high patches in all three types of heterogeneous environments. Interestingly, growth of invasive alien plants benefited significantly more from resource-high patches than native plants in all heterogeneous environments. Overall, invasive had higher biomass parameters per ramet than natives. Ramet parameters of invasive plants also benefited more from resource-low patches than natives. Three different selective placement patterns of ramets in resource-low patches were exhibited in invasive plants: ramet increasing shoot investment (above pattern), increasing root investment (below pattern) and increasing both investments (complete pattern) in the light, soil water and nutrient heterogeneity, respectively. Investment on less, larger ramet was the adaptive strategy of invasive plants in resource-poor patches. The results suggest that adaptively selective placement patterns of ramets promote a higher morphology plasticity and performance in invasive clonal plants over natives. When alien clonal plants spread new areas with light, soil nutrients or water heterogeneity, selective placement patterns of ramets might play an important role in plant performance and competitive superior by capitalizing more on additional resources.
当前入侵生物学中一个值得注意的模式是，世界上许多最严重的入侵植物具有克隆能力。分株（即觅食行为）的选择性放置可以增强分株的性能和分配，并将更多的分株放置在更有利的小生境中，从而最大限度地利用资源并在异质环境中分担风险。但是，对于入侵外来植物和本地克隆植物在入侵克隆植物中分株的选择性放置模式是否存在差异，我们知之甚少。我们使用了中国五个自然共生的入侵外来植物和本地克隆植物的同属对。在温室中，我们在同质和三种异质条件（即光照、土壤养分或水）下将所有物种种植在盆中，这些条件下存在资源高或低的斑块。在所有三种异质环境中，资源高斑块中的所有生物量参数和分株数量都显著增加。有趣的是，在所有异质环境中，入侵外来植物的生长从资源高斑块中获益比本地植物更多。总体而言，入侵植物的每个分株的生物量参数都高于本地植物。入侵植物的分株参数也从资源低斑块中获益更多。在光照、土壤水分和养分异质性中，入侵植物在资源低斑块中分株表现出三种不同的选择性放置模式：增加地上部投资的分株（上模式）、增加根系投资的分株（下模式）以及增加两者投资的分株（完全模式）。在资源匮乏的斑块中，投资于较小、较大的分株是入侵植物的适应策略。研究结果表明，分株的适应性选择性放置模式促进了入侵克隆植物比本地植物更高的形态可塑性和性能。当外来克隆植物在光照、土壤养分或水分异质性的新地区传播时，分株的选择性放置模式可能通过更充分地利用额外资源在植物性能和竞争优势方面发挥重要作用。
