Physiological integration in an introduced, invasive plant increases its spread into experimental communities and modifies their structure.
Physiological integration in an introduced, invasive plant increases its spread into experimental communities and modifies their structure.
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DOI：
10.3732/ajb.0800426
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发表时间：
2009-11
影响因子：
3
通讯作者：
F. Yu;Ning Wang;P. Alpert;Weiming He;M. Dong
中科院分区：
文献类型：
--
作者：
F. Yu;Ning Wang;P. Alpert;Weiming He;M. Dong
是什么决定了引进植物的侵入性，人们仍然知之甚少。许多入侵最严重的植物物种是克隆的，克隆植物的相连个体(分株)之间的生理整合可能有助于它们扩散到群落中，并降低现有物种的性能。在密度较大的群落中，整合对克隆植物入侵的贡献可能更大。一项温室研究被用来检验这两个假说。通过播种8种草地树种，形成高密度和低密度群落。每个群落种植了三株有匍匐茎的引种植物空心莲子草，这些植物与生长在裸地上的分株脱节或保持连接。连接增加了莲子草在群落内的传播，但并没有减少群落生物量。莲子草在高密度群落中生长较少，但Connection对其生长的促进作用并不比低密度群落中的更大。低密度群落在连接莲子草时的均匀度比不连接时高，这是因为群落中丰富度较高的物种枝条质量较低，而丰富度较低的物种枝条质量较高。这些结果部分支持了第一种假设，但不支持第二种假设。整合对群落结构的影响可能是由于离优势种较近的莲子草分株具有更高的资源输入。因此，整合可以增加新的克隆植物物种向群落的初始传播，并改变这种传播对群落结构的影响。
What determines the invasiveness of introduced plants is still poorly known. Many of the most invasive plant species are clonal, and physiological integration between connected individuals (ramets) of clonal plants may contribute to their ability to spread into communities and reduce performance of existing species. This contribution of integration to the invasiveness of clonal plants may be greater in denser communities. A greenhouse study was conducted to test these two hypotheses. High- and low-density communities were created by sowing seeds of eight grassland species. Each community was planted with three ramets of the stoloniferous, introduced plant Alternanthera philoxeroides that were disconnected from or left connected to ramets growing on bare soil. Connection increased the spread of Alternanthera within a community, but did not reduce community biomass. Alternanthera grew less in high-density communities, but connection did not improve its growth more than in low-density communities. Low-density communities had higher evenness when Alternanthera was connected than when it was disconnected because shoot mass was lower in the more abundant species in the community and higher in the less abundant ones. These results partly supported the first hypothesis, but not the second. The effect of integration on community structure could be due to higher resource import by the ramets of Alternanthera closer to the dominant species. Integration therefore can increase the initial spread of new clonal plant species into communities and modify the effects of this spread on community structure.