Reductions in native grass biomass associated with drought facilitates the invasion of an exotic grass into a model grassland system
Reductions in native grass biomass associated with drought facilitates the invasion of an exotic grass into a model grassland system
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DOI：
10.1007/s00442-016-3553-1
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发表时间：
2016-05-01
期刊：
影响因子：
2.7
通讯作者：
Leishman, Michelle R.
中科院分区：
文献类型：
--
作者：
Manea, Anthony;Sloane, Daniel R.;Leishman, Michelle R.
外来植物物种的入侵成功往往取决于资源的可用性。气候变化的各个方面，如大气中二氧化碳浓度的上升和极端气候事件，将直接和间接地改变生态社区的资源供应。了解这些与气候变化相关的资源可用性变化将如何相互作用，以影响外来植物物种的入侵成功是复杂的。这项研究的目的是评估一种外来入侵物种在应对极端干旱导致的与气候变化相关的资源可用性变化（二氧化碳水平和土壤水可用性）方面的成功建立。我们生长的草原围隔组成的四个共同发生的原生草种常见的坎伯兰平原林地西部悉尼，澳大利亚，在环境和升高的CO2水平下，并进行了极端干旱处理。然后，我们添加了高度侵入性的C-3草Ehrharta erecta的种子，并评估了其建立成功（生物量生产和生殖输出）。我们发现，在极端干旱条件下，本地牧草生物量的减少促进了E.通过在光和空间中创造资源脉冲来直立。CO2浓度对E.直立的我们的研究结果表明，未来草原的入侵风险可能与土壤水分供应和当地植被的后续反应相耦合，因此具有很强的背景依赖性。
The invasion success of exotic plant species is often dependent on resource availability. Aspects of climate change such as rising atmospheric CO2 concentration and extreme climatic events will directly and indirectly alter resource availability in ecological communities. Understanding how these climate change-associated changes in resource availability will interact with one another to influence the invasion success of exotic plant species is complex. The aim of the study was to assess the establishment success of an invasive exotic species in response to climate change-associated changes in resource availability (CO2 levels and soil water availability) as a result of extreme drought. We grew grassland mesocosms consisting of four co-occurring native grass species common to the Cumberland Plain Woodland of western Sydney, Australia, under ambient and elevated CO2 levels and subjected them to an extreme drought treatment. We then added seeds of a highly invasive C-3 grass, Ehrharta erecta, and assessed its establishment success (biomass production and reproductive output). We found that reduced biomass production of the native grasses in response to the extreme drought treatment enhanced the establishment success of E. erecta by creating resource pulses in light and space. Surprisingly, CO2 level did not affect the establishment success of E. erecta. Our results suggest that the invasion risk of grasslands in the future may be coupled to soil water availability and the subsequent response of resident native vegetation therefore making it strongly context- dependent.