College of Landscape Architecture and Forestry, Qingdao Agricultural University, Qingdao, 266109, People's Republic of China.
Institute of Ecology and Biodiversity, College of Life Sciences, Shandong University, Qingdao, 266237, People's Republic of China.
BMC Ecol. 2020 Mar 30;20(1):17. doi: 10.1186/s12898-020-00284-9.
Invasive exotic species have caused significant problems, and the effects of extreme precipitation and drought, which might occur more frequently under the global climate change scenarios, on interspecific relationship between invasive and native species remain unclear.
We conducted a greenhouse experiment with three soil water levels (30-40%, 50-60%, and 70-80% of field capacity) and two cultivation treatments (monoculture pots, one seedling of either species and mixture pots, one seedling of each species) to investigate soil water content effects on the relationship between invasive Rhus typhina and native Cotinus coggygria. Rhus typhina had lower height but bigger crown area than C. coggygria in the monoculture treatment. Rhus typhina had higher height, bigger crown area and total biomass than C. coggygria in the mixture treatment. Drought decreased the growth parameters, total chlorophyll concentration, and leaf biomass, but did not change gas exchange and other biomass parameters in R. typhina. The growth parameters, leaf area index, biomass parameters, total chlorophyll concentration, and net photosynthetic rate of C. coggygria decreased under drought conditions. The log response ratio (lnRR), calculated as ln (total biomass of a target plant grown in monoculture/total biomass of a target plant grown in mixed culture), of R. typhina was lower than that of C. coggygria. The lnRR of R. typhina and C. coggygria decreased and increased with increase in soil water content, respectively.
Rhus typhina has greater capacity to relatively stable growth to the drought condition than C. coggygria and has strong competition advantages in the mixture with C. coggygria, especially in the drought condition. Our study will help understand the causes of invasiveness and wide distribution of R. typhina under various moisture conditions and predict its expansion under climate change scenarios.
入侵外来物种已造成严重问题，而在全球气候变化情景下可能更为频繁发生的极端降水和干旱对入侵种与本地种之间的种间关系的影响仍不清楚。
我们进行了一项温室实验，设置了三个土壤水分水平（田间持水量的 30-40%、50-60%和 70-80%）和两种栽培处理（单一种植盆，每种物种各有一个幼苗和混合种植盆，每种物种各有一个幼苗），以研究土壤水分含量对入侵物种麻栎和本地物种黄栌之间关系的影响。在单一种植处理中，麻栎的高度较低，但冠幅较大。在混合种植处理中，麻栎的高度、冠幅和总生物量均大于黄栌。干旱降低了麻栎的生长参数、总叶绿素浓度和叶片生物量，但对其气体交换和其他生物量参数没有影响。干旱条件下，黄栌的生长参数、叶面积指数、生物量参数、总叶绿素浓度和净光合速率均下降。麻栎的对数响应比（lnRR），即单种种植的目标植物的总生物量/混合种植的目标植物的总生物量的自然对数，低于黄栌。随着土壤水分含量的增加，麻栎和黄栌的 lnRR 分别减小和增加。
与黄栌相比，麻栎具有更强的耐旱能力，在与黄栌混合种植时具有更强的竞争优势，尤其是在干旱条件下。我们的研究将有助于理解麻栎在各种水分条件下的入侵性和广泛分布的原因，并预测其在气候变化情景下的扩张。
