Influence of tree cover on herbaceous layer development and carbon and water fluxes in a Portuguese cork-oak woodland
Influence of tree cover on herbaceous layer development and carbon and water fluxes in a Portuguese cork-oak woodland
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DOI：
10.1016/j.actao.2014.05.007
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发表时间：
2014-08-01
影响因子：
1.8
通讯作者：
Werner, Christiane
中科院分区：
文献类型：
--
作者：
Dubbert, Maren;Mosena, Alexander;Werner, Christiane
不同植被层之间的促进和竞争可能对小规模植被发展产生很大影响。我们建议，这不仅应该影响整体草本层产量，但物种分布和林下植物寿命，因此，生态系统的碳吸收能力，特别是在春季。我们分析了树木对小气候和土壤性质的影响（水和硝酸盐含量）以及在葡萄牙软木橡树林地中关于物种组成、地上生物量和净水和碳通量的草本群落层的发展，树木的存在导致光合有效辐射显著减少35 mol m（-2）d（-1），4 - 10月土壤温度5 ℃。同时，可以观察到位于开阔地和树下的实验地块之间的物种组成差异：从4月中旬开始，不同地点之间的物种组成和功能群丰度变得越来越不同。在晚春干旱适应本地杂类草有显着较高的覆盖率和生物量在开放区，而覆盖和生物量的草和固氮杂类草是最高的树下。此外，蒸散量和净碳交换减少显着更强的树冠下相比，开放在晚春和草本植物的枯死发生在树下更早，更快。这是最有可能造成的种间竞争的树木和草本植物之间的水分，尽管更有利的小气候条件下的树木在夏季干旱的发病。(C)2014年Elsevier Masson SAS。All rights reserved.
Facilitation and competition between different vegetation layers may have a large impact on small-scale vegetation development. We propose that this should not only influence overall herbaceous layer yield but also species distribution and understory longevity, and hence the ecosystems carbon uptake capacity especially during spring. We analyzed the effects of trees on microclimate and soil properties (water and nitrate content) as well as the development of an herbaceous community layer regarding species composition, aboveground biomass and net water and carbon fluxes in a cork-oak woodland in Portugal, between April and November 2011.The presence of trees caused a significant reduction in photosynthetic active radiation of 35 mol m(-2) d(-1) and in soil temperature of 5 degrees C from April to October. At the same time differences in species composition between experimental plots located in open areas and directly below trees could be observed: species composition and abundance of functional groups became increasingly different between locations from mid April onwards. During late spring drought adapted native forbs had significantly higher cover and biomass in the open area while cover and biomass of grasses and nitrogen fixing forbs was highest under the trees. Further, evapotranspiration and net carbon exchange decreased significantly stronger under the tree crowns compared to the open during late spring and the die back of herbaceous plants occurred earlier and faster under trees. This was most likely caused by interspecific competition for water between trees and herbaceous plants, despite the more favorable microclimate conditions under the trees during the onset of summer drought. (C) 2014 Elsevier Masson SAS. All rights reserved.