Tree species diversity increases fine root productivity through increased soil volume filling
Tree species diversity increases fine root productivity through increased soil volume filling
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DOI：
10.1111/1365-2745.12023
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发表时间：
2013-01-01
影响因子：
5.5
通讯作者：
Yuan, Zhiyou
中科院分区：
文献类型：
--
作者：
Brassard, Brian W.;Chen, Han Y. H.;Yuan, Zhiyou
1.细根（直径< 2 mm）是陆地生态系统生产力的主要组成部分，但其多样性对细根生产力的影响及其机制尚不清楚.我们假设：（i）细根生产力随树种多样性而增加，（ii）由于根的放置和增殖的物种特异性模式，细根生产力较高是土壤体积填充较大的结果，以及（iii）与树种多样性相关的细根生产力和土壤体积填充的差异在植物生理活跃、对水分和养分需求最大的夏季更为明显.我们调查了树种多样性对相似地点自然生长85年的北方森林细根生产力和土壤体积填充的影响.年细根生产量在均匀混合比单一树种占主导地位的林分高19-83%，并增加树种均匀度，但不是树种丰富度。细根生物量较高，均匀混合比单一物种占主导地位的立场在夏季，但不是在春季或秋季。均匀混交林比单种林细根生产力更高，是由于深根和浅根树种混交林在水平和垂直方向上的土壤填充量比深根树种混交林更深的矿质土壤填充量大.合成.我们的研究结果提供了一些第一个直接的证据地下物种的互补性在异质的天然林，通过证明树种均匀度增加细根生产力填充/利用土壤环境更完全的空间和时间，驱动的组成物种的内在生根性状的差异和物种内的根生长的变化。
1. Although fine roots (< 2 mm in diameter) account for a major share of the production of terrestrial ecosystems, diversity effects on fine root productivity and their mechanisms remain unclear.2. We hypothesized that: (i) fine root productivity increases with tree species diversity, (ii) higher fine root productivity is a result of greater soil volume filling due to species-specific patterns of root placement and proliferation, and (iii) differences in fine root productivity and soil volume filling associated with tree species diversity are more pronounced in summer when plants are physiologically active and demand for water and nutrients is at its greatest.3. We investigated the effects of tree species diversity on fine root productivity and soil volume filling of boreal forest stands that have grown naturally for 85 years on similar sites.4. Annual fine root production was 19-83% higher in evenly mixed-than single-species-dominated stands, and increased with tree species evenness, but not tree species richness. Fine root biomass was higher in evenly mixed-than single-species-dominated stands in summer months, but not in spring or fall. Higher fine root productivity in evenly mixed-than single-species-dominated stands was realized by filling more soil volume horizontally and vertically in the forest floor in the mixtures of deep-and shallow-rooted species vs. the deeper mineral soil in the mixtures of deep-rooted species.5. Synthesis. Our results provide some of the first direct evidence for below-ground species complementarity in heterogeneous natural forests, by demonstrating that tree species evenness increases fine root productivity by filling/exploiting the soil environment more completely in space and time, driven by differences in the inherent rooting traits of the component species and variations of root growth within species.