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首頁> 外文期刊>The Science of the Total Environment >Individual tree size inequality enhances aboveground biomass in homegarden agroforestry systems in the dry zone of Sri Lanka
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Individual tree size inequality enhances aboveground biomass in homegarden agroforestry systems in the dry zone of Sri Lanka

機(jī)譯：單個(gè)樹木大小的不平等增加了斯里蘭卡干旱地區(qū)家庭園藝農(nóng)林業(yè)系統(tǒng)中地上生物量

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摘要

Individual tree size variation, which is generally quantified by variances in tree diameter at breast height (DBH) and height in isolation or conjunction, plays a central role in ecosystem functioning in both controlled and natural environments, including forests. However, none of the studies have been conducted in homegarden agroforestry systems. In this study, aboveground biomass, stand quality, cation exchange capacity (CEC), DBH variation, and species diversity were determined across 45 homegardens in the dry zone of Sri Lanka. We employed structural equation modeling (SEM) to test for the direct and indirect effects of stand quality and CEC via tree size inequality and species diversity, on aboveground biomass. The SEM accounted for 26,8, and 1 % of the variation in above-ground biomass, species diversity and DBH variation, respectively. DBH variation had the strongest positive direct effect on aboveground biomass (β = 0.49), followed by the non-significant direct effect of species diversity (β = 0.17), stand quality (β = 0.17) and CEC (β = - 0.05). There were non-significant direct effects of CEC and stand quality on DBH variation and species diversity. Stand quality and CEC had also non-significant indirect effects, via DBH variation and species diversity, on aboveground biomass. Our study revealed that aboveground biomass substantially increased with individual tree size variation only, which supports the niche complementarity mechanism. However, aboveground biomass was not considerably increased with species diversity, stand quality and soil fertility, which might be attributable to the adaptation of certain productive species to the local site conditions. Stand structure shaped by few productive species or independent of species diversity is a main determinant for the variation in aboveground biomass in the studied homegardens. Maintaining stand structure through management practices could be an effective approach for enhancing aboveground biomass in these dry zone homegarden agroforestry systems.
機(jī)譯：個(gè)體樹的大小變化通常通過胸高（DBH）處的樹徑變化和孤立或聯(lián)合處的樹高變化來量化，在包括森林在內(nèi)的受控環(huán)境和自然環(huán)境中，生態(tài)系統(tǒng)功能發(fā)揮著核心作用。然而，這些研究都沒有在家庭農(nóng)用林業(yè)系統(tǒng)中進(jìn)行。在這項(xiàng)研究中，確定了斯里蘭卡干旱地區(qū)45個(gè)家園的地上生物量，林分質(zhì)量，陽離子交換能力（CEC），DBH變化和物種多樣性。我們采用結(jié)構(gòu)方程模型（SEM）來測(cè)試林分質(zhì)量和CEC通過樹木大小不平等和物種多樣性對(duì)地上生物量的直接和間接影響。 SEM分別占地上生物量，物種多樣性和DBH變化的26.8％和1％。 DBH變化對(duì)地上生物量具有最強(qiáng)的正效應(yīng)（β= 0.49），其次是物種多樣性（β= 0.17），林分質(zhì)量（β= 0.17）和CEC（β=-0.05）的非顯著正效應(yīng)。 CEC和林分質(zhì)量對(duì)DBH變化和物種多樣性沒有直接影響。林分質(zhì)量和CEC通過DBH變異和物種多樣性對(duì)地上生物量也具有非顯著的間接影響。我們的研究表明，地上生物量?jī)H隨個(gè)體樹木大小變化而顯著增加，這支持了生態(tài)位互補(bǔ)機(jī)制。但是，地上生物量并未隨物種多樣性，林分質(zhì)量和土壤肥力的增加而顯著增加，這可能歸因于某些生產(chǎn)性物種適應(yīng)了當(dāng)?shù)氐牡攸c(diǎn)條件。林分結(jié)構(gòu)幾乎沒有生產(chǎn)性物種，也不受物種多樣性的影響，是決定所研究家園地上生物量變化的主要決定因素。通過管理實(shí)踐來維持林分結(jié)構(gòu)可能是在這些干旱地區(qū)的花園式農(nóng)林業(yè)系統(tǒng)中提高地上生物量的有效方法。

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  • 來源
    《The Science of the Total Environment》 |2017年第1期|6-11|共6頁
  • 作者

    Arshad Ali; Eskil Mattsson;

  • 作者單位

    School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China,Forest Ecosystem Research and Observation Station in Putuo Island, Zhoushan, Zhejiang 316100, China,Tiantong National Forest Ecosystem Observation and Research Station, Ningbo 315114, Zhejiang, China;

    Centre for Environment and Sustainability, University of Gothenburg, 412 96 Goeteborg, Sweden;

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  • 正文語種 eng
  • 中圖分類
  • 關(guān)鍵詞

    Agroforestry systems; Biodiversity; Carbon storage; Species diversity; Stand structure; Structural equation model;

    機(jī)譯：農(nóng)林業(yè)系統(tǒng);生物多樣性;碳儲(chǔ)存;物種多樣性;展臺(tái)結(jié)構(gòu);結(jié)構(gòu)方程模型;

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