西安市4种城市绿化灌木单株生物量估算模型

以西安市常见的4种绿化灌木(小叶女贞、雀舌黄杨、紫叶小檗、大叶黄杨)为研究对象,利用不同函数和自变量构建单一物种的器官及个体生物量估算模型,筛选出相关性最高、拟合度最好的模型作为生物量最佳估算模型.结果表明： 4种灌木各器官及个体生物量最优估算模型除大叶黄杨叶生物量模型为对数函数(VAR)模型外,其余无论是器官生物量模型还是个体生物量模型均为幂函数(CAR)模型.模型包含的自变量有基径、植株冠幅直径、植株冠幅直径与株高乘积、植冠面积和植冠体积.大叶黄杨和其他3种灌木在自变量选取上有着明显不同.大叶黄杨生物量模型主要以基径为自变量,其他3种灌木生物量模型主要以与冠幅相关的因子为自变量.
     

亚热带喀斯特地区不同地形植物群落物种多度分布格局

为探究亚热带喀斯特地区不同地形下植物群落物种多度分布格局,揭示不同地形下群落的物种多度格局形成的作用机制,丰富该地区植物群落构建理论,该文以贵州茂兰喀斯特地区山脊、槽谷、鞍部、洼地4种典型地形下植物群落的乔木层与灌木层为对象,统计物种多度,采用累计经验分布曲线(ECDF)表征多度分布格局,采取Wilcoxon秩和检验探究不同地形之间物种多度的差异性。采用不同生态学模型进行多度拟合,利用Kolmogorov-Smirnov(K-S)检验与赤池信息量准则(AIC)检验模型接受与拟合优度。结果表明:(1)不同地形下植物群落的个体数量与物种数存在差异,鞍部个体数最多,洼地的物种数最多,山脊的个体数、物种数均最少。(2)不同地形下植物群落的乔木层物种多度格局无显著差异,灌木层之间出现显著差异,山脊与鞍部、洼部,鞍部与槽谷、洼部都存在显著差异。(3)不同地形下乔木层物种多度对中性模型接受较好,其中山脊拟合最优,对生态位模型接受较差,仅山脊与鞍部通过两种生态位模型,拟合优度不及中性模型。灌木层对中性模型接受也较好,鞍部拟合最优,对生态位模型接受较差,仅洼地通过断棍模型。整体而言,乔木层比灌木层能更好地接受两种生态学模型,可能乔木层物种多度格局有更明显生态过程的印记,但不同地形下灌木层拟合优度差异更大,可能与灌木层物种对环境变化更剧烈有关。不同地形会引起群落构建不同程度的生态学过程,物种多度分布格局会逐渐适应地形。     

科尔沁沙地封育恢复过程中植物群落特征变化及影响因素

封育是退化沙地植被恢复与生态重建的重要措施, 理解长期处于封育状态下不同类型沙地植物群落特征变化及其影响因素有利于沙地植被恢复和生态重建。该文基于对科尔沁沙地长期封育的流动沙丘(2005年封育)、固定沙丘(1985年封育)和沙质草地(1997年封育)连续多年(2005-2017年)的植物群落调查, 结合土壤种子库、土壤养分以及气象数据, 分析了植物群落特征变化及其对环境变化的响应。研究结果表明流动沙丘植被盖度显著增加, 群落生物量和物种多样性年际间波动变化, 但无明显趋势; 固定沙丘植物群落存在逆行演替趋势, 具体表现为群落生物量、灌木和半灌木以及豆科优势度显著下降, 而一年生和多年生杂类草优势度显著增加; 沙质草地群落物种丰富度和多年生禾草优势度存在降低趋势, 并且一年生杂类草优势度明显高于其他功能群, 群落存在退化现象。3类沙地土壤种子密度变化不显著, 而种子丰富度在流动沙丘显著增加, 在固定沙丘和沙质草地有下降趋势, 土壤养分仅有有效氮和有效磷含量增加。回归分析结果表明气温和降水是影响年内生物量积累的主要因素, 但对年际间群落生物量和物种丰富度变化影响不大。除趋势对应分析结果显示土壤种子库与植物群落之间存在很高的相似性, 典型相关分析结果表明沙质草地植物群落与土壤养分紧密相关, 而固定沙丘群落主要与土壤水分紧密相关。综合以上结果可知, 封育33年的固定沙丘群落和封育21年的沙质草地群落都存在退化现象, 而封育11年的流动沙丘群落正在缓慢恢复, 因此封育年限的设定对退化沙地植被恢复至关重要, 封育时间过长不仅不利于植物群落恢复, 反而会使群落发生逆行演替, 建议封育年限的设定应综合考虑植被退化程度、土壤养分状况、土壤种子库基础以及气候条件等因素的影响。     

科尔沁沙地封育恢复过程中植物群落特征变化及影响因素

封育是退化沙地植被恢复与生态重建的重要措施,理解长期处于封育状态下不同类型沙地植物群落特征变化及其影响因素有利于沙地植被恢复和生态重建。该文基于对科尔沁沙地长期封育的流动沙丘(2005年封育)、固定沙丘(1985年封育)和沙质草地(1997年封育)连续多年(2005–2017年)的植物群落调查,结合土壤种子库、土壤养分以及气象数据,分析了植物群落特征变化及其对环境变化的响应。研究结果表明流动沙丘植被盖度显著增加,群落生物量和物种多样性年际间波动变化,但无明显趋势;固定沙丘植物群落存在逆行演替趋势,具体表现为群落生物量、灌木和半灌木以及豆科优势度显著下降,而一年生和多年生杂类草优势度显著增加;沙质草地群落物种丰富度和多年生禾草优势度存在降低趋势,并且一年生杂类草优势度明显高于其他功能群,群落存在退化现象。3类沙地土壤种子密度变化不显著,而种子丰富度在流动沙丘显著增加,在固定沙丘和沙质草地有下降趋势,土壤养分仅有有效氮和有效磷含量增加。回归分析结果表明气温和降水是影响年内生物量积累的主要因素,但对年际间群落生物量和物种丰富度变化影响不大。除趋势对应分析结果显示土壤种子库与植物群落之间存在很高的相似性,典型相关分析结果表明沙质草地植物群落与土壤养分紧密相关,而固定沙丘群落主要与土壤水分紧密相关。综合以上结果可知,封育33年的固定沙丘群落和封育21年的沙质草地群落都存在退化现象,而封育11年的流动沙丘群落正在缓慢恢复,因此封育年限的设定对退化沙地植被恢复至关重要,封育时间过长不仅不利于植物群落恢复,反而会使群落发生逆行演替,建议封育年限的设定应综合考虑植被退化程度、土壤养分状况、土壤种子库基础以及气候条件等因素的影响。     

华东热湿地区四种植物群落类型对降温效应的影响研究

中国城市化进程不断推进,城市热岛效应的强度和负面影响越来越大,因此研究绿地植物群落类型对城市降温效应的影响具有重要意义。在实地调研的基础上,采用多元统计和拟合函数模型等方法,利用叶面积指数、三维绿量等因子分析4种植物群落类型的降温效应,以揭示绿地植物群落类型对降温效应影响的内在机制。夏季,4种植物群落类型对降温效应影响趋势分布排序为：乔木—灌木—草坪群落>群植小乔木群落> 乔木—草坪群落>乔木—硬质铺装群落;其中乔木—草坪群落与乔木—硬质铺装群落的降温效应较为接近。将反映植物群落特征的因子导入拟合数学方程模型,从而形成对降温效应作用较好的群落结构。研究结果和研究创新之处在于研究结果阐述了绿地植物群落类型对降温效应影响的内在作用机制。     

关帝山神尾沟森林群落木本植物种间联结性与相关性研究

用χ²检验和Pearson相关系数检验研究了关帝山神尾沟植物群落的种间关系,分别测定了8种乔木和18种灌木植物在神尾沟植物群落中的总体关联性以及它们在7类不同群落中的种间联结性和相关性。结果清楚地反映了木本植物种间关系以及它们在资源利用和生态位上的差异。     

浙江天童枫香树群落不同垂直层次物种间的联结性与相关性

种间关系是植物群落重要的数量和结构特征之一, 分析群落不同垂直层次物种的种间联结和相关性对于理解群落结构、动态和分类等具有重要的生态意义。该研究选取浙江省天童处于演替前期的枫香树(Liquidambar formosana)群落乔木层3个物种、亚乔木层3个物种以及灌木层28个物种为研究对象, 应用基于二元数据的方差比率法、χ²统计量检验和基于数量数据的Spearman秩相关系数检验研究了3个垂直层次间物种的联结性与相关性。结果发现: (1)乔木层与亚乔木层物种总体间存在不显著正联结, 乔木层与亚乔木层主要物种间相互独立的种对较多, 较少种对显著联结或相关; (2)乔木层与灌木层物种总体显著正联结, 显著关联或相关的种对较多, 种对间依赖性较强; (3)亚乔木层与灌木层物种总体同样存在显著正联结, 种对间关系较为紧密。该研究结果表明: 群落垂直层次间物种生态习性和对生境适应的趋同性, 以及在垂直方向上对生境要求的互补性差异是决定演替前期种对关系的主要因素。     

古尔班通古特沙漠固沙灌木的冠幅预测模型

以古尔班通古特沙漠中三种类型沙丘(固定沙丘、半固定沙丘和流动沙丘)上主要固沙灌木梭梭(Haloxylon ammodendron)、白梭梭(Haloxylon persicum)、沙拐枣(Calligonum mongolicum)、蛇麻黄(Ephedra distachya)和油蒿(Artemisia ordosica)为研究对象, 利用12个基础模型建立了不同沙丘类型上所有灌木和不同类型灌木的冠幅模型。模型拟合结果表明: 不论是不同沙丘类型上所有灌木的拟合效果还是不同类型灌木的拟合效果, 固定沙丘和半固定沙丘均优于流动沙丘。同时, 两个近“S”形模型M7(Gompertz Model)和M12(HossfeldⅠ Model)对三种类型沙丘上的固沙灌木均有较好拟合效果; M1(Linear Model)、M2(Quadratic Model)、M3(Power Model)、M6(Logistic Model)、M7、M9(Gauss Model)、M10(Mitscherlinch Model)和M12八个模型适用于研究区绝大部分固沙灌木冠幅模型的模拟。但不同沙丘类型上所有灌木和不同类型的灌木都有不同的最优冠幅模型。研究可为今后该地区相关生态模型建立和防风固沙效益的评价提供科学依据。     

南宁市植物群落结构特征与局地小气候效应关系分析

着重探讨植物群落结构特征与生态小气候因子间的相关性。结果表明:(1)在林荫处,植物群落总冠幅盖度、总密度、群落重要值均与温度成极显著的负相关;植物群落群落重要值还与相对湿度达到显著正相关。(2)在林隙处,植物群落总平均株高与光照强度成显著正相关,与风速成极显著负相关。(3)植物群落结构特征与其小气候生态效应间的相关性是:总平均株高与遮光效应值达到极显著的正相关,与挡风效应值亦达到显著的正相关。另外,总冠幅盖度与降温效应值成极显著的正相关。同时,总密度与降温效应值亦成极显著的正相关。特别是群落重要值与降温、增湿、挡风、遮光等生态效应值都成显著甚至极显著的正相关。通过分析与探讨南宁市植物群落结构和小气候因子间的相关性机理,可为科学地进行城市绿化、生态城市建设提供理论依据。     

北京九龙山植物群落物种多样性特征对比分析

根据对北京九龙山植物群落的样地调查数据,采用Shannon-Wiener多样性指数、群落均匀度和生态优势度指标研究了九龙山封育植被乔灌草各层的物种多样性,并分别就阳坡和阴坡进行了乔木材、灌价群落的指标对比分析,结果表明,这3种指标能够有效地表征暖温带植物群落的组成结构特征,在九龙山封育植被中,阴阳坡的灌丛群落与乔木材相比,其灌木层的物种多样性Shannon-Wiener指数D高于乔木林中乔木层,而低于其灌木层;灌丛群落的草本层Shannon-Wiener指数小于乔木材中草本层;乔木材的草本层的物种多样性Shannon-Wiener指数大于灌木层,灌木层又大于乔木层,而生态优势度系数C在上述3种比较中与Shannon-Wiener指数表现相反,而群落均匀度指数J在比较中阴阳坡的表现不同,最后讨论了九龙坡地区植被演替序列及加速其进展演替的恢复措施。     

Responses of different herb life-history groups to a dominant shrub species along a dune stabilization gradient

Shrubs play a pivotal role in reversing desertification and in promoting ecological rehabilitation in severe environments. However, how the interactions between shrubs and their understorey species change during restoration remains unclear. Here, we report the results of an observational study conducted in the Mu Us Desert of northern China. This study explored how dune stabilization and the size of individual shrubs affect shrub–herb interactions. In particular, we aimed to determine how different life-history groups and performance indicators (e.g., biomass and richness) of subordinate species respond to shrub–herb interactions during dune stabilization. The shrub Artemisia ordosica had positive effects on understorey species in this dune system. The ability of the shrub to promote the growth of understorey species increased with dune stabilization, but decreased from small to large shrubs. This effect was due to an increase in the relative abundance and biomass of perennials and their higher sensitivity to the positive effects of the shrubs. In contrast, the ability of shrubs to improve the richness of understorey species decreased with dune stabilization, but increased from small to large shrubs. This effect occurred because perennials suffered high strain during recruitment in disturbed open patches of the semi-fixed dunes, particularly below small shrubs. Our results support the theory claiming that communities are sets of hidden interaction groups that have contrasting responses (neutral for annuals, but facilitative for perennials) to dominant neighbors in a single community, depending on their functional strategies. Furthermore, our study highlights the high efficiency of A. ordosica in facilitating ecological restoration of dry and disturbed sandy communities.     

Cover as a simple predictor of biomass for two shrubs in Tibet

Knowledge of the quantitative relationship between plant cover and its corresponding biomass for shrubs is not well known, especially for those on the Tibetan Plateau. Based on investigations of 35 sites, 90 plots and 95 standard individuals for two typical shrub species (Rhododendron nivale Hook. f. and Sophora moorcroftiana (Benth.) Baker) across Tibet, we developed allometric models for biomass estimation from measurements of crown diameter and/or height. We found that the parameters of crown projection area (CPA), height and their product (volume) were all significantly (p < 0.01) correlated with dry mass of different organs for both species at individual level. The CPA rather than volume best predicted aboveground dry mass. This is because that the bulk density declined significantly with increasing plant height, leading to the inappropriateness for plant height itself being employed as a parameter in biomass estimation, especially for shrubs in smaller size groups. At community level, cover was tightly correlated with the aboveground, belowground and total biomass (R² = 0.97–0.99). Therefore, biomass for the two shrubs can be simply estimated by measuring plant cover, which enables rapid estimation of shrubland carbon stock at large scales by using satellite data and repeated experiments over time. This non-destructive method using cover to estimate shrub biomass can be applied not only in arid ecosystems but also in alpine or subalpine environment.     

Aboveground biomass allocation and water content relationships in Mediterranean trees and shrubs in two climatological regions in Israel

Thisstudy investigated the variation along basipetal gradients of the relationshipsbetween the foliage/wood allocation ratios of biomass and of water content, inMediterranean trees and shrubs, at two different locations along a climaticgradient. Understanding of the biomass allocation and water relations inMediterranean trees and shrubs provides useful information on growth patternsofthese species, and on resource dynamics of these plant communities. Twoexperimental sites were selected along a climatological transect that runs fromthe foothills of the Judean Hills to the northern Negev desert in Israel. Ateach site, 16 quadrats of 10 × 10 m (eight on south-facingslopes and eight on north-facing slopes) were marked. The aboveground biomassofdominant tree and shrub species were estimated. Main branches of trees andshrubs were cut, their foliage and wood biomass were separately weighed, andtheir respective water contents were determined. The species studied includedthe evergreen sclerophylls, Quercus calliprinos, Phillyrealatifolia and Pistacia lentiscus, and thesemi-deciduous species, Cistus creticus, Coridothymuscapitatus and Sarcopoterium spinosum. Theresults indicated that the foliage/wood ratio decreased from the periphery ofthe crown to the interior of the trees and shrubs: foliage biomass and waterwere mainly limited to the top 30 cm of the crown in all studiedspecies. Leaves had higher relative water contents than woody tissues in theupper part of the crown. However; when the whole tree or shrub was considered,the relative water content was found to be mostly allocated to the woodystructures. The results are discussed in terms of biomass allocation in variouslife forms of the eastern-Mediterranean plant communities and how they areaffected by slope aspect and climatic conditions.     

不同林分起源的相容性生物量模型构建

目前为止已有不同方法构建生物量相容性模型,但不同林分起源的生物量相容性模型很少报道。针对此问题,以150株南方马尾松(Pinus masson iana)地上生物量数据为例,利用比例平差法和非线性联立方程组法建立不同起源地上生物量以及干材、干皮、树枝和树叶各分项生物量相容的通用性模型。根据分配层次不同,两种方法又各自考虑总量直接控制和分级联合控制两种方案。从直径、树高、地径、枝下高和冠幅5个林分变量中选取不同的变量构建一元、二元和三元生物量模型,并利用加权最小二乘回归法消除生物量模型中存在的异方差性。结果为:比例平差法和非线性联立方程组法都能有效保证各分项生物量总和等于总生物量,模型预测精度满足要求。总体而言,非线性联立方程组方法比比例平差方法精度高,同时两种方法中总量直接控制法比分级联合控制法预测效果好;各分项生物量模型本身作为权函数能有效消除异方差;各分项对应的三元生物量模型预测精度最高,其次是二元生物量模型,最低是一元生物量模型,但这些差异不是很大。总之,为权衡考虑模型预测精度和调查成本,建议把直径和树高作为协变量利用总量直接控制非线性联立方程组法对不同起源生物量建模。     

An analysis of structure: biomass structure relationships for characteristic species of the western Kalahari,Botswana

Savannah ecosystems are important carbon stocks on the Earth, and their quantification is crucial for understanding the global impact of climate and land‐use changes in savannahs. The estimation of aboveground/belowground plant biomass requires tested allometric relationships that can be used to determine total plant biomass as a function of easy‐to‐measure morphological indicators. Despite recent advances in savannah ecology, research on allometric relations in savannahs remains confined to a few site‐specific studies where basal area is typically used as the main morphometric parameter with plant biomass. We investigate allometric relations at four sites along a 950‐km transect in the Kalahari across mean rainfall gradient 170 mm yr^?1–550 mm yr^?1. Using data from 342 harvested trees/shrubs, we relate basal area, height and crown diameter to aboveground biomass. These relationships are strongest in trees and weakest in small shrubs. Strong allometric relationships are also determined for morphologically similar groups of woody vegetation. We show that crown diameter can be used as an alternative to basal area in allometric relationships with plant biomass. This finding may enhance the ability to determine aboveground biomass over large areas using high‐resolution aerial or satellite imagery without requiring ground‐based measurements of basal area.     

基于异速生长理论的准噶尔盆地荒漠灌丛形态研究

为了揭示荒漠灌丛形态的发生发展机制并认识其在荒漠生态系统中的功能, 从形态和结构决定功能的原理出发, 对生长在准噶尔荒漠东南部的岛状灌丛进行了形态学调查。依据Malthusian方程微分形式, 根据异速生长理论, 建立了冠幅与株高生长、灌丛表面积与体积生长的数学关系式, 利用植被调查数据进行了验证, 并最终得出不同灌丛在不同株高时的情景示意图。结果表明: 1)将荒漠灌丛形态假设成半三轴椭球体是合理的; 2)虽然灌丛形态发展趋势可以是扁平、近半球和竖直3种类型, 但是形态建成后, 一般维持在扁平和近半球两种类型; 3) 18类荒漠灌丛的体积和表面积的数量关系具有一定的一致性, 可能与同处于相同环境条件下的水分利用效率相近有关。     

Testing the generality of above‐ground biomass allometry across plant functional types at the continent scale

Accurate ground‐based estimation of the carbon stored in terrestrial ecosystems is critical to quantifying the global carbon budget. Allometric models provide cost‐effective methods for biomass prediction. But do such models vary with ecoregion or plant functional type? We compiled 15 054 measurements of individual tree or shrub biomass from across Australia to examine the generality of allometric models for above‐ground biomass prediction. This provided a robust case study because Australia includes ecoregions ranging from arid shrublands to tropical rainforests, and has a rich history of biomass research, particularly in planted forests. Regardless of ecoregion, for five broad categories of plant functional type (shrubs; multistemmed trees; trees of the genus Eucalyptus and closely related genera; other trees of high wood density; and other trees of low wood density), relationships between biomass and stem diameter were generic. Simple power‐law models explained 84–95% of the variation in biomass, with little improvement in model performance when other plant variables (height, bole wood density), or site characteristics (climate, age, management) were included. Predictions of stand‐based biomass from allometric models of varying levels of generalization (species‐specific, plant functional type) were validated using whole‐plot harvest data from 17 contrasting stands (range: 9–356 Mg ha^?1). Losses in efficiency of prediction were <1% if generalized models were used in place of species‐specific models. Furthermore, application of generalized multispecies models did not introduce significant bias in biomass prediction in 92% of the 53 species tested. Further, overall efficiency of stand‐level biomass prediction was 99%, with a mean absolute prediction error of only 13%. Hence, for cost‐effective prediction of biomass across a wide range of stands, we recommend use of generic allometric models based on plant functional types. Development of new species‐specific models is only warranted when gains in accuracy of stand‐based predictions are relatively high (e.g. high‐value monocultures).     

Biomass estimation models and allocation patterns of 14 shrub species in Mountain Luya,Shanxi, China

Aims Shrub species have evolved specific strategies to regulate biomass allocation among various organs or between above- and belowground biomass and shrub biomass model is an important approach to estimate biomass allocation among different shrub species. This study was designed to establish the optimal estimation models for each organ (leaf, stem, and root), aboveground and total biomass of 14 common shrub species in Mountain Luya, Shanxi Province, China. Furthermore, we explored biomass allocation characteristics of these shrub species by using the index of leaf biomass fraction (leaf to total biomass), stem biomass fraction (stem to total biomass), root biomass fraction (root to total biomass), and root to shoot mass ratio (R/S) (belowground to aboveground biomass).
Methods We used plant height, basal diameter, canopy diameter and their combination as variables to establish the optimal biomass estimation models for each shrub species. In addition, we used the ratios of leaf, stem, root to total biomass, and belowground to aboveground biomass to explore the difference of biomass allocation patterns of 14 shrub species.
Important findings Most of biomass estimation models could be well expressed by the exponential and linear functions. Biomass for shorter shrub species with more stems could be better estimated by canopy area; biomass for taller shrub species with less stems could be better estimated by the sum of the square of total base diameter multiply stem height; and biomass for the rest shrub species could be better estimated by canopy volume. The averaged value for these shrub species was 0.61, 0.17, 0.48, and 0.35 for R/S, leaf biomass fraction, stem biomass fraction, and root biomass fraction, respectively. Except for leaf biomass fraction, R/S, stem biomass fraction, and root biomass fraction for shrubs with thorn was significantly greater than that for shrubs without thorn.     

腾格里沙漠人工植被区固沙灌木影响深层土壤水分的动态模拟研究

灌木是我国沙漠地区主要的优势植物类型,固沙灌木的存在有益于沙丘的固定进而有利于退化沙漠生态系统的生态恢复。基于腾格里沙漠沙坡头地区50多年的人工植被区长期观测研究,建立生态-水文模型模拟了该地区固沙灌木盖度和深层土壤水分的动态变化过程,结果表明,固沙灌木的建立改变了沙区原有的生态-水文过程,在固沙灌木建立40多年后,固沙灌木的盖度和深层土壤水分达到了新的平衡状态。灌木盖度逐渐稳定在(10±0.9)%左右,而深层土壤水分稳定在(2.58±0.2)%左右。因此,在年均降雨量为186mm的腾格里沙漠沙坡头地区,土壤水分的最大植被承载力为:灌木和生物土壤结皮的盖度分别维持在10%和60%,深层土壤水分维持在3%左右。