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1.
森林凋落物动态是森林生态系统过程中的重要组成部分, 探索森林凋落物动态特征与微气候间的关系, 对深入了解生态系统变化过程运行机理具有重要意义。该研究以浙江普陀山岛典型森林类型枫香(Liquidambar formosana)林、天竺桂(Cinnamomum japonicum)+红楠(Machilus thunbergii)林、马尾松(Pinus massoniana)林、青冈(Cyclobalanopsis glauca)林、台湾蚊母树(Distylium gracile)林为研究对象, 探究森林凋落量与微气候的关系。结果表明: 1)森林年凋落量介于3.45-5.36 t·hm-2·a-1, 年凋落量各组分比例表现出不同的组成特征, 森林类型与森林月凋落量无关。2)森林月凋落量动态模式主要呈双峰型和三峰型, 凋落峰值和风速峰值趋势相一致, 主要集中在台风干扰较大的4、7、12月份。3)冗余分析结果表明, 影响不同组分月凋落量的微气候因子不同: 月总凋落量、叶凋落量、果凋落量和碎屑凋落量的主要控制因素均为空气温度, 随空气温度的升高而增大; 枝凋落量的主要影响因素是森林上层风速, 同样起着显著的正向作用; 花凋落量与空气湿度之间呈负相关关系。森林年凋落量各组分所占比例存在差异, 森林月凋落量和森林类型无关, 主要与空气温度、空气湿度、森林上层风速等微气候因子有关。 相似文献
2.
《植物生态学报》2017,41(1):71
Aims The shrublands of northern China have poor soil and nitrogen (N) deposition has greatly increased the local soil available N for decades. Shrub growth is one of important components of C sequestration in shrublands and litterfall acts as a vital link between plants and soil. Both are key factors in nutrient and energy cycling of terrestrial ecosystems, which greatly affected by nitrogen (N) addition (adding N fertilizer to the surface soil directly). However, the effects and significance of N addition on C sequestration and litterfall in shrublands remain unclear. Thus, a study was designed to investigate how N deposition and related treatments affected shrublands growth related to C sequestration and litterfall production of Vitex negundo var. heterophylla and Spiraea salicifolia in Mt. Dongling region of China.
Methods A N enrichment experiment has been conducted for V. negundo var. heterophylla and S. salicifolia shrublands in Mt. Dongling, Beijing, including four N addition treatment levels (control (N0, 0 kg N·hm-2·a-1), low N (N1, 20 kg N·hm-2·a-1), medium N (N2, 50 kg N·hm-2·a-1) and high N (N3, 100 kg N·hm-2·a-1)). Basal diameter and plant height of shrub were measured from 2012-2013 within all treatments, and allometric models for different species of shrub’s live branch, leaf and root biomass were developed based on independent variables of basal diameter and plant height, which will be used to calculate biomass increment of shrub layer. Litterfall (litterfall sometimes is named litter, referring to the collective name for all organic matter produced by the aboveground part of plants and returned to the surface, and mainly includes leaves, bark, dead twigs, flowers and fruits.) also was investigated from 2012-2013 within all treatments.
Important findings The results showed 1) mean basal diameter of shrubs in the V. negundo var. heterophylla and S. salicifolia shrublands were increased by 1.69%, 2.78%, 2.51%, 1.80% and 1.38%, 1.37%, 1.59%, 2.05% every year; 2) The height growth rate (the shrub height relative growth rate is defined with the percentage increase of plant height) of shrubs in the V. negundo var. heterophylla and S. salicifolia shrublands were 8.36%, 8.48%, 9.49%, 9.83% and 2.12%, 2.86%, 2.36%, 2.52% every year, respectively. Thee results indicated that N deposition stimulated growth of shrub layer both in V. negundo var. heterophylla and S. salicifolia shrublands, but did not reach statistical significance among all nitrogen treatments. The above-ground biomass increment of shrub layer in the V. negundo var. heterophylla and S. salicifolia shrublands were 0.19, 0.23, 0.14, 0.15 and 0.027, 0.025, 0.032, 0.041 t C·hm-2·a-1 respectively, which demonstrated that short-term N addition had no significant effects on the accumulation of C storage of the two shrublands. The litter production of the V. negundo var. heterophylla and S. salicifolia communities in 2013 were 135.7 and 129.6 g·m-2 under natural conditions, respectively. Nitrogen addition promoted annual production of total litterfall and different components of litterfall to a certain extent, but did not reach statistical significance among all nitrogen treatments. Above results indicated that short-term fertilization, together with extremely low soil moisture content and other related factors, lead to inefficient use of soil available nitrogen and slow response of shrublands to N addition treatments. 相似文献
Methods A N enrichment experiment has been conducted for V. negundo var. heterophylla and S. salicifolia shrublands in Mt. Dongling, Beijing, including four N addition treatment levels (control (N0, 0 kg N·hm-2·a-1), low N (N1, 20 kg N·hm-2·a-1), medium N (N2, 50 kg N·hm-2·a-1) and high N (N3, 100 kg N·hm-2·a-1)). Basal diameter and plant height of shrub were measured from 2012-2013 within all treatments, and allometric models for different species of shrub’s live branch, leaf and root biomass were developed based on independent variables of basal diameter and plant height, which will be used to calculate biomass increment of shrub layer. Litterfall (litterfall sometimes is named litter, referring to the collective name for all organic matter produced by the aboveground part of plants and returned to the surface, and mainly includes leaves, bark, dead twigs, flowers and fruits.) also was investigated from 2012-2013 within all treatments.
Important findings The results showed 1) mean basal diameter of shrubs in the V. negundo var. heterophylla and S. salicifolia shrublands were increased by 1.69%, 2.78%, 2.51%, 1.80% and 1.38%, 1.37%, 1.59%, 2.05% every year; 2) The height growth rate (the shrub height relative growth rate is defined with the percentage increase of plant height) of shrubs in the V. negundo var. heterophylla and S. salicifolia shrublands were 8.36%, 8.48%, 9.49%, 9.83% and 2.12%, 2.86%, 2.36%, 2.52% every year, respectively. Thee results indicated that N deposition stimulated growth of shrub layer both in V. negundo var. heterophylla and S. salicifolia shrublands, but did not reach statistical significance among all nitrogen treatments. The above-ground biomass increment of shrub layer in the V. negundo var. heterophylla and S. salicifolia shrublands were 0.19, 0.23, 0.14, 0.15 and 0.027, 0.025, 0.032, 0.041 t C·hm-2·a-1 respectively, which demonstrated that short-term N addition had no significant effects on the accumulation of C storage of the two shrublands. The litter production of the V. negundo var. heterophylla and S. salicifolia communities in 2013 were 135.7 and 129.6 g·m-2 under natural conditions, respectively. Nitrogen addition promoted annual production of total litterfall and different components of litterfall to a certain extent, but did not reach statistical significance among all nitrogen treatments. Above results indicated that short-term fertilization, together with extremely low soil moisture content and other related factors, lead to inefficient use of soil available nitrogen and slow response of shrublands to N addition treatments. 相似文献
3.
《植物生态学报》2016,40(8):760
Aims Stoichiometric ratios of carbon (C), nitrogen (N) and phosphorus (P) are important characteristics of the ecological processes and functions. Studies on population ecological stoichiometry can refine the content of flora chemometrics, determine the limited nutrient, and provide data for process-based modeling over large scale. Phyllostachys edulis is an important forest type, whose area accounts for 74% of total bamboo forest area in Southern China. However, little is known about the ecological stoichiometric in P. edulis. This study aimed to reveal C:N, C:P and N:P stoichiometry characteristics of the “plant-soil-litter” continuum and to provide a better understanding nutrient cycling and stability mechanisms in P. edulis forest in China. Methods The data were collected from the published literature containing C、N、P content in leaf or surface soil (0-20 cm) or littefall in P. edulis forests. Important findings 1) The leaf C, N, P content were estimated at 478.30 mg·g-1, 22.20 mg·g-1, 1.90 mg·g-1 in P. edulis, and the corresponding C: N, C: P and N: P were 26.80, 299.60 and 14.40, respectively. Soil C, N, and P content in 0-20 cm were 21.53 mg·g-1, 1.66 mg·g-1, 0.41 mg·g-1, with ratios of 14.20 for C:N, 66.74 for C:P and 4.28 for N:P. The C, N and P contents were 438.49 mg·g-1, 13.39 mg·g-1, 0.86 mg·g-1 for litterfall, with the litter C:N, C:P and N:P being 25.53, 665.67, 22.55, respectively. 2) In the plant-soil-litter system in P. edulis forest, leaf had higher C:N, litter had higher C:P and N:P, while soil were the lowest. The N, P resorption rate was 39.68% and 54.74%, indicating that P. edulis forest growth and development was constrained by P or by both of N and P in China. 3) N content and N:P in leaf showed a tendency to increase with latitude, while the C:N of leaf declined with latitude. N:P of leaf increased with longitude, but the P content and the C:N of leaf showed a opposite trend. C: N of soil increased with longitude, whereas the N content of soil declined longitude. The N content of litter declined with longitude. 4) The leaf N content was negatively correlated with mean annual temperature and mean annual precipitation, but being more sensitive to temperature than precipitation. The positive correlations between N content and latitude support “Temperature-Plant Physiological” hypothesis, reflecting an adaptive strategy to environmental conditions. 相似文献
4.
《植物生态学报》2016,40(1):24
5.
浙江普陀山岛晚更新世的两种木化石 总被引：1，自引：0，他引：1
报道普陀山岛飞沙岙晚更新世湖泊相沉积地层中发现的槐树属Ｓｏｐｈｏｒａ ｊａｐｏｎｉｃａ和枫杨属Ｐｔｅｒｏｃａｒｙａ ｓｔｅｎｏｐｔｅｔａ化石。在其邻近层位还发现Ｅｕｒｙａｌｅ ｆｅｒｏｘ;Ｎｅｌｕｍｂｏ ｎｕｃｉｆｅｒａ;Ｓｃｌｅｒｉａ ｏｒｙｚｏｉｄｅｓ;Ｐａｔａｍｏｇｅｔｏｎ ｄｉｓｔｉｎｃｔｕｓ;Ｅｌｅｏｃｈａｔｒｉｓ ｐｌａｎｔａｇｉｎｅｉｆｏｍｉｓ和昆虫化石Ｃｈｙｓｏｍｅｌｉｄｅａｅ,。 相似文献
6.
繁殖是植物生命活动的重要环节, 了解植物的繁殖特征是解释植物生态适应性和制定有效管理措施的重要依据。该研究以荒漠草原猪毛蒿(Artemisia scoparia)种群为研究对象, 通过测定不同土壤类型的理化性质和猪毛蒿的繁殖特征, 以期探讨影响其繁殖特征的主要土壤驱动因子。结果表明: 灰钙土、风沙土和基岩风化残积土的水溶性碳含量、全氮含量、全磷含量、全盐含量、土壤水分含量、土壤硬度存在显著差异。猪毛蒿平均个体大小、单株头状花序的平均质量和数量均以灰钙土生境下最大, 基岩风化残积土最小。繁殖分配在不同土壤类型下无显著差异, 但与单个头状花序质量、单株头状花序数量和质量间呈极显著正相关关系。单株头状花序数量与单个头状花序质量间呈负相关关系。在风沙土生境下, 单株头状花序质量主要受到土壤水溶性碳含量、土壤水分含量以及pH值的共同影响; 单株头状花序数量受全盐含量的影响最大; 繁殖分配和单个头状花序质量主要受全碳含量的影响。灰钙土生境下, 单株头状花序质量与土壤水溶性碳含量、土壤水分含量和有机碳含量呈正相关关系; 速效氮含量显著影响着单株头状花序数量。而基岩风化残积土生境下, 繁殖特征的变异主要受到土壤水溶性碳含量、土壤硬度、土壤水分含量、全磷和速效磷含量的影响。综合分析发现, 土壤因子对猪毛蒿繁殖特征的影响程度不同, 其中单株头状花序数量和质量极显著地受到土壤水溶性碳含量和土壤水分含量的影响, 繁殖分配和单个头状花序质量与土壤水溶性碳含量、土壤水分含量呈负相关关系。因此, 土壤水溶性碳含量和土壤水分是荒漠草原地区影响猪毛蒿种群繁殖特征的主要土壤因子。 相似文献
7.
《植物生态学报》2017,41(10):1033
Aims Plant-herbivore interaction is a hot topic in the study of biodiversity and ecosystem functions. Herbivores can negatively affect seedling growth and therefore can alter the dynamics of plant recruitment. However, previous studies do not fully reveal the relative importance of different plant functional traits on herbivory intensity and rarely link herbivory to the relative abundance of plant species.Methods Here, we measured 11 plant functional traits and the relative abundance of seedlings of 16 common woody species in the subtropical forests on 29 islands in Thousand Island Lake, East China. We then used multivariate regression and variance partitioning to test the contribution of functional traits and the relative abundance to interspecific differences of insect herbivory intensity.Important findings Our study found that both plant functional traits (e.g. carbon nitrogen ratio, leaf thickness) and the relative abundance of woody species played important roles in herbivory intensity, and they jointly contributed 54% of the variance of the interspecific differences. Among these factors, species with higher defensive ability, lower nutrient content and higher relative abundance had lower herbivory intensity. We suggest to consider both individual level traits (functional traits) and community level attributes (the relative abundance) in future herbivory studies. 相似文献
8.
《植物生态学报》2018,42(12):1131
生态过程模型的发展为研究者在长时间序列和区域尺度的研究提供了便利, 但模型模拟的准确性受到模型自身结构、模型参数估计合理性的影响。敏感性分析能够定量或定性筛选出对模型模拟结果影响较大的敏感参数, 是模型参数校准过程中的重要工具, 也是建模和应用的先决条件。该文以阔叶红松林为研究对象, 采用全局敏感性分析方法——傅里叶幅度灵敏度检验扩展法(EFAST)对Biome-BGC模型的生理生态参数进行了敏感性分析, 分别分析了红松(Pinus koraiensis)和阔叶树的净初级生产力(NPP)、蒸散(ET)对参数变化的敏感性。结果表明: (1)模拟红松NPP的不确定性高于阔叶树, 但二者的模拟ET的不确定性均较小。阔叶树的NPP和ET对生理生态参数的敏感性总体上都小于红松。(2)无论是红松、阔叶或其他植被类型, 模拟NPP均表现出对叶片碳氮比、细根碳氮比、比叶面积(SLA)和冠层截留系数的敏感性, 这4个参数的高敏感性主要是由模型自身结构所决定的, 与植被类型和研究地区的关系较小。对模拟ET而言, 细根与叶片碳分配比、新茎与新叶碳分配比和SLA均是影响红松和阔叶树ET的敏感参数, 但红松ET主要受参数与参数间的二阶或多阶交互作用的间接影响, 而阔叶树ET则主要是受到敏感参数直接效应的影响。(3)除了上述影响红松和阔叶树碳水通量的共性参数外, 诸如核酮糖-1,5-二磷酸羧化酶中叶氮含量、叶片与细根周转率、所有叶面积与投影叶面积之比等也是对模拟结果有影响的重要参数, 但是其敏感程度随物种不同和研究区不同而不同, 所以这类参数可以根据具体情况进行参数本地化, 对于其他不敏感参数则可以采用模型缺省值。 相似文献
9.
研究群落构建机制是群落生态学的一个重要目标, 群落动态过程中的构建规律对于了解群落演替机理有重要的作用。该文以海南岛刀耕火种干扰后自然恢复的10 hm 2热带低地雨林为研究对象, 通过比较不同恢复阶段的次生林(15年、30年和60年)和老龄林在幼苗、幼树和成年树群落的物种组成, 揭示次生演替过程中的群落构建规律。研究结果表明, 老龄林中不同径级群落的物种多样性及不同径级间的物种相似度显著高于各恢复阶段的次生林, 但优势种在群落中的比例低于各恢复阶段的次生林。随着自然恢复过程的进行, 次生林群落物种组成与老龄林的相似性也逐渐增大, 支持演替平衡理论。所有恢复阶段样地中幼苗的个体、物种丰富度和基于多度涵盖估计量(ACE)都低于幼树和成年树群落, 幼苗层物种组成与幼树、成年树也有较大差异, 说明新增到幼苗群落可能是一个难于预测的过程。研究结果说明了确定过程和随机过程共同决定了次生演替的群落构建。 相似文献
10.
《植物生态学报》2018,42(11):1082
热量匮乏是高山树线的主要成因, 在全球变暖趋势下对高山树线及其建群种的生态学过程及特征的研究具有重要意义。该文以青藏高原东缘的折多山和剪子弯山两处高山树线(海拔分别为4 265 m和4 425 m)作为研究对象, 通过设置垂直样带, 同时结合区域温度、降水的长时间序列分析, 探究两处树线的时空动态过程, 并明确了建群种冷杉(Abies spp.)的生态学特征。结果表明: 1)折多山和剪子弯山区域的气温在过去58年均存在显著的上升趋势(分别上升了0.72和0.91 ℃), 而折多山和剪子弯山区域降水均存在微弱的降低趋势。2)折多山的峨眉冷杉(A. fabri)龄级结构呈反J形, 剪子弯山的鳞皮冷杉(A. squamata)龄级结构呈双峰形, 二者种群结构均相对稳定。3)在小尺度上, 种子扩散限制使得两处树线的冷杉聚集分布。在大尺度上, 折多山峨眉冷杉亦呈聚集分布, 而剪子弯山鳞皮冷杉受生长环境以及种内或种间关系的影响呈随机分布。4)两处样地建群树种的树高和基径均随海拔升高而降低, 位于树线交错带上部的冷杉均呈现树高生长大于径向生长的异速生长关系, 而位于样地中、下部位的冷杉大部分呈等速生长关系。5)相比10年前, 折多山和剪子弯山的树线及树种线位置均无明显变化, 剪子弯山鳞皮冷杉种群的树木密度亦无明显变化, 而折多山的树木个体数提高了约25%; 相比20年前, 折多山和剪子弯山的树种线分别上移了50和30 m, 树线位置分别升高了75和40 m, 树木个体数亦明显增加, 分别提高了约220%和100%。树线及其建群种在较大时空尺度上主要受热量的控制, 而在较小时空尺度上受温度及生长环境共同作用的影响。 相似文献
11.
《植物生态学报》1958,44(7):699
法瑞学派也称Braun-Blanquet学派, 盛行于欧洲大陆, 也是当今全球植被科学的一个重要学派。该文对这一学派的发展历史、植被科学理论和野外实践, 以及群落分类系统做了简要介绍。法瑞学派的发展可分为开创(1910-1943年)、发展(1945-1980年)、分化(1980-1990年)和融合(1990年至今)四个时期。法瑞学派重视野外实践, 强调植物群落内的相互关系和动态发展, 强调植物群落主要属性是物种组成, 以及特征种(或鉴别种)在群落分类和评价环境中的重要作用; 制定了一套详细的野外调查方法和样地归类的程序; 建立了以“群丛”为基本等级的一个自下而上、严谨的、正规的植被分类体系; 具有理论上的兼容性和技术上的开放性等优点。这些都为当代植被生态学的发展奠定了坚实的基础。同时, 法瑞学派在特征种界定、群丛定义、样地数据集成与转换、与生态外貌系统连接等方面存在一些尚需改进的地方。最后, 该文概述了法瑞学派在中国的发展历史与现状, 以及目前在中国植被研究中所能发挥的作用。 相似文献
12.
《植物生态学报》2016,40(8):748
Aims Grazing intensity and grazing exclusion affect ecosystem carbon cycling by changing the plant community and soil micro-environment in grassland ecosystems. The aims of this study were: 1) to determine the effects of grazing intensity and grazing exclusion on litter decomposition in the temperate grasslands of Nei Mongol; 2) to compare the difference between above-ground and below-ground litter decomposition; 3) to identify the effects of precipitation on litter production and decomposition. Methods We measured litter production, quality, decomposition rates and soil nutrient contents during the growing season in 2011 and 2012 in four plots, i.e. light grazing, heavy grazing, light grazing exclusion and heavy grazing exclusion. Quadrate surveys and litter bags were used to measure litter production and decomposition rates. All data were analyzed with ANOVA and Pearson’s correlation procedures in SPSS. Important findings Litter production and decomposition rates differed greatly among four plots. During the two years of our study, above-ground litter production and decomposition in heavy-grazing plots were faster than those in light-grazing plots. In the dry year, below-ground litter production and decomposition in light-grazing plots were faster than those in heavy-grazing plots, which is opposite to the findings in the wet year. Short-term grazing exclusion could promote litter production, and the exclusion of light-grazing could increase litter decomposition and nutrient cycling. In contrast, heavy-grazing exclusion decreased litter decomposition. Thus, grazing exclusion is beneficial to the restoration of the light-grazing grasslands, and more human management measures are needed during the restoration of heavy-grazing grasslands. Precipitation increased litter production and decomposition, and below-ground litter was more vulnerable to the inter-annual change of precipitation than above-ground litter. Compared to the light-grazing grasslands, heavy-grazing grasslands had higher sensitivity to precipitation. The above-ground litter decomposition was strongly positively correlated with the litter N content (R2 = 0.489, p < 0.01) and strongly negatively correlated with the soil total N content (R2 = 0.450, p < 0.01), but it was not significantly correlated with C:N and lignin:N. Below-ground litter decomposition was negatively correlated with the litter C (R2 = 0.263, p < 0.01), C:N (R2 = 0.349, p < 0.01) and cellulose content (R2 = 0.460, p < 0.01). Our results will provide a theoretical basis for ecosystem restoration and the research of carbon cycling. 相似文献
13.
《植物生态学报》2014,38(6):550
亚高山森林冬季不同厚度雪被斑块下显著的冻融格局差异可能对凋落物分解过程中钾(K)和钠(Na)的动态具有重要影响, 然而已有研究还不足以清晰地认识这一过程。以川西亚高山森林6种代表性树种凋落物为研究对象, 采用凋落物网袋法, 探讨冬季不同厚度雪被斑块下雪被形成期、覆盖期和融化期凋落物分解过程中K和Na元素释放或富集的特征。整个雪被覆盖时期, 6种凋落物分解过程中Na均表现为富集特征, 且以覆盖期最为明显; 而K表现为释放特征, 以雪被融化期释放率最大。相对于其他雪被斑块, 厚型和中型雪被斑块下凋落物K释放率相对较高; 除康定柳(Salix paraplesia)和高山杜鹃(Rhododendron lapponicum)外, 其他物种凋落物在厚型和中型雪被斑块下Na富集率较高。同时, 统计分析结果表明, 物种和雪被显著影响冬季不同关键时期凋落物K和Na元素动态。除红桦(Betula albosinensis)和方枝柏(Sabina saltuaria)凋落物外, 温度因子与凋落物K和Na动态变化呈显著正相关。这些结果表明气候变暖情景下冬季雪被覆盖的减小将抑制亚高山森林冬季凋落物分解过程中K和Na元素的释放, 但是释放程度受凋落物质量和雪被覆盖时期的显著影响。 相似文献
14.
《植物生态学报》2018,42(9):906
季节性是北京植物景观的典型特征, 而个体物候是植物景观季节动态的基础。该研究基于北京植物园内120种落叶树种的周年物候数据, 对北京植物景观的物候季节动态进行分析。物候观测以中国物候观测法为标准, 采用a、b、c三级物候代码进行物候记录; 数据分析以二十四节气中的候(5日)为基本时间变量, 基于频率分布型法探究北京物候季节划分及其物候构成动态, 基于SPSS 20.0频数分布统计等探究各类物候现象发生期及持续期的时间分布特征等。物候季节划分及物候构成特征结果为: 6-19候为春, 物候期发生频数占全年总量的54.03%, 以发芽、展叶、开花为主要物候特征, 后期有少数树种结果; 20-45候为夏, 物候量占全年的12.95%, 此期全部观测树种完成展叶, 春花树种进入结果期, 并有较少夏花开放及秋色叶出现; 46-59候为秋, 物候量占全年的27.19%, 以秋色叶及落叶物候为主并伴有较少结果和开花物候发生; 60候至次年春季起始前为冬, 其中60-72候物候量仅占全年的0.6%, 全为落叶物候。各类物候期的时间分布特征如下: 展叶物候期分布于3-23候, 华北珍珠梅(Sorbaria kirilowii)、旱柳(Salix matsudana)等展叶最早, 展叶期平均持续3.27候。秋色物候期分布于40-63候, 49-56候为最佳观赏期, 蒙椴(Tilia mongolica)、山杏(Armeniaca sibirica)等最早显秋色; 秋色期平均持续8.2候, 卫矛(Euonymus alatus)、接骨木(Sambucus williamsii)等秋色期较长。叶幕期平均持续44.2候, 糯米条(Abelia chinensis)、旱柳、棣棠(Kerria japonica)等叶幕期最长。花物候期分布于1-53候, 始花期为1-41候, 盛花期平均发生于始花后1.81候, 8-23候为集中观赏期, 蜡梅(Chimonanthus praecox)、迎春(Jasminum nudiflorum)、榆(Ulmus pumila)、毛白杨(Populus tomentosa)等开花最早, 木香薷(Elsholtzia stauntoni)开花最晚; 花期平均持续 6.7候, 华北珍珠梅、木槿(Hibiscus syriacus)、紫薇(Lagerstroemia indica)等夏秋开花树种花期最长。果物候期分布于8-59候, 榆、郁香忍冬(Lonicera fragrantissima)等果实成熟最早; 持果期平均持续29.0候, 果实宿存树种及黑果荚蒾(Viburnum melanocarpum)、‘金叶’风箱果(Physocarpus opulifolius ‘Luteus’)等具有较长的果实观赏期。与20世纪80年代同类研究结果对比分析, 北京2017年的物候季节与30年前相比, 入春提早1候, 夏季延长4候, 入秋延后3候, 秋季缩短2候, 且不同季节持续期长短的差距加大。 相似文献
15.
《植物生态学报》2018,42(6):619
凋落物是陆地生态系统的重要组成部分, 凋落物动态特征可以反映出生态系统的存在状况以及环境对植被的影响作用。为探究北亚热带常绿落叶阔叶混交林凋落物产量及现存量的动态及其影响因素, 该研究观测了神农架地区一处典型植被2009-2015年的凋落物产量及现存量, 据此分析其动态特征及其与气象因素的关系。研究结果表明: 该森林凋落物平均年产量及现存量分别为5.94 t·hm -2和10.46 t·hm -2, 2009至2014年均无明显年际变化趋势, 但在2015年均显著降低, 且当年倒春寒天数显著高于其他年份; 季节动态变化呈现双峰型, 峰值分别出现在3-5月和10月; 凋落物月产量与当月的前第1-4个月的月平均气温正相关, 与当月的前第8-10个月的月平均气温负相关, 且与当月的前第6-7及第10个月的月平均相对湿度负相关; 凋落物产量季节性指数平均值为0.032, 与年平均气温显著正相关。可见, 长时间倒春寒现象会显著影响凋落物年产量及现存量, 月平均气温和相对湿度对凋落物产量季节动态的影响有明显的滞后性, 且年平均气温对北亚热带主要森林类型的凋落物产量季节性指数有显著影响。 相似文献
16.
《植物生态学报》2014,38(3):219
太阳辐射是陆地生态系统碳水循环的能量来源。太阳辐射的变化对植被吸收大气CO2具有重要影响。该文通过辐射观测数据建立散射辐射比例与晴空指数的关系, 结合生态过程模型(BEPS)和通量观测数据, 模拟分析了太阳辐射变化对千烟洲常绿针叶林总初级生产力(GPP)的影响。研究结果表明: 千烟洲森林生态系统的阴叶对年GPP总量的贡献达67%, 太阳辐射变化对阴叶光合作用的影响决定了冠层GPP的变化; 太阳辐射强度和分布的年际差异导致年GPP对太阳辐射变化的响应不同, 2003、2004和2005年太阳辐射分别变化-5.44%、-1.83%和6.26%, 可使千烟洲生态系统当年GPP总量达到最大值; 在季节上, 太阳辐射的增加会导致5-6月GPP上升, 7-9月GPP下降, 使年GPP变化程度降低; 在天尺度上, 晴空指数在0.43时, 太阳辐射变化对GPP的影响最小。 相似文献
17.
《植物生态学报》2017,41(6):597
Aims Soil microbes play a key role in the biogeochemical cycling in terrestrial ecosystems and are important for the nutrient recovery of degraded soils due to disturbances. However, dynamics in soil microbial biomass during the development of the secondary forest after logging are little known. Our objectives were to examine the temporal dynamics and influencing factors of soil microbial biomass carbon content (Cmic) and nitrogen content (Nmic) along a temperate forest logging chronosequence.Methods The logging chronosequence included four sites with 0-year, 10-year, 25-year, and 56-year sites since clear cutting of a deciduous broadleaved forest and was established in 2014 in the Mao’ershan Forest Ecosystem Research Station, Northeast China. The Cmic and Nmic at all the sites were measured monthly during the growing season (from April to October) with the chloroform fumigation extraction method; the soil dissolved organic carbon content (Cdis), total nitrogen content (Ndis), soil water content and temperature were simultaneously measured. Important findings (1) There were significant differences in soil microbial biomass among the four sites: the means of Cmic at the 56-year and 0-year sites were significantly higher than those at the 25-year and 10-year sites; the means of Nmic at the 0-year and 56-year sites were significantly higher than those at the 10-year site, while the 25-year site had intermediate Nmic; The Cmic/Nmic ratios at the 56-year and 10-year sites were significantly higher than those at the 25-year and 0-year sites. (2) The Cmic and Nmic at the 0-year site tended to decrease at the end of the growing season compared to earlier times, while those at the rest sites showed an increasing trend or no significant change. Soil microbial biomass among the 10-year, 25-year, and 56-year sites differed at the early growing season, and its amplitude of variations decreased as the stand age increased. The Cmic/Nmic ratios at all sites showed a “W-shaped” seasonal pattern. (3) The main influencing factors of the seasonality of soil microbial biomass varied with the stand ages: they switched from soil water content at the 0-year and 10-year sites to the soil dissolved nutrients contents at the 10-year, 25-year, and 56-year sites. The seasonality of Cmic/Nmic ratios at the 0-year site was mainly influenced by soil temperature and Cdis, while those at the other three sites were driven by the Cdis/Ndisratio. It was concluded that with the forest development after clear cutting, the characteristics of vegetation and soil have been changing, inducing increased soil microbial biomass and thereby improved soil nutrient regime, which reflected strong links between aboveground changes in vegetation and belowground dynamics in soil microbes. 相似文献
18.
《植物生态学报》2018,42(4):453
水分利用效率(WUE)既是衡量植被生长适应性的重要指标, 也是连接生态系统水碳循环的纽带。认识不同类型植被WUE的时间变化特征及驱动机制有助于增进对生态系统水碳循环过程的理解。已有研究表明, 在不同时间尺度下, WUE呈现不同的时间变化特征, 但现有研究多是集中在单一的时间尺度下开展的, 对不同植被类型在不同时间尺度下的动态变化及影响因子分析开展得较少。该研究选用中国北方地区9个定位观测台站的通量与气象数据, 分析了WUE的日内变化和季节变化特征, 并在0.5 h、1 d、8 d以及月尺度下, 分别分析了气温(Ta)、相对湿度(RH)、饱和水汽压差(VPD)以及光合有效辐射(PAR)等非生物因子对WUE的影响。同时, 该研究也分析了植被叶面积指数(LAI)和降水(P)对WUE的影响。研究发现: (1) WUE的日变化呈现不对称的“U”型特征, 日出时的WUE普遍高于日落时。荒漠地区WUE的季节变化呈“U”型, 而其他站点呈现单峰型。不同站点WUE的季节变化可以分为总初级生产力(GPP)主导型和蒸发散(ET)主导型, 并随着时间尺度的扩大, GPP或ET的主导作用逐渐增强。(2)在较短的时间尺度(0.5 h、1 d)上, Ta、RH、VPD和PAR是影响WUE变化的主要因子, 但随着时间尺度的扩大, Ta和RH成为影响WUE变化的主要因子, 并且与WUE的相关关系受GPP或ET对WUE主导作用的影响, 随着时间尺度增大, Ta和RH与WUE的线性关系更加显著。(3) WUE大体上随LAI的增加而增加, 但当LAI超过一定值时, 在长白山、海北和张掖站, WUE对LAI的敏感性降低。降水与WUE的关系在研究区域内并不显著。(4)不同植被类型的WUE由大到小依次为森林、农田、草地、湿地和荒漠。 相似文献
19.
降水格局的变化是气候变化影响干旱和半干旱区草原植物群落结构和功能的关键过程。作为植物群落结构和功能的基本组成单位——植物功能群——对气候变化的响应差异明显。有关不同植物功能群如何响应降水格局的研究, 有助于揭示气候变化对干旱与半干旱区生态系统关键功能与过程稳定性的变异机制。该文利用1982-2015年的典型草原群落地上生物量长期动态监测数据及其所对应的气候数据, 系统揭示降水变化对干旱与半干旱区生态系统生产力的影响。主要研究结果如下: 1) 1982-2015年内蒙古典型草原区降水变化特征明显, 主要表现在降水集中度呈显著的降低趋势; 小降水事件(≤5 mm)明显增多。2)降水变化导致群落生物量呈下降趋势。其中, 多年生丛生禾草的生物量呈上升趋势; 一二年生植物、多年生杂类草、多年生根茎禾类草的生物量均呈下降趋势。3)群落生物量与生长季降水量、降水集中度呈显著的正相关关系。各功能群中, 多年生杂类草、半灌木和生长季降水量呈显著正相关关系, 灌木与降水集中度呈显著负相关关系。4)群落生物量与各等级降水的频率相关性均不显著, 但与I-II类(0.1-10 mm)降水贡献率显著负相关。各功能群中, 多年生杂类草与I类降水(0.1-5.0 mm)的发生频率和降水贡献率均呈显著的负相关关系, 与VI类降水(20-25 mm)的发生频率和贡献率均呈显著的正相关关系。多年生根茎禾类草和VIII类降水(>35 mm)的发生频率和贡献率均呈显著的正相关关系。说明小降水事件的增加将显著降低群落的地上生物量, 小降水事件对干旱、半干旱区植被生长具有重要的生态学意义。 相似文献