Carbon Reserve Characteristics of Arbor Layer in Mid-subtropical Evergreen Broad-leaved Forest

In this paper, secondary forest of Pinus massoniana , coniferous-broad-leaved mixed forest and broad-leaved evergreen forest were taken as research objects, to explore carbon reserve of arbor layer and its spatial distribution characteristics. At different succession stages, the sequence of organic carbon content in each organ was secondary forest of P. massoniana > coniferous-broad-leaved mixed forest> broad-leaved evergreen forest. Carbon reserve of arbor layer was the highest in broad-leaved evergreen forest, which was 129.34 t/hm 2, followed by coniferous-broad-leaved mixed forest (95.83 t/hm 2), and the minimum was 85.27 t/hm 2 in secondary forest of P. massoniana . In each stand type, the sequence of carbon reserve of each organ in arbor layer was trunk>root>branch>leaf>bark. Carbon reserve of arbor layer mainly concentrated in trunk, and the proportion to carbon reserve of arbor layer declined from secondary forest of P. massoniana to broad-leaved evergreen forest, while it had increasing relationship in root. In secondary forest of P. massoniana , coniferous-broad-leaved mixed forest and broad-leaved evergreen forest, individual with the diameter more than 20 cm accounted for the majority of carbon reserve in the arbor layer.

Role of urban remnant evergreen broad-leaved forests on natural restoration of artificial forests in Chongqing metropolis

The effects of urban remnant natural evergreen broad-leaved forest (EBLF) on the restoration of artificial pine forests surrounding it were studied with reference to species composition,biodiversity,dominant species and stand structure on Mt. Tieshanping in Chongqing metropolis,Southwest China. The seeds from the remnant EBLF naturally facilitate the restoration process of artificial Pinus massoniana forests near it. The similarity of species composition between the artificial Pinus massoniana forests and the remnant EBLF and biodiversity index of the artificial Pinus massoniana forests decrease as the distance from the remnant EBLF increases. Castanopsis carlesii var. spinusa is the dominant species in the ground vegetation,shrub layer and sub-tree layer of the Pinus massoniana forests near the remnant EBLF. However,the natural restoration processes of those farther away from the remnant EBLF are restricted for the absence of seed source of the inherent components of the remnant EBLF,and the anthropogenic measures should be taken to facilitate the restoration process.

Comparative Study of Carbon Storage and Allocation Characteristics of Mature Evergreen Broad-leaved Forest

Evergreen broad-leaved forest is an important forest type in China.This paper analyzes the allocation characteristics of vegetation and soil carbon pool of evergreen broad-leaved forest,to understand the current status of research on the carbon storage of evergreen broadleaved forest as well as shortcomings.In the context of global climate change,it is necessary to carry out the long-term research of evergreen broad-leaved forest,in order to grasp the formation mechanism of evergreen broad-leaved forest productivity,and the impact of climate change on the carbon sequestration function of evergreen broad-leaved forest ecosystem.

Biomass Characteristics of the Arbor Layer in Different Stands of the Evergreen Broad-Leaved Forest

In this paper, the Pinus massoniana forest in the early stage of succession, the coniferous broad-leaved mixed forest in the middle stage of succession, and the evergreen broad-leaved forest in the late stage of succession were studied, and the biomass and its spatial distribution characteristics of the tree layer in different succession stages of the ecosystem were discussed. The results showed that the biomass of the arbor layer was the highest in the evergreen broad-leaved forest, which was 292.51 t/ hm2, followed by the coniferous and broad-leaved mixed forest, which was 206.87 t/hm2, and the Pinus massoniana forest, which was 171.76 t/hm2. The biomass of trunks accounted for the largest proportion in the total biomass of the arbor layer, which reduced from the Pinus massoniana forest to the evergreen broad-leaved forest. The proportion of the biomass of roots in the total biomass of the arbor layer increased from the Pinus massoniana forest to the evergreen broad-leaved forest. The biomass of the diameter class above 20 cm in the Pinus massoniana forest, the coniferous and broad-leaved mixed forest and the evergreen broad-leaved forest accounted for a large proportion of total biomass.

Long-term response of living forest biomass to extensive logging in subtropical China

Forest disturbance and recovery are critical ecosystem processes,but the temporal patterns of disturbance have not been studied in subtropical China.Using a tree-ring analysis approach,we studied post-logging above-ground(ABG)biomass recovery dynamics over a 26-year period in four plots with different degrees of logging disturbance.Before logging,the ABG biomass ranged from 291 to 309 t ha-1.Soon after logging,the plots in primary forest,secondary forest,mixed forest and singlespecies forest had lost 33,91,90 and 100%of their initial ABG biomass,respectively.Twenty-six years after logging,the plots had regained 147,62,80 and 92%of their original ABG biomass,respectively.Over the 26 years following logging,the mean CAI(Current annual increment)were 10.1,5.5,6.4 and 10.8 t ha^-1 a^-1 and the average MAI(Mean annual increment)8.7,2.5,5.6 and 7.8 t ha^-1 a^-1 for the four forest types,respectively.The results indicate that subtropical forests subjected to moderate logging or disturbances do not require intensive management and single-species plantings can rapidly restore the above-ground biomass to levels prior to heavy logging.

Woody Debris Storage of Evergreen Broad-leaf Forest

In Yingzuijie National Nature Reserve, Pinus massoniana forest, mixed broadleaf-coniferous forest and evergreen broad-leaf forest were investigated to study the changing characteristics of woody debris （WD） during various succession stages o1 evergreen broad-leaf forest. The results showed that during various succession stages of evergreen broad-leaf forest in Yingzuijie National Nature Reserve, WD storage of each forest ranged from 1.26 to 8.82 t/hm^2, with the order of P. massoniana forest 〈 mixed broadleaf-coniferous forest 〈 evergreen broad-leaf forest, that is, it increased from early to late stages of the succession. At different succession stages, coarse woody debris （CWD） storage was 2 -9 times more than fine woody debris （FWD） storage, revealing that CWD was dominant in WD of each forest. CWD biomass accounted for 0.66% -2.21% of arbor biomass, so the forests were at the developmental stage.

Community Dynamics of Seed Rain in Mixed Evergreen Broad-leaved and Deciduous Forests in a Subtropical Mountain of Central China

Seed dispersal is a key process within community dynamics. The spatial and temporal variations of seed dispersal and the interspecific differences are crucial for understanding species coexistence and community dynamics. This might also hold for the mixed evergreen broadleaved and deciduous forests in the mountains of subtropical China, but until now little existing knowledge is available for this question. In 2001, we chose to monitor the seed rain process of our mixed evergreen broad-leaved and deciduous forest communities in Mount Dalaoling National Forest Park, Yichang, Hubei Province, China. The preliminary analyses show obvious variations in seed rain density, species compositions and timing of seed rain among four communities. The average seed rain densities of the four communities are 2.43 ± 5.15, 54.13 ±182.75, 10.05 ±19.30 and 24.91 ± 58.86 inds/m^2, respectively; about one tenth the values in other studies in subtropical forests of China. in each community, the seed production is dominated by a limited number of species, and the contributions from the others are generally minor. Fecundity of evergreen broadleaved tree species is weaker than deciduous species. The seed rain of four communities begins earlier than September, and stops before December, peaking from early September to late October. The beginning date, ending date and peak times of seed rain are extensively varied among the species, indicating different types of dispersal strategies. According to the existing data, the timing of seed rain is not determined by the climate conditions in the same period, while the density of seed rain may be affected by the disturbances of weather variations at a finer temporal resolution.

南亚热带常绿阔叶林地上碳储量空间分布特征及其影响因素

旨在探讨南亚热带常绿阔叶林地上碳储量空间分布特征及其影响因素,为了解该区域森林的碳汇功能提供理论依据。通过对鼎湖山南亚热带常绿阔叶林20 hm2固定森林样地调查数据,采用一元线性回归分析和主成分分析方法,划分优势种和非优势种,研究地上碳储量的空间分布和生物/非生物因素的影响,获取了以下结果:(1)优势种对鼎湖山南亚热带常绿阔叶林地上碳储量贡献更大(1533.85 Mg,74.72%),尤其是大径级物种(1389.68 Mg,67.69%)。优势种地上碳储量(CV=0.635)的空间分布较非优势种(CV=0.690)更加均匀。(2)物种多样性与优势种和总体地上碳储量负相关,而与非优势种正相关。(3)群落总体、优势种和非优势种的地上碳储量均与结构多样性显著正相关。然而,结构多样性对非优势种地上碳储量的影响程度高于优势种。(4)群落中的土壤营养度、凹凸度与地上碳储量正相关。综上所述,通过提升非优势种的物种多样性可以增加鼎湖山南亚热带常绿阔叶林地上碳储量。此外,改善土壤营养条件也有助于提升南亚热带森林的碳汇功能。

Belowground carbon balance and carbon accumulation rate in the successional series of monsoon evergreen broad-leaved forest

The balance, accumulation rate and temporal dynamics of belowground carbon in the successional series of monsoon evergreen broadleaved forest are obtained in this paper, based on long-term observations to the soil organic matter, input and standing biomass of litter and coarse woody debris, and dissolved organic carbon carried in the hydrological process of subtropical climax forest ecosystem—monsoon evergreen broad-leaved forest, and its two successional forests of natural restoration—coniferous and broad-leaved mixed forest and Pinus massoniana forest, as well as data of root biomass obtained once every five years and respiration measurement of soil, litter and coarse woody debris respiration for 1 year. The major results include: the belowground carbon pools of monsoon evergreen broad-leaved forest, coniferous and broad-leaved mixed forest, and Pinus massoniana forest are 23191 ± 2538 g·m?2, 16889 ± 1936 g·m?2 and 12680 ± 1854 g·m?2, respec- tively, in 2002. Mean annual carbon accumulation rates of the three forest types during the 24a from 1978 to 2002 are 383 ± 97 g·m?2·a?1, 193 ± 85 g·m?2·a?1 and 213 ± 86 g·m?2·a?1, respectively. The belowground carbon pools in the three forest types keep increasing during the observation period, suggesting that belowground carbon pools are carbon sinks to the atmosphere. There are seasonal variations, namely, they are strong carbon sources from April to June, weak carbon sources from July to September; while they are strong carbon sinks from October to November, weak carbon sinks from December to March.

南亚热带常绿阔叶林土壤微生物生物量碳氮年际动态特征及其影响因子

土壤微生物是土壤有机质和养分循环的主要驱动者,研究土壤微生物生物量碳氮变化、稳态特征及其对环境因子内在的长期响应机理具有重要意义。以南亚热带常绿阔叶林土壤为对象,对土壤微生物生物量碳和氮(MBC和MBN)、土壤有机碳(SOC)、总氮(TN)、总磷(TP)、可溶性碳(ROC)、速效氮(AN)、pH、土壤温度(ST)和土壤含水量(SWC)进行连续10年监测;应用方差分析、相关性和回归分析及稳态分析等探究MBC和MBN的年际变化和稳态特征及主要影响因素。研究结果表明:(1)旱季MBC和MBN含量分别在171.32—358.45和25.90—54.08 mg/kg区间波动,雨季分别在394.01—507.97和68.40—88.05 mg/kg区间波动;旱、雨季的MBC含量年际间变化显著(P<0.05),但MBN含量仅在旱季变化显著(P<0.05)。雨季MBC和MBN含量均显著高于旱季(P<0.01),且雨季的MBC和MBN含量是旱季的2倍以上。(2)旱、雨季的MBC与MBN之间均呈显著正相关(P<0.05)。在旱季,MBC和MBN均与ROC和AN含量显著正相关(P<0.05),此外,MBN含量也与TP(P<0.05)和SOC(P<0.01)显著正相关。在雨季,仅SOC与MBN呈显著正相关(P<0.05)。(3)在旱季,MBC含量变化主要受ROC(P<0.05)和AN(P<0.001)影响,MBN则受AN控制(P<0.05)。在雨季,AN(P<0.05)主导了MBC的变化,TP(P<0.05)和SOC(P<0.05)是MBN变异的主导因子。AN(P<0.001)和SOC(P<0.001)是旱、雨季土壤MBC和MBN变化的主导因子。(4)土壤MBC和MBC/MBN稳态指数在年际间均为绝对稳态型(P>0.05);雨季的MBN(P=0.685)为绝对稳态型,但旱季为非稳态(P<0.01,H>1)。雨季微生物熵显著高于旱季(P<0.01),表明土壤有机质质量及养分利用效率更高。综上,MBC和MBN含量受季节更替显著影响,且主要受土壤SOC和AN的影响;受旱季水分限制,MBN的稳态更差。

广西十万大山山地常绿阔叶林优势种空间分布格局与关联性

【目的】山地常绿阔叶林是十万大山的主要植被类型,揭示其群落种群空间分布格局与关联性特征,有利于探讨群落物种竞争关系与维持机制。【方法】以十万大山1 hm^(2)山地常绿阔叶林样地重要值排名前6位的树种为研究对象,采用g(r)函数、方差比率法、Spearman秩相关系数分析种群空间分布格局和种内、种间相关性。【结果】以完全随机模型对样地群落优势种空间分布格局进行分析,发现优势种在1~11 m尺度上均呈聚集分布,云南桤叶树Clethra delavayi、银木荷Schima argentea、柔毛紫茎Stewartia villosa在1~25 m尺度上呈聚集分布;以异质泊松模型分析时,发现优势种在10~25 m尺度上均呈随机分布,表明优势种空间分布格局受生境异质性影响,且不同种群受影响的程度不同;样地微地形因子中海拔和坡度对优势种的格局分布影响较大;不同种群的龄级空间分布格局受个体密度影响较大,增长型种群幼龄个体聚集分布,随着龄级的增加其空间分布趋于随机分布,衰退型种群成年个体小尺度上聚集分布,幼龄个体随机分布;样地群落优势种的幼树、小树、成年树之间无种内竞争排斥关系,种内关联性均为正相关或无关联,种内关联性与尺度相关;群落优势种种间关联性总体呈正关联,种间正相关和无关联种对多于负相关种对,表明群落中优势种的种间竞争关系较弱,优势种间相互独立,利于物种共存。【结论】十万大山山地常绿阔叶林优势种的分布格局受生境异质性和密度制约的影响,且分布格局随尺度和发育阶段而变化。种内、种间关系多为正相关或无关联,群落优势种排斥竞争关系不显著,群落种群结构稳定。

天目山常绿落叶阔叶混交林种子雨特征及其与群落组成的关系

林木种子是森林更新的重要物质基础,其数量多少与组成会对群落动态和生态系统的结构与功能产生深刻影响。为了更好的了解天目山常绿落叶阔叶混交林动态变化,利用种子收集器对天目山常绿落叶阔叶混交林种子雨进行了一年定位监测,分析了种子雨物种组成、季节动态、空间动态、种子性状以及种子雨与群落树种空间关系。结果表明:(1)天目山常绿落叶阔叶混交林种子雨密度为921.33粒m^(-2) a^(-1),一年中每月都能收集到一定数量种子,月平均种子雨密度为76.78粒/m^(2),种子雨密度最大高峰是在10月份,达到263.78粒/m^(2),种子雨散布具有很大的空间变异,群落种子雨空间分布格局呈聚集分布。(2)一年中共收集到30个物种的种子,单粒种子平均重量为0.065 g,其中小叶青冈重量最大为0.405 g,最小的为柳杉重量为0.003 g,不同散布方式和不同果实类型的物种种子重量差异显著,在散布方式中重力散布的种子重量最大,在果实类型中坚果的种子重量最大。(3)植物群落物种对种子雨组成,特别是优势种的物种丰富度有很大贡献,种子不同的散布方式会影响种子雨与母树组成的相似性,风力散布的相似系数的最高值(R_(max))和距种子雨收集器的距离(d)均最大(风力散布:R_(max)=0.212,d=8 m;动物散布:R_(max)=0.143,d=6 m;重力散布:R_(max)=0.100,d=7 m),种子雨密度与周围母树数量在一定范围内呈显著正相关。综上,天目山常绿落叶阔叶混交林种子物种种类丰富,种子雨具有明显的季节动态和空间变异,符合亚热带常绿落叶阔叶混交林种子雨时空动态的典型特征,通过风力散布的种子在远距离传播上有更大的优势。

基于功能性状的中亚热带岩溶常绿落叶阔叶混交林物种多样性维持研究

理解植物功能性状和功能实体在森林群落的分布,有助于探讨物种丧失对森林生态系统功能、冗余和恢复力的影响。为了解脆弱的岩溶石山森林在应对生物多样性丧失的生态系统反馈,对桂林岩溶石山两块1hm~2的常绿落叶阔叶混交林的木本植物数据进行了分析。包括基于功能性状计算功能多样性、构建功能实体计算功能冗余以及采用Pearson相关分析和Mantel检验评估物种多样性指标在生态系统的维持机制。结果显示:(1)青冈+大叶榉树群落的功能多样性指标均低于鱼骨木+青冈+圆叶乌桕群落,且两个群落间功能均匀度不相关(P>0.05),功能丰富度、功能离散度和Rao′s二次熵呈现极显著相关性(P<0.001),功能分散度呈现显著相关性(P<0.05)。(2)两个群落的物种丰富度与功能冗余指标表现出相似的线性关系,即物种丰富度与功能实体等级、功能冗余、功能超冗余呈正相关,与功能脆弱性呈负相关关系。(3)不同植物功能性状间、不同功能多样性指标间和不同功能冗余指标间的相关性较强,功能多样性指标和功能冗余指标间无显著相关性,但功能性状与功能多样性指标、功能性状与功能冗余指标均存在不同程度的相关性。而在功能实体与物种多样性指标的相关性方面,呈现出同物种丰富度与物种多样性指标相似的显著度。另外,物种多度与物种丰富度、功能分散度、功能离散度、Rao′s二次熵及功能脆弱性均显著相关。总之,在岩溶石山常绿落叶阔叶混交林中,高功能多样性的群落存在高功能冗余的现象,但功能多样性和功能冗余是相互独立的因素;物种丰富度高的群落所提供的保险效应无法抵消其生态系统的脆弱性。因此,不能仅通过保护物种丰富度来维持生态系统的特有功能,还应充分考虑多度对生态系统功能的贡献,以更有效地实现对岩溶石山森林生态系统的保护。

喀斯特常绿落叶阔叶混交林凋落叶养分含量时空分布特征

森林生态系统中凋落物养分含量通常具有明显的时空异质性,为探究喀斯特常绿落叶阔叶混交林凋落叶养分含量的时空分布特征及其影响因素,以广西木论喀斯特常绿落叶阔叶混交林25hm2动态监测样地内151个凋落物收集器所收集的凋落叶为研究对象,选取连续12个月的凋落叶进行元素含量分析。结果显示:该森林群落凋落叶元素含量大小顺序为碳(C)>钙(Ca)>氮(N)>镁(Mg)>钾(K)>硫(S)>磷(P),分别介于471.85—496.33、20.27—28.29、17.34—23.10、2.79—5.49、1.80—4.38、1.82—2.22、0.96—1.21g/kg之间,呈现高Ca、Mg,低P、K的分布规律,并且随时间出现明显波动,其中C、N、P、S和Ca元素均在4月出现较大值,而K、Mg则在1月出现峰值。生物因子在5m和10m邻域范围内对凋落叶含量的影响基本一致,但10m尺度上地形因子和土壤因子对凋落叶元素含量的影响更为明显。10m邻域范围内生物和非生物因子对凋落叶P元素的随机森林累积解释率最高,达80.27%,C元素累积解释率最低,仅10.49%,其中海拔和坡度对凋落叶C、N、P、S、K、Ca和Mg含量均有强烈影响,岩石出露率和土壤铁(Fe)含量也会在一定程度上对凋落叶元素含量产生较大影响。综上所述,喀斯特常绿落叶阔叶混交林不同月际间凋落叶养分含量存在显著差异,10m尺度上海拔和坡度是凋落叶养分含量产生空间变异的主要原因。

神农架南坡小叶青冈+曼青冈常绿阔叶林主要木本植物生态位与种间联结

为揭示神农架南坡代表性常绿阔叶林主要木本植物的种间生态联系及群落演替趋势,以小叶青冈+曼青冈群系20个主要木本植物的190组种对为研究对象,通过生态位测定并区分生态位特化种和生态位泛化种以及种间联结性检验,分析该群落主要物种生态位与种间联结特征。主要结果:(1)该常绿阔叶林群落物种丰富,群落组成复杂,小叶青冈(Cyclobalanopsis myrsinifolia)的重要值(11.13%)和生态位宽度(58.3)均最大,占绝对优势,生态位宽度排序和重要值排序不一致,分布频度对生态位宽度影响较大。(2)将20种主要木本植物划分为生态位特化种(6种)、生态位泛化种(3种)、中性类群(11种),生态位分化程度较高,资源利用差异以及生境适应性是影响生态位分化的主要因素。(3)生态位宽度大的物种其生态位重叠和相似度较高,生态位重叠指数总体略低,大部分物种对环境或资源需求相似,但相似度不高,种间竞争较弱,种间关系比较稳定。(4)主要木本植物总体正联结显著(P<0.05),χ^(2)检验、联结系数AC、Spearman秩相关检验结果均显示种间正联结作用占优势,但大多数种对联结不显著,物种趋于独立分布。(5)通过聚类分析,将20种主要木本植物划分三大生态种组:建群种组,共生种组和边缘种组。研究表明,神农架南坡小叶青冈+曼青冈常绿阔叶林目前正处于相对稳定的演替中后期阶段,群落发育较成熟,生态位分化、生境选择以及资源需求互补或互利是影响该群落物种共存的主要原因。研究阐明了神农架南坡代表性常绿阔叶林主要物种之间实际相互作用以及群落特征,为深入理解群落物种共存原因以及群落演替规律提供依据。

2010-2014年哀牢山亚热带常绿阔叶林土壤呼吸数据集

亚热带森林是我国分布面积最大的森林类型,在调控全球气候变化和维持大气碳平衡中具有重要作用。土壤通过呼吸作用排放的碳是大气CO_(2)的主要来源,土壤碳库的细微变化也会显著影响大气CO_(2)的浓度,因此目前亚热带森林土壤碳储量的大小及动态变化特征受到广泛关注。云南哀牢山是我国重要的亚热带森林分布区。本研究依托云南哀牢山森林生态系统国家野外科学观测研究站,利用全自动多通道观测系统开展了亚热带常绿阔叶林土壤呼吸的连续测定,经过严格的数据质量控制和评估,将2010-2014年的土壤呼吸的监测数据收集与整理,包括土壤5 cm温度(Ts)、土壤10 cm含水量(SWC)和土壤呼吸(Rs),并形成日、月和年尺度三类数据集。本数据集对于揭示气候变化对亚热带常绿阔叶林土壤生态过程的影响、正确评估土壤有机碳排放和森林生态系统管理具有重要意义,也为进一步研究气候变暖等全球变化对土壤呼吸组分尤其是土壤有机碳排放的影响提供经验和理论基础。

十万大山山地常绿阔叶林群落物种组成与结构特征

十万大山是广西生物多样性热点区域之一,其主要植被类型是山地常绿阔叶林。为了解区域内山地常绿阔叶林的群落现状及优势种群结构的发展现状,该文以十万大山山地常绿阔叶林1 hm^(2)固定监测样地中胸径(DBH)≥1 cm的木本植物为研究对象,分析其物种组成、径级结构、树高结构并用g(r)函数分析优势种的空间分布格局。结果表明:(1)群落中DBH≥1 cm的木本植物共计7517株,隶属52科108属153种;群落的优势种有云南桤叶树(Clethra delavayi)、银木荷(Schima argentea)、毛折柄茶(Hartia villosa)、红锥(Castanopsis hystrix)、黄杞(Engelhardtia roxburghiana)、罗伞树(Ardisia quinquegona)、鼠刺(Itea chinensis)、腺叶山矾(Symplocos adenophylla)、假杨桐(Eurya subintegra)、毛冬青(Ilex pubescens),但优势种的优势地位不明显。(2)群落整体平均DBH为5.51 cm,径级、树高分布呈近似倒“J”型;优势种的径级分布多呈倒“J”型或“L”型,群落有较强的更新能力。(3)群落优势种稳定共存;优势种在样地中呈聚集分布,但优势种间聚集分布的位置有差异。总体而言,群落目前更新状态良好,群落中已有顶极群落优势种的存在,但群落具有一定的次生性特征,还未到达稳定的顶极群落状态,优势种间能稳定共存,有向稳定顶极群落演替的潜力,应继续加强管护,促进十万大山山地常绿阔叶林群落的更新与生存。

不同年限梅花鹿干扰对亚热带森林土壤和植物生物量的影响

有蹄类动物的采食、践踏、排泄等行为会影响森林土壤理化特性与植物群落特征。选取浙江清凉峰国家级自然保护区典型亚热带针阔混交林地,设置4个华南梅花鹿干扰处理(禁养,圈养10、15、20 a),以探讨华南梅花鹿圈养对亚热带林地土壤和植被功能的影响。结果表明:(1)随着华南梅花鹿圈养年限的增加,土壤pH、含水率、毛管孔隙度、有机质和阳离子交换量呈现降低的趋势,土壤容重、碱解氮、有效磷和速效钾呈现升高的趋势。(2)华南梅花鹿圈养对0—40 cm土层土壤容重、含水率、毛管孔隙度、有机质、阳离子交换量以及0—20 cm土层碱解氮和有效磷的影响显著,均为圈养20 a处理与对照处理之间差异性达到显著水平(P<0.05)。(3)华南梅花鹿干扰能显著降低林下植被的地上生物量(P<0.05)。研究结果揭示亚热带森林土壤-植被对梅花鹿干扰的响应特征,为探讨森林蹄类动物栖息地退化机制和优化区域生态恢复模式提供科学的数据与理论基础。

天目山常绿落叶阔叶林生产力及其影响因素

在浙江省杭州市临安区的天目山国家级自然保护区内,以分布在海拔850~1100 m的常绿落叶阔叶林为研究对象,2017年在海拔1000 m的常绿落叶阔叶林内设置1个100 m×100 m的监测样地,对胸径1 cm及以上的树木,记录种名、测定生长指标(胸径、树高、冠幅等),2022年采用与2017年相同方法测定样木相关指标;采用网格取样和随机取样相结合的方法,在样地土层深度0~20 cm采集土壤样品,参照相关标准和方法测定土壤理化性质指标;以树种重要值、森林生产力(树木生物量)、物种多样性(皮卢(Pielou)均匀度指数、马格利夫(Margalef)物种丰富度指数、香农-维纳(Shannon-Wiener)多样性指数、辛普森(Simpson)多样性指数)、结构多样性(胸径香农-维纳多样性指数、胸径辛普森多样性指数、胸径标准偏差、胸径基尼系数)为评价指标,以2次调查和测定的数据为基础,采用回归分析法、层次分割法,分析天目山常绿落叶阔叶林组成变化、各因素对森林生产力的影响。结果表明:①天目山常绿落叶阔叶林在5 a间,有24种退出、16种进入,有33.90%物种发生了变化,变化物种均为偶见种和稀有种;落叶树种减少,常绿树种占比增加,有向常绿阔叶林演替的趋势。②天目山常绿落叶阔叶林,生物量为147.90 t·hm^(-2),生产力为5.90 t·hm^(-2)·a^(-1);常绿树种占总生产力63.04%、落叶树种占总生产力39.96%,常绿树种是生产力的主要贡献者。③天目山常绿落叶阔叶林生产力主要受结构多样性的影响,土壤因子中碱解氮为主要影响因素。各影响因子中,结构多样性贡献率最高(为20.79%);结构多样性中,胸径香农-维纳多样性指数的贡献率最高(为9.11%),与生产力呈极显著正相关(P<0.01);碱解氮对生产力的贡献率为6.68%,与生产力呈极显著正相关(P<0.01)。

氮磷添加对常绿阔叶林土壤团聚体有机碳及其与磷组分相关的影响

[目的]为探究磷输入如何调节大气氮沉降对土壤团聚体有机碳含量及碳与磷关系的影响。[方法]在常绿阔叶林土壤建立长达6年(2015-2021年)的养分添加长期监测试验平台,包括4个处理:对照[P0+N0,P0 kg/(hm^(2)·a)+N0 kg/(hm^(2)·a)]、氮添加[P0+N100,P0 kg/(hm^(2)·a)+N100 kg/(hm^(2)·a)]、磷输入[P50+N0,P50 kg/(hm^(2)·a)+N0 kg/(hm^(2)·a)]以及氮磷同时输入[P50+N100,P50 kg/(hm^(2)·a)+N100 kg/(hm^(2)·a)],各处理设3次重复,共计12个样地。于2021年8月采集样地0-10 cm土层土壤样品,测定基础理化性质、土壤粒径分布规律、不同粒径土壤团聚体磷组分及有机碳(SOC)含量。[结果](1)P0处理下,氮添加显著增加大团聚体占比,减少黏粒和粉粒含量,提高各团聚体粒径中SOC含量;氮添加分别显著降低和增加团聚体黏粒、粉粒中易分解态磷组分(LP)和难分解态磷组分(RP)含量。(2)P50处理下,氮添加显著提高土壤团聚体平均几何直径(GMD),对各粒径团聚体中磷组分和SOC含量均无显著影响。(3)P0处理下,土壤团聚体SOC与难分解态磷呈正相关关系;P50处理下,土壤团聚体SOC与各功能磷组分无显著相关。由此推断,P0处理下,氮添加通过提高常绿阔叶林土壤团聚体黏粒、粉粒径中难分解态磷而增加土壤有机碳的固持;P50处理下,氮添加对各粒径中有机碳的影响可能受到生物因素的调节,与磷的有效性无关。[结论]氮沉降对常绿阔叶林土壤团聚体中碳磷内在关系的影响受到磷的调控,研究结果为森林土壤碳循环应对全球气候变化提供数据支撑。