我国温带次生林生态系统中木腐真菌群落组成特征

木腐真菌是一类能够降解木材基质并利用其营养物质进行生长的生物类群,在森林生态系统的物质循环中起关键作用,是森林生态系统重要的组成部分。温带次生林生态系统是木腐真菌生长的重要区域,为了解木腐真菌在温带次生林生态系统中的群落组成,本研究选取吉林长白山次生杨桦林、辽宁白石砬子自然保护区、北京东灵山自然保护区、河南宝天曼自然保护区4个具有代表性的温带次生林开展了木腐真菌的调查。结果发现,长白山杨桦林中木腐真菌种类为73种,白石砬子为104种,东灵山为106种,宝天曼为124种,这4个地区的共有物种为18种。4个地区的优势属分别是Phellinus、Trametes、Hymenochaete和Polyporus,分别占各地区总种数的9.8%、6.7%、8.5%和8.1%。比较不同地区寄主频度-物种数的稀疏曲线发现,4个地区优势物种与当地林分中的优势寄主有着明显相关性。从4个地区木腐真菌的多样性、优势寄主选择和降解方式差异来看,林分的树种组成对木腐真菌的群落组成具有关键作用。上述地区多孔菌的属地理成分均以世界广布和北温带分布为主,具有明显的北温带成分区系特征。     

森林水文学：全球变化背景下的森林与水的关系

森林水循环是陆地水循环中的重要组成部分,不但影响森林植被的结构、功能与分布格局,还影响地球表面系统的能量收支、转换和分配,在陆地生态系统的碳氮平衡过程中发挥着重要作用。森林生态系统的水文功能不仅是其服务功能的重要组成部分,而且对系统生产力、养分循环等其它功能产生影响。森林与水分循环间的关系早在20世纪初就受到关注,     

西藏高原主要森林类型凋落物碳储量及空间分布格局

凋落物是森林生态系统的重要组成部分,其作为养分的基本载体,在养分循环中是连接植物与土壤的"纽带",其碳库直接影响着土壤碳库及森林生态系统的碳库。本文以西藏高原冷杉、云杉、高山松、云南松、高山栎、柏木森林类型为研究对象,采用直接收获法对森林凋落物碳储量进行研究。结果显示:凋落物碳储量随着龄级的增大而增加;凋落物碳储量随海拔的升高而增加,在3200~3600 m碳储量最大,随后碳储量开始下降;林芝地区凋落物碳储量最大,其次是山南地区和日喀则地区,最小的是昌都地区。     

高山森林林窗和生长基质对苔藓植物氮和磷含量的影响

苔藓在森林生态系统养分富集和循环方面有重要作用,苔藓植物在氮磷循环中的作用可能受到森林更新和生长基质的影响.为理解苔藓在森林生态系统养分循环中的作用,研究了高山森林不同位置(林窗中心、林窗边缘、林下)和不同生长基质(活立木、倒木、枯立木、大枯枝、根桩、地表)上的苔藓植物氮磷含量.结果表明:地表苔藓氮含量(3.12 mg·g^-1)显著低于其他生长基质上的苔藓,尽管枯立木附生苔藓氮含量高达17.41 mg·g^-1,但倒木、大枯枝、枯立木和活立木苔藓氮含量差异不显著;最高(1.09 mg·g^-1)和最低(0.61 mg·g^-1)的磷含量分别出现在森林地表和枯立木的苔藓,且森林地表的苔藓磷含量显著高于其他生长基质上的苔藓,但倒木、大枯枝、根桩和活立木上的苔藓磷含量差异不显著.林窗位置显著影响了倒木和大枯枝上的苔藓氮、磷含量,林窗内倒木和大枯枝上的苔藓氮、磷含量显著高于林窗边缘.粗木质残体的类型、腐烂等级对苔藓氮、磷含量的影响存在差异,两者交互作用的影响显著;第Ⅴ腐烂等级倒木上的苔藓氮含量显著高于其他腐烂等级;第Ⅲ腐烂等级大枯枝上的苔藓氮含量显著高于其他腐烂等级;第Ⅱ腐烂等级倒木上的苔藓磷含量显著高于其他腐烂等级;第Ⅳ腐烂等级枯立木上的苔藓磷含量显著高于其他腐烂等级.可见,森林林窗更新和粗木质残体腐解过程会影响苔藓植物的氮、磷含量,同时影响森林生态系统的养分循环过程.     

丽江老君山国家公园木腐真菌区系组成与分布特征

木腐真菌是自然界中以木材为主要生长基质的一类大型真菌,通过分解倒死木的木质素、纤维素和半纤维素实现森林生态系统的物质循环,是森林生态系统的重要组成部分。研究木腐真菌的生态分布及其与环境因子的关系对分析其在森林生态系统中的生态功能有重要作用。本文在野外调查的基础上对云南省丽江老君山国家公园的木腐真菌物种组成和生态习性进行了分析,共采集标本196份,经鉴定为68种,隶属于8目21科40属,优势科为多孔菌科、拟层孔菌科和锈革孔菌科,优势属为异担子菌属,其区系组成以北温带成分为最多(38.2%),其次是世界广布成分,表现出明显的北温带特征。从生态习性来看,63种为腐生菌,其中51种造成白色腐朽,12种造成褐色腐朽;5种为外生菌根菌。木腐真菌的物种组成在不同林分中存在明显差异,落叶阔叶林中种类最多,共34种;其次为针阔混交林,有26种;暗针叶林有22种。脆波斯特孔菌与粗毛韧革菌在3种林分类型中均有分布且多度较高,是该地区的优势种。     

基于SOFM网络对黄土高原森林生态系统的养分循环分类研究

对森林生态系统进行分类是认识森林生态过程的根本途径,传统的从结构角度对森林生态系统分类只能反映森林的外在特征,而无法从功能角度区别森林的本质差异.通过对黄土高原3个生物气候区18个不同森林生态系统的养分循环特征测算和分析,选取了能全面反映养分的积累和分布(生物量、枯落物积累量、养分积累量)、循环通量(年吸收量、年存留量、年归还量)以及养分循环效率(循环系数、利用系数、养分生产力)等多方面指标作为分类指标体系,利用自组织映射特征网络(SelfOrganizing Feature Maps,SOFM)聚类方法,从养分循环的角度将黄土高原森林生态系统划分为2个一级类型,6个二级类型.该分类结果与实际较符,从而探索了森林生态系统的功能分类方法,也验证了SOFM网络模型应用于森林养分循环分类的可行性.     

大小兴安岭针叶树倒木上木腐真菌的物种多样性

木腐真菌在森林生态系统中具有丰富的物种多样性, 并在倒木的降解过程中发挥重要的生态功能。针叶树是大小兴安岭森林生态系统的优势树种, 因此研究针叶树倒木木腐真菌物种多样性和影响其物种分布的相关环境因子有助于揭示大小兴安岭森林生态系统物质循环的机理。本研究收集了近16年对大小兴安岭地区冷杉属(Abies)、落叶松属(Larix)、云杉属(Picea)和松属(Pinus) 4类针叶树倒木上1,561份木腐真菌标本的采集信息, 统计了物种种类及其腐朽类型, 并选取具有代表性的地点开展木腐真菌群落多样性及其与环境因子的相关性分析。结果显示, 大小兴安岭针叶树倒木木腐真菌有166种, 隶属于70属, 其中白腐真菌有111种, 占所有种类的66.9%, 褐腐真菌为55种, 占所有种类的33.1%。在4类针叶树倒木上均能生长的真菌种类有19种, 占所有种类的11.5%, 其中柔丝干酪孔菌(Oligoporus sericeomollis)是各类倒木上木腐真菌群落中的优势种。大兴安岭地区落叶松属为优势寄主, 其倒木上生长的木腐真菌种类数和个体数在4类倒木中均为最高; 而小兴安岭地区松属倒木上木腐真菌种类数和个体数比其他3类倒木高, 是该地区的优势寄主。对6个代表性地区木腐真菌群落的研究显示, 有11种真菌在6个地区均有分布, 小兴安岭地区木腐真菌多样性普遍高于大兴安岭地区; 聚类分析显示树种比地理位置对木腐真菌物种分布的影响更大。     

丰林国家级自然保护区木腐真菌多样性与寄主倒木的关系

木腐真菌是一类以木材为生长基质的大型真菌, 通过分泌各种水解酶全部或部分降解木材中的木质素、纤维素和半纤维素, 促进森林生态系统的物质循环, 具有重要的生态功能。本研究调查了丰林国家级自然保护区固定样地中木腐真菌的多样性和倒木特征, 并进行了木腐真菌的物种多样性和数量与倒木的种类、数量、腐朽程度、直径大小等的相关性分析。结果显示: 在样地内共采集木腐真菌标本295份, 经鉴定为93种, Shannon多样性指数为3.86, Simpson指数为0.96。相关性分析发现木腐真菌的数量和种类与直径为2-5 cm和5-10 cm的倒木、2级腐烂的倒木和红松倒木均显著相关。样地中优势倒木寄主分别为槭属(Acer)、榛属(Corylus)、云杉属(Picea)和松属(Pinus), 这4类倒木上生长的木腐真菌种类组成具有明显的差异, 槭属和榛属倒木上的共有优势种主要是三色拟迷孔菌(Daedaleopsis tricolor)、云芝(Trametes versicolor)和桦附毛孔菌(Trichaptum pargamenum), 而松属和云杉属的共有优势种主要有白囊耙齿菌(Irpex lacteus)、云芝、冷杉附毛孔菌(Trichaptum abietinum)和褐紫附毛孔菌(T. fuscoviolaceum)。倒木产生真菌子实体的概率研究表明, 同一类寄主倒木上发生木腐真菌子实体的概率在调查面积增加到0.36 ha后趋于一个定值, 松属倒木中仅有10.2%产生真菌子实体, 槭属和云杉属分别是12.9%和13.4%, 榛属最高, 达到53.7%。本研究结果对于预测森林生态系统中木腐真菌的发生具有重要理论意义。     

林火干扰对森林生态系统土壤有机碳的影响研究进展

林火干扰是森林生态系统特殊而重要的生态因子,可改变生态系统的养分循环与能量传递。研究林火干扰对森林生态系统土壤有机碳的影响,有助于理解森林生态系统中土壤碳固持和碳循环过程,为制定科学合理的旨在减缓全球变化的林火管理策略具有重要意义。从4个方面阐述了林火干扰对森林生态系统土壤有机碳的影响及内在机制:分别从大尺度和小尺度两个方面阐述了林火干扰对土壤有机碳的影响及对森林生态系统碳循环与碳平衡的作用机制;探讨了不同林火干扰类型和林火干扰强度下,土壤活性有机碳对林火干扰的响应机制;阐明了林火干扰对土壤惰性有机碳的影响及作用机制;论述了林火干扰主要通过改变土壤有机碳的输入和输出过程进而影响土壤有机碳的稳定性及内在机制。最后提出了提高林火干扰对森林生态系统土壤有机碳影响定量化研究的4种路径选择:(1)全面比较研究不同林火干扰类型对土壤有机碳循环及其碳素再分配过程的功能特征;(2)进一步阐明林火干扰通过改变植被结构进而影响土壤生物群落结构,剖析土壤碳库循环的内在机制;(3)完善不同时空尺度下林火干扰对森林生态系统土壤碳库周转过程的定量化研究;(4)加强不同林火干扰类型土壤碳库稳定性差异的研究。     

森林生态系统碳氮循环功能耦合研究综述

在大气CO2浓度升高和氮沉降增加等全球变化背景下,森林生态系统减缓CO2浓度升高的作用及其对全球变化的响应和反馈存在诸多不确定性.森林生态系统碳氮循环相互作用及功能耦合规律的研究是揭示这些不确定性的基础,也是反映森林生态系统生物产量与养分之间作用规律,涉及林地持久生产力（sustainability of long-term site productivity）的生态学机理问题.森林生态系统碳氮循环的耦合作用表现在林冠层光合作用的碳固定过程,森林植物组织呼吸、土壤凋落物与土壤有机质分解、地下部分根系周转与呼吸等碳释放过程,这些过程存在反馈机理和非线性作用,最终决定森林生态系统的碳平衡.着重在生态系统尺度上,综述了碳氮循环耦合作用研究的一些进展与存在的问题,对今后研究方向进行了展望.     

Linking wood-decay fungal communities to decay rates: Using a long-term experimental manipulation of deadwood and canopy gaps

Decomposition transfers carbon (C) from detrital organic matter to soil and atmospheric pools. In forested ecosystems, deadwood accounts for a large proportion of the detrital C pool and is primarily decomposed by wood-inhabiting fungi (WIF). Deadwood reductions linked to forest harvesting may alter WIF richness and composition, thus indirectly influencing the persistence of deadwood and its contribution to C and nutrient cycling. Forest structure was enhanced via canopy gap creation and coarse woody debris (CWD) addition that mimic natural disturbance by windfall within a deciduous northern hardwood forest (Wisconsin, USA) to examine its effect on deadwood-associated biodiversity and function. Experimental sugar maple (Acer saccharum) logs were sampled, for DNA extraction, ten years after placement to determine the assembly of fungal community composition and its relationship to wood decay rates.Our findings suggest that the WIF community responded to gap disturbance by favoring species able to persist under more extreme microclimates caused by gaps. CWD addition under closed canopy tended to favor a different species assemblage from gap creation treatments and the control, where canopy was undisturbed and CWD was not added. This was presumably due to consistent microclimatic conditions and the abundance of CWD substrates for host specialists. Fungal OTU richness was significantly and inversely related to CWD decay rates, likely due to competition for resources. In contrast, fungal OTU composition was not significantly related to CWD decay rates, canopy openness or CWD addition amounts. Our study site represents a diverse fungal community in which complex interactions among wood-inhabiting organisms and abiotic factors are likely to slow CWD decomposition, which suggests that maintaining a biodiverse and microsite-rich ecosystem may enhance the capacity for C storage within temperate forests.     

The role of novel forest ecosystems in the conservation of wood‐inhabiting fungi in boreal broadleaved forests

The increasing human impact on the earth's biosphere is inflicting changes at all spatial scales. As well as deterioration and fragmentation of natural biological systems, these changes also led to other, unprecedented effects and emergence of novel habitats. In boreal zone, intensive forest management has negatively impacted a multitude of deadwood‐associated species. This is especially alarming given the important role wood‐inhabiting fungi have in the natural decay processes. In the boreal zone, natural broad‐leaved‐dominated, herb‐rich forests are threatened habitats which have high wood‐inhabiting fungal species richness. Fungal diversity in other broadleaved forest habitat types is poorly known. Traditional wood pastures and man‐made afforested fields are novel habitats that could potentially be important for wood‐inhabiting fungi. This study compares species richness and fungal community composition across the aforementioned habitat types, based on data collected for wood‐inhabiting fungi occupying all deadwood diameter fractions. Corticioid and polyporoid fungi were surveyed from 67 130 deadwood particles in four natural herb‐rich forests, four birch‐dominated wood pastures, and four birch‐dominated afforested field sites in central Finland. As predicted, natural herb‐rich forests were the most species‐rich habitat. However, afforested fields also had considerably higher overall species richness than wood pastures. Many rare or rarely collected species were detected in each forest type. Finally, fungal community composition showed some divergence not only among the different habitat types, but also among deadwood diameter fractions. Synthesis and applications: In order to maintain biodiversity at both local and regional scales, conserving threatened natural habitat types and managing traditional landscapes is essential. Man‐made secondary woody habitats could provide the necessary resources and serve as surrogate habitats for many broadleaved deadwood‐associated species, and thus complement the existing conservation network of natural forests.     

Increased CO<Subscript>2</Subscript> evolution caused by heat treatment in wood-decaying fungi

Wood-decaying fungi are regarded as the main decomposers of woody debris in boreal forests. Given that fungal respiration makes a significant contribution to terrestrial carbon flows, it is important to understand how the wood-decaying fungal metabolism is regulated in relation to different environmental conditions and disturbances. In the present study, we investigated the effect of temperature stress on wood decomposition rate in 18 species of wood-decaying fungi, representing a broad range of species–habitat associations. Heat shock duration and temperature were calibrated to match the conditions of a forest fire. We found a general increase in fungal decay rate after heat shock; the response was more pronounced in species associated with fire-prone forests. The underlying mechanism is unclear, but possibly relates to an up-regulation at the cellular level in response to heat shock. Our results show that the decomposition rate of dead wood can be strongly affected by environmental triggers.     

木材腐朽菌在森林生态系统中的功能

木材腐朽菌是森林生态系统的重要组成部分,在森林生态系统中起着极为重要的降解还原作用,主要包括担子菌门非褶菌目、子囊菌门盘菌纲和半知菌类的部分真菌,能全部或部分降解木材中的木质素、纤维素和半纤维素,其降解机制有3种：白色腐朽、褐色腐朽和软腐朽．木材腐朽菌与生态系统中其它生物关系密切,为很多昆虫、鸟类提供营养,有些昆虫也能使木腐菌得到传播．保护木材腐朽菌的生物多样性是保护森林生态系统、维护生态系统健康的重要因素．     

Wood decomposition is more strongly controlled by temperature than by tree species and decomposer diversity in highly species rich subtropical forests

While the number of studies on the role of biodiversity on ecosystem functioning is steadily increasing, a key component of biogeochemical cycling in forests, dead wood decay, has been largely neglected. It remains widely unknown whether and how dead wood decay is affected by diversity loss in forests. We studied the hierarchical effects of tree species diversity on wood decay rates in a subtropical forest landscape in southeast China via its influence on fungal OTU richness and invertebrate diversity using piecewise structural equation models. The experiment was conducted in natural forest plots that span a wide gradient of tree species diversity embedded in a heterogeneous topography. To account for interactions between macro‐invertebrates and fungi, that potentially modify the influence of tree biodiversity and climate on dead wood decay, we compared a macro‐invertebrate exclusion treatment with a control treatment that allowed access to all types of decomposers. Diversity effects of trees on wood decay rates were mostly negative and mediated by the diversity of macro‐invertebrates. However, the effects of tree species diversity or fungal OTU richness and macro‐invertebrate diversity on wood decay rates were comparatively weak. Temperature affected decay rates positively and had the strongest influence in all treatments. While the exclusion of macro‐invertebrates did not lead to a reduction of wood decay rates, our results suggest that they may however have a mediating role in the process. In the presence of invertebrates the predictability of wood decay rates was higher and we observed a tendency of a stronger temperature control. Our results suggest that there is evidence for diversity effects on wood decomposition, but the temperature control is still more important. Thus, an increase in mean annual temperature will increase carbon and nutrient turnover through wood decomposition in subtropical forest irrespective of biotic composition.     

Stand-replacing wildfires alter the community structure of wood-inhabiting fungi in southwestern ponderosa pine forests of the USA

Increases in stand-replacing wildfires in the western USA have widespread implications for ecosystem carbon (C) cycling, in part because the decomposition of trees killed by fire can be a long-term source of CO₂ to the atmosphere. Knowledge of the composition and function of decay fungi communities may be important to understanding how wildfire alters C cycles. We assessed the effects of stand-replacing wildfires on the community structure of wood-inhabiting fungi along a 32-yr wildfire chronosequence. Fire was associated with low species richness for up to 4 yr and altered species composition relative to unburned forest for the length of the chronosequence. A laboratory incubation demonstrated that species varied in their capacity to decompose wood; Hypocrea lixii, an indicator of the most recent burn, caused the lowest decomposition rate. Our results show that stand-replacing wildfires have long-term effects on fungal communities, which may have consequences for wood decomposition and C cycling.     

Tree species identity determines wood decomposition via microclimatic effects

Empirical evidence suggests that the rich set of ecosystem functions and nature's contributions to people provided by forests depends on tree diversity. Biodiversity–ecosystem functioning research revealed that not only species richness per se but also other facets of tree diversity, such as tree identity, have to be considered to understand the underlying mechanisms. One important ecosystem function in forests is the decomposition of deadwood that plays a vital role in carbon and nutrient cycling and is assumed to be determined by above‐ and belowground interactions. However, the actual influence of tree diversity on wood decay in forests remains inconclusive. Recent studies suggest an important role of microclimate and advocate a systematical consideration of small‐scale environmental conditions. We studied the influence of tree species richness, tree species identity, and microclimatic conditions on wood decomposition in a 12‐year‐old tree diversity experiment in Germany, containing six native species within a tree species richness gradient. We assessed wood mass loss, soil microbial properties, and soil surface temperature in high temporal resolution. Our study shows a significant influence of tree species identity on all three variables. The presence of Scots pine strongly increased wood mass loss, while the presence of Norway spruce decreased it. This could be attributed to structural differences in the litter layer that were modifying the capability of plots to hold the soil surface temperature at night, consequently leading to enhanced decomposition rates in plots with higher nighttime surface temperatures. Therefore, our study confirmed the critical role of microclimate for wood decomposition in forests and showed that soil microbial properties alone were not sufficient to predict wood decay. We conclude that tree diversity effects on ecosystem functions may include different biodiversity facets, such as tree identity, tree traits, and functional and structural diversity, in influencing the abiotic and biotic soil properties.     

古田山国家级自然保护区木腐真菌物种多样性及分布

木腐真菌是微生物的一个重要类群, 主要以倒木为生长基质, 通过产生各种水解酶将倒木的纤维素、木质素和半纤维素分解为小分子物质, 对促进森林生态系统中的营养物质循环发挥着重要的生态功能。于2016年8月在浙江古田山国家级自然保护区开展的木腐真菌野外调查, 利用形态学和DNA序列分析对采集的标本进行了物种鉴定, 并分析了木腐真菌的物种组成和地理成分。在采集的158份标本中鉴定木腐真菌45属92种, 其中白腐真菌78种, 褐腐真菌14种。古田山的木腐真菌物种区系组成中, 热带-亚热带成分比例最高。在158份木腐真菌标本中, 97份标本采自直径大于10 cm的倒木或树桩上, 分属于76个种, 是木腐真菌生长的主要基质大小类型; 48份标本采自直径为2-10 cm的枝干上, 分属38个种; 13份标本采自直径小于2 cm的枝干上, 分属12种。不同腐烂等级倒木上生长的真菌数量和种类差异明显, 其中一级腐烂倒木上采集到9份标本(7种), 二级腐烂倒木上采集到86份标本(45种), 三级腐烂倒木上49份标本(29种), 四级腐烂倒木上14份标本(14种)。结果表明, 林分中倒木直径大小和腐烂程度是影响木腐真菌生长与分布的重要因子。     

Linking taxonomical and functional biodiversity of saproxylic fungi and beetles in broad‐leaved forests in southern Italy with varying management histories

Abstract

The fundamental ecological significance of deadwood decomposition in forests has been highlighted in several reviews, some conclusions regarding silviculture being drawn. Old‐growth forests are natural centres of biodiversity. Saproxylic fungi and beetles, which are vital components of these ecosystems, occupy a variety of spatial and trophic niches. Fungal and beetle diversity on coarse woody debris (CWD) was analysed in 36 forest sites in the Cilento and Vallo di Diano National Park, Italy. The data were analysed by DCA and Spearman’s rank correlation. The results provide empirical evidence of the existence of a pattern of joint colonization of the woody substrate by fungi and beetles, which includes an assemblage of reciprocal trophic roles within fungal/beetle communities. These organisms act together to form a dynamic taxonomical and functional ecosystem component within the complex set of processes involved in wood decay. The variables most predictive of correlations between management‐related structural attributes and fungal/beetle species richness and their trophic roles for old‐growth forest are: number of logs, number of decay classes and CWD total volume. Deadwood spatio‐temporal continuity should be the main objective of forest planning to stop the loss of saproxylic fungal and insect biodiversity.