50年来山东塔山植被与物种多样性的变化

为分析塔山植被与物种多样性50a自然演替和动态变化,2009-2010年,采用系统勘踏法和典型取样法进行了调查。当前塔山主要植被类型为"黑松林-赤松林-栓皮栎林"。50a间,该区针叶林从黑松(Pinus thunbergii)林演替为黑松林、赤松(P. densiflora)林和油松林(P. tabulaeformis)为主的混合针叶林,但针叶林的整体优势度下降,以栓皮栎(Quercus variabilis)和麻栎(Q. acutissima)为建群种的阔叶林面积明显增大,由针叶林向阔叶林的演替趋势明朗。物种丰富度为草本层>灌木层>乔木层,Shannon-wiener指数和Simpson指数为灌木层>草本层>乔木层,物种多样性较低,处于森林演替初期。     

海南岛热带森林植被的类群及其特征

对海南岛热带森林植被的历史变迁进行了回顾。讨论了海南岛热带森林植被类型的分类单位与等级 ,提出了海南岛热带森林的植被分类系统 ,海南岛热带森林植被可分为 2个植被型组 ,7个植被型 ,4个植被亚型 ,35个群系 ,2 1个亚群系 ,1 0 9个群丛组或群丛 ;并对代表类群进行了描述     

表征亚热带常绿林光合作用季节变化特征的多种植被指数

利用遥感方法可以在区域尺度反演地表植被的光合生理状况和生产力变化,但亚热带常绿林冠层结构季节变化较小,传统的光谱植被指数对植被光合作用难以准确捕捉。利用2014—2015年中国科学院广东省鼎湖山森林生态试验站多角度自动光谱观测系统的光谱反射数据,分别反演传统冠层结构型植被指数(NDVI)、光合生理生化型植被指数(CCI)和叶绿素荧光型植被指数(NDFI_(685)和NDFI_(760)),并利用不同类型植被指数的组合,构建多元线性回归模型。结果表明:亚热带常绿针阔混交林三种类型植被指数均与GPP的动态变化有显著的相关性,其中,NDVI是表征GPP较优的植被指数(R~2=0.60,P0.01),其次为CCI(R~2=0.55,P0.01),而NDFI能够作为辅助指数,有效提高NDVI(R~2=0.68,P0.001)和CCI(R~2=0.67,P0.001)表征GPP的程度。多个植被指数参与构建的多元回归模型能够有效提高亚热带地区常绿林GPP季节动态变化的拟合精度,提升遥感精确评估亚热带森林生产力的能力。     

上海城市近自然森林的重建动态

近自然森林作为城市植被恢复的重要模式,已在我国多地开展了实践,并衍生了新的造林模式。为评估不同近自然森林建设模式的群落恢复进程,本研究以上海城市裸地上重建的近自然森林为对象,通过长期监测两处分别应用原"宫胁法"与新"异龄复层落叶—常绿混交林"种植模式的近自然森林重建过程,从物种组成、垂直结构、生活型组成和目标恢复物种4个方面解析恢复动态。结果表明:两种造林模式恢复的近自然森林,随恢复进程其物种组成逐渐趋同,在十多年内已形成了落叶—常绿垂直混交结构;"异龄复层落叶—常绿混交林"造林模式可更好地促进常绿阔叶树种的恢复,尤其是常绿建群种红楠与小叶青冈。本研究证实了近自然森林恢复技术可以缩短亚热森林群落向演替后期发展的时间,以及新造林模式的有效性,为近自然森林技术的应用与实施提供了科学依据。     

基于遥感技术的森林健康研究综述

遥感技术可以有效完成复杂时空尺度海量信息的收集处理,其与森林健康研究的交叉、融合大大提高了复杂时空尺度上森林健康研究的表达能力.目前,森林健康遥感研究正处于各学科交叉、融合、调整,由静态向动态、单一向复杂、零散向系统转变的关键发展时期,但缺乏对森林健康问题的全面考量、逻辑安排和系统的顶层设计.在把握森林健康活力、组织结构和恢复力核心理念的基础上,从森林资源调查、森林生态功能评估、森林健康风险控制和森林植被参数提取四个方面构建和丰富基于遥感技术森林健康研究体系,对国内外森林健康遥感研究进行综述.通过对以上研究内容的总结分析,明确基于遥感技术的森林健康研究各领域的研究进展,及其在理论、技术和应用方面的不足.分析认为:(1)未来应加强森林生态和遥感技术重大基础理论研究,以明确森林结构、过程、功能与遥感数据之间的耦合关系;(2)发展完善新型遥感技术、遥感数据解译算法与软件工具,提高遥感数据的精确度、利用率和利用效率;(3)提升森林健康遥感研究成果的科技转化水平,推进快速分析评价与辅助决策功能研究,指导相关森林健康经营活动和科学研究的开展,以及林业政策的制定.     

Mineral cycling in a tropical palm forest

Nutrient cycling and biomass characteristics of a tropical palm forest dominated byOrbignya cohune were found to be different from thsoe of hardwood dominated forests. The cohune palm forest had a high proportion of biomass in leaves (5%), a reduced sapling layer, a large amount of standing forest litter and an exceptionally low decomposition rate factor (0.1 year^–1). Mineral concentrations in palm leaves were generally lower than in hardwood species with the exception of Na, which was exceptionally high inOrbignya cohune. Biomass was estimated at 226 tons ha^–1 containing 1173 kg ha^–1 N; 126 kg ha^–1 P; 437 kg ha^–1 K; 1869 kg ha^–1 Mg; 125 kg ha^–1 Ca, and 2177 kg ha^–1 Na. Soils of cohune association did not differ significantly from those of neighbouring hardwood dominated associations with the exception of Na which occurred in higher concentration because of bioaccumulation in the dominant. The results suggest that the growth habits and physiology of a dominant can strongly influence some of the ecological parameters used to describe aforest association.     

Dark septate endophyte and arbuscular mycorrhizal status of vegetation colonizing a bottomland hardwood forest after a 100 year flood

Levels of arbuscular mycorrhizal (AM) colonization and dark septate endophyte (DSE) colonization were assessed in the vegetation recolonizing a remnant bottomland hardwood forest in north central Texas following a 100 year flood. Thirty seven plant species representing 21 dicotyledonous and 2 montocotyledonous families established following floodwater recession. AM and/or DSE were found in all species. AM colonization was found in 31 out of the 37 species assessed including both monocotyledonous families (Poaceae and Cyperaceae) and 17 out of 21 dicotyledonous families (Acanthaceae, Asteraceae, Boraginaceae, Cucurbitaceae, Euphorbiaceae, Lamiaceae, Loganiaceae, Lythraceae, Malvaceae, Onagraceae, Pedaliaceae, Ranunculaceae, Sapindaceae, Scrophulariaceae, Solanaceae, Verbanaceae and Violaceae). DSE were found in 31 out of 37 species assessed including both monocotyledonous families and 15 out of 21 dicotyledonous families (Amaranthaceae, Asteraceae, Boraginaceae, Brassicaceae, Cucurbitaceae, Euphorbiaceae, Lamiaceae, Lythraceae, Malvaceae, Pedaliaceae, Phytolaccaceae, Polygonaceae, Ranunculaceae, Sapindaceae, Scrophulariaceae and Violaceae). There were no detectable differences in AM or DSE colonization levels among wetland indicator groups (p > 0.05). Levels of DSE colonization were negatively correlated with vesicular colonization and hyphal colonization for the obligate wetland species. There were no other significant relationships between AM and DSE colonization detected. Spearman rank order correlation coefficients did not differ significantly among wetland indicatory category for any level of AM or DSE colonization.     

基于随机森林回归的草场植被盖度反演模型研究——以新疆阿勒泰地区布尔津县为例

作为草地资源大国,我国正面临严峻的草场退化形势。掌握草场植被盖度的历史演变趋势,是草场退化驱动力识别及风险评估的基础。目前已有研究多以参数回归方法估算植被盖度,但并未充分考虑其苛刻的使用条件。利用Landsat系列卫星遥感影像及地面植被盖度监测资料建立非参数回归——随机森林回归模型,并与传统线性回归方法进行比较,在此基础上应用随机森林回归模型估算近10年来布尔津县草场植被盖度的变化趋势,并对结果的不确定性进行分析。结果显示:传统的线性回归方法很难满足其基本的统计学假设条件,而随机森林模型不但无需进行假设条件检验,而且预测的准确性也优于以往普遍应用的线性模型。基于Landsat ETM+标准数据得到的反演结果较之TM和OLI数据普遍偏小,地表反射率数据虽然可以大幅降低传感器不同对反演结果所造成的影响,但结果仍存在约±10%的不确定性。涉及的草场类型众多,为了提高反演精度,后续研究需要分别计算其植被指数,并尽量减低传感器差异带来的不确定性。     

Strategic light manipulation as a restoration strategy to reduce alien grasses and encourage native regeneration in Hawaiian mesic forests

Question: Is there a light level at which alien grass biomass is reduced while still supporting growth and survival of native woody species, allowing for native species regeneration in abandoned pastures? Location: Island of Hawaii, USA. Methods: In a two‐part study we examined the effect of light availability on common native woody and alien grass species found in secondary forests in Hawaii. A field survey was conducted to examine the relationship between light availability and canopy type (open pasture, planted canopy and secondary forest) on understory grass biomass and litter accumulation. We then experimentally manipulated light levels to determine the effect of light availability on growth and survival of six native woody species and three alien grasses. Low‐light (5%), medium‐light (10%) and high‐light (20‐30%) treatments were created using shade structures erected beneath the existing secondary koa canopy. Results: In the field survey, alien grass biomass was greatest under the open pasture and lowest in the secondary forest. There was a positive correlation between understory light availability and alien grass biomass. In the experimental study, large reductions in relative growth rates were documented for all of the grass species and four of the six woody species under the lowest light level. Although growth at 5% light is substantially reduced, survival is still high (84‐100%), indicating that these species may persist under closed canopy. Conclusion: Low‐light conditions result in the greatest reduction in alien grass biomass while creating an environment in which native woody species can grow and survive.     

Tree and Liana Enumeration and Diversity on a One-Hectare Plot in Papua New Guinea1

Enumeration of a one hectare plot at 900 m a.s.l in Papua New Guinea revealed 693 individuals of 228 tree and liana species ≥ 10 cm DBH. A 0.1 hectare subplot contained 302 individuals of 106 species 2.5 ≥ DBH < 10 cm. Lauraceae, Moraceae, and Myristicaceae were the most important families in both size classes. This site is very diverse compared with other tropical forests, and like other species-rich sites worldwide, it has high aseasonal rainfall and high rates of natural disturbance.     

Climate change-driven forest fires marginalize the impact of ice cap wasting on Kilimanjaro

The disappearing glaciers of Kilimanjaro are attracting broad interest. Less conspicuous but ecologically far more significant is the associated increase of frequency and intensity of fires on the slopes of Kilimanjaro, which leads to a downward shift of the upper forest line by several hundred meters as a result of a drier (warmer) climate since the last century. In contrast to common belief, global warming does not necessarily cause upward migration of plants and animals. Here, it is shown that on Kilimanjaro the opposite trend is under way, with consequences more harmful than those due to the loss of the showy ice cap of Africa's highest mountain.     

Topographical pattern of the forest vegetation on a river basin in a warm-temperate hilly region,central Japan

The relationship between tree distribution and topography was examined in a small river basin (3.4 ha) comprising a complex mosaic of topographical units at 10² to 10³ m² order, each of which had a shallow valley bordered by small ridges or breaks of slopes. Twenty-five major woody species were divided into two groups (groups A and B) based on a cluster analysis using the distribution data in the basin. Group A, which mainly consisted of early-successional species, was distributed around the valley sites of the topographical units, while group B, which mainly consisted of late-successional species, was distributed around the ridge sites of the topographical units. This vegetation pattern coincided with erosional condition in the basin. That is, the valley sites were eroded more actively than the ridge sites, as soil depth tended to be thin in the valley sites and thick in the ridge sites, and because large (canopy) trees were restricted in the ridge sites. There was no tendency that group B was replacing group A, and hence it was suggested that repeated disturbance by slope failures or small-scale shallow landslides have prevented compositional change from the early-successional (group A) to the late-successional (group B) species by preventing the invasion of the latter into valley sites.     

江苏森林自然保护区植被基本特征及其生态学意义

江苏地少人多,历来是我国政治、经济、文化发达的地区。人为因素对自然植被的影响严重。南北过渡的气候条件孕育了三个不同的生物气候带的森林植被类型,在不同生物气候带内建立相应有代表性的森林自然保护区,无论在理论上或生产实际上都有很大的意义。一、自然条件特点及森林自然保护区的布局(一) 自然条件特点江苏位于北纬30°46′—35°02′,东经116°22′—121°55′。全省地势平坦,平原占85%,岗地占10%,低山丘陵占5%,大多     

林火迹地森林恢复研究进展

火灾对森林造成不同程度的破坏,火后如何恢复森林是人们面临的关键问题,为了掌握火灾后迹地的变化及演替规律,使森林生态系统向良性发展,国内外专家对此作了大量的研究。本文就国内外的研究进行综述与比较,为完善该领域的研究提出相应的对策,对未来的发展趋势加以展望。     

A forest typology for monitoring sustainable forest management: The case of European Forest Types

Abstract

Sustainable forest management (SFM) is presently widely accepted as the overriding objective for forest policy and practice. Regional processes are in progress all over the world to develop and implement criteria and indicators of SFM. In continental Europe, a set of 35 Pan-European indicators has been endorsed under the Ministerial Conference on the Protection of Forests in Europe (MCPFE) to measure progress towards SFM in the 44 countries of the region. The formulation of seven indicators (forest area, growing stock, age structure/diameter distribution, deadwood, tree species composition, damaging agents, naturalness) requires national data to be reported by forest types. Within the vast European forest area the values taken by these indicators show a considerable range of variation, due to variable natural conditions and anthropogenic influences. Given this variability, it is very difficult to grasp the meaning of these indicators when taken out of their ecological background. The paper discusses the concepts behind, and the requirements of, a classification more soundly ecologically framed and suitable for MCPFE reporting than the three (un-informative) classes adopted so far: broadleaved forest, coniferous forest, mixed broadleaved and coniferous forest. We propose a European Forest Types scheme structured into a reasonably higher number of classes, that would improve the specificity of the indicators reported under the MCPFE process and its understanding.     

越南红河流域区不同沉积环境的植被分布

根据中日越三方合作对越南红河流域周边/沿岸植被、生境、土壤和地貌特征等进行的野外踏勘和调查结果,结合前人研究成果,以红河汇水盆地沉积物中植物碎屑及相关微体的潜在源区为出发点,从地形地貌学的角度,阐述了越南红河流域周边植被的组合分布规律。结果表明:(Ⅰ)上游番西邦山区河谷体系:植被垂直分分带明显,海拔由低到高依次分布有热带雨林、季雨林、亚热带常绿阔叶林、山地苔藓林、温带阔叶林、针阔叶混交林、高山灌丛和草地8类植被;(Ⅱ)河床河漫滩堤岸的河流体系:水生植物及沼泽植物—草地、低矮灌丛—热带树种;(Ⅲ)三角洲平原—沿海滩涂体系:沼泽森林—红树林。另外,原始植被经自然火灾或人类种植火烧后形成独特的次生植被类型主要为竹林、松林、草地等。     

Observations and modeling of aboveground tree carbon stocks and fluxes following a bark beetle outbreak in the western United States

Bark beetle epidemics result in tree mortality across millions of hectares in North America. However, few studies have quantified impacts on carbon (C) cycling. In this study, we quantified the immediate response and subsequent trajectories of stand‐level aboveground tree C stocks and fluxes using field measurements and modeling for a location in central Idaho, USA that experienced an outbreak of mountain pine beetle (Dendroctonus ponderosae Hopkins). We measured tree characteristics in lodgepole pine (Pinus contorta) plots spanning a range of structure and mortality conditions. We then initialized the forest vegetation simulator, an individual tree‐based model, with these measurements and simulated the response of aboveground production of C fluxes as well as trajectories of C stocks and fluxes in the coming decades. Mountain pine beetles killed up to 52% of the trees within plots, with more larger trees killed. C stocks in lodgepole pine were reduced by 31–83% following the outbreak, and plot‐level C fluxes decreased 28–73%. Modeled C stocks increased nearly continuously following the infestation, recovering to preoutbreak levels in 25 years or less. Simulated aboveground tree C fluxes increased following the immediate postoutbreak decrease, then subsequently declined. Substantial variability of C stocks and fluxes among plots resulted from the number and size of killed and surviving trees. Our study illustrates that bark beetle epidemics alter forest C cycling unlike stand‐replacement wildfires or clear‐cut harvests, due in part to incomplete mortality coupled with the preference by beetles for larger trees. The dependency of postoutbreak C stocks and fluxes on stand structure suggests that C budget models and studies in areas experiencing mountain pine beetle disturbances need to include size distribution of trees for the most accurate results.     

Land use change emission scenarios: anticipating a forest transition process in the Brazilian Amazon

Following an intense occupation process that was initiated in the 1960s, deforestation rates in the Brazilian Amazon have decreased significantly since 2004, stabilizing around 6000 km² yr^?1 in the last 5 years. A convergence of conditions contributed to this, including the creation of protected areas, the use of effective monitoring systems, and credit restriction mechanisms. Nevertheless, other threats remain, including the rapidly expanding global markets for agricultural commodities, large‐scale transportation and energy infrastructure projects, and weak institutions. We propose three updated qualitative and quantitative land‐use scenarios for the Brazilian Amazon, including a normative ‘Sustainability’ scenario in which we envision major socio‐economic, institutional, and environmental achievements in the region. We developed an innovative spatially explicit modelling approach capable of representing alternative pathways of the clear‐cut deforestation, secondary vegetation dynamics, and the old‐growth forest degradation. We use the computational models to estimate net deforestation‐driven carbon emissions for the different scenarios. The region would become a sink of carbon after 2020 in a scenario of residual deforestation (~1000 km² yr^?1) and a change in the current dynamics of the secondary vegetation – in a forest transition scenario. However, our results also show that the continuation of the current situation of relatively low deforestation rates and short life cycle of the secondary vegetation would maintain the region as a source of CO₂ – even if a large portion of the deforested area is covered by secondary vegetation. In relation to the old‐growth forest degradation process, we estimated average gross emission corresponding to 47% of the clear‐cut deforestation from 2007 to 2013 (using the DEGRAD system data), although the aggregate effects of the postdisturbance regeneration can partially offset these emissions. Both processes (secondary vegetation and forest degradation) need to be better understood as they potentially will play a decisive role in the future regional carbon balance.