大亚湾大型底栖动物生产力变化特征

利用1988年1月、7月和2004年3月、5月、9月、12月在大亚湾海域开展的7个航次63个站次的大型底栖动物调查数据,通过Brey经验公式对两个时段的大型底栖动物生产力和P/B值的变化特征进行研究.结果表明: 目前该海域大型底栖动物年生产力为10.22 g AFDM ·m^-2 ,平均P/B值为0.85·a^-1,在我国各海域中处于中上水平.两个指标的数值均高于1988年的7.25 g AFDM ·m^-2·a^-1和0.76·a^-1,印证了大亚湾高输出系统是依赖快速周转来维持系统的高生产力的结论;大亚湾大型底栖动物4个主要类群的生产力和P/B值变化存在较大差异;湾内生产力的平面分布也发生了较大变化,生产力和P/B值的区域差异与人类活动影响密切相关, 生产力变化最显著的区域内人类活动影响显著.     

The effects of forest fragmentation on species richness on the Obudu Plateau,south‐eastern Nigeria

This study examines how fragmentation through changes in patch size and increasing distances between forest patches affects bird species richness. Numbers of bird species were higher in large forest patches and decrease with decreasing patch size. Bird species richness also decreased with increased isolation of forest patches. Suitable trees should be planted in the gaps between the forests that will create wildlife corridors to maintain connectivity.     

邻体竞争对城市森林微景观中针叶树视觉形态性状的影响

树木视觉形态性状是城市绿地微景观美学质量的重要影响因素之一,树木视觉形态性状的变化与其周围邻体木的竞争作用息息相关,但邻体竞争对树木视觉性状的作用机制尚不明确。研究于2022年8-10月对北京市城市公园中常见的针叶树种白皮松、侧柏、油松、圆柏展开调查,从树冠形态、干冠协调、树干形态3个方面构建了9个树木视觉形态性状指标,采用3个不同的竞争指标分析邻体竞争对针叶树种视觉形态性状的影响。结果表明,针叶树的树冠形态对邻体竞争的响应比较敏感,竞争中的白皮松、侧柏、油松、圆柏偏冠指数与孤立木相比分别提高了16.95%、28.95%、22.76%、17.67%;树冠缺失率分别提高了3.92%、6.09%、4.87%、4.95%。与孤立木相比,部分针叶树种高径比、分枝角变异度在多侧竞争环境中显著提高,而树冠舒展度则显著降低。邻体竞争强度越大,针叶树树冠的偏移与缺失程度越大。当针叶树受到强烈的侧方竞争时,对象木树冠和树干的径向生长显著受阻,表现为树冠舒展度大幅度下降、高径比显著提高,使树冠向细高方向发展。当针叶树上方的生长空间被占据时,其轴向生长同样受到严重阻碍,树木的冠径比和高径比维持较稳定状态。总体而言,四种针叶树种在视觉形态上对竞争胁迫的响应具有一定差异性,其中油松最为敏感,圆柏次之。综上,在城市森林微景观中,邻体竞争会导致针叶树种的树冠及树形发生明显变化,这种变化主要受综合资源竞争的影响,与其周围潜在生长空间的大小及对称性有关。在城市森林景观营建时,建议将针叶树栽植在对称的竞争环境中,但是其邻体木不宜过高,通过四周邻体木的适度竞争,能够促进针叶树的轴向生长,同时降低树冠偏移或变形的风险,提高其视觉美学效果。     

森林所有制对景观格局和动物生境的影响研究进展

在欧美等地区的林业发达国家,多种森林所有制长期并存,至今,多种所有制影响下森林景观和生境格局的变化以及与动物保护之间的关系成为研究热点和重点.本文首先阐述了森林所有制对森林景观格局和动物生境的影响,以及林权分散和林权流转的加剧带来的生态后果,包括提供多样化的生境和导致原有大面积生境的破碎化;其次,总结了林业发达国家解决林权分散与生物保护之间矛盾的两个理论途径--改变所有制格局和相对统一各所有制的管理行为,分析现多采用后一种途径的原因,并指出目前森林所有制研究中模拟方法的局限;最后,论述我国的研究现状以及面临的机遇和挑战,提出近期发展建议.     

森林风景功能的计量评价

采用被视频度、林型权重、被视可能性 ,对富阳市富春江两岸风景森林进行计量评价 ,为两岸风景防护林的配置、管理提供正确的决策。通过地形及土地利用图、数值地形模型和视线入射角来确定景观的被视频度 ;引进人口重力模型来表示森林的被视可能性 ;采取一对一比较法判断林型权重 ;利用 Thurstone的比较判断矩阵得到各景观的评价值。通过使用林型权重 ,可判断景区森林布局的合理性 ,而评价值 (Li)的高低可作为森林景观是否需要改造的标志值。研究表明 ,景观的评价值 (Li)受被视可能性 (Gi)和林型权重 (Vi)的影响。景观评价值最高的为杨树苏柳银芽柳条带状混交林、杨树香椿枫香复层林两种木森林类型 ,其次为杨树河柳林带、杨柳枫杨桤木香樟块状混交林、桤木纯林、杨树纸浆林、柳树纸浆林、街道公园绿化带、枫杨纯林、桑树。森林是以小班为单位经营管理的 ,植被、林龄等在同一小班内基本一致 ,森林风景管理也至少要求对每个小班进行评价 ,因此 ,研究时网格大小起码在小班内含有几个网格 ,最适大小为 5 0 m× 5 0 m。     

The effects of forest clear-cutting and scarification on the water quality of small brooks

The Nurmes-study has monitored water quality and hydrology of brooks in six basins since 1978. All brooks were investigated in their untreated state for five years and two basins throughout the whole study period. The first stage of clear-cutting and forestry drainage was carried out in 1983, followed by scarification (forest ploughing, hummocking and drainage) in the clear-cut areas in 1986. These standard forestry practices were carried out in two of the basins (Murtopuro and Kivipuro) while the third (Liuhapuro) remained untouched.The brooks are naturally acid (pH 4.1–6.3) with low temperature (max. 13.5 °C) and conductivity. High amounts of organic matter and iron are typical, as well as a low average concentration of suspended solids.The reduction of the tree cover caused a significant increase in water temperature. The clear-cutting and subsequent scarification increased the phosphorus (P_tot, PO₄-P), nitrogen (N_tot, NO₃-N, NH₄-N) and iron (Fe) concentrations. The most harmful effects were the noticeable increase in suspended solids, the 3-year mean being 83 tn km^–2 a^–1, over 200 × that during the pretreatment period (0.4 tn km^–2 a^–1). After scarification the amounts of dissolved organic matter were diminished. A protective zone along the brook clearly reduced the impacts of clear-cutting and scarification.     

天然阔叶林景观质量评价及其垂直结构优化技术

以江西省婺源县天然阔叶林近景景观为对象,收集了30个有代表性的近景景观图片和相关资料,采用大众评判法获得美景度值,运用多元数量化模型Ⅰ建立美景度与景观要素的关系模型．结果表明：树干形态、林木密度、林下层总盖度、林下层高度、自然整枝和色彩丰富度是影响天然阔叶林近景景观质量的主要要素,其偏相关系数在0．4482～0．7724之间,t检验结果为极显著或显著;复相关系数达0．9508,F检验结果为极显著（F=36．11^＊＊）．分析表明,树干通直、自然整枝良好、色彩富于变化有利于提高景观的美景度,而林木密度、林下层总盖度和林下层高度过高或过低（矮）均会给景观美学质量带来负面影响．针对这些景观要素特征提出了天然阔叶林景观垂直结构优化的相应经营措施．     

基于LANDIS-II的陕西黄龙山森林景观演变动态模拟

应用空间直观景观模型LANDIS-II模拟了陕西黄龙山森林景观在不考虑风、火、病虫害及采伐等干扰因素前提下300a(2004—2304年)的自然演替进行动态,采用景观格局统计软件APACK计算了林区内优势树种所占的面积百分比以及反映物种分布格局的聚集度指数,分析了各个树种在模拟的时间尺度上龄级组成的变化趋势。结果表明:油松是针叶树中的优势种,辽东栎是阔叶树中的优势种;在演替后期油松取代辽东栎成为所占面积比例最大的优势树种;油松和辽东栎的相对聚集度较其它几类树种小;随着模拟年代的推进,树种年龄结构发生显著变化,呈现出复杂多样的异龄林空间分布格局。     

Not seeing the ocean for the islands: the mediating influence of matrix-based processes on forest fragmentation effects

The pervasive influence of island biogeography theory on forest fragmentation research has often led to a misleading conceptualization of landscapes as areas of forest/habitat and 'non-forest/non-habitat' and an overriding focus on processes within forest remnants at the expense of research in the human-modified matrix. The matrix, however, may be neither uniformly unsuitable as habitat nor serve as a fully–absorbing barrier to the dispersal of forest taxa. In this paper, we present a conceptual model that addresses how forest habitat loss and fragmentation affect biodiversity through reduction of the resource base, subdivision of populations, alterations of species interactions and disturbance regimes, modifications of microclimate and increases in the presence of invasive species and human pressures on remnants. While we acknowledge the importance of changes associated with the forest remnants themselves (e.g. decreased forest area and increased isolation of forest patches), we stress that the extent, intensity and permanence of alterations to the matrix will have an overriding influence on area and isolation effects and emphasize the potential roles of the matrix as not only a barrier but also as habitat, source and conduit. Our intention is to argue for shifting the examination of forest fragmentation effects away from a patch-based perspective focused on factors such as patch area and distance metrics to a landscape mosaic perspective that recognizes the importance of gradients in habitat conditions.     

秦岭火地塘森林生态系统不同层次的水质效应

根据降水与森林生态系统相互作用的空间顺序,分别对火地塘林区火地沟流域大气降水、林内雨、枯透水、支沟溪流水和流域出口径流水质进行了比较分析和变化机理分析。结果表明：森林生态系统不同层次均有使微酸性降水pH值升高的作用,但以林冠层和森林土壤的作用最大,升幅分别为0．58和0．61;森林生态系统对NO3^-、NH4^＋、K、PO4^3均有净化作用,净化NO3^-的关键阶段为沟道径流阶段,净化NH4^＋、K、PO4^3的主要方式则为土壤吸附;森林生态系统各层次均增加Ca含量,除土壤外,也增加Mg,但Ca主要来源于土壤和岩石,Mg主要来源于岩石;降水中的Cd、Pb、Mn、Zn经过森林生态系统不同层次的阻减,含量分别降低了0．721μg·L^-1、6．528μg·L^-1、0．0128mg·L^-1和1．4674mg·L^-1,其中以林冠层的阻减作用最大,阻减效果分别为83％、76．7％、54％和99％。总体上,林冠层是净化水质的关键层次,其次为森林土壤。     

基于景观镶嵌度指数的森林破碎化模式动态——以美国俄勒冈州为例

有效的景观模式特征评价及其变动预测是合理调控和管理森林景观、维持景观安全格局的基本前提.利用3期美国国家土地覆盖数据库(1992、2001和2006年),采用景观镶嵌度指数与马尔科夫模型相结合的方法,分析了美国俄勒冈州的森林破碎化模式及森林与其他土地利用类型空间交互特征的变化.结果表明: 景观镶嵌度模型中,开发主导的景观镶嵌类型(D)转变为单一的开发类型(DD)的概率最大,为0.319,说明城市化是推动区域景观格局变化的主要动力;森林安全度模型中,主要为农业和开发景观镶嵌类型(ad)的森林损失率最高,表明在城市与农业占主导的景观上森林被吞噬的可能性最大;稳态分布表明,森林破碎化趋势日益加剧,到稳定状态时森林占总区域的面积比例不到50%,空间分布趋向于混合型的景观格局.景观镶嵌度模型2006年模拟值与实际值Kappa系数达到0.82,模型精度较高;森林安全度模型Kappa系数为0.21,模型精度较差.     

黑龙江林口林业局森林景观格局特征

以黑龙江林口林业局1∶50000林相图作为基本信息源,利用地理信息系统软件ArcView和景观结构分析软件Fragstats,从景观格局的总体特征、景观破碎度、景观形状指数、分形维数和平均最近距离等方面,对该林业局的景观格局进行了分析.结果表明:该林业局以森林景观为主体(56.74%),居民点和农田景观也占有较高比例,而沼泽、灌木、荒山荒地、河流、迹地和裸地等景观零星分布于森林景观中;该林业局的森林景观主要以人工针叶纯林(40.47%)和天然蒙古栎林(20.96%)为主,斑块分布集中、形状复杂、边缘褶皱度高.人工林与天然林的面积基本相等,但破碎度较大、斑块形状相对简单、斑块分布较集中,软阔叶林及硬阔叶林斑块分别占11.89%和7.38%.研究表明,该林业局的森林景观受人为干扰程度过大,景观结构不合理,要实现林业的可持续发展,必须对景观斑块结构进行调整.     

长白山森林景观破碎的遥感探测

天然林数量的减少以及质量的降低对中国的生态环境和经济发展产生不利影响。虽然林地的破碎对各种自然灾害起到关键性作用,林地是如何被破碎的尚不十分清楚。应用卫星遥感技术,以及地理信息系统和空间分析手段研究中国东北－原始的针阔混交林的破碎过程。结果表明,本来完整的原始森林,已经被一种“复叶”状小面积皆伐作业分割为零碎的斑真。采伐地的面积平均为15hm^2, 但随着采伐的继续、采伐地段连为一体,增大了采伐迹地的面积,从而保留的林地面积越来越小。采伐地点的选择没有考虑物种和环境的保护,林地破碎的特征是保留林地面积的缩小,中、小林地数量的增加,林地斑块形状的改变,以及林缘长度的增加。最后就保护东北森林植被完整性的角度提出林业政策与森林经营的改进意见。     

森林火旋风研究进展

火旋风是林火蔓延过程中的特殊火行为现象,与树冠火和飞火关系密切.火旋风的发生机理在于旋转涡的生成和发展.构建室内火旋风模拟发生装置是当前火旋风研究的常用方法.在室内模拟试验中,红外热像和热电偶可用于测量火焰温度,高速摄影、三维激光多普勒和皮托管用于测量火旋风的转速.基于室内实验数据,可构建模拟火旋风发生发展的三维模型.     

地形因子对森林景观格局多尺度效应分析

以TM影像和野外调查为数据源,3S技术为研究手段,分析了泰山的森林景观结构动态变化以及景观格局沿高程的分异。选择相对高差较大的区域设计了8个地形方位,采用3种由连续样方组成的辐射状样带,在遥感影像上进行信息采集,研究地形对森林景观格局的多尺度效应,分析了不同地形因子对森林景观分异的影响。结果表明,在景观尺度上,地形方位、海拔、山地类型是影响森林景观镶嵌格局的控制因素,坡向、坡度是重要因素,坡形、坡位是不明显因素。以TM影像为信息源,从森林景观分异和梯度分析上,首先要考虑海拔坡向指数、坡形坡位指数和海拔,并立足于地形方位。地形主要因子间存在着稳定的显著正相关,为森林分异多尺度格局提供了较强的综合解释能力。     

Effects of environment,habitat configuration and forest continuity on the distribution of forest plant species

In present day European landscapes many forest plant species are restricted to isolated remnants of a formerly more or less continuous forest cover. The two major objectives of this study were (1) to determine the relative importance of habitat quality (mainly in terms of soil parameters), habitat configuration (patch size and isolation) and habitat continuity for the distribution of herbaceous forest plant species in a highly fragmented landscape and (2) to examine if groups of species with different habitat requirements are affected differently. Deciduous forest patches in northwestern Germany were surveyed for the presence of a large set of forest species. For each patch, habitat quality, configuration and continuity were determined. Data were analysed by Redundancy Analysis with variation partitioning for effects on total species composition and multivariate logistic regression for effects on individual species, for two different data sets (base‐rich and base‐poor forest patches). Overall, we found strong effects of habitat quality (particularly of soil pH, water content and topographic heterogeneity in the base‐rich forest patches; and of calcium content and disturbance in the base‐poor patches), but only relatively weak effects of habitat configuration and habitat continuity. However, a number of species were positively affected by patch area and negatively affected by patch isolation. Furthermore, the relative importance of habitat configuration tended to be higher for species predominantly growing in closed forests compared to species occurring both in the forest and in the open landscape.     

Scale‐dependent effects of forest restoration on Neotropical fruit bats

Neotropical fruit bats (family Phyllostomidae) facilitate forest regeneration on degraded lands by dispersing shrub and tree seeds. Accordingly, if fruit bats can be attracted to restoration sites, seed dispersal could be enhanced. We surveyed bat communities at 10 sites in southern Costa Rica to evaluate whether restoration treatments attracted more fruit bats if trees were planted on degraded farmlands in plantations or island configurations versus natural regeneration. We also compared the relative influence of tree cover at local and landscape spatial scales on bat abundances. We captured 68% more fruit bat individuals in tree plantations as in controls, whereas tree island plots were intermediate. Bat activity also responded to landscape tree cover within a 200‐m radius of restoration plots, with greater abundance but lower species richness in deforested landscapes. Fruit bat captures in controls and tree island plots declined with increasing landscape tree cover, but captures in plantations were relatively constant. Individual species responded differentially to tree cover measured at different spatial scales. We attribute restoration effects primarily to habitat structure rather than food resources because no planted trees produced fruits regularly eaten by bats. The magnitude of tree planting effects on fruit bats was less than previous studies have found for frugivorous birds, suggesting that bats may play a particularly important role in dispersing seeds in heavily deforested and naturally regenerating areas. Nonetheless, our results show that larger tree plantations in more intact landscapes are more likely to attract diverse fruit bats, potentially enhancing seed dispersal.     

The effects of light pollution on migratory animal behavior

Light pollution is a global threat to biodiversity, especially migratory organisms, some of which traverse hemispheric scales. Research on light pollution has grown significantly over the past decades, but our review of migratory organisms demonstrates gaps in our understanding, particularly beyond migratory birds. Research across spatial scales reveals the multifaceted effects of artificial light on migratory species, ranging from local and regional to macroscale impacts. These threats extend beyond species that are active at night – broadening the scope of this threat. Emerging tools for measuring light pollution and its impacts, as well as ecological forecasting techniques, present new pathways for conservation, including transdisciplinary approaches.     

The relative importance of climatic effects, wildfires and management for future forest landscape dynamics in the Swiss Alps

Forest landscape dynamics result from the complex interaction of driving forces and ecological processes operating on various scales. Projected climate change for the 21st century will alter climate‐sensitive processes, causing shifts in species composition and also bringing about changes in disturbance regimes, particularly regarding wildfires. Previous studies of the impact of climate change on forests have focused mainly on the direct effects of climate. In the present study, we assessed the interactions among forest dynamics, climate change and large‐scale disturbances such as fire, wind and forest management. We used the Land Clim model to investigate the influence, interactions and the relative importance of these different drivers of landscape dynamics in two case study areas of the European Alps. The simulations revealed that projected future climate change would cause extensive forest cover changes, beginning in the coming decades. Fire is likely to become almost as important for shaping the landscape as the direct effects of climate change, even in areas where major wildfires do not occur under current climatic conditions. The effects of variable wind disturbances and harvesting regimes, however, are less likely to have a considerable impact on forest development compared with the direct effects of climate change coupled with the indirect effects of increased fire activity. We conclude that the joint direct and indirect effects of climate change are likely to have major consequences for mountain forests in the European Alps, including their ability to provide protection against natural hazards.     

基于SWAT模型的北京平原区森林景观格局对雨洪减缓的影响研究

景观格局及其变化是影响地表径流及空间分布的重要因素,也是管理城市雨洪、治理生态环境的途径。以北京市平原区百万亩造林项目为背景,选取第一轮造林时间（2011、2013、2015、2017年）的遥感数据,以三环、五环、六环路为界,将平原区划分为核心区、中心区、近郊区、远郊区四个区域,分别分析整体及分区林地景观格局的变化。运用SWAT模型模拟不同格局对不同区域暴雨径流的影响,探究影响径流变化的主导林地景观指数。研究发现：1）平原区林地面积呈增长趋势,增幅为12.96％。除核心区和中心区的部分地区外,林地斑块更聚集、形状更复杂。2）百万亩造林工程对平原区雨洪风险的减缓有积极作用,但受城市建设及人类活动的影响,不同区域造林对径流的减缓强度与建设扩张的影响强度大小关系略有不同。核心区、中心区造林对径流的减缓强度大于建设扩张对径流的副作用,径流总量减小,减少比例为1.98％、4.29％。而近郊区、远郊区相反,径流总量变大,增大比例为0.09％与6.82％,其中远郊区建设扩张的强度是影响平原区径流风险的主导原因。3）不同区域雨洪减缓的关键性林地景观指数不同。核心区径流的主导林地因子为斑块数量与形状因子,中心区为面积因子,近郊区为聚合度因子和形状因子,远郊区为面积与聚合度因子。主导林地因子的大小调控将更高效的减缓雨洪风险。本研究通过SWAT模拟分析得到第一轮造林期间平原区森林格局与径流特征的空间变化及各区域径流减缓的关键性林地因子,为第二轮造林提高雨洪减缓功效提供参考。