浑河上游植被群落特征及其生态适应性

以浑河上游植被为研究对象,运用二元指示种分析法(TWINSPAN)对研究地区植被进行群落分类,对各群落类型特征进行分析。在提出河岸带植被生态功能适应性指标的基础上,对河岸带植被进行了生态功能适应性分组。研究发现,浑河上游河岸带植被可划分为香蒲草丛、球子蕨草丛、灯心草草丛、柳属灌丛、珍珠梅灌丛、核桃楸阔叶混交林、家榆阔叶混交林、长白落叶松林和油松林等9个群落类型,群落类型表现出突出的多样性特征,且物种组成复杂;研究地区9个群落类型可以划分为强入侵性功能组、弱入侵性功能组和高逃避性功能组3个生态适应性功能组,不同生态适应性功能组的群落中的主要物种具有明显的不同的生态对策。     

巴林地区用材林立地分类的研究

通过对海拔、坡度、土层厚等１７个主要地形、土壤因子的主成份分析，并利用各因子相互关系和对用材林林木生长的影响进行分析。结果表明，坡度级加指示植物是巴林地区划分立地类型组的主要依据，土种加植被类型是划分立地类型的主导因子，利用这些相对稳定、直观易划因子，将巴林地区用材林类型区划分出１５个立地类型组，２７个立地类型。     

楚雄州森林立地类型的划分

将地形因子(海拔、坡位、坡度、坡向)、土壤厚度、植被类型等因素作为依据,进行了楚雄州森林立地类型划分.公布了划分结果.     

文峪河上游河岸林的群落结构与多样性特征

文峪河上游垂直河岸40 m的区域存在泛滥平原和山坡两种地貌.在实地踏查和河岸林群落划分的基础上,对河岸带两种地貌的森林群落结构与多样性进行了差异比较,以期为该区河岸带宽度确定提供植被依据.结果表明,56个样地分别属于13种群落,泛滥平原的林分密度、物种丰富度与植物多样性都显著大于毗邻山坡,而林木断面积与均匀度在两种地貌...     

蒙坝河上游小流域立地条件类型划分的研究

针对蒙坝河上游小流域综合治理示范区的自然特点,提出了营造水保林、水源林立地类型划分的依据和方法。根据地貌、地形、岩性、林草覆盖度、坡度和土层厚度等综合因子将示范区划分为一个类型区、4个类型亚区、10个类型组、54个立地类型。     

蒙坝河小流域立地类型划分与评价的研究

本文针对蒙坝河上游小流域综合治理示范区的自然特点,提出营造水保林、水源林立地类型划分的依据和方法。并根据地貌、岩性、地形、林草覆盖度、坡度和土层厚度等综合因子将示范区划分1个类型区、4个类型亚区、15个类型组、69个立地类型。并结合侵蚀性状,分别进行定性、定量评价。     

基于河岸带植物多样性的河流健康评价——以柏条河-府河河段为例

基于河流健康评价目的,将柏条河-府河河段划分为上游、中游、下游3个区域针对河岸带植物多样性进行多层次调查。在多个指标构建的评价系统中对各河段进行评分,上游、中游和下游河段得分分别为72.7分、59.1分和59.3分。评分结果直观反映出柏条河-府河不同河段河岸带植物多样性的状况。依据调查结果为各河段维持和提升植物多样性、河流健康提出了管理措施与建议。     

河岸带自然度综合评价指标体系的构建

针对我国北方河岸带的特点,提出了从地貌结构、植被群落、景观三个方面的13个因子组成的河岸带自然度综合评价指标体系,包括：河岸弯曲度、河岸断面几何形态、河岸带宽度、河岸林群落物种多样性、均匀度、郁闭度、顶级适应值、乡土树种比例、建群种胸径级、实生幼株丰富度、群落形态指标、群落色彩指标、动物指标;并根据近自然程度,将河岸带划分为自然、较自然、半自然、人工四种类型。     

我国河岸带生态学的研究进展

我国河岸带植被生态学的研究目前主要集中在河岸带植物的群落格局、生物多样性、珍稀濒危分布以及荒漠河岸带植被与环境关系等方面,河岸带土壤和污染生态学研究主要集中在土壤反硝化过程、污染物的分布格局和苯胺降解机理等方面。针对国内河岸带研究现状及存在问题,建议未来我国河岸带的研究从6个方面进行：1）河岸带及其背景区植被景观空间镶嵌格局分析。2）河岸带边界的判定方法及河岸带植被特征沿横向空间梯度的变化格局。3）对河岸带生境类型的划分,在斑块、河段和支流3个尺度上对河岸带物种多样性格局进行分析,并阐明其控制因素和机制。4）河岸带对高地面源营养物、沉淀物和污染物的拦截过滤过程研究,建立量化传输模型。5）对典型流域河岸带向溪流输入有机质输入过程及数量进行研究,并建立周转过程模型。6）对河岸带的研究成果进行系统整合,建立能够揭示河岸带空间格局、组成结构与功能过程概念模型和数量模型。     

浑河上游不同植被类型河岸带土壤物理性质分析

利用环刀法对浑河上游珍珠梅灌丛、落叶松纯林、杂木林3种不同植被类型河岸带土壤物理性质进行分析,其结果表明,珍珠梅灌丛、落叶松纯林、杂木林3种河岸带类型中,杂木林河岸带下的土壤,不论是表层土壤还是下层土壤,都有较低的土壤容重、较高的持水量,同样地标径流条件下,能吸附相对多的泥沙和养分污染物。同一类型河岸带内距溪流边缘越近,其土壤持水量高;同一类型河岸带表层和底层土壤物理性质总体差异不显著。     

长白山二道白河森林流域河岸带阔叶红松林最小面积与a多样性(英文)

河岸带是森林小流域单元的重要组成部分之一。由于河水的影响和边缘效应等因素的综合作用,河岸带植物群落与远离河岸带的森林群落在组成、结构和分布格局等方面存在较大差异,其群落最小面积也不同。本文对长白山原始阔叶红松林河岸带植物群落最小面积和物种丰富度进行了探讨。结果表明河岸带植物群落的最小面积均小于森林内部植物群落的最小面积。对于长白山原始阔叶红松林群落而言,在河岸带,包括群落的60%、80%、90%植物种类时的平均最小面积分别为80m2、180m2和320m2左右;;对应于远离河岸带的森林内部,包括群落的60%、80%、90%植物种类时的平均最小面积分别为260m2、380m2和480m2左右。河岸带植物群落的物种丰富度、均匀度和Shannon-Wiener指数普遍高于森林内部植物群落,但优势度则相反。表4参20。     

Large-scale ecological restoration of high-diversity tropical forests in SE Brazil

The complex interactions among endangered ecosystems, landowners’ interests, and different models of land tenure and use, constitute an important series of challenges for those seeking to maintain and restore biodiversity and augment the flow of ecosystem services. Over the past 10 years, we have developed a data-based approach to address these challenges and to achieve medium and large-scale ecological restoration of riparian areas on private lands in the state of São Paulo, southeastern Brazil. Given varying motivations for ecological restoration, the location of riparian areas within landholdings, environmental zoning of different riparian areas, and best-practice restoration methods were developed for each situation. A total of 32 ongoing projects, covering 527,982 ha, were evaluated in large sugarcane farms and small mixed farms, and six different restoration techniques have been developed to help upscale the effort. Small mixed farms had higher portions of land requiring protection as riparian areas (13.3%), and lower forest cover of riparian areas (18.3%), than large sugarcane farms (10.0% and 36.9%, respectively for riparian areas and forest cover values). In both types of farms, forest fragments required some degree of restoration. Historical anthropogenic degradation has compromised forest ecosystem structure and functioning, despite their high-diversity of native tree and shrub species. Notably, land use patterns in riparian areas differed markedly. Large sugarcane farms had higher portions of riparian areas occupied by highly mechanized agriculture, abandoned fields, and anthropogenic wet fields created by siltation in water courses. In contrast, in small mixed crop farms, low or non-mechanized agriculture and pasturelands were predominant. Despite these differences, plantations of native tree species covering the entire area was by far the main restoration method needed both by large sugarcane farms (76.0%) and small mixed farms (92.4%), in view of the low resilience of target sites, reduced forest cover, and high fragmentation, all of which limit the potential for autogenic restoration. We propose that plantations should be carried out with a high-diversity of native species in order to create biologically viable restored forests, and to assist long-term biodiversity persistence at the landscape scale. Finally, we propose strategies to integrate the political, socio-economic and methodological aspects needed to upscale restoration efforts in tropical forest regions throughout Latin America and elsewhere.     

A comparison of riparian plant community response to herbivory by beavers (Castor canadensis) and ungulates in Canada's boreal mixed-wood forest

Herbivores, such as beavers (Castor canadensis) and ungulates, can dramatically alter the species composition and structure of riparian vegetation communities. We examined how four different levels of beaver presence and ungulate density influenced the structure and composition of riparian vegetation communities in the mixed-wood boreal region of east-central Alberta, Canada. Beavers, as central-place foragers, focus on similar species utilized by the six ungulate species in our study area. However, we found that vegetation responded differently relative to the percent cover and heights of emergent, shrub, herbaceous dicots, and tree species depending on the varying combinations of beaver presence and ungulate densities. There was an obvious negative effect of ungulate herbivory on shrub heights and cover; however, we were unable to find any significant effects on the overall composition and structure of vegetation communities that were exclusively related to beaver activities. In areas with no beavers and lower ungulate densities there was a positive growth response in preferred species (e.g., Salix spp., Prunus spp.), which clearly demonstrated the degree of combined influence that these herbivores have on riparian communities. In these areas, Salix spp. was four times shorter than in areas where beavers were not present and ungulate densities were lower. In addition percent cover was lowest for emergent vegetation and herbaceous dicots in areas with higher ungulate densities. Many studies focus on single-species effects on forage resources, yet our research shows that the study of combined effects of multiple herbivores can provide a new insight into these complex systems.     

Influence of wildfire severity on riparian plant community heterogeneity in an Idaho,USA wilderness

Despite the increasing recognition of riparian zones as important ecotones that link terrestrial and aquatic ecosystems and of fire as a critical natural disturbance, much remains unknown regarding the influence of fire on stream-riparian ecosystems. To further this understanding, we evaluated the effects of mixed severity wildfire on riparian plant community structure and composition in headwater streams of the Big Creek Watershed of the Frank Church ‘River of No Return’ Wilderness of central Idaho. Five years after a large stand-replacing fire, we conducted riparian vegetation surveys at sixteen reaches across a range of burn types. Non-metric Multidimensional Scaling (NMS) and Multi-Response Permutation Procedure (MRPP) analyses showed an overall shift in community composition and structure between vegetation at unburned and severely burned reaches. Although total plant cover was significantly less at severely burned areas, recovery of the deciduous understory was apparent. Severely burned reaches were characterized by a marked increase in cheatgrass (Bromus tectorum). Reaches that were exposed to low-severity fire were indistinguishable from unburned reaches relative to vegetation community composition and structure, pointing to a possible disturbance threshold that may need to be crossed in order to alter riparian plant communities.     

Riparian forest structure and succession in second-growth stands of the central Cascade Mountains,Washington, USA

We examined the relationship between landform types and riparian forest structure and succession in second-growth stands along mid order streams in the Cascade Mountains, Washington, USA. We sampled tree, sapling, seedling, and shrub characteristics across a range of fluvial geomorphic surfaces, which were classified into four landform classes, including low floodplain, high floodplain, terrace and hillslope. Landform classification was based on topographic characteristics, position relative to the stream channel, and estimated flood frequency. Statistical analyses using generalized estimating equations (GEE) showed that landform exerted a strong influence on the distribution and abundance of conifer and deciduous species and of different tree life stages. The floodplain landforms were characterized by initial disturbance from timber harvest, and ongoing fluvial disturbance, which favored the establishment of deciduous communities dominated by red alder (Alnus rubra) and maintenance of early successional riparian stands. In contrast, the terrace and hillslope landforms were also subject to timber harvest as the stand initiating agent but were unaffected by fluvial disturbance. However, based on differences in species distribution, we infer that forest structure on these two landforms differed from one another as a result of differences in soil moisture levels. Terraces and hillslopes were found to have high conifer tree abundance, but frequency of younger conifers was higher on hillslopes. Deciduous tree reproduction was very low on terraces and hillslopes. Our results also suggest that conifer recruitment in these second-growth riparian forests may be more successful on soil substrates than on coarse woody debris. We propose that the interplay between the disturbance regime (including type, frequency and intensity) and soil moisture conditions played an important role in influencing the course of riparian succession, present stand structure, and future successional trajectories and these were the primary mechanisms driving vegetation differences among landforms.     

黄山率水流域水陆交错带植被类型及群落特征

研究以黄山市率水流域水陆交错带典型植物群落为对象,沿主河道设置了 33 个样方,采用 法瑞学派调查法记录样方的物种组成和群落结构;并根据离水面距离和土壤基质类型划分了 3 种生境类 型：砾石型河漫滩、粘土型河漫滩以及河岸边坡,进而进行群落类型划分与生态梯度分析。结果表明： 调查区域有维管束植物共计 67 科 124 属 146 种;水陆交错带植被可分成 15 个群落类型,包含 3 个森林 群落、3 个灌丛群落和 9 个草本群落;森林群落均出现在河岸边坡生境类型中,灌从群落多见于粘土型河 漫滩,草本群落主要集中于砾石型河漫滩;非度量多维标度分析表明,存在于上下游之间和水陆之间的 两个生态梯度是影响群落物种组成的重要因素,并且在两个生态梯度中心过渡区,植物群落丰富度达到 最大。     

Vegetation structure,composition and effect of pine plantation harvesting on riparian buffers in New Zealand

The composition and structure of vegetation within riparian buffers prior to, and immediately post-harvesting in a managed radiata pine (Pinus radiata D.Don) forest is described and compared with riparian buffers in residual adjoining native forest on the Coromandel Peninsula, New Zealand. One hundred and twenty-one species (71% native) representing life forms from grasses to trees were recorded. The highest species richness, including both native and adventive (non-native) species, was found in riparian buffers in the post-harvest and native reference sites which had 18–25 species per site. Riparian buffers in mature pine plantations contained a mix of native species that was generally similar to, and not significantly reduced in species richness, from the reference native forest. Native species comprised 82–92% of the total cover in mature pre-harvest sites (irrespective of riparian width), and 99.8% in native reference sites. Compared with native forest the principal difference was a reduction of total cover in the upper tiers (5–12 m), and some increase in cover in the lower tiers. Adventive species in post-harvest sites comprised 16–67% of the total cover and were most frequently found in riparian areas highly disturbed by recent harvesting of the pines, particularly where riparian buffers were narrow or absent. Invasion by light-demanding adventives is expected to be temporary and most species are likely to be shaded out as the new rotation of pine trees develops. Radiata pine plantations in Whangapoua Forest can provide suitable conditions for the development of riparian buffer zones that will become dominated by native species, similar in richness and structure to neighbouring native forest.     

A comparison of impacts from silviculture practices and North American beaver invasion on stream benthic macroinvertebrate community structure and function in Nothofagus forests of Tierra del Fuego

The sub-Antarctic biome of South America is the world's southernmost forested ecosystem and one of the last remaining wilderness areas on the planet. Nonetheless, the region confronts various anthropogenic environmental impacts, such as the invasive North American beaver (Castor canadensis) and timber harvesting, particularly in stands of Nothofagus pumilio. Both of these disturbances can affect terrestrial and aquatic systems. To understand the influence and relative importance of these disturbances on sub-Antarctic watersheds, we characterized in-stream and riparian habitat conditions (pH, dissolved oxygen, conductivity, temperature, stream size, distance to riparian forest, bank slope, substrate heterogeneity, benthic organic matter) and benthic macroinvertebrate community structure (density, richness, diversity, evenness) and function (biomass, functional feeding group percent) in 19 streams on Tierra del Fuego Island. To explain the effects of beaver invasion and timber harvesting, we compared these physical and biotic variables among four habitat types: (a) beaver meadows, (b) shelterwood cut harvested areas without forested riparian zones, (c) variable retention harvested areas with riparian buffers, and (d) unmanaged old-growth primary forests. Most habitat variables were similar at all sites, except for dissolved oxygen (significantly higher in streams from old-growth primary forests). Benthic communities in beaver meadows had significantly lower diversity, compared to streams of unmanaged old-growth primary forests, and managed sites presented intermediate values between the two. Functionally, the benthic community in beaver meadows displayed a reduction of all functional feeding groups except collector-gatherers; again variable retention harvested areas with riparian buffers were similar to unmanaged old-growth primary forest streams, while shelterwood cut harvested areas occupied an intermediate position. These results indicated that current forestry practices that include both variable retention and legally mandated riparian forested buffers may be effective in mitigating impacts on stream benthic communities. Finally, these data demonstrated that C. canadensis invasion was a relatively larger impact on these streams than well-managed forestry practices.