A study on the relationship between vegetation pattern and environment in the upstream of Minjiang River,China

The vegetation pattern in the upstream of Minjiang River,and its relationship with environment factors,such as landscape position(elevation,slope,aspect),precipitation and temperature and soil are analyzed in this paper.The data used in this Paper were based on the landscape map derived from 1994 TM imagery.The results were as follows:1)dominant landscape types were forest,shrub land and grassland,which were very similar in terms of area ratio(32.87%,31.85% and 28.44%,respectively);2)the patch shape of conifer forest and mixed forest was complicated while that of broad-leaved forest and cultivated land was simple;3)the fragmentation of conifer forest and mixed forest was serious in contrast with low fragmentation of broad-leaved forest and cultivated land;and 4)closed scrub and grassland had a high contagion and good connectivity while mixed forest had a lower contagion and bad connectivity.In addition,the vegetation distribution pattern of upstream of Minjiang River Was closely related with elevation and temperature,but the relationship between vegetation and precipitation was not statistically significant.     

A study on the relationship between vegetation pattern and environment in the upstream of Minjiang River, China

The vegetation pattern in the upstream of Minjiang River, and its relationship with environment factors, such as landscape position (elevation, slope, aspect), precipitation and temperature and soil are analyzed in this paper. The data used in this paper were based on the landscape map derived from 1994 TM imagery. The results were as follows: 1) dominant landscape types were forest, shrub land and grassland, which were very similar in terms of area ratio (32.87%, 31.85% and 28.44%, respectively); 2) the patch shape of conifer forest and mixed forest was complicated while that of broad-leaved forest and cultivated land was simple; 3) the fragmentation of conifer forest and mixed forest was serious in contrast with low fragmentation of broad-leaved forest and cultivated land; and 4) closed scrub and grassland had a high contagion and good connectivity while mixed forest had a lower contagion and bad connectivity. In addition, the vegetation distribution pattern of upstream of Minjiang River was closely related with elevation and temperature, but the relationship between vegetation and precipitation was not statistically significant. __________ Translated from Journal of Beijing Normal University (Natural Science), 2005,41(4) [译自: 北京师范大学学报(自然科学版), 2005,41(4)]     

植被与水土流失关系研究进展

水土流失是世界性的环境问题之一,对人类社会可持续发展构成威胁,控制水土流失成为迫切需要,有许多水土流失控制措施,而生物措施尤其植被一直是人们研究的焦点.根据前人的研究,从斑块、坡面和流域/区域尺度总结了植被与水土流失的关系.斑块尺度植被对降雨和径流侵蚀能量具有很大的减弱或消除作用,可以改变植株底部的土壤性质,改善其结构,进而降低土壤可蚀性,增加入渗能力,从而减轻土壤侵蚀程度.不同植被类型、植被的不同层次结构,不同植被的形态结构具有不同的土壤侵蚀控制作用.坡面尺度主要从坡位、坡度、坡向对植被生长和分布格局的影响、对水土流失过程和格局的影响以及裸地-植被镶嵌格局、植被的条带格局对水土流失的影响和反映水土流失过程的景观格局指数的构建等方面进行了研究.更多是从植被恢复及其水土流失效应方面进行了探讨,为退化生态系统恢复和格局设计提供了极其有用的信息.流域/区域尺度植被与水土流失的关系更大程度上受到气候、地貌特征的影响,因此研究多从一定气候条件控制的土地覆盖（植被覆盖）及其格局的水土流失效应方面进行的.由于大尺度监测非常困难,研究多从遥感监测、GIS集成和模型模拟方面开展,是流域、区域等大尺度生态安全格局设计的有力支持.前人的研究为生态环境建设和保护提供了大量参考信息,但仍有一些问题需要进一步探讨,对此进行了初步的概括和归纳,希望能够对植被和水土流失关系的研究起到一定促进作用.     

新疆表土中云杉花粉与植被的关系

通过对新疆天山、阿尔泰山、昆仑山、塔里木盆地、准噶尔盆地不同植被带中所取的 131个表土样中云杉花粉含量进行百分比统计分析 ,从而确定了影响表土中云杉花粉含量的主要因素是距云杉林地距离、海拔高度、气流和水流等。进而指出在荒漠、荒漠草原表土中云杉花粉含量稳定在 5 %以下 ;林带内表土中云杉花粉含量稳定在 30 %以上 ;在森林线以上的亚高山、高山草甸、高山垫状植被以及高山流石滩植被中表土中云杉花粉含量主要受气流的影响 ,而平原河谷林和平原低地草甸表土中的云杉含量则受水流的制约。     

黄土高原不同植被类型土壤特性与植被生产力关系研究进展

针对黄土高原不同类型植被,不同立地条件下植被及不同的演替阶段的土壤特性进行了综述,包括土壤养分,土壤酸碱度和土壤水热条件与植被生产力的关系。众多的研究表明,土壤水分与营养供应是影响植被生产力的主要因素,而植被的根系分布和细根周转能够影响土壤有机质和理化性质,植被的演替过程改变着土壤的特性,土壤特性的改变驱动着植被演替。     

Protected area networks and savannah bird biodiversity in the face of climate change and land degradation

The extent to which climate change might diminish the efficacy of protected areas is one of the most pressing conservation questions. Many projections suggest that climate‐driven species distribution shifts will leave protected areas impoverished and species inadequately protected while other evidence suggests that intact ecosystems within protected areas will be resilient to change. Here, we tackle this problem empirically. We show how recent changes in distribution of 139 Tanzanian savannah bird species are linked to climate change, protected area status and land degradation. We provide the first evidence of climate‐driven range shifts for an African bird community. Our results suggest that the continued maintenance of existing protected areas is an appropriate conservation response to the challenge of climate and environmental change.     

Synergy between small- and large-scale feedbacks of vegetation on the water cycle

Predictions of the effects of climate change on the extent of forests, savannas and deserts are usually based on simple response models derived from actual vegetation distributions. In this review, we show two major problems with the implicitly assumed straightforward cause–effect relationship. Firstly, several studies suggest that vegetation itself may have considerable effects on regional climate implying a positive feedback, which can potentially lead to large‐scale hysteresis. Secondly, vegetation ecologists have found that effects of plants on microclimate and soils can cause a microscale positive feedback, implying that critical precipitation conditions for colonization of a site may differ from those for disappearance from that site. We argue that it is important to integrate these nonlinearities at disparate scales in models to produce more realistic predictions of potential effects of climate change and deforestation.     

A vegetation map of The Netherlands,based on the relationship between ecotopes and types of potential natural vegetation

Summary The method of mapping the vegetation on scale 1: 200,000 and the starting points in relation to the potential natural vegetation and ecotopes, are discussed.In view of the planological background of this study, some restrictions have been added to the concept of potential natural vegetation, concerning the period of development and the human influence.The relationship between soil, ground water and vegetation was studied, which resulted in the map of the potential natural vegetation.Each type of potential natural vegetation stands for a series of vegetation types on the same site. Seven main series, with a number of sub-series are distinguished. Within each vegetation series the plant communities have been spread over five groups, according to their structure and naturalness.Ecotopes and ecotope complexes are considered as landscape ecological units. A list of ecotopes was obtained by interpreting topographical maps and by inventory data.The actual vegetation was mapped by estimating the size of the ecotopes within the separate areas. It was expressed in a five figure code for the five groups from the vegetation and ecotopes is combined into the vegetation map of The Netherlands.Interpretation problems, some of them specific for The Netherlands, are discussed and some remarks are made on the necessity of further research.Contribution to the Symposium on Plant Species and Plant Communities, held at Nijmegen, 11–12 November 1976, on the occasion of the 60th birthday of Professor Victor Westhoff.Nomenclature follows Heukels-van Ooststroom, Flora van Nederland, 18e druk, 1975, Wolters-Noordhoff, Groningen; nomenclature of syntaxa follows Westhoff & den Held (1969)     

Simulated responses of potential vegetation to doubled-CO2 climate change and feedbacks on near-surface temperature

Increases in the atmospheric concentration of carbon dioxide and associated changes in climate may exert large impacts on plant physiology and the density of vegetation cover. These may in turn provide feedbacks on climate through a modification of surface‐atmosphere fluxes of energy and moisture. This paper uses asynchronously coupled models of global vegetation and climate to examine the responses of potential vegetation to different aspects of a doubled‐CO₂ environmental change, and compares the feedbacks on near‐surface temperature arising from physiological and structural components of the vegetation response. Stomatal conductance reduces in response to the higher CO₂ concentration, but rising temperatures and a redistribution of precipitation also exert significant impacts on this property as well as leading to major changes in potential vegetation structure. Overall, physiological responses act to enhance the warming near the surface, but in many areas this is offset by increases in leaf area resulting from greater precipitation and higher temperatures. Interactions with seasonal snow cover result in a positive feedback on winter warming in the boreal forest regions.     

Data-driven estimation of nitric oxide emissions from global soils based on dominant vegetation covers

Soils are a major source of global nitric oxide (NO) emissions. However, estimates of soil NO emissions have large uncertainties due to limited observations and multifactorial impacts. Here, we mapped global soil NO emissions, integrating 1356 in-situ NO observations from globally distributed sites with high-resolution climate, soil, and management practice data. We then calculated global and national total NO budgets and revealed the contributions of cropland, grassland, and forest to global soil NO emissions at the national level. The results showed that soil NO emissions were explained mainly by N input, water input and soil pH. Total above-soil NO emissions of the three vegetation cover types were 9.4 Tg N year⁻¹ in 2014, including 5.9 Tg N year⁻¹ (1.04, 95% confidence interval [95% CI]: 0.09–1.99 kg N ha⁻¹ year⁻¹) emitted from forest, 1.7 Tg N year⁻¹ (0.68, 95% CI: 0.10–1.26 kg N ha⁻¹ year⁻¹) from grassland, and 1.8 Tg N year⁻¹ (0.98, 95% CI: 0.42–1.53 kg N ha⁻¹ year⁻¹) from cropland. Soil NO emissions in approximately 57% of 213 countries surveyed were dominated by forests. Our results provide updated inventories of global and national soil NO emissions based on robust data-driven models. These estimates are critical to guiding the mitigation of soil NO emissions and can be used in combination with biogeochemical models.     

砒砂岩区植被覆盖度环境驱动因子量化分析——基于地理探测器

砒砂岩区地形破碎,生态环境恶劣,降水量少且以暴雨为主,研究该区植被覆盖变化及环境驱动因子作用机制对区域植被建设具有重要的理论意义。基于1999—2018年的NDVI数据分析了砒砂岩区近20年植被覆盖度时空变化特征,利用了地理探测器方法量化分析了不同环境因子对植被覆盖度的影响。结果表明：1)近20年砒砂岩区平均植被覆盖度为42.3%,时间尺度上1999—2018年区域植被覆盖度呈增加趋势,平均上升幅度为0.086/10 a,空间尺度上植被覆盖度呈现从东南向西北递减的空间分布特征;2)近20年区域植被覆盖整体得到改善要比退化的区域面积大,45.5%的区域面积植被覆盖度极显著增加,主要分布在砒砂岩区东部区域,该区植被覆盖度未来变化趋势将以持续性改善为主,但仍有约41.6%的植被将由改善向退化方向变化;3)降水、土壤水分和气温是影响砒砂岩区植被覆盖空间分布的主导环境因子,且降水同其他环境因子的交互作用对植被覆盖影响最大。     

A model-based framework for assessing the vulnerability of low dispersal vertebrates to landscape fragmentation under environmental change

Environmental changes are driving rapid geographic shifts of suitable environmental conditions for species. These might survive by tracking those shifts, however successful responses will depend on the spatial distribution of suitable habitats (current and future) and on their connectivity. Most herptiles (i.e., amphibians and reptiles) have low dispersal abilities, and therefore herptiles are among the most vulnerable groups to environmental changes. Here we assessed the vulnerability of herptile species to future climate and land use changes in fragmented landscapes. We developed and tested a methodological approach combining the strengths of Species Distribution Models (SDMs) and of functional connectivity analysis. First, using SDMs we forecasted current and future distributions of potential suitable areas as well as range dynamics for four herptile species in Portugal. SDM forecasts for 2050 were obtained under two contrasting emission scenarios, translated into moderate (low-emissions scenario) or large (high-emissions scenario) changes in climate and land use conditions. Then, we calculated and analysed functional connectivity from areas projected to lose environmental suitability towards areas keeping suitable conditions. Landscape matrix resistance and barrier effects of the national motorway network were incorporated as the main sources of fragmentation. Potential suitable area was projected to decrease under future conditions for most test species, with the high-emissions scenario amplifying the losses or gains. Spatiotemporal patterns of connectivity between potentially suitable areas signalled the most important locations for maintaining linkages and migration corridors, as well as potential conflicts due to overlaps with the current motorway network. By integrating SDM projections with functional connectivity analysis, we were able to assess and map the vulnerability of distinct herptile species to isolation or extinction under environmental change scenarios. Our framework provides valuable information, with fairly low data requirements, for optimizing biodiversity management and mitigation efforts, aiming to reduce the complex and often synergistic negative impacts of multiple environmental change drivers. Implications for conservation planning and management are discussed from a global change adaptation perspective.     

河岸带生态系统植被与土壤对水文变化的响应研究进展

河岸带的植被与土壤是生态系统重要组成部分,对于维持河岸带的生态健康、生态系统服务与可持续性具有至关重要的作用。水文变化是河岸带生态系统的首要干扰因子,系统总结了水文变化对河岸带植被的特征以及植被形态、群落分布、繁殖、生存策略的影响,并阐述了河岸带水文和植被对土壤氮磷迁移转化的影响机制。根系作为土壤与植物地上部分之间物质、能量流动与信号传导的关键纽带,目前对根系的研究还较欠缺,需要加强水文变化对河岸带湿地植物根系形态、结构、功能特征的影响机理研究,以及湿地植物对水文变化的适应机制和耐受阈值方面的探究。在微观方面,应加强水文变化与植被等多因素耦合对土壤氮磷迁移转化过程的机理研究。河流形态和土壤的多样性决定着河岸带水文作用特征的复杂性,今后需注重河岸带个性特征与水文响应的关系研究。河岸带是横向的水陆生态过渡带和河流上下游的纵向生态廊道,亟需综合考虑和模拟流域土壤、植被与水文、人类活动之间的耦合关系,预测未来气候与社会经济情境下的河岸带生态系统演变规律,为河岸带生态系统的生态调节、生物多样性保护与生态恢复等提供理论依据与技术支撑。     

乌兰巴托-锡林浩特样带草地植被特征与水热因子的关系

2012年夏季,研究人员对蒙古高原长约1100km的乌兰巴托—锡林浩特草地样带开展考察,获取了46个样地的物种数量、地上生物量等数据;基于全球GHCN(全球历史气象网络)数据集,提取了样带夏季(6—8月)月均温度和降水总量;继而根据自然地理和行政区边界,将草地样带大致分成北部(蒙古国乌兰巴托—蒙古国艾日格)、中部(蒙古国艾日格—中国苏尼特左旗)和南部(中国苏尼特左旗—中国锡林浩特),开展了分析。研究表明:(1)样带夏季平均温度的空间分布形态呈现明显的倒"U"型分布,南北两端温度较低,中部温度较高;夏季降水量在空间上的分布形态则与之相反,呈现南北两端降水量较高,中部降水量较低的正"U"型分布;(2)样带上植物物种数量、地上生物量的空间分布形态均呈现正"U"型分布,即在生态景观类型为典型温性草原的样带南部和北部地区,其生物多样性、地上生物量明显好于呈现为温性荒漠草原、温性荒漠景观的样带中部地区。(3)相关分析体现了大尺度(高原样带尺度)上植被特征与水热环境因子间的关系:植物物种数量、地上生物量与夏季月均温度均呈现负相关,而与夏季降水总量则呈现正相关关系。(4)偏相关分析反映了局地小尺度上植被特征与水热环境因子间的关系:温度和降水要素对于植物物种数量、地上生物量均呈现正相关。     

A conceptual framework for understanding thermal constraints on ectotherm activity with implications for predicting responses to global change

Activity budgets influence the expression of life history traits as well as population dynamics. For ectotherms, a major constraint on activity is environmental temperature. Nonetheless, we currently lack a comprehensive conceptual framework for understanding thermal constraints on activity, which hinders our ability to rigorously apply activity data to answer ecological and evolutionary questions. Here, we integrate multiple aspects of temperature‐dependent activity into a single unified framework that has general applicability. We also provide examples of the implementation of this framework to address fundamental questions in ecology relating to climate change vulnerability and species’ distributions using empirical data from a tropical lizard.     

陕北黄土高原植被恢复与生态系统服务的时空关系

陕北黄土高原作为退耕还林还草核心区域,是地表格局及植被显著变化的区域之一。评估植被恢复成果及其对生态系统服务的影响,对促进区域生态环境提升具有重要作用。本研究选择植被覆盖度作为指标评估区域植被恢复状况,以碳固定服务、土壤保持服务、生境质量及产水服务作为指标表征区域生态系统服务,分析权衡协同关系及不同尺度的时空变化,同时运用双变量空间自相关分析植被恢复对生态系统服务的影响。结果表明: 2000—2020年,陕北黄土高原植被覆盖度呈波动上升趋势,年均值由31.7%升至47.1%,植被改善显著;研究区碳固定服务、土壤保持服务呈明显上升趋势,生境质量几乎保持不变,产水服务先升后下降总体呈上升趋势,各生态系统服务时空变化存在明显的尺度效应;4种生态系统服务间的关系主要为协同;植被覆盖与生态系统服务之间存在显著的空间依赖性,相关程度存在一定差异,植被覆盖度对土壤保持服务影响最明显,其次为碳固定服务,而植被覆盖增强条件下林草耗水增多则导致区域产水量下降,造成一定的负效应。总的来说,陕北黄土高原地区植被建设已取得显著成效,生态环境得到明显改善。     

基于NDVI的三江源地区植被生长对气候变化和人类活动的响应研究

采用Spot VEGETATION 逐旬NDVI数据、1 ∶ 100万植被类型图和气象站资料,在掌握近10a三江源地区植被变化趋势基础上,分不同植被类型探讨植被生长对气候变化的响应机制,并通过分离气候要素与人类活动对NDVI的贡献,定量评估生态保护与建设工程的实施效果。结果表明,区域尺度上,三江源地区2001-2010年植被生长呈好转趋势,植被增长从东南向西北递减;在10a时间尺度上,气候变化是影响植被生长的决定性因素,但人类活动可在短期内加快植被变化速率,气候要素和人类活动对植被生长的贡献分别为79.32%和20.68%;降水和气温对植被生长的影响程度相当,其中受春季和秋季的降水和气温影响最大,尤其是植被生长季前后一个月(4月份和10月份)的气候条件;与林地和灌丛相比,高寒草地受气候条件的抑制作用更为明显,其中高寒草甸受气候变化的影响最大,NDVI与降水和气温均具有较高相关性,高寒草原受气温的影响比较大,而高山植被受降水的抑制作用更为明显;在气候条件利于植被生长的趋势下,2001-2010年三江源地区的人类活动对生态环境表现出正影响,实测NDVI_max与模拟NDVI_max之间的残差为0.0863,表明生态保护与建设行动取得初步成效,其中黄河源区东部和长江源区通天河两侧的生态恢复效益最为明显,而在唐古拉山、昆仑山、布青山、阿尼玛卿山等山脉的周边地区,人类活动对生态环境仍表现为负影响;时间尺度上人类活动对植被的正影响呈现出下降趋势,2001-2010年NDVI_max残差的回归斜率为-0.0039,表明生态项目实施的短期行为严重,生态建设的效果缺乏长效性。     

Annual variation in the distribution of summer snowdrifts in the Kosciuszko alpine area,Australia, and its effect on the composition and structure of alpine vegetation

Abstract Australian alpine ecosystems are expected to diminish in extent as global warming intensifies. Alpine vegetation patterns are influenced by the duration of snow cover including the presence of snowdrifts in summer, but there is little quantitative information on landscape‐scale relationships between vegetation patterns and the frequency of occurrence of persistent summer snowdrifts in the Australian alps. We mapped annual changes in summer snowdrifts in the Kosciuszko alpine region, Australia, from Landsat TM images and modelled the frequency of occurrence of persistent summer snowdrifts from long‐term records (1954–2003) of winter snow depth. We then compared vegetation composition and structure among four classes that differed in the frequency of occurrence of persistent summer snowdrifts. We found a curvilinear relationship between annual winter snow depth and the area occupied by persistent snowdrifts in the following summer (r² = 0.9756). Only 21 ha (0.42% of study area) was predicted to have supported summer snowdrifts in 80% of the past 50 years, while 440 ha supported persistent summer snow in 10% of years. Mean cover and species richness of vascular plants declined significantly, and species composition varied significantly, as the frequency of summer snow persistence increased. Cushion plants and rushes were most abundant where summer snowdrifts occurred most frequently, and shrubs, grasses and sedges were most abundant in areas that did not support snowdrifts in summer. The results demonstrate strong regional relationships between vegetation composition and structure and the frequency of occurrence of persistent summer snowdrifts. Reductions in winter snow depth due to global warming are expected to lead to substantial reductions in the extent of persistent summer snowdrifts. As a consequence, shrubs, grasses and sedges are predicted to expand at the expense of cushion plants and rushes, reducing landscape vegetation diversity. Fortunately, few vascular plant species (e.g. Ranunculus niphophilus) appear to be totally restricted to areas where summer snow occurs most frequently. The results from this study highlight potential indicator species that could be monitored to assess the effects of global warming on Australian alpine environments.