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1.
油蒿群落植物多样性动态   总被引:15,自引:4,他引:11  
王庆锁  梁艳英 《中国沙漠》1997,17(2):159-163
油蒿为鄂尔多斯高原植被的优势种和建群种,油蒿群落的植物多样性有向顶极阶段增加的趋势。植物多样性的季节变化与气候的季节变化密切相关。人类活动特别是过度放牧,引起油蒿群落的退化,导致植物多样性降低。围育可使退化的油蒿群落向正向演替进行,使群落的植物多样性提高。  相似文献   

2.
An analysis is made of the geobotanical forecasting technique. Mapping is known to be recognized as the most powerful method of forecasting-geobotanical investigations. A close interrelation between geobotanical forecasting and vegetation mapping is demonstrated. To improve objectivity of the findings used cartographic models of modern and predicted vegetation which most fully represent the entire structuralcenotic diversity of plant communities in Prebaikalia, the central region of Baikalian Siberia. The predictive constructions are based on analyzing modern vegetation which always includes structural features of its future that manifest themselves in primary and stable derivative communities. We developed the legend and compiled the map (sc 1:200 000) of the region’s modern vegetation. The state of the natural environment of the Lena- Angara interfluve is assessed having regard to the various functions of plant communities in geosystems. The 1:200 000 map of probability-forecasted (within 200 years) vegetation is presented for Lena-Angara interfluve. It is shown that complete recovery of the primary structure will not occur within 200 years. It is found that it is necessary to carry out predictive-cartographic investigations for the whole of Baikalian Siberia as vegetation of this region is characterized by a decreased activity of recovery processes occurring under the influence of anthropogenic factors. The reason has to do with the harsh natural conditions where it is not worthwhile to pursue extensive nature management, such as is universally the case to date, leading to undesirable economic consequences, because the degree of disturbance to vegetation in a number of areas of Prebaikalia has now reached as critical level. It is concluded that a further policy of nature management on this territory must be built upon the new principles to be approved by government documents.  相似文献   

3.
生态干扰度:一种评价植被天然性程度的方法   总被引:24,自引:1,他引:24  
地球上现存的植物或森林群落都是植被与其环境长期适应及人类长期干扰影响的结果 ,因此 ,现实的植被反映着历史上人类对它们不同程度的影响。‘生态干扰’的概念常常被用来描述历史上人类对植被或森林影响的大小 ,即‘生态干扰度’;或用来表示现实植被离开它的‘天然植被’的距离 ,即现实植被的‘天然性程度’。如此的‘天然植被’可以是 :( 1 )历史上从未受过人类任何干扰的‘原始植被’;( 2 )基于当前立地的‘潜在的自然植被’。然而 ,成百上千年以来人类对自然的利用干扰 ,致使真正的‘原始植被’现在几乎无处可寻。因此 ,‘潜在的自然植被’被用来作为生态干扰度估计或植被天然性程度评价的参照系。作为一种很实用的生态分析手段 ,生态干扰度的方法已被广泛地应用在农、林、水、景观、城市及自然保护等诸多领域的生态评价上。为此 ,本文论述了生态干扰度的概念、原理、方法和应用实例。  相似文献   

4.
A central role in the formation of the natural environment of Prebaikalia is played by vegetation having the environment-forming and environment-protective functions. Nowadays, it is experiencing ever increasing anthropogenic impacts which lead to disturbances in its structure and decrease its ecological potential. This creates certain challenges of a local and regional character, because the main territory of the region is within the zone of atmospheric influence and within the western portion of the central ecological zone of the Baikal natural territory focus on preserving the ecosystem of Lake Baikal as the UNESCO World Natural Heritage site. Therefore, the main direction of nature conservation activity aimed at improving the quality of the region’s natural environment remains focused on the preservation and recovery and of its primary vegetation. Some measures are suggested concerning ecologically oriented nature management in Prebaikalia. We have defined the goals for the scientific accompaniment of the measures for the preservation of vegetation as an important factor of the environmental quality. The paper demonstrates the effectiveness of integrated study into the entire florocenotic diversity of modern vegetation, its evolutionary-genetic basis and the ecological and dynamical potentials of plant communities for the purposes of forecasting the ecologically oriented development of the region’s natural environment. The recommendations are formulated in accordance with the State Ecological Program for the period until 2030. The map entitled “Protection of vegetation in Prebaikalia (recommendations for optimization of the ecological policy)” has been developed, which provides information on territories with a different environmental quality having regard to the ecological potential. The legend includes the following parts of the map: special preservation of primary vegetation (full and partial), recovery of disturbed vegetation (active and passive recovery of primary forests), and economic rational (ecologically oriented) use of vegetation.  相似文献   

5.
Species diversity influences plant community structure and function. This paper examines the patterns and dynamics of species diversity along a chronosequence of vegetation recovery on sand dunes in a semi-arid region to assess the probability of vegetation recovery via succession, and provides some implications for revegetation practices in this region. Species richness and diversity indices gradually increased with succession, except for a decline in the community of 18 years, which is attributed to the strong dominance of Artemisia halodendron. In each stage of the restoration process, there was a dominant species with particular life history traits which contribute to the dominance of this species. Species replacement and habitat changes were the main drivers of succession, while plant species and community succession drove the process of vegetation recovery. Results showed that restoration via succession holds promise for vegetation recovery and desertification control within protected, fenced enclosures.  相似文献   

6.
古尔班通古特沙漠纵向沙垄植被空间异质性   总被引:5,自引:3,他引:2  
在古尔班通古特沙漠南部纵向沙垄上按5 m×10 m的网格测度植被样方100个,采集浅层风沙土样品184件。调查发现,乔灌木层片和草本层片的分布及相互关系明显受沙垄地形影响,并且在干旱环境下种群间的竞争和空间上的互补使两层片生态优势度具有显著的相关性。地统计分析结果显示,纵向沙垄上植被空间异质性表现为木本层片的物种多样性呈斑块状分布,草本层片物种多样性呈现平行沙垄的带状结构和斑块结构叠加的特点,而植被盖度则在垂直沙垄走向的方向上具有强烈的梯度性变化。和沙垄土壤理化性质空间格局特征相对比,植被盖度及物种多样性与风沙土浅层含水量在自相关空间(变程)及空间异质性程度上比较接近。这是纵向沙垄小生态系统中草本植物和浅层土壤水分耦合关系在空间上的反映,也是木本植物对水分和土壤资源在小尺度(m)上竞争及中小尺度(10~100 m)上互补的结果。  相似文献   

7.
塔里木河下游植被生态需水量(英文)   总被引:4,自引:0,他引:4  
We have appraised the relationships between soil moisture,groundwater depth, and plant species diversity in the lower reaches of the Tarim River in western China,by analyzing field data from 25 monitoring wells across eight study sites and 25 permanent vegetation survey plots.It is noted that groundwater depth,soil moisture and plant species diversity are closely related.It has been proven that the critical phreatic water depth is five meters in the lower reaches of the Tarim River.We acquired the mean phreatic evaporation of different groundwater levels every month by averaging the two results of phreatic evaporation using the Qunk and Averyanov formulas.Based on different vegetation types and acreage with different groundwater depth,the total ecological water demand(EWD)of natural vegetation in 2005 was 2.4×108m 3in the lower reaches of the Tarim River.Analyzing the monthly EWD,we found that the EWD in the growth season(from April to September)is 81%of the year's total EWD.The EWD in May,June and July was 47%of the year's total EWD,which indicates the best time for dispensing artificial water.This research aims at realizing the sustainable development of water resources and provides a scientific basis for water resource management and sound collocation of the Tarim River Basin.  相似文献   

8.
Chagusaba, which is traditional tea-grass integrated system in Shizuoka, is one of Globally Important Agricultural Heritage Systems (GIAHS) sites in Japan. Chagusaba provide an important habitat for natural plant species. In this study, we investigated the flora in Chagusaba and environmental factors to affect the number of native species estimated their diversity. Fifty Chagusaba were classified in to five vegetation types by Two-way indicator species analysis. In addition, high number of native plant species Chagusaba had low soil pH, covered large areas, and were in places where the land had not been modified. Through statistical analysis (GLM), we found that land modification had an especially significant effect on the diversity of native plants, and that the diversity of native plants was reflected in the history of the use of the land.  相似文献   

9.
对洪河湿地主要植被类型物种多样性特征、土壤性质特征及二者之间的相互关系进行了研究。结果表明:按沼泽—沼泽化草甸—湿草甸—灌丛草甸—岛状林的序列,物种丰富度呈逐渐增加的变化格局,物种多样性、均匀度呈先下降后上升的格局,优势度呈先上升后下降的格局;而土壤性质特征则呈不规则变化格局。植物物种多样性与土壤性质之间只有均匀度与速效氮之间存在着极显著正相关,其他均无显著相关。这说明在洪河湿地,土壤性质不是决定上述序列的植被类型的物种多样性的主要因素,而土壤速效氮含量是影响物种均匀度的关键因素,同时,对其他物种多样性特征也有一定影响。  相似文献   

10.
Plant assemblages' dynamics have been studied to evaluate the influence of different environmental factors. The aim of our work was to assess the effect of a disturbance in the form of livestock grazing on annual plants, in a South American desert. We tested the exclusion of cattle grazing by comparing the composition of annual plants in three major vegetation types within a MaB Reserve in the Monte Desert of Argentina, with those of an adjacent grazed field. Sampling was conducted in two consecutive years that differed in precipitation. We established three sampling sites within each vegetation type at the reserve and the grazed field. Transects were set to assess plant cover, abundance, and richness. Theoretically, changes in diversity are explained by changes in one of its components: species richness. Species richness of annual plants was not different between the grazed and ungrazed sites. However, plant cover and diversity were lower in grazed sites, whereas abundance increased. Owing to a strong species-specific effect, we propose that it is evenness the main parameter involved in diversity dynamics in the heterogeneous vegetation mosaic of the Monte desert. Finally, vegetation types (spatial heterogeneity) and rainfall regime (temporal heterogeneity) greatly interacted with grazing effects. We endorse the idea that rapid responses of annual plant assemblages to changes in rainfall conditions coupled with herbivore control, might result in a restoration pathway for degraded arid landscapes.  相似文献   

11.
We have appraised the relationships between soil moisture, groundwater depth, and plant species diversity in the lower reaches of the Tarim River in western China, by analyzing field data from 25 monitoring wells across eight study sites and 25 permanent vegetation survey plots. It is noted that groundwater depth, soil moisture and plant species diversity are closely related. It has been proven that the critical phreatic water depth is five meters in the lower reaches of the Tarim River. We acquired the mean phreatic evaporation of different groundwater levels every month by averaging the two results of phreatic evaporation using the Qunk and Averyanov formulas. Based on different vegetation types and acreage with different groundwater depth, the total ecological water demand (EWD) of natural vegetation in 2005 was 2.4×108 m3 in the lower reaches of the Tarim River. Analyzing the monthly EWD, we found that the EWD in the growth season (from April to September) is 81% of the year’s total EWD. The EWD in May, June and July was 47% of the year’s total EWD, which indicates the best time for dispensing artificial water. This research aims at realizing the sustainable development of water resources and provides a scientific basis for water resource management and sound collocation of the Tarim River Basin.  相似文献   

12.
以额河源流采金后废弃矿区为研究对象,于2011—2015年期间,通过采取不同恢复措施从被破坏矿区草地植物多样性和生物量的角度分析植被恢复效果。结果表明:(1)不同恢复措施促使各植物群落的物种数增加了5%~30%,说明采取恢复措施使得矿区生态环境得到了一定程度的恢复。(2)综合植被群落结构、盖度和地上生物量、物种多样性指数分析,措施A5(推平+圈羊)、A4(推平+补水)、A3(推平+覆土+黑加仑)较其他措施恢复效果更为显著。(3)通过对各样地植被丰富度指数(R)、Shannon Wiener指数(H′)、Simpson指数(D)、Pielou (Jsw)指数与地上生物量分别进行回归分析,发现指数曲线拟合关系最好。表明物种多样性与地上生物量均存在较显著的正相关关系(P <0.05)。本研究可为类似矿区的植被恢复与重建提供参考和借鉴。  相似文献   

13.
科尔沁沙地植物多样性对生产力的影响及分布格局   总被引:1,自引:3,他引:1  
采用种丰富度和以Shannon-Wiener指数为计算方法的功能多样性和组成多样性为指标,探讨了植物多样性对科尔沁沙地草场生产力的影响以及其分布格局特征。结果表明,科尔沁沙地植被不同的物种多样性指数对系统生产力的影响以组成多样性最大,功能多样性次之,植物种丰富度最小。在小尺度上,组成多样性只存在一种格局且具有分形结构,其格局对干扰过程反应不明显;功能多样性有多种格局存在,对多种干扰过程反应敏感。从提高沙地草场生产力和增强系统的稳定性角度出发,草场改良的依据应建立在种的引进和引进种所产生的组成多样性上。  相似文献   

14.
Schwarzsee is located in the western Swiss Alps, in a region that has been affected by numerous landslides during the Holocene, as evidenced by geological surveys. Lacustrine sediments were cored to a depth of 13 m. The vegetation history of the lake's catchment was reconstructed and investigated to identify possible impacts on slope stability. The pollen analyses record development of forest cover during the middle and late Holocene, and provide strong evidence for regional anthropogenic influence such as forest clearing and agricultural activity. Vegetation change is characterized by continuous landscape denudation that begins at ca. 4300 cal. yrs BP, with five distinct pulses of increased deforestation, at 3650, 2700, 1500, 900, and 450 cal. yrs BP. Each pulse can be attributed to increased human impact, recorded by the appearance or increase of specific anthropogenic indicator plant taxa. These periods of intensified deforestation also appear to be correlated with increased landslide activity in the lake's catchment and increased turbidite frequency in the sediment record. Therefore, this study gives new evidence for a strong influence of vegetation changes on slope stability during the middle and late Holocene in the western Swiss Alps, and may be used as a case study for anthropogenically induced landslide activity.  相似文献   

15.
We assessed components of woody plant diversity within and between 16 sites dispersed across the nearly 200,000 ha of the Semi-arid Chaco vegetation of the Copo Conservation Unit, northern Argentina. Argentina's Semi-arid Chaco is an object of international conservation concern, as it is under pressure from conversion to agroindustry supplanting long-standing practices of logging and livestock grazing. We recorded from 16 (shrubby grassland following forest fire) to 27 (selectively logged forest) woody plant species per site and 37 species in total (gamma diversity). Additive partitioning showed that alpha diversity contributed 59% to gamma diversity and beta diversity only 41%. A separate additive partitioning of gamma diversity of the 13 forested sites alone showed that beta diversity attributable to logging history was considerably lower than remaining beta diversity and alpha diversity. Ordination analyses confirmed this finding: species composition of unlogged, selectively logged and intensively logged forest sites was quite similar. Results suggest that (1) woody vegetation, at least, of the Semi-arid Chaco is quite tolerant to traditional modes of land use and that (2) conservation of this vegetation as a whole must include not only “pristine” sites varying in edaphic conditions but also sites varying in land use and management histories.  相似文献   

16.
程占红  赵蒙 《干旱区地理》2012,35(4):578-586
 物种多样性是衡量景区生态环境质量的重要指标之一。通过计算物种的多样性指数、科属、区系、生活型和生态型特征,利用除趋势对应分析方法对五台山旅游干扰下植物多样性的格局进行了研究,结果表明:在不同地理因子和物种多样性的作用下,各类植被景观区表现出一定的格局规律。在排序图上,以灌木层和草本层植物为主的Ⅲ区、Ⅳ区和Ⅶ区位于左侧,以乔木层、灌木层和草本层植物为主的Ⅰ区、Ⅱ区、Ⅵ区和Ⅴ区位于中间,仅有乔木层的Ⅸ区位于右侧。坡位、海拔和旅游影响系数与DCA第一轴和第二轴的相关性均较大,说明这3个因子对植物多样性的格局有重要影响。研究结果有益于五台山景区的生态管理。  相似文献   

17.
We analyzed the structural differences associated with grazing exclusion on vegetation by studying 24 grazed-ungrazed paired sites in Patagonia (Argentina). Our objectives were to evaluate the effect of grazing on plant species composition, plant diversity, the relative abundance of plant functional types, and the vertical and horizontal structure of the plant community. This study across the shrub-grass steppes of Patagonia highlights some important characteristics of the vegetation response to a major disturbance factor we show that shrub encroachment is not a generalized response of the steppe to grazing. Grazed areas presented lower richness and diversity than exclosures. Physiognomic changes (as describe by relative abundance of plant functional types) were less important than those observed at the species level. These results shown that the status of the shrub-grass steppes of the Occidental district of Patagonia can not be characterized in terms of contrasting physiognomic states as in the case of the grass steppes of the Subandean district. Forbs and a few mesophytic and xerophytic grasses are the key elements to identify the condition of the steppe. Monitoring programs should focus on the relative abundance of these components.  相似文献   

18.
We bring up the issue related to the need and importance of undertaking an assessment of the present status of vegetation in Prebaikalia. The vegetation of this region has long been experiencing strong anthropogenic destructions, especially in the southern, more developed, areas. Anthropogenic impacts on vegetation continue to be enhanced thus influencing the processes of spontaneous development of vegetation and decreasing its ecological potential. Assessment of the present status of vegetation as a complex self-evolving autotrophic natural entity having its own evolutionary history of development and dynamical potential is used in reference to identifying and evaluating the degree of disturbance of its native (spontaneous) florocenotic structure. To improve objectivity of research results uses a cartographic method supported by GIS technologies. On the basis of the principles of a structural-dynamical classification of plant communities as suggested by V. B. Sochava, we compiled a universal geobotanical medium-scale (1:500 000) map for Prebaikalia. The map was generated for two purposes: inventory, i.e. identifying the typological belonging of existing plant communities in the region, and for assessment–dynamical purpose to identify the epitaxon structure of the entire vegetation cover. These efforts were accompanied by a formalized assessment of the age structure of tree stands of the region’s forest communities as well as a clear differentiation between forest and non-forest vegetation by identifying new burns and felling areas. The findings formed the basis for generating a detailed 1:500 000 map of disturbances to Prebaikalia’s vegetation displaying 11 kinds of vegetation disturbances ranging from the persisting native communities to those substituted by agrocenoses and introductions of urban settlements. A general outline of the present status of vegetation is provided as well as the main directions for nature management optimization in the region within the framework of the state ecological policy.  相似文献   

19.
Plant diversity is used as an indicator of the well-being of vegetation and ecological systems. Human activities and global change drive vegetation change in composition and competition of species through plant invasions and replacement of existing species on a given scale. However, species diversity indices do not consider the effects of invasions on the diversity value and on the functions of ecosystems. On the other hand, the existing methods for diversity index can not be used directly for cross-scale evaluation of vegetation data. Therefore, we proposed a 3-dimensional model derived from the logistic equation for estimating vegetation change, using native and non-native plant diversity. The two variables, based on the current and the theoretical maximum diversity of native plants on a given scale, and the result of the model are relative values without units, and are therefore scale-independent. Hence, this method developed can be used directly for cross-scale evaluations of vegetation data, and indirectly for estimating ecosystem or environmental change.  相似文献   

20.
This article offers a review of published knowledge and a new state-of-the-art analysis regarding the floristic composition, the functional composition and the plant communities found in the central Namib Desert. At the same time, this paper contributes to the understanding of the relationship between the plant species composition of the central Namib Desert and the prevailing environmental gradients, with an emphasis on diversity and ecology in space and time. This article builds on three thematic foci. The first focus (1) lies on the present knowledge of the composition and the characteristics of the flora. A comprehensive floristic database has been compiled based on all available sources. A second focus (2) lies on the characterization and spatial distribution of the vegetation units. Therefore, we created a new vegetation classification based on a unique vegetation-plot database (http://www.givd.info/ID/AF-00-007) and additional data summing up to 2000 relevés, resulting in 21 large-scale vegetation classes. Using a supervised classification approach based on the vegetation classification, remote sensing and environmental data, we were able to produce a new vegetation map of the Central Namib. This was updated using expert knowledge, field visits and through manual preprocessing. With the third focus (3) we explore the spatial patterns of the previous foci and discuss their relation to environmental parameters and gradients.  相似文献   

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