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1.
A prerequisite to sustaining ecosystems is the inventory and classification of landscape structure and composition. Ecological classification and mapping involves the delineation of landscapes into easily recognizable units. Topography, soils, vegetation, physical landscape form, and successional pathways are delineation criteria commonly used.Damman (1967) developed a forest type classification system for Newfoundland using vegetation, soil and landforms as the defining criteria. Damman's forest types were used in combination with mensurational data to assign forest types to timber volume productivity classes. Since each of the Damman forest types is associated with characteristic soils, parent materials, moisture regime and topographic position, the mapping units are similar to Canada Land Inventory (CLI) mapping units. Field work to confirm the correlation between Damman forest types and CLI capability classes was initiated in 1993. CLI maps were recoded in 1994 and Damman forest types were determined; resulting ecosystem-based maps provide a common framework to assess forestry/wildlife interactions in an ecosystem planning process.  相似文献   

2.
Land cover changes affect ecological landscape spatial pattern, and evolving landscape patterns inevitably cause an evolution in ecosystem functionality. Various ecological landscape variables, such as biological productivity (plant biomass and stock capacity), soil nutrients (organic matter and N content) and water source conservation capacity are identified as landscape function characteristics. A quantitative method and digital model for analyzing evolving landscape functionality in the headwaters areas of the Yangtze River, China were devised. In the period 1986–2000, patch transitions of the region's evolving landscapes have been predominantly characterized by alpine cold swamp meadow, with the highest coverage tending to be steppified meadow or steppe, and desertification landscape such as sand and bare rock land expansion. As the result of such changes, alpine swamp areas decreased by 3.08 × 103 km2 and the alpine cold sparse steppe and bare rock and soil land increased by 6.48 × 103 km2 and 5.82 × 103 km2, respectively. Consequently, the grass biomass production decreased by 2627.15 Gg, of which alpine cold swamp meadows accounted for 55.9% of this loss. The overall stock capacity of the headwaters area of the Yangtze River decreased by 920.64 thousand sheep units, of which 502.02 thousand sheep units decreased in ACS (Alpine cold swamp) meadow transition. Soil organic matter and N contents decreased significantly in most alpine cold meadow and swamp meadow landscape patches. From 1986 to 2000 the total losses of soil organic matter and total N in the entire headwaters region amounted to 150.2 Gkg and 7.67 Gkg. Meanwhile, the landscape soil water capacity declined by 935.9 Mm3, of which 83.9% occurred in the ACS meadow transition. In the headwater area of the Yangtze River, the complex transition of landscape resulted in sharp eco-environmental deterioration. The main indication for these changes involved the intensity of the climate in this region is becoming drier and warmer, resulting in a gradual degradation of the permafrost.  相似文献   

3.
Susceptibility to landslides in mountain areas results from the interaction of various factors related to relief formation and soil development. The assessment of landslide susceptibility has generally taken into account individual events, or it has been aimed at establishing relationships between landslide-inventory maps and maps of environmental factors, without considering that such relationships can change in space and time. In this work, temporal and space changes in landslides were analysed in six different combinations of date and geomorphological conditions, including two different geological units, in a mountainous area in the north-centre of Venezuela, in northern South America. Landslide inventories from different years were compared with a number of environmental factors by means of logistic regression analysis. The resulting equations predicted landslide susceptibility from a range of geomorphometric parameters and a vegetation index, with diverse accuracy, in the study area. The variation of the obtained models and their prediction accuracy between geological units and dates suggests that the complexity of the landslide processes and their explanatory factors changed over space and time in the studied area. This calls into question the use of a single model to evaluate landslide susceptibility over large regions.  相似文献   

4.
Transboundary air pollution from industries in Nikel and Zapolyarnij has caused severe damage to the environment in Southern-Varanger in Norway and in Pechenga municipality in Russia. The work presented in this paper focuses on the integration of in-situ air pollution data with remote sensing based land cover maps. Land cover maps have been utilised to detect changes in the major land cover types within the area. The major change in the environment was the decrease of the sensitive lichen-dominated land cover types, and the increase of bilberry-dominated land cover types and finally the increase of the land cover types with the greatest air pollution stress (industrial barren, barren, and partly damaged vegetation, defoliated forests, lichen removal). A GIS based method for assessing the relationship of the remotely sensed land cover maps with the environmental condition parameters was developed and applied. By comparing the results from this analysis we observed that the land cover types with the greatest stress had the largest concentrations of SO2 in the ground air layer, while the land cover types with minor damage (the remaining lichen-dominated vegetation) had rather low concentrations of sulphur dioxide in the ground air layer. The area of the land cover types with the greatest stress (industrial barren, barren and partly damaged vegetation) has increased in the period 1973–1988, and the degradation is carried out in a such manner that sensitive mountain and lichen vegetation formations have been transformed into a more barren-like environment. The increase in the emissions has also transferred the natural barrens which also consisted of some sparse vegetation into a complete barren with little vegetation left. Also the epilitic lichens and mosses on bare rocks and stones were also removed by the high concentrations of SO2. The land cover types with minor damage (with the remaining lichen-dominated vegetation) had rather low concentrations of the contaminants (SO2, Ni and S), while the partly damaged and damaged land cover types had the highest concentrations of the contaminants. An exception was the Ni and S concentrations found in class 11 Industrial barrens which were lower than expected. Associations between the degradation and the SO2 concentration in the air were also documented. The conclusion from this analysis is that the in-situ data support the observations of damaged vegetation and industrial barrens imaged by the Landsat satellites, especially in the surroundings of Nikel and Zapolyarnij.  相似文献   

5.
Both the net primary productivity (NPP) and the normalized difference vegetation index (NDVI) are commonly used as indicators to characterize vegetation vigor, and NDVI has been used as a surrogate estimator of NPP in some cases. To evaluate the reliability of such surrogation, here we examined the quantitative difference between NPP and NDVI in their outcomes of vegetation vigor assessment at a landscape scale. Using Landsat ETM+ data and a process model, the Boreal Ecosystem Productivity Simulator, NPP distribution was mapped at a resolution of 90 m, and total NDVI during the growing season was calculated in Heihe River Basin, Northwest China in 2002. The results from a comparison between the NPP and NDVI classification maps show that there existed a substantial difference in terms of both area and spatial distribution between the assessment outcomes of these two indicators, despite that they are strongly correlated. The degree of difference can be influenced by assessment schemes, as well as the type of vegetation and ecozone. Overall, NDVI is not a good surrogate of NPP as the indicators of vegetation vigor assessment in the study area. Nonetheless, NDVI could serve as a fairish surrogate indicator under the condition that the target region has low vegetation cover and the assessment has relatively coarse classification schemes (i.e., the class number is small). It is suggested that the use of NPP and NDVI should be carefully selected in landscape assessment. Their differences need to be further evaluated across geographic areas and biomes.  相似文献   

6.
Mentougou District acts as a crucial component in the ecological buffer in western Beijing mountainous areas, Beijing, China. Using two Landsat MSS/TM images acquired on July 14, 1979 and July 23, 2005, the vegetation coverage of Mentougou District was calculated based on normalized difference vegetation index and spectral mixture analysis (NDVI-SMA) model. Its temporal and spatial changes were analyzed according to digital elevation model (DEM) image, social and economic data. The results showed that the vegetation coverage decreased from 76.4% in 1979 to 72.7% in 2005. Vegetation degradation was probably the result of human disturbance, such as outspreading of resident areas, and coal and stone mining activities, while vegetation restoration might be contributed by the combined effects of both natural processes and ecological construction effort. Vegetation changes were closely related to topographical characteristics. Plants at high altitude were more stable and less degraded than the plants at low altitude, while the plants on steep slope or northwest aspect were more vulnerable to degradation. During the period of 26 years, landscape appeared to become more fragmental, and ecological quality of the land seemed deteriorated sharply in that highly-covered vegetation area has been decreased by 24%.  相似文献   

7.
Ozone levels in the Jizerske hory Mts. measured at 13 sites by diffusive samplers during the 2006 and 2007 vegetation seasons are presented. A significant ozone gradient (5.4 ppb in 2006 and 4.0 ppb in 2007) per 100 m difference in altitude between 370 and 1,100 m a.s.l. was recorded. High-resolution maps of phytotoxic potential were developed. The AOT40 threshold (5 ppm h) was exceeded over the entire area with the highest levels exceeding this threshold by 12 times in the upper portions of the mountains. Ozone visible injury was evaluated at four of the monitoring sites on seven native plant and tree species. Four species showed ozone-like symptoms, two of which (Rubus idaeus and Fagus sylvatica) were confirmed as ozone-induced. Our results indicate that ambient ozone is likely to have a much lower impact on the Jizerske hory Mts. vegetation than expected, considering the measured ambient ozone exposures and favourable environmental conditions for ozone uptake.  相似文献   

8.
Wetland loss has been the major environmental problem in Sanjiang Plain, NE China in recent years because of the dramatic agricultural development. We determined the spatial associations of the wetland loss rates in an 11,000-km2 study area for two intervals of period 1 (1975–1989) and period 2 (1989–2004) spanning 30 years by using geographic information systems. The landscape of this area was simple with five categories, composed of ten types, and including three natural wetland types—open water, marsh, and wet meadow. Extensive agriculture was the principal cultivation form in terms of large size farm units in the area. Agriculture has become the principal land use category replacing natural wetlands over the 30-year period. It has changed the whole landscape of the region and the landscape pattern, causing wetland loss and fragmentation. The wetland loss rate of the area was very different between the two intervals, while wetland loss was not uniform throughout the region and was influenced by the landscape characteristics, such as topography, geomorphology, and the location of the wetlands in the watershed. Despite the remarkable land use changes, the wetlands distribution in the landscapes was similar compared to their original pattern. These results indicated that agricultural development affected the areas more than the distribution pattern of the wetlands in this region.  相似文献   

9.
Bafa Lake Nature Park is one of Turkey’s most important legally protected areas. This study aimed at analyzing spatial change in the park environment by using object-based classification technique and landscape structure metrics. SPOT 2X (1994) and ASTER (2005) images are the primary research materials. Results show that artificial surfaces, low maqui, garrigue, and moderately high maqui covers have increased and coniferous forests, arable lands, permanent crop, and high maqui covers have decreased; coniferous forest, high maqui, grassland, and saline areas are in a disappearance stage of the land transformation; and the landscape pattern is more fragmented outside the park boundaries. The management actions should support ongoing vegetation regeneration, mitigate transformation of vegetation structure to less dense and discontinuous cover, control the dynamics at the agricultural–natural landscape interface, and concentrate on relatively low but steady increase of artificial surfaces.  相似文献   

10.
Urban green spaces play a significant role in management of physical activity, psychological well-being, and public health of urban residents. With the expansion of urban areas in Turkey during the past decades, urban green spaces have been fragmented and dispersed causing impairment and environmental degradation. The purpose of this study is to model urban green space distribution by focusing on the landscape fragmentation in city of Osmaniye using remote sensing and geographic information system technology. Normalized difference vegetation index (NDVI) and urban landscape ratio (ULR) were used to assess the proximity and spatial arrangement of urban green spaces within the neighbor landscapes to quantify the urban land use effect. The geospatial analysis results showed that increase in total built-up area and population has significantly decreased the urban green space cover because of high levels of landscape fragmentation in urban city center. Also, due to high levels of landscape fragmentation, approximately 45% of the Osmaniye city is estimated to become urbanized by 2030. This study demonstrated the benefits of directional vegetation index application with geospatial analyses in characterizing the environmental quality for planning and management of urban green spaces. This approach could be used for determining the future urban land development scenarios correlating with regional planning procedures.  相似文献   

11.
新疆艾比湖流域平原区景观植被属性特征研究   总被引:1,自引:0,他引:1  
李新琪  朱海涌 《干旱环境监测》2009,23(4):236-240,F0004
在对新疆艾比湖流域平原区进行景观生态分类的基础上,利用“3S”技术叠置研究区草地资源类型图与景观类型图,对研究区景观植被属性特征进行分析。结果表明,研究区主要为荒漠、草原和草甸,共有33个植物群落类型,小蓬荒漠、梭梭荒漠、刚毛柽柳荒漠等各类荒漠面积合计约占研究区总面积的74.10%,芦苇草甸、含胡杨的芦苇草甸及矮嵩草草甸等各类草甸及草原面积也较大,占研究区总面积的18.34%。  相似文献   

12.
平顶山地区景观格局动态特征及驱动力分析   总被引:1,自引:0,他引:1  
以平顶山地区为研究对象,利用平顶山地区1992年Landsat-TM影像和2006年中巴资源卫星遥感影像,运用景观生态学原理,借助遥感和GIS技术,选取景观多样性、景观优势度、景观均匀度、景观破碎度等指标指数进行分析,揭示平顶山地区近14 a来城市景观格局演变及其驱动力。研究结果表明:交通用地、工矿及居民点和耕地用地显著增加,林地、水域显著减少;除工矿及居民点外,该地区各类型斑块数量均有增加,其中林地增加最为显著;交通用地、工矿及居民点的破碎度降低,水域、林地、耕地的景观类型破碎度增高;耕地的分维数、形状指数呈下降趋势,而林地的分维数和形状指数呈上升趋势;平顶山地区景观多样性和均匀度都呈下降趋势,而优势度和破碎度增加;景观格局变化受人为因素影响较大,人口增加、经济发展、城镇化和工业发展是平顶山地区景观格局演变的主要驱动力。  相似文献   

13.
In this research, the improved Terrestrial Ecosystem Regional (TECO-R) model was adapted to steppe ecosystems and then utilized to simulate the soil organic carbon pool in the period from 1989 to 2011 (excluding 1994, 2002, 2009, and 2010) for a typical steppe in Xilingol League of Inner Mongolia in China. The improved TECO-R model is an ecological model in combination of remote sensing data, which allows the spatial scale for the analysis of soil organic carbon which is not limited to vegetation or soil type. The spatial and temporal resolution advantages of remote sensing image can be well utilized in this model. The results indicate that in addition to an accurate simulation of the soil carbon pool of a steppe ecosystem, the vegetation aboveground carbon pool, grazing intensity of herbivores, mowing coefficient, litter carbon pool, root carbon pools of different vegetation layers, root-shoot ratio, actual residence time of different carbon pools, and allocation coefficients of different carbon pools in corresponding years are also available from the TECO-R model. Some of the above data are difficult to obtain through macro-observation but can be simulated with the TECO-R model by combining the model with input data; this is very important for a correct understanding of the feedback relationships between the steppe ecosystem’s carbon cycle and climate change (e.g., global warming) and human activities such as grazing.  相似文献   

14.
Monitoring land use and land cover change (LUCC) and understanding forest cover dynamics is extremely important in sustainable development and management of forest ecosystems. This study analyzed the spatial and temporal pattern of LUCC in the Yaln?zçam and U?urlu forest planning units which are located in the northeast corner of Turkey. The investigation also evaluates the temporal changes of the spatial structure of forest conditions through the spatial analysis of forest-cover type maps from 1972 and 2005 using geographical information systems and FRAGSTATSTM. As an overall change between 1972 and 2005, there was a net increase of 1,823 ha in forested areas, and cumulative forest improvement accounted for 2.06 %. In terms of spatial configuration, the landscape structure in the study area changed substantially over the 33-year study period, resulting in fragmentation of the landscape as indicated by large patch numbers and smaller mean patch sizes, owing to heavy grazing, illegal cutting, and uncontrolled stand treatments.  相似文献   

15.
16.
This study was aimed at analyzing and interpreting changes in landscape pattern and connectivity in the Urla district, Turkey using core landscape metrics based on a 42-year data derived from 1963 CORONA and 2005 ASTER satellite images and ten 1/25,000 topographical maps (1963–2005). The district represents a distinctive example of re-emerged suburbanization in the Izmir metropolitan area. In order to explore landscape characteristics of the study area, nine landscape composition and configuration metrics were chosen as follows: class area, percentage of landscape, number of patches, patch density, largest patch index, landscape shape index, mean patch size, perimeter area fractal dimension, and connectance index. The landscape configurations in the Urla district changed significantly by 2005 in that the process of (sub-)urbanization in the study area evolved from a rural, monocentric urban typology to a more suburban, polycentric morphology. Agricultural, maquis-phrygana, and forest areas decreased, while the built-up, olive plantation and phrygana areas increased. There was nearly a fivefold increase in the built-up areas during the study period, and the connectivity of the natural landscape declined. To prevent further fragmentation, it is important to keep the existing natural land cover types and agricultural areas intact. More importantly, a sustainable development scenario is required that contains a green infrastructure, or an ecological network planning for conservation and rehabilitation of the vital natural resources in the study area.  相似文献   

17.
We utilized landscape and breeding bird assemblage data from three Breeding Bird Survey (BBS) routes sampled from 1965–1995 to develop and test a grassland integrity index (GII) in a mixed-grass prairie area of Oklahoma. The overall study region is extensively fragmented from long-term agricultural activity, and native habitat remnants have been degraded by recent encroachment of woody vegetation, namely eastern redcedar (Juniperus virginiana L.). The 50 individual bird survey points along the BBS routes, known as stops, were used as sample sites. Our process first focused on developing a grassland disturbance index (GDI) as a measure of cumulative landscape disturbances for these sites. The GDI was based on five key landscape variables identified in an earlier species-level study of long-term avian community dynamics: total tree, shrub, and herbaceous vegetation cover indices, overall mean landscape patch size, and grassland patch core size. The GII was then developed based on breeding bird assemblage data. Assemblages were based on commonly used response guilds reflective of five avian life history parameters: foraging mode/location, nesting location, habitat specificity, migratory pattern, and dietary guild. We tested the response of 78 candidate assemblage metrics to the GDI, and eliminated those with no or poor response or with high correlations (redundant), resulting in 13 metrics for use in the final index. Individual metric scores were scaled to fall between 0 and 10, and the cumulative index to range from 0 to 100. Although broader application and refinement are possible, the avian-based GII has an advantage over labor-intensive, habitat-based monitoring in that the GII is derived from readily available long-term BBS data. Therefore, the GII shows promise as an inexpensive tool that could easily be applied over other areas to monitor changes in regional grassland conditions.  相似文献   

18.
李磊  李艳红 《干旱环境监测》2013,(4):154-159,183
选取艾比湖流域1990年、2001年、2011年同期(9月)3期I.and.satTM遥感影像,基于归一化植被指数NDVI,提取植被覆盖等级图,利用ArcGIS9.3和Fragstas3.3对该流域植被景观的变化进行了分析研究。结果表明:1990—2011年,该流域植被覆盖度变化明显,低植被覆盖区和较低植被覆盖区都有所减少,分别由1990年的34.05%和32.94%减少到2011年的32.8%和24.06%;较高植被覆盖区和高植被覆盖区有所增加,分别由8.49%和5.20%增长到15.13%和9.83%,但水域面积退化明显,由1990年的525.9765km2缩小至494.9876km2,减少了30.9889km2,退缩幅度达O.4%;最大斑块指数(LPI)由17.04上升到21.10,香农多样性指数(SHDI)和香农均势度指数(SHEI)分别由1.5387和0.8588增长到1.6395和0.9150。表明艾比湖流域景观格局混杂程度愈来愈高,空间异质性在逐年加强,总体空间格局向破碎化趋势发展。  相似文献   

19.
通过对新疆那拉提高寒草甸天然草地进行围栏(3、5、30 a)和自由放牧处理,探讨草地不同利用方式对草地植物多样性和生物量的影响。结果表明,在自由放牧制度下,由于干扰过于剧烈,草地已呈退化趋势,物种多样性和生物量均较低;在围栏草地中,随着围封年限的增加,群落高度、盖度、地上生物量逐渐增加;地上生物量的变化趋势为放牧草地围栏3 a草地围栏5 a草地围栏30 a草地。  相似文献   

20.
The potential ecological impact of ongoing climate change has been much discussed. High mountain ecosystems were identified early on as potentially very sensitive areas. Scenarios of upward species movement and vegetation shift are commonly discussed in the literature. Mountains being characteristically conic in shape, impact scenarios usually assume that a smaller surface area will be available as species move up. However, as the frequency distribution of additional physiographic factors (e.g., slope angle) changes with increasing elevation (e.g., with few gentle slopes available at higher elevation), species migrating upslope may encounter increasingly unsuitable conditions. As a result, many species could suffer severe reduction of their habitat surface, which could in turn affect patterns of biodiversity. In this paper, results from static plant distribution modeling are used to derive climate change impact scenarios in a high mountain environment. Models are adjusted with presence/absence of species. Environmental predictors used are: annual mean air temperature, slope, indices of topographic position, geology, rock cover, modeled permafrost and several indices of solar radiation and snow cover duration. Potential Habitat Distribution maps were drawn for 62 higher plant species, from which three separate climate change impact scenarios were derived. These scenarios show a great range of response, depending on the species and the degree of warming. Alpine species would be at greatest risk of local extinction, whereas species with a large elevation range would run the lowest risk. Limitations of the models and scenarios are further discussed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

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