Areas Of Vegetation Types Research Articles

Vegetation type classification and vegetation cover percentage estimation in urban green zone using pleiades imagery

Open green space in the urban area has aims to maintain the availability of land as a water catchment area, creating aspects of urban planning through a balance between the natural environment and the built environment that are useful for the public needs. Local governments have to make the green zone plan map and monitor the green space changes in their territory. Medium and high resolution satellite imageries have been widely utilized to map and monitor the changes of vegetation cover as an indicator of green space area. This paper describes the use of pleaides imagery to classify vegetation types and estimate vegetation cover percentage in the green zone. Vegetation cover was mapped using a combination of NDVI and blue band. Furthermore, vegetation types in the green space were classified using unsupervised and supervised (ISODATA and MLEN) methods. Vegetation types in the study area were divided into sparse vegetation, low-medium vegetation and medium-high vegetation. The classification accuracies were 97.9% and 98.9% for unsupervised and supervised method respectively. The vegetation cover percentage was determined by calculating the ratio between the vegetation type area and the green zone area. These information are useful to support green zone management activities.

山西植物功能型划分及其空间格局

PDF HTML阅读 XML下载 导出引用 引用提醒 山西植物功能型划分及其空间格局 DOI: 10.5846/stxb201312042886 作者: 作者单位: 山西大学黄土高原研究所,山西大学生命科学学院 山西大学黄土高原研究所,山西大学生命科学学院;山西大学黄土高原研究所 作者简介: 通讯作者: 中图分类号: Q948 基金项目: 科技部科技基础性工作专项(2011FY110300); 山西省自然科学基金项目(2013011037-1); 山西省回国留学人员科研资助项目(20100012) Classification of plant functional types and spatial pattern in Shanxi Province Author: Affiliation: Institute of Loess Plateau,Shanxi University;Institute of Loess Plateau,Shanxi University,,School of Life Science,Shanxi University;Institute of Loess Plateau,Shanxi University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:随着全球气候变化的加剧,作为沟通陆地生态系统与气候变化的桥梁,植物功能型(Plant Functional Types, PFTs)越来越受到生态学家的关注。PFTs不仅是简化生态系统复杂性的有效工具,而且可将植物的生理生态过程、生物物理特征及物候变化等引入到动态植被模型中,研究气候变化下的植被反应及其反馈机制。为了在区域尺度上研究气候变化和植被反应,基于"生态-外貌"原则,依据植物特征(如生长型、叶的性状)及其对水分、温度的需求,结合区域的气候与地理条件,对山西植被进行植物功能型的划分,并在此基础上对其空间格局进行分析。结果表明:(1)山西植被可划分为19类植物功能型(其中包括4类栽培作物功能型),分别是:寒温性常绿针叶林、温性常绿针叶林、寒温性落叶针叶林、温性落叶阔叶林、高寒落叶灌丛、温性落叶灌丛、多年生禾草草原、多年生禾草草丛、多年生禾草草甸、多年生莎草草甸、多年生杂类草草原、多年生杂类草草丛、多年生杂类草草甸。1年生杂类草草甸、多年生豆科草原、果树、一年一熟栽培作物、一年二熟栽培作物和二年三熟栽培作物。植物功能型的划分和分布与山西植被区划有较好的一致性,基本反映了植物固有特征及其对水热条件的需求。(2)农作物在山西占有较大比重,占植被类型面积的53.15%,森林类型以温性常绿针叶林和温性落叶阔叶林为主,灌丛类型以温性落叶灌丛为主,草本类型中多年生禾草草丛占较大比例,占草本类型面积的50.98%。(3)由于水热条件及地理条件的差异,植物功能型(不考虑栽培作物)在各区域表现出较大差异,如多年生杂类草草原主要分布于北部地区,在南部并不存在这种植物功能型;森林类型的功能型主要分布于中、南部地区,且结构复杂、类型多样。(4)除栽培作物表现出较好的整体性和连通性,其他植物功能型均表现出不同程度的破碎化和离散化。(5)山西植物功能型整体上表现出较高的多样性,其中中部地区比其他地区的多样性和破碎化程度高,斑块类型更加趋向于离散的小斑块状,北部地区则以一年一熟栽培作物占明显优势,表现出较强的优势度,而南部地区并没有表现出很强的破碎度或优势度。 Abstract:Plant Functional Types (PFTs) have been paid increasing attention last decades as the linkage between terrestrial ecosystem and climate change with the intensification of global climate change. PFTs are not only an effective tool to simplify the complexity of ecosystem, but also helpful when exploring the response and feedback mechanism of plant to the climate changes by introducing plant physiological, ecological process, biophysical characteristics and phenological change into the vegetation dynamic model. In order to investigate climate change and response to vegetation at regional scale, PFTs classification system was proposed under the "eco-physiognomy" principle based on plant characteristics (such as vegetative form, leaf traits), thermal characteristics and water availability, combined with the regional climate and geographical conditions in Shanxi. Furthermore, the spatial pattern of PFTs was discussed in this paper. The results showed that: (1) Nineteen PFTs, including four PFTs of cultivated crops were identified, namely, cold warm-temperate evergreen coniferous forest, warm-temperate evergreen coniferous forest, cold warm-temperate deciduous coniferous forest, warm-temperate deciduous broadleaf forest, cold warm-temperate deciduous shrub, warm-temperate deciduous shrub, perennial grass steppe, perennial grass community, perennial grass meadow, perennial sedge meadow, perennial forbs steppe, perennial forbs community, perennial forbs meadow, annual forbs meadow, perennial Legume steppe, fruit tree, one crop per annual, two crop per annual, and three crop two annual. The classification and distribution of plant functional types reflect the inherent characteristics and demand for water and thermal of plants, being consistent with vegetation regionalization of Shanxi Province. (2) Crops are dominant in Shanxi, accounting for 53.15% of the total vegetation type area. Forest and shrubs types are dominated by warm-temperate evergreen coniferous forest, warm-temperate deciduous broadleaf forest and warm deciduous shrubs, respectively. Perennial grass community occupies a large proportion, accounting for 50.98% of the total area of the herbaceous types. (3) PFTs (except for crop cultivation) show bigger difference in different regions due to hydrothermal and geographical conditions. For example, perennial forbs steppe mainly distributed in north Shanxi, rather than in the south Shanxi. Compared with north Shanxi, the functional types of forest mainly distributed in the central and south Shanxi, and its structure and types were complex and diverse. (4) The cultivation crops show good integrity and connectivity, while the other PFTs show the fragmentation and discretization. (5) PFTs of Shanxi show integrally high diversity. Compared with the other two parts, more fragmentation and higher diversity are found in the central Shanxi. One crop per annual mainly distributed in North Shanxi, while south Shanxi did not exhibit significant fragmentation and dominance. 参考文献 相似文献 引证文献

Breeding Bird Relationships to Landscape Metrics in Coastal Plain Georgia

Some avian species in the southeastern United States are declining, and population decreases may arise from changes in vegetation type area or structural condition. Our objective was to compare abundance of conservation priority bird species with landscape variables. We found, even in the highly forested Coastal Plain of Georgia, that areal extent and core area of cover types were related to abundance for certain bird species. Acadian flycatcher and field sparrow had models that incorporated positive area variables. Downy woodpecker, northern parula, orchard oriole, prairie warbler, and summer tanager had models that included positive area and edge associations with varying scales and vegetation types. Edge appeared in models for red-bellied woodpecker, blue jay, and brown-headed cowbird. More than half of all species did not have models that met prediction thresholds. Systematic assessment of area requirements for declining species provides information for management, conservation, and research.

The high‐latitude terrestrial carbon sink: a model analysis

SummaryA dynamic, global vegetation model, hybrid v4.1 (Friend et al. 1997), was driven by transient climate output from the UK Hadley Centre GCM (HadCM2) with the IS92a scenario of increasing atmospheric CO2 equivalent, sulphate aerosols and predicted patterns of atmospheric N deposition. Changes in areas of vegetation types and carbon storage in biomass and soils were predicted for areas north of 50°N from 1860 to 2100. Hybrid is a combined biogeochemical, biophysical and biogeographical model of natural, potential ecosystems. The effect of periodic boreal forest fires was assessed by adding a simple stochastic fire model. Hybrid represents plant physiological and soil processes regulating the carbon, water and N cycles and competition between individuals of parameterized generalized plant types. The latter were combined to represent tundra, temperate grassland, temperate/mixed forest and coniferous forest. The model simulated the current areas and estimated carbon stocks in the four vegetation types.It was predicted that land areas above 50°N (about 23% of the vegetated global land area) are currently accumulating about 0.4 PgC y−1 (about 30% of the estimated global terrestrial sink) and that this sink could grow to 0.8–1.0 PgC y−1 by the second half of the next century and persist undiminished until 2100. This sink was due mainly to an increase in forest productivity and biomass in response to increasing atmospheric CO2, temperature and N deposition, and includes an estimate of the effect of boreal forest fire, which was estimated to diminish the sink approximately by the amount of carbon emitted to the atmosphere during fires. Averaged over the region, N deposition contributed about 18% to the sink by the 2080 s. As expected, climate change (temperature, precipitation, solar radiation and saturation pressure deficit) and N deposition without increasing atmospheric CO2 produced a carbon source. Forest areas expanded both south and north, halving the current tundra area by 2100. This expansion contributed about 30% to the sink by the 2090 s. Tundra areas which were not invaded by forest fluctuated from sink to source. It was concluded that a high latitude carbon sink exists at present and, even assuming little effect of N deposition, no forest expansion and continued boreal forest fires, the sink is likely to persist at its current level for a century.

Changes in ecosystem carbon storage over 40 years on an old-field/forest landscape in east-central Minnesota

Organic carbon (C) storage in complex landscapes and its temporal change can be important in the global C budget. Change in C storage between 1938 and 1977 was estimated for a 2224 ha old-field/forest landscape in east-central Minnesota by coupling change in area of seven vegetation types (five forest and two non-forest) with vegetation-specific C densities (mg ha −1). Carbon densities were based on sampling carried out between 1974 and 1990. Areas of vegetation types in 1938 and 1977 were determined from aerial photographs. Carbon density was greatest in forest overstory (60–100 Mg ha −1) and organic and mineral soil (30–100 Mg ha −1 to 25 cm depth). Ecosystem C storage was approximately 212000 Mg in 1938 and 225000 Mg in 1977, an increase of ca. 13000 Mg across the study area. This was due largely to an increase in upland forest at the expense of non-forest area. The largest proportional increase in C storage was in trees (a 13% gain), while mineral soil gained 4% and herbs gained 6%. C storage in O horizon and shrubs remained constant. For the 20% of the landscape originally occupied by cultivated fields, an empirical model based on chronosequence studies indicated a 40% increase in C storage over 40 years; C increased in mineral soil, O horizon and trees as both herbaceous succession and forest encroachment occurred. Uncertainties of the estimates, based on propagation of standard errors, were 5% to 19% for C storage and 6% to 1000% for change in C storage. Uncertainty was due primarily to sample variability, but included uncertainty in biomass equations and GIS processing. This uncertainty demonstrates the difficulties associated with expanding from point sample data to landscape-scale estimates of C storage.