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1.
The shortage of fresh water in Turkmenistan may be partially alleviated by runoff water from takyrs. However, anthropogenic degradation of takyrs over the past few decades has reduced their efficacy as catchment areas. The main goal of this study was to map the spatial extent of takyrs and their change over time. Digital image processing of Landsat MSS and Landsat 7 ETM+ images were used to identify, map and classify the takyrs and estimate their overall area and degradation rates. Thereafter, a change detection procedure was applied. Results retrieved from Landsat MSS images of southern Turkmenistan (1972-1975) showed a total area of non-degraded takyr surfaces of ∼20,000 km2, whereas those from Landsat 7 ETM+ images (2002-2003) showed a total non-degraded takyr area of ∼16,000 km2. These include ∼8000 km2 which were degraded and ∼4000 km2 that were only detected by the ETM+ due to its improved spectral resolution. Accuracy was assessed by comparing the Landsat results with higher spatial resolution images of QuickBird. Additional ground points located with GPS measurements validated the classification results. We were thus able to assess the takyr areas degraded over the past decades, and find ∼16,000 km2 of non-degraded takyrs suitable for water harvesting.  相似文献   

2.
The Nord region of northern France, comprising the départements of the Nord and the Pas-de-Calais, epitomises the economic and social problems endured by many areas of the developed world which underwent rapid industrial growth and urbanisation in the nineteenth and early twentieth centuries but have experienced economic contraction and social depression since 1950. In 1968 the Nord region contained 3.8 million inhabitants (7.6 per cent of the French population) on 12,000 km2 (2.3 per cent of the national area) at an average density of 308 persons/km2, by comparison with the national average of 91/km2 (Roques 1969, p. 7). Eighty-one per cent of the regional population lived in urban areas, by contrast with 67 per cent nationally.  相似文献   

3.
Glacial lakes and glaciers are sensitive indicators of recent climate change. In the Poiqu River basin of southern Tibet, 60–100 km NW of Mt. Everest, Landsat imagery defines post-1986 changes in the size and distribution of both glacial lakes and glaciers. Total area of glaciers in the 229-km2 drainage area has decreased by 20%. The number of glacial lakes with areas in excess of 0.020 km2 has increased by 11%, and the total area of glacial lakes has increased by 47%. The areas of typical large glacial lakes of the area (Galongco, Gangxico, and Cirenmaco) have increased by 104, 118, and 156%, respectively, and these increases are confirmed by field investigations.Comparing the 1986 data, the area of glaciers in the basin headwaters has decreased by 46.18 km2 to a present total area of 183.12 km2, an annual rate of change of 3.30 km2/year. Trends indicate that the total area of glaciers will continue to decrease and that both the numbers and areas of glacial lakes will continue to increase. Accompanying these trends will be an increased risk of debris flows, formed by entrainment of sediment in glacial-outburst floods and in surges from both failure and avalanche- and landslide-induced overtopping of moraine dams. Based on both the local and world-wide history of catastrophes from flows of these origins, disaster mitigation must be planned and appropriate engineering countermeasures put in place as soon as possible.  相似文献   

4.
Unplanned urban growth, particularly in developing countries has led to changes in land use/land cover (LULC). Numerous Indian cities face problems of unplanned LULC change due to nominal or non-existent planning efforts compounded by rapid urban population growth. The Guwahati Metropolitan Area (GMA) is one such urban centre. The present study assesses the trajectories of LULC change using Landsat imageries acquired in 1976, 1989, 2002 and 2015. Natural and semi natural vegetated area and artificial and natural water bodies decreased while built-up areas, cultivated and managed areas, and natural and semi natural non-vegetated areas increased. The built-up area increased from 23.9 in 1976 to 115.1 km2 in 2015 becoming the dominant land cover class accounting for 41.8% of the total geographical area. During this period, natural and semi natural vegetated land were reduced by 88.9 km2 at an annual rate of 2.2 km2. Over the years there was an increasing trend of built-up land and cultivated and managed areas in the peripheral areas of the city while natural and semi natural vegetated land diminished. Consequently, as in many other developing countries, there is an urgent need for the governmental authorities and other stakeholders to implement effective urban planning policies.  相似文献   

5.
Glaciers in the Altai Mountains of Mongolia provide an estimated 11% of the total water resources within the country. Yet, their number and area in inconsistent. Using satellite imagery acquired from Landsat 4, 5, and 7, and SRTM digital elevation model (DEM) data, we present here an intuitive, robust, and inexpensive methodology to map the exposed ice of glaciers in the Altai Mountains for the period 1989 to 2011. The total glacierized area was 515 km2 in 1989/1991, 428 km2 in 1998/2001, and 372 km2 in 2010/2011; it decreased by 17% from 1989/1991 to 1998/2001, 13% from 1998/2001 to 2010/2011, and 28% for the entire period 1989/1991 to 2010/2011. In analyzing a sub‐sample of 260 glaciers, 6% advanced, 11% were stable, and 83% receded from 1989 to 2011. The glacier dataset is available to the public free of charge at the Global Land Ice Measurements from Space (GLIMS) website.  相似文献   

6.
Floods are a frequently occurring calamity in deltaic Bangladesh. This paper aims to assess the temporal expansion of waterbodies during flooding using geospatial techniques. Several water indices were applied to classify the satellite images at various temporal scales. Among them, the Normalized Difference Water Index (NDWI) showed the highest correlation (r = 0.831; where p = 0.01) with rainfall data. Specifically, the NDWI results showed that perennial waterbodies measured 37 km2 and 60 km2 in Sunamganj District in 2017 and 2019, respectively. The area of waterbodies notably increased 52-fold from March to April (37 km2 to 1958 km2) during the pre-monsoon flash flood of 2017. During the July 2019 monsoon flood, waterbodies started to extend after May and flooded 2784 km2 in area. NDVI analysis showed that in 2019, floodwater submerged 361.7 km2 of vegetation cover. At the same time, the Surma River's flooding resulted in a 73.9 per cent inundation of the total area of the Sunamganj District. We hope that this study will provide better understanding of the varying nature of floods that occur in the low lying bowl shaped Haor region which will in turn assist the government with flood mitigation.  相似文献   

7.
This paper describes the recent evolution of Italian glaciers through an analysis of all available terminus fluctuation data that the authors have entered in a glaciers database (named GLAD) containing 883 records collected on glaciers from 1908 to 2002. Furthermore, a representative subset of data (249 glaciers located in Lombardy) was analysed regarding surface area changes. For the analysis of terminus fluctuations, the glaciers were sorted by size classes according to length. The data showed that during the 20th century Italian Alpine glaciers underwent a generalized retreat, with one distinct and well documented readvance episode that occurred between the 1970s and mid‐1980s, and a poorly documented one around the early 1920s. The rates of terminus advance and retreat have changed without significant delays for the larger glaciers with respect to the smaller ones. However, the smaller the glacier, the more limited the advance (if any) during the 1970s and early 1980s. The behaviour of glaciers shorter than 1 km appears to have changed in the last decade, and between 1993 and 2002 they retreated at a very high rate. The analysis of the subset of data led to a quanti‐fication of surface reduction of c. 10% from 1992 to 1999 for glaciers in Lombardy. Small glaciers proved to contribute strongly to total area loss: in 1999, 232 glaciers (c. 90% of the total) were smaller than 1 km2, covering 27.2 km2 (less than 30% of the total area), but accounted for 58% of the total loss in area (they had lost 7.4 km2).  相似文献   

8.
In this paper, we analyzed the spatial patterns of cultivated land change between 1982 and 2011 using global vector-based land use/land cover data. (1) Our analysis showed that the total global cultivated land area increased by 528.768×104 km2 with a rate of 7.920×104 km2/a, although this increasing trend was not significant. The global cultivated land increased fastest in the 1980s. Since the 1980s, the cultivated land area in North America, South America and Oceania increased by 170.854×104 km2, 107.890×104 km2, and 186.492×104 km2, respectively. In contrast, that in Asia, Europe and Africa decreased by 23.769×104 km2, 4.035×104 km2 and 86.76×104 km2, respectively. Furthermore, the cultivated land area in North America, South America and Oceania exhibited significant increasing trends of 7.236× 104 km2/a, 2.780×104 km2/a and 3.758×104 km2/a, respectively. On the other hand, that of Asia, Europe and Africa exhibited decreasing trend rates of–5.641×104 km2/a,–0.831×104 km2/a and–0.595×104 km2/a, respectively. Moreover, the decreasing trend in Asia was significant. (2) Since the 1980s, the increase in global cultivated lands was mainly due to converted grasslands and woodlands, which accounted for 53.536% and 26.148% of the total increase, respectively. The increase was found in southern and central Africa, eastern and northern Australia, southeastern South America, central US and Alaska, central Canada, western Russia, northern Finland and northern Mongolia. Among them, Botswana in southern Africa experienced an 80%–90% increase, making it the country with the highest increase worldwide. (3) Since the 1980s, the total area of cultivated lands converted to other types of land was 1071.946×104 km2. The reduction was mainly converted to grasslands and woodlands, which accounted for 57.482% and 36.000%, respectively. The reduction occurred mainly in southern Sudan in central Africa, southern and central US, southern Russia, and southern European countries including Bulgaria, Romania, Serbia and Hungary. The greatest reduction occurred in southern Africa with a 60% reduction. (4) The cultivated lands in all the continents analyzed exhibited a trend of expansion to high latitudes. Additionally, most countries displayed an expansion of newly increased cultivated lands and the reduction of the original cultivated lands.  相似文献   

9.
The study employs slope,aspect,relief degree of land surface,land use,vegetation index,hydrology and climate,as evaluation indexes to set up the Human Settlements Environmental Index(HEI) model to evaluate the environmental suitability for human settlements in the Shiyang River Basin.By using GIS spatial analysis technology,such as spatial overlay analysis,buffer analysis and density analysis,the environmental suitability of the human settlement spatial situation and spatial pattern are established to analyze their spatial distribution.The results show that the index of suitability for human settlements in the Shiyang River Basin is between 17.13 and 84.32.In general,suitability for human settlements decreases from the southwest to the northeast.Seen from an area pattern,the suitable region is mainly distributed in the Minqin oasis,Wuwei oasis and Changning basin,which are about 1080.01 km 2 and account for 2.59% of the total area.Rather and comparatively suitable region is mainly distributed around the counties of Gulang,Yongchang and north of Tianzhu,which is about 1100.30 km 2.The common suitable region is mainly distributed outside the counties of Yongchang,Jinchuan and most parts of Minqin County,which are about 23328.04 km 2,accounting for 56.08% of the total area.The unsuitable region is mainly distributed upstream and to the north of the river,which is about 9937.60 km 2,accounting for 23.89% of the total area.Meanwhile,the least suitable region is distributed around the Qilian Mountains,which are covered by snow and cold desert and lie in the intersecting area between the Tengger Desert and Badain Jaran Desert.The total area is about 6154.05 km 2,accounting for 14.79% of the total area.Suitable regions for human habitation are mainly distributed around rivers in the form of ribbons and batches,while others are scattered.The distribution pattern is identical to the residential spatial pattern.In addition,the relationships between HEI and other factors have been analyzed.There is a clear logarithmic correlation between the residential environment and population,that is,the correlation coefficient between the evaluation value and population density reaches 0.851.There is also a positive correlation between the residential environment and economy,which reaches an evaluation value of 0.845 between the residential environment and GDP.Results also show that the environment is out of bearing with the existing population in Shiyang River Basin.Spatial distribution of population is profoundly affected by severe environmental problems,such as the expanded deserts,the hilly terrain and the changing climate.Surface water shortage and slow economic growth are bottlenecks for suitable human settlement in the Shiyang River Basin.Combining these problems with planning for construction of new country and the exploitation of local land,some residential areas should be relocated to improve the residential environment.  相似文献   

10.
In the present study, spatio-temporal urban sprawl and land consumption patterns were analysed in seven capital cities located in the Himalayan region during 1972, 1991 and 2015 using multi-temporal satellite images. The study exhibits that capital Himalayan cities experienced rapid growth (830.92%) with high population increase (333.45%) during the observation period (1972–2015). The significant urban growth was observed in the cities of western and middle Himalayan region viz., Srinagar (9.36 km2–142.19 km2), Kathmandu (11.38 km2–92.58 km2) and Dehradun (4.1 km2–50.09 km2) in the higher altitudes due to remarkable increase in the population (0.5–1 million persons) during 1972–2015. On the contrary, Itanagar (7.19 km2), Gangtok (7.09 km2), Shimla (3.04 km2) and Thimphu (2.93 km2) observed less urban growth with moderate to low population growth (i.e., 0.05 to 0.15 million persons). The Shannon entropy based study exhibits that the cities viz., Kathmandu, Gangtok and Itanagar observed comparatively more dispersed urban growth during later period (1991–2015) as compared to the previous period (1972–1991) whereas, the remaining cities observed comparatively less dispersed urban growth during later period. The temporal land consumption pattern exhibits low density urban growth in Srinagar, Dehradun and Kathmandu, as observed with decrease in population density and increasing land consumption during 1972–2015 as compared to other cities, wherein urban densification was evident with increase in population density and decrease in land consumption. The cities in central and western Himalayan region observed high urban growth as compared to cities in eastern Himalayan region. The result shows that the capital cities contributes insignificant proportion (0.5%; 314 km2) of urban area in Himalayan region and accommodating large (ca. 4 million) population during 2015. The study indicates unplanned and haphazard growth in all capital Himalayan cities, leading towards urban densification as well as dispersion in the periphery with varied pattern and intensity. The specific trends and patterns of urban and population growth are governed by geographical as well as socio-economic-political factors at local to regional scale. The high population pressure induced higher risk to the urban residents as well as constrained urban growth over higher vulnerable zones. The study necessitates implementation of suitable urban planning methods considering socio-economic and physico-cultural characteristics of the region.  相似文献   

11.
Three introduced predators, the dingo (Canis lupus dingo), the fox (Vulpes vulpes) and the feral cat (Felis catus) are widespread throughout the arid interior of Western Australia. While the dingo has been present for an estimated 3500–4000 years, the fox and the feral cat are relatively recent arrivals and have been implicated in the modern decline and in some cases extinction of arid zone fauna, especially medium size mammals. This paper reports on a long-term, large-scale project aimed at developing control strategies for these introduced predators. Broad area control of foxes and dingoes in the Gibson Desert using 40–60 g dried meat baits impregnated with the poison sodium monofluoroacetate (1080) and delivered by aircraft at a density of 5 baits km−2 proved to be highly effective. Following a single aerial baiting of some 1600 km2, foxes and dingoes were virtually eradicated from a core area for up to 15 months, but feral cats appeared to increase in abundance. Two aerial baitings (each 400 km2) carried out during periods of below average rainfall using a small (about 30 g) fresh meat bait developed to be attractive to feral cats reduced their abundance by an estimated 75% and 100% when baits were delivered at a density of 10 and 22 km−2, respectively. A third aerial baiting at a density of 11 baits km−2 carried out during a period of above average rainfall reduced feral cat density by only 25% when surveyed 3 months after baiting. Baiting density, frequency and season are key factors likely to affect the impact of baiting on feral cat populations. Preliminary studies reveal that the home range of feral cats in this environment varies from about 700 to 1200 ha. Reptiles and small native mammals form the major dietary items of feral cats and the seasonal variation in abundance of these items is likely to affect bait uptake. These observations have important implications for control strategies.  相似文献   

12.
This study assesses the influence of development on landslide occurrences in a rapidly developing area, Kota Kinabalu in Sabah Malaysia, across three assessment years (1978, 1994 and 2010). Two development indicators, land use and road density, were used to measure the influence of development on landslide occurrence. Land use was classified into four categories (barren, forest, developed and other), and road density was classified into low (< 50 m/40 000 m2), moderate (50–150 m/40 000 m2) and high (> 150 m/40 000 m2). Landslide density analysis was used to calculate the concentration of landslide for the different land use and road density categories. The number of landslides in developed areas increased from 19 landslides/100 km2 in 1978, to 29 landslides/100 km2 in 1994 and to 50 landslides/100 km2 in 2010, mirroring an increase in land use for development purposes from 8 per cent in 1978 to 27 per cent in 2010. Landslide density also gradually increased in the high road density class from 10 landslides/100 km2 in 1978, to 30 landslides/100 km2 in 1994 and 62 landslides/100 km2 in 2010. These results show that road construction activities influence landslide occurrences.  相似文献   

13.
1973-2010年阿尔金山冰川变化   总被引：3，自引：0，他引：3  
祝合勇  杨太保  田洪阵 《地理研究》2013,32(8):1430-1438
利用1973 年MSS、1999 年ETM+和2010 年TM遥感影像资料,通过遥感图像处理和GIS技术,提取了阿尔金山地区三个时期的冰川信息,同时结合周边气象资料进行分析。结果表明:① 1973-2010 年,研究区冰川面积从347.99 km2 减少到293.77 km2,退缩了54.22km2,占1973 年冰川总面积的15.58%,年均退缩速率为0.42%·a-1。近10 年来冰川退缩尤为剧烈,年均退缩速率达到0.58%·a-1;② 研究区东段冰川退缩速率快于中段和西段;③ 冰川规模越小,退缩越明显;④ 研究区东坡冰川的面积退缩率最大,北坡次之,东南坡最小;⑤ 气温升高和降水在波动中变化不大是造成研究区冰川退缩的主要原因;⑥ 通过分形理论对研究区冰川空间结构特征进行分析,预计研究区冰川今后的消融速率仍将处于较高状态。  相似文献   

14.
Glaciers are the most important fresh-water resources in arid and semi-arid regions of western China. According to the Second Chinese Glacier Inventory (SCGI), primarily compiled from Landsat TM/ETM+ images, the Qilian Mountains had 2684 glaciers covering an area of 1597.81±70.30 km2 and an ice volume of ~84.48 km3 from 2005 to 2010. While most glaciers are small (85.66% are <1.0 km2), some larger ones (12.74% in the range 1.0–5.0 km2) cover 42.44% of the total glacier area. The Laohugou Glacier No.12 (20.42 km2) located on the north slope of the Daxue Range is the only glacier >20 km2 in the Qilian Mountains. Median glacier elevation was 4972.7 m and gradually increased from east to west. Glaciers in the Qilian Mountains are distributed in Gansu and Qinghai provinces, which have 1492 glaciers (760.96 km2) and 1192 glaciers (836.85 km2), respectively. The Shule River basin contains the most glaciers in both area and volume. However, the Heihe River, the second largest inland river in China, has the minimum average glacier area. A comparison of glaciers from the SCGI and revised glacier inventory based on topographic maps and aerial photos taken from 1956 to 1983 indicate that all glaciers have receded, which is consistent with other mountain and plateau areas in western China. In the past half-century, the area and volume of glaciers decreased by 420.81 km2 (–20.88%) and 21.63 km3 (–20.26%), respectively. Glaciers with areas <1.0 km2 decreased the most in number and area recession. Due to glacier shrinkage, glaciers below 4000 m completely disappeared. Glacier changes in the Qilian Mountains presented a clear longitudinal zonality, i.e., the glaciers rapidly shrank in the east but slowly in the central-west. The primary cause of glacier recession was warming temperatures, which was slightly mitigated with increased precipitation.  相似文献   

15.
This paper uses Landsat TM images, GIS technology, Digital Elevation and Habitat Assessment Models to assess the habitat suitability of the endangered plant Tetraena mongolica in western Ordos Plateau of China by selecting terrain, soil, climate, and human activity factors as assessment indices. The results are as follows: natural factors such as climate and terrain are not restrictive factors for the survival and development of T. mongolica in the research region, whereas human activity causes habitat quality of T. mongolica to change intensively in quantity and distribution. The area of less suitable habitat increased by 23.87 km2 compared to potential habitat suitability. Thus, in some areas, human activity may be a key factor causing the endangerment of T. mongolica. There were obvious differences of potential and practical habitat suitability between different habitat regions in the study area. The habitat quality was better in Wujiamiao, Dishan and Qipanjing regions, and worse in Wuda and Qianlishan regions.  相似文献   

16.
天山北麓经济发展与绿洲扩张   总被引：27，自引：0，他引：27  
借助地学信息图谱技术，以不同时相、不同尺度的图像数据源为基础，编制出1949年以来天山北麓绿洲分布图4幅，绿洲演化规律为：1949－1967年为绿洲迅速扩张阶段，耕地面积急剧增加，1967－2000年绿洲扩张速度减缓，耕地面积总量基本保持平衡，城市化进程加快，分析了天山北绿洲经济带发展现状，论述了北麓经济带，城市群和主导产业分布格局，讨论了绿洲扩张过程中水资源利用变化以及生态环境问题，这些对研究50年来北麓绿洲经济带的变化具有重要意义，也对未来北麓绿洲经济带的发展具有指导作用。  相似文献   

17.
基于遥感和GIS的中国20世纪90年代毁林开荒状况分析   总被引：10，自引：0，他引：10  
毁林开荒过程是一种林地变为耕地的土地利用变化过程,可以通过遥感和GIS技术对这一过程进行监测。本文通过覆盖全国的TM影像数据,对20世纪90年代林地转为耕地的面积及其空间分布进行分析,从而对全国毁林开荒过程进行遥感监测。结果表明,该时期有17630km2的林地被开垦为耕地。不同面积等级的开垦过程在不同流域分布也不同:面积小于10hm2和介于10～100hm2的被开垦林地较广泛地分布于各大流域;而面积介于100～1000hm2的被开垦林地主要分布于松辽流域、黑龙江流域和东北东部流域、长江流域、珠江流域和云南省所在流域;大于1000hm2的被开垦林地则几乎全部分布于松辽流域、黑龙江流域和东北东部流域。坡度大于3°的毁林开荒地面积占总面积的295%;对土壤侵蚀背景的分析表明,土壤侵蚀强度以微度和轻度为主  相似文献   

18.
新疆阿勒泰地区2002-2011年地表水资源变化趋势   总被引：1，自引：0，他引：1  
在RS技术支持下,应用气象数据（主要为气温、降水）、基础地理数据及2002-2011年时间序列的Landsat TM、ETM+、MODIS/Terra+Aqua MCD43A4遥感影像产品,对阿勒泰地区地表水资源时空变化特征进行了分析,探索气象因素影响下阿尔泰山冰川积雪和地表水资源之间的相互作用。结果表明：在研究时段内,阿尔泰山6月2日的冰川积雪面积呈波动增加趋势,8月21日的冰川积雪面积则呈波动减少趋势。从景观格局的特征来看,随着夏季冰雪融水量增加,水资源量总体呈上升趋势,在研究时段内水域总面积增加了57.91 km2,增加面积主要来源于湖泊和水库,2011年的湖泊和水库面积分别为1 044.33 km2和196.27 km2,比2002年分别增加了16.67 km2和101.79 km2;沼泽湿地和坑塘湿地的面积变化呈一定的起伏,2002-2011年间面积分别减少了35.91 km2和24.27 km2,湖泊和水库的破碎度较低,沼泽湿地、河流和坑塘湿地的破碎度高,表明沼泽湿地、河流和坑塘湿地对气象因素变化较敏感。  相似文献   

19.
Carbon stocks and carbon accumulation in the earth's drylands have gained increasing attention. The winter-cold deserts of Middle Asia, i.e. in Kazakhstan, Uzbekistan, and Turkmenistan, cover an area of 2.5 million km2. Within these deserts, the two Saxaul species White Saxaul (Haloxylon persicum Bunge ex Boiss. & Buhse) and Black Saxaul (Haloxylon aphyllum (Minkw.) Iljin) are dominant woody species with a potential distribution area of about 500,000 km2. From the 1950s until today, the Saxaul vegetation has been degraded through logging and over-grazing. In this paper, we estimate the current and potential living above ground and below ground biomass of the Saxaul vegetation and its carbon stock. The living above ground biomass ranges between 1.5 t/ha and 3 t/ha. The potential carbon stocks above ground and below ground amount to 29.4–52.1 million t and 22–81.4 million t, respectively. Today, only 11%–28% of the potential biomass and carbon stock have remained. The carbon stock of the Saxaul vegetation is low compared to other ecosystems of the earth, but restoration and conservation of Saxaul vegetation is one way to sequester carbon through vegetation for Uzbekistan and Turkmenistan, which do not have much other woody vegetation.  相似文献   

20.
The reservoir wetland, which is the largest artificial wetland in Beijing, constitutes one of the important urban ecological infrastructures. Considering two elements of natural environment and socio-economy, this paper established the driving factor indexing system of Beijing reservoir wetland evolution. Natural environment driving factors include precipitation, temperature, entry water and groundwater depth; social economic driving factors include resident population, urbanization rate and per capita GDP. Using multi-temporal Landsat TM images from 1984 to 2010 in Beijing, the spatial extent and the distribution of Beijing reservoir wetlands were extracted, and the change of the wetland area about the three decade years were analyzed. Logistic regression model was used to explore for each of the three periods： from 1984 to 1998, from 1998 to 2004 and from 2004 to 2010. The results showed that the leading driving factors and their influences on reservoir wetland evolution were different for each period. During 1984-1998, two natural environment indices： average annual precipitation and entry water index were the major factors driving the increase in wetland area with the contribution rate of Logistic regression being 5.78 and 3.50, respectively, and caused the wetland growth from total area of 104.93 km 2 to 219.96 km 2 . From 1998 to 2004, as the impact of human activities intensified the main driving factors were the number of residents, groundwater depth and urbanization rate with the contribution rate of Logistic regression 9.41, 9.18, and 7.77, respectively, and caused the wetland shrinkage rapidly from the total area of 219.96 km 2 to 95.71 km 2 . During 2004-2010, reservoir wetland evolution was impacted by both natural and socio-economic factors, and the dominant driving factors were urbanization rate and precipitation with the contribution rate of 6.62 and 4.22, respectively, and caused the wetland total area growth slightly to 109.73 km 2 .  相似文献   

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