基于景观格局定量分析的流域治理--以文峪河流域为例

以航片、森林资源调查资料和林相图为基础资料,在地理信息系统软件及数据库管理系统的支持下,应用景观多样性指数、景观要素优势度指数、类斑形状指数、景观要素斑块分数维等景观格局分析指标,对流域景观空间总体分布、景观组成结构、景观要素斑块形状特征进行分析,揭示了山西文峪河流域植被景观的总体格局。基于分析成果,针对目前文峪河流域植被景观格局存在的问题,建议在今后的流域管理和建设中应开展的工作,即上游及中高海拔带重点进行寒温性针叶林保护;中下游山地积极增加阔叶林,营造混交林;河谷重点开展河岸植被和河岸林规划设计和建设。     

Longitudinal analysis of the road network development and land-cover change in Lop Buri province, Thailand, 1989-2006

Land use and land-cover change (LUCC) is mainly a consequence of human activities such as road network development. In Thailand, the explicit objective of road network development has been to foster economic and social development. The extent of change in roads and land-cover change in Lop Buri between 1989-2006 is analyzed. We hypothesized that road development is a key driver of land-cover change and will cause, substantial changes in areas of forest cover, cultivated food and cash crops. We used land-cover classifications of Landsat imagery and resultant class trajectories to measure change. We then analyzed the relationships between roads, land-cover types, and land-cover trajectories. Overall, cash crops increased while forest and food crops declined between 1989-2006. The relationships between distance to roads and land- cover trajectories indicate that as the distance to roads increase, there are fewer changes in LUCC. The results suggest that in this case study, an increase in road network contributes to an increase in upland crops. In turn, the increase in upland crop production is one of the factors linked to economic development.     

Characterization of landscape pattern based on land economic niche change: A case study in Ganzhou,Gansu Province,China

Land use change has a profound impact on biodiversity and ecological processes, and is closely related to changes in landscape patterns. This paper introduces the theory and method of land economic niche into landscape ecology, which provides a new method for spatial characterization of urban and rural spatial landscape patterns. Based on this theory, this paper analyzes the landscape pattern of Ganzhou District by using Landsat images as data source in 1995, 2000, 2005,2010 and 2015. We calculated the land economic niche by applying the niche potential theory. Combined with the theory of landscape ecology, we explored the effects of the land economic niche change on the landscape pattern at a county scale.The results show that economic niche of construction land, watershed and farmland increased during 1995–2015, and grassland declined significantly. The economic niche of farmland, construction land, watershed and grassland show a negative correlation with the number of patches(NP), fragmentation index(FN) and the fractal dimension index(FD), and had a positive correlation with the aggregation index(AI). There was no significant correlation between the forest land economic niche and landscape metrics. The change of land economic niche has a driving effect on the landscape pattern of the county, which can represent the economic development direction of Ganzhou District. The land economic niche is closely related to the landscape type which can directly obtain an economic benefit.     

深圳市近20年城市景观格局演变及其驱动因素

基于深圳市1996—2015年土地利用数据,利用景观指数、景观转移矩阵和景观扩张指数等方法探究了深圳市近20年景观格局时空变化、主要景观类型转移和建筑用地扩张模式,最后使用Binary Logit模型考察了市级和区级建筑用地景观扩张的主要驱动因素。结果表明：① 1996—2015年,深圳市建筑用地景观优势性逐步增强,面积增加15.81%,以蔓延式（61.9%）和填充式（36.27%）扩张为主;② 1996—2006年为城市化快速扩张期,建筑用地扩张呈集中开发形态,景观多样性和均匀性增加,城市扩张中心略微向北部和东部移动,2006—2015为城市化低速过渡期,景观破碎化加剧,城市扩张重心向北部和西部偏移;③ 在市级尺度上,GDP密度和人口密度对建筑用地景观扩张有显著正影响,生态控制线、高程、坡度和至道路的距离有着显著负影响。每单位生态控制线范围、坡度的增加分别将使建筑用地景观扩张的机会比率将平均减少到原来0.8168倍、0.8841倍。各驱动因素表现出区域和尺度差异性,GDP对宝安区、南山区和坪山区,人口增长对宝安区、龙华区,以及交通可达性对大鹏新区、龙岗区驱动分别最为突出。研究结果可以为中国城市快速扩张过程中的景观格局变化提供科学实践。     

Multi-scale analysis of spatially varying relationships between agricultural landscape patterns and urbanization using geographically weighted regression

Scientific interpretation of the relationships between agricultural landscape patterns and urbanization is important for ecological planning and management. Ordinary least squares (OLS) regression is the primary statistical method in previous studies. However, this global regression lacks the ability to uncover some local-specific relationships and spatial autocorrelation in model residuals. This study employed geographically weighted regression (GWR) to examine the spatially varying relationships between several urbanization indicators (urbanization intensity index, distance to urban centers and distance to road) and changes in metrics describing agricultural landscape patterns (total area, patch density, perimeter area ratio distribution and aggregation index) at two block scales (5 km and 10 km). Results denoted that GWR was more powerful than OLS in interpreting relationships between agricultural landscape patterns and urbanization, since GWR was characterized by higher adjust R², lower Akaike Information Criterion values and reduced spatial autocorrelations in model residuals. Character and strength of the relationships identified by GWR varied spatially. In addition, GWR results were scale-dependent and scale effects were particularly significant in three aspects: kernel bandwidth of weight determination, block scale of pattern analysis, and window size of local variance analysis. Homogeneity and heterogeneity in the relationships between agricultural landscape patterns and urbanization were subject to the coupled influences of the three scale effects. We argue that the spatially varying relationships between agricultural landscape patterns and urbanization are not accidental but nearly universal. This study demonstrated that GWR has the potential to provide references for ecological planners and managers to address agricultural landscapes issues at all scales.     

和田绿洲景观破碎化特征及驱动因素

景观破碎化改变着区域景观结构的完整性和系统的连通性,对景观的稳定性和可持续发展具有重要影响。选取新疆和田绿洲为研究区,以1970年新疆考察数据与MSS影像,1990、2000、2013、2018年4期Landsat TM/ETM+同月相数据为主要数据源,采用景观指数法、移动窗口法、梯度分析及归因分析等方法开展绿洲景观破碎化的时空格局变化及驱动因素的研究。结果表明：近50年来,景观分裂指数（DIVISION）由0.94减少到0.89,香浓多样性指数（SHDI）从1.44减少到1.28,绿洲景观破碎化整体呈现减缓趋势。其中,城市景观破碎化程度最低,沿破碎化梯度从城市中心向外围呈现出先上升后下降的趋势。此外,景观破碎化程度与农业的发展呈倒“U”型函数关系,当农业扩张在绿洲面积的40%—50%时,景观破碎化程度达到峰值。人口增长,农业扩张与社会经济发展共同影响着绿洲破碎化的时空格局。本研究不仅为干旱区绿洲景观破碎化格局的空间变化分析及驱动因素研究提供科学依据,也对绿洲生态景观的规划与可持续管理具有重要的意义。     

海岸带土地持续利用景观生态评价

应用景观生态学理论研究土地持续利用问题,从景观生产力、景观受胁度与景观稳定性3方面构建海岸带土地利用可持续性的景观生态评价指标体系,并辅以山东省无棣县土地持续利用的个案分析,将土地持续利用的多重目标与景观格局结合在一起进行土地持续利用时空尺度上的综合评价,是土地持续利用评价研究的有益拓展。评价结果表明,无棣县土地利用可持续性景观生态评价值整体较低,区域差异大。通过聚类分析,将无棣县11个乡镇划分为土地利用的强可持续区、可持续区、弱可持续区、弱不可持续区与强不可持续区等5个梯度区,并分析了自然资源禀赋、乡村现代化、人口规模与人口素质等区域差异成因。     

地理探测器方法下甘肃白龙江流域景观破碎化与驱动因子分析

基于GIS技术、景观格局指数、主成分分析和地理探测器的方法,定量分析了1990~2014年甘肃白龙江流域的景观破碎化及其驱动因子。结果表明：1990~2014年甘肃白龙江流域景观破碎化程度先增加后降低;研究期间流域东南部的景观指数变化最为剧烈和复杂,主要是文县和武都区;人类干扰（人类活动强度和土地利用类型）和地形因子（高程、坡度和坡向）对景观破碎化空间分异的影响显著不同,其中人类干扰是景观破碎化空间分异的主要驱动因子。     

流溪河流域土地利用景观生态安全动态分析

在GIS技术支持下,基于景观干扰指数和景观脆弱度指数构建景观生态安全评价指标体系,分析流溪河流域2000年、2005年和2009年3相土地利用景观生态安全变化。景观生态安全指数定量化地表征了流域景观生态安全状况,结果表明：（1）流域景观生态安全格局受城市化及人类活动干扰显著增强,林草地和耕地面积减少,园地面积增加,10年间各景观类型的破碎度、分离度总体呈现增加趋势,且流域内优势景观类型发生改变,2000年和2005年以林草地和耕地为优势景观,而2009年优势景观转变为林草地和园地;（2）2000-2005年,流域过半景观生态安全格局发生了变化;2005-2009年期间流域景观生态安全转移率约为60%,约有90%的流域景观生态安全格局在空间分布上发生了变化;（3）2000年整个流域景观生态安全指数都大于0.6,其中大于0.8的面积占99.99%;2005年,生态安全度大于0.6的面积比例为98.48%,景观生态安全指数大于0.8的面积较2000年降低55.93%;景观生态安全度大于0.6的区域2009年比2005年减少了72.93%,主要分布于流域上游;整个流域范围内没有生态安全指数大于0.8的区域分布,流域景观生态安全度呈现整体降低趋势。     

基于遥感和GIS的干旱区绿洲景观破碎化分析--以金塔绿洲为例

以2个时期的遥感图像所解译的土地利用数据为基本信息源，基于GIS工具，选用斑块密度、廊道密度、斑块破碎度、分离度和斑块面积变异系数5个指标对金塔绿洲的破碎化程度进行了分析。结果表明：(1)1990～2000年，金塔绿洲总体的景观破碎化程度轻微地降低。(2)从景观类型上看，基质的破碎化程度增强；水浇地面积增大，趋于集中分布，破碎化程度降低；城镇用地破碎度增加，分离度减小。这些变化与人类开发利用活动的程度和方式有关，体现了荒漠基质受人类影响而逐步形成的典型农业型绿洲的特点。     

干旱区典型流域近30 a土地利用/覆被变化和景观破碎化分析——以玛纳斯河流域为例

 利用1976年、1989年、2005年三期遥感影像,运用GIS和FRAGSTATS景观分析软件对玛纳斯河流域近30 a的土地利用/覆被变化和景观破碎化进行了研究。结果表明：①玛纳斯河流域土地利用/覆被在过去30 a间发生了普遍的变化。耕地、建设用地不断增加,而草地、林地、水域、盐碱地不断减少。耕地主要是在草地上开垦出来的。②绿洲内部的耕地趋于集聚状态,破碎性降低,而绿洲边缘的耕地,破碎性增强。草地面积大减,破碎性增强,退化严重。沙地、水域破碎性也不断增强,林地、未利用土地的破碎化于1989年增强,2005年减缓。③驱动力分析表明,流域变化是自然和人类活动共同作用的结果,其中人口的快速增长、政策环境的变化和自然环境变化如干旱等是最主要的驱动因素。     

The Nichols' Relief Model of the United States

Abstract

The agricultural system in West Pakistan is largely subsistence-oriented, and extensive areas are devoted to produce the low-value crops. Only a small portion of the total cropped area is used to raise cash crops. However, there are regional differences in cropland use in the province. The study focuses on regional variations in the cropping patterns in West Pakistan by establishing the crop combination areas. The crop combination areas also point out a land-use distinction between the areas. Also, the changes in some of the important crops in terms of their land occupancy in the area during the fifteen-year period have been analyzed.     

Using kernel density estimation to assess the spatial pattern of road density and its impact on landscape fragmentation

Road density (i.e., km/km²) is a useful broad index of the road network in a landscape and has been linked to several ecological effects of roads. However, previous studies have shown that road density, estimated by grid computing, has weak correlation with landscape fragmentation. In this article, we propose a new measure of road density, namely, kernel density estimation function (KDE) and quantify the relation between road density and landscape fragmentation. The results show that road density estimated by KDE (km/km²) elucidates the spatial pattern of the road network in the region. Areas with higher road density are dominated by a larger proportion of built-up landscape and less possession of forest and vice versa. Road networks segregated the landscape into smaller pieces and a greater number of patches. Furthermore, Spearman rank correlation model indicates that road density (km/km²) is positively related to landscape fragmentation. Our results suggest that road density, estimated by KDE, may be a better correlate with effects of the road on landscape fragmentation. Through KDE, the regional spatial pattern of road density and the prediction of the impact of the road on landscape fragmentation could be effectively acquired.     

Study on inter-seasonal and intra-seasonal relationships of meteorological and agricultural drought indices in the Rajasthan State of India

Use of rainfall anomaly based Standardized Precipitation Index (SPI) and satellite-derived Vegetation Condition Index (VCI) are becoming common to assess the impacts of drought on crops. This study analysed spatio-temporal intra-seasonal and inter-seasonal relationships for 24 years between rainfall and NDVI and between SPI and VCI to understand crop response to water availability in the Rajasthan State, India. To separate the effect of weather and technology on crop growth over time, a modification in VCI was proposed and called “Trend Adjusted VCI” (VCI_Tadj). The VCI_Tadj was computed for early, mid, late and whole crop seasons by deriving pixel wise crop phenology metrics from NDVI profile. Significant linear relationships were found between NDVI and rainfall but phase of crop season affected the strength of this relationship. The SPI and VCI_Tadj were linearly related in all the four seasons, the strength of relationship improved with the progress of crop season and these relationships were stronger than between rainfall and NDVI. These relationships broke down in irrigated croplands. As a result, the anomaly indices of SPI and VCI_Tadj and their intra-seasonal relationships can be used to study the response of crops to water availability for early detection and better prognosis of agricultural drought.     

都市农业景观破碎化过程对生态系统服务价值的影响——以西安市为例

利用西安市土地利用解译图及社会经济数据,在界定都市农业景观的前提下,分析西安市都市农业景观破碎化过程,在此基础上分析都市农业景观破碎化对生态系统服务价值的影响。结果表明：① 1999-2011 年,西安市都市农业景观的斑块密度、分离度指数增加,都市农业景观呈破碎化趋势;② 都市农业景观分离度与都市农业生态系统服务总价值及各项价值均呈较强的负相关关系;破碎化过程中废物处理及土壤形成价值减少量最大,同时食物生产价值减少率最大,减少了12.73%,娱乐文化减少的价值量及减少率最小,为1.93%;③ 耕地、林地、水域呈景观破碎化趋势,而园地聚集度上升,同时耕地、林地、水域的生态系统服务价值下降,园地生态系统服务价值增加。     

黄河三角洲滨海湿地的景观格局空间演变分析

利用GIS技术、RS影像和Fragstats3.3等景观统计软件,从景观面积变化、景观斑块特征和景观整体水平格局等方面,对比研究了黄河三角洲2000年和2009年湿地不同时空尺度的景观格局变化。结果表明:10 a间黄河三角洲滨海湿地海岸线和陆地面积整体呈增长趋势,天然湿地面积急剧减少,平均分维数大部分降低,湿地景观破碎度降低,多样性和均匀性指数增加,蔓延度指数增加。湿地景观格局指数的变化反映了旱田及水田的大面积种植,盐田养殖业的大力发展以及石油开采等人为活动对景观格局的深刻影响,人类活动已经成为黄河三角洲滨海湿地景观格局变化的主要驱动因子。     

内陆河小流域综合治理对景观格局的影响——以童子坝河流域为例

以1987年、2000年、2008年3期Landsat TM影像为信息源,在GIS 技术和景观分析软件Fragstats3.3支持下,获得了民乐县童子坝河流域研究区不同时期的景观类型信息和描述景观格局特征的8个景观指数数据,利用这些数据分析了实施综合治理前后流域景观格局的变化。结果表明:①在类型水平上,各种草地景观类型的斑块呈现边缘整齐、形状规则的特点,斑块的破碎化程度减小,聚合度增加;特别是高覆盖度草地的斑块数目、平均斑块面积都呈增加趋势,斑块边界形状变得连续、规则,显现出人为干扰的痕迹;河床、河漫滩景观的斑块数目减少,斑块边界形状趋于规整,贯穿连通性增强\.②在景观水平上,景观空间格局规整有序,景观多样性提高,异质性增加,破碎化程度减小,空间连接性增强,以高覆盖度草地为主的景观优势显著体现出来。③综合治理措施实施对童子坝河流域景观格局的影响是积极有效的,这可为内陆河小流域继续开展生态环境建设提供科学依据。     

Coping with land scarcity. Farmers' changing land-use and management practices in two mountain watersheds of Nepal

In this study some light is shed on farmers' changing land-use and management practices in two mountain watersheds located in the Western Hills of Nepal. The study is based on a survey of 300 households, group discussion, interviews of key informants, and field observation in project and non-project watersheds conducted from April to September 1999. Confronted with shrinking landholding size, owing to a steadily growing population and scarcity of non-farming employment opportunities, farmers in both watersheds have gradually intensified land use and cultivated new crops to increase farm production and income. They are shifting from cereal crops to livestock husbandry, particularly along the road in the project watershed, and to vegetables and other cash crops in the accessible foothills of the non-project watershed. They have also adopted various structural and biological measures to control soil erosion, landslides, gully expansion and soil nutrient loss in order to maintain or enhance land productivity. The degree of adoption of the structural and biological measures is higher in the project watershed than in the non-project watershed. Contrary to the traditionally held belief of some researchers, population pressure on a finite land resource has brought about positive changes in land-use and management practices. Farmers have innovated and adopted different land management technologies to increase farm production as they are exposed to the risk of food insecurity because of shrinking landholding size and land degradation.     

Identifying determinants of urban growth from a multi-scale perspective: A case study of the urban agglomeration around Hangzhou Bay,China

Analyzing the spatial determinants of urban growth is helpful for urban planning and management. In a case study of urban agglomeration around Hangzhou Bay (China), four landscape metrics (total area, total edge, landscape shape index and aggregation index) were used to describe the landscape characteristics of the urban growth at two block scales (4 km and 7 km) during two temporal intervals (1994–2003 and 2003–2009). Spatial autocorrelation regression was employed to identify the geographic determinants of the urban landscape changes. The results indicated that the urban landscapes became more dominant, unstable, irregular and compact, especially in the centers of cities. These changes exhibited notable spatial variations and spatial autocorrelation at the two block scales. The distances to national and provincial roads influenced the urban pattern changes. The impacts of the urban centers on urban expansion gradually declined with the urbanization progress. The slope factor was the most influential determinant of urban growth. Our study emphasized the importance of considering the autocorrelation and scale effects when analyzing the determinants of urban growth. These findings may help land planners create policies and strategies for future urban development.     

Analyzing the Impacts of Urban Expansion on Green Fragmentation Using Constraint Gradient Analysis

Many existing gradient analysis methods are arbitrary or too simple in gradient partitioning and unsuitable for cities with irregular forms. We propose an improved gradient analysis method with urban structural features as spatial constraints to properly partition an urban area into more homogeneous buffers. Taking the Wuhan metropolitan area in China as an example, we use the improved gradient partitioning method and six landscape metrics to characterize urban expansion and green space fragmentation in 1989, 2001, and 2013 and investigate the relationship between urban green fragmentation and urban expansion using correlation analysis and regression modeling. The results show that the fragmentation of built-up area in each buffer generally decreases from 1989 to 2013, but the fragmentation of green space increases. For each time point, with growing distance from urban centers, the fragmentation of built-up area increases and green space fragmentation decreases. This shows that urbanization exerts a significant influence on fragmentation of urban green space from both a temporal and a spatial perspective. Intensive urban expansion moved outward mainly at the cost of agricultural land and resulted in more fragmented green space in the urban fringe. Further quantitative analyses show that the area ratio and fragmentation of the built-up area are statistically negatively correlated with the fragmentation of green space. The improved gradient analysis with spatial constraints can generate more homogeneous ring gradients and then lead to more reasonable results, thereby helping to better understand how urban expansion affects landscape dynamics.