Slope aspect, slope length and slope inclination controls of shallow soils vegetated by sclerophyllous heath—links to long-term landscape evolution

On upland Triassic sandstone slopes of the western Blue Mountains, nonswamp, sclerophyllous heath (shrub-dominated vegetation) on shallow soils is commonly found downslope and adjacent to sclerophyllous forest on deeper soils. Some consider heath—and thus shallow soils—as favouring west-facing slopes, which are expected to experience drier microclimates due to insolation, strong and desiccating winds, and severe summer fires. However, our analysis of extensive areas with heath on shallow soils, based on vegetation and topographic maps, and fieldwork of uplands with various degrees of dissection, suggests that aspect is a poor predictor of shallow soils. Rather, shallow soils and heath are found on short slopes and the lower segments of longer slopes with the latter significantly steeper than forested segments.The shallow–deep soil boundary, marked by contrasting modern vegetation structures, does not signify a catchment area threshold, and correspondingly, the vegetation patterns are not in balance with distributary catchment processes, as short slopes are mantled exclusively by shallow soils. Instead, the soil depth boundary represents the propagation of base-level lowering signals, which takes place not only by the headward retreat of knickpoints but also via increased lowering of slope segments adjacent to drainage lines. This leads to steep slopes immediately adjacent to canyons, narrow gorges, and small steep valleys, that are mantled by shallow, discontinuous soils undergoing rapid erosion. These steep slopes persist in the landscape for ≥ 10 My after upland stream rejuvenation until incision of more weatherable Permian sediments, underlying the Triassic cliff-forming sandstones, triggers rapid lateral expansion of gorges. Once shallowly mantled and steeper slopes adjacent to streams are consumed by gorge widening, slopes adjacent to wide gorge clifflines reflect former upland drainage patterns rather than the redirected flow to rapidly widening gorges. Hence, modern vegetation patterns reflect a significant phase of landform development, perhaps combined with enhanced erosion during the Last Glacial Period that is compounded by a humped soil production function on bedrock.     

Comparative analysis of land use/cover change trajectories and their driving forces in two small watersheds in the western Loess Plateau of China

To prevent soil loss and achieve better ecological environments, soil conservation measures have been taken during the past decades in the western Loess Plateau of China. In this paper, a case study was taken in Luoyu valley and Lver valley, two sub-watersheds of Xihe watershed and comparison was carried out between them. The main object of this study is to monitor land use/cover changes in the two similar small watersheds utilizing SPOT5 imageries by object-oriented human–computer interactive classification method, further develop the method of spatio-temporal analysis of land use/cover change by using pattern metrics of change trajectories and relative land use suitability index (R) in smaller watersheds, and make comparisons between the two similar small watersheds, taking water and soil conservation measures into consideration. Results show that combining GIS and RS, this method can be perfectly applied to make comparisons between different small watersheds with similar geographical backgrounds. And land use/cover spatiotemporal dynamic change characteristics can be preferably expressed by pattern metrics of change trajectories and R values based on topographical data. Different emphases have been laid according to their own geological backgrounds in the two watersheds and human activities have different effects on the landscapes of the two watersheds. The main change pattern is from slope farmland to terrace (322, the largest in Luoyu valley) or to economic fruit forest (344, the largest in Lver valley). R value of every slope grade in both of the two watersheds drops with the rising of slope degree on the whole and it shows that there is still much to do for people in the two watersheds in consideration that all the R values are still lower than 0.7.     

景观格局在沙漠化研究中的作用

应用景观生态学中格局分析的一些方法对４种典型沙漠化土地景观进行了分析,研究结果表明：景观和景观中斑块的格局通过影响边界长度和组合状况,进而影响沙漠化过程中的各种生物学和生态学过程。其中,分维数的变化可以反映景观和斑块格局的变化,分维数越大格局越复杂,两者关系呈正相关;修改分维数可以反映景观格局的多样性和景观中斑块之间的相邻性,两者关系也呈正相关;沙漠化土地景观格局的数量化分析和描述,为研究沙漠化过程和景观格局的相互关系奠定了基础。同时还指出了景观格局在沙漠化危害程度判定中有重要作用。     

Exploring spatial data uncertainties in land‐use change scenarios

This paper evaluates errors and uncertainties in representing landscapes that arise from different data rasterization methods, spatial resolutions, and downscaled land‐use change (LUC) scenarios. A vector LU dataset for Luxembourg (minimum mapping unit: 0.15 ha; year 2000) was used as the baseline reference map. This map was rasterized at three spatial resolutions using three cell class assignment methods. The landscape composition and configuration of these maps were compared. Four alternative scenarios of future LUC were also generated for the three resolutions using existing LUC scenarios and a statistical downscaling method creating 37 maps of LUC for the year 2050. These maps were compared in terms of composition and spatial configuration using simple metrics of landscape fragmentation and an analysis of variance (ANOVA). Differences in landscape composition and configuration between the three cell class assignment methods and the three spatial resolutions were found to be at least as large as the differences between the LUC scenarios. This occurred in spite of the large LUC projected by the scenarios. This demonstrates the importance of the rasterization method and the level of aggregation as a contribution to uncertainty when developing future LUC scenarios and in analysing landscape structure in ecological studies.     

A remote sensing-based analysis on the impact of Wenchuan Earthquake on the core value of World Nature Heritage Sichuan Giant Panda Sanctuary

In this study,we used remotely sensed data,GIS modeling,and statistical methods to evaluate the damage caused by the Wenchuan Earthquake (May 12,2008) to the giant panda (Ailuropoda melanoleuca) habitat in the World Nature Heritage Sichuan Giant Panda Sanctuary (WHSGPS) in China.A landscape ecological analysis found increases of landscape heterogeneity,complexity,and fragmentation in the giant panda habitat after the earthquake.A terrain analysis found that slope and elevation are directly associated with t...     

Responses of landscape pattern of China’s two largest freshwater lakes to early dry season after the impoundment of Three-Gorges Dam

The effects of hydrologic cycle change (caused by human activity and global climate change) on ecosystems attract the increasing attention around the world. As a result of impounding of the Three Gorges Dam (TGD), climate change and sand mining, the dry season of Poyang Lake and Dongting Lake (China’s two largest freshwater lakes) came early after the TGD impoundment. It was the primary cause of the increasing need for sluice/dam construction to store water in the Lakes and attracted increasing attention. In this paper, we compared the landscape pattern between three hydrologic years with early dry season (EY) and three normal hydrologic years (NY) of each lake by remote sensing technology, to reveal the effect of early dry season on landscape pattern. The results showed that early dry season caused expanding of Phalaris to mudflat zone in Poyang Lake, while caused expanding of Carex to Phalaris zone and expanding of Phalaris to mudflat zone in Dongting Lake. In landscape level, there was no significant difference in landscape grain size, landscape grain shape, habitat connectivity and landscape diversity between EY and NY in the two lakes. While in habitat class level, there were significant changes in area of mudflat and Phalaris and grain size of mudflat in Poyang Lake, and in area of Carex, grain size of Phalaris and grain shape of Carex and Phalaris in Dongting Lake. These changes will impact migrating birds of East Asian and migratory fishes of Yangtze River.     

An analysis of 200-year-long changes in a landscape affected by large-scale surface coal mining: History,present and future

We have investigated almost 200 years of landscape transformations in a traditional brown coal mining region in northwest Bohemia, Czech Republic. The investigation was focused on the central part of the North Bohemian Basin including 44 cadastral areas representing a total area of 228.48 km². Within this area, an analysis of land use in six different time periods (1845, 1954, 1975, 1989, 2010, 2050) was performed. The analysis therefore includes the transitory period of a boom and slow-down of surface coal mining and also provides a unique comparison with the planned future condition of the landscape after the year 2050, when the mines have been closed down and the landscape restored. Practically all available geographic data resources on land use have been used – the stable cadastre, topographic maps, current landscape mapping and aerial photographs. We differentiated twelve land-use categories. Both Friedman test and detrended correspondence analysis show significant differences in the representation of individual land-use categories and characteristics of the landscape before and during mining operations and after their discontinuance and revitalisation of spoil tips and in residual pits. For a long period of time, agricultural landscape was changed into an industrial one. The basin part of the studied territory almost completely lacks eco-stabilising features that could be used as a basis for planning of a new landscape. This is because the original landscape had been intensively used for agriculture previously, and almost one half of the territory was over-exploited and other areas were affected by operation facilities and coal processing industrial plants. With the growing number of reclamation projects, the diversity of the landscape has been increasing, as well as the proportion of ecologically valuable elements (mostly forests and water bodies), whose total area could exceed 70% of the landscape's surface in the future, approximating its characteristics to a natural landscape with a high degree of ecological stability.     

景观生态学的学科整合与中国景观生态学展望

分析了国际景观生态学三个相互联系的研究领域,指出了各领域的主要研究内容。在阐述景观生态学三个发展阶段的基础上,指出了景观生态学学科发展的基本趋势。从三个方向的整合、时空尺度的匹配、多学科的整合和三个群体的整合4?个方面,阐述了走向整合的景观生态学的发展方向和途径。介绍了当前国际景观生态学研究的热点问题和热点地区,并就中国景观生态学发展的方向和任务提出了作者的看法。     

山东省损毁山体景观影响度分析

档案是一种重要的信息资源,是众多信息资源的基础部分。国土资源档案是国土资源管理机关在土地资源管理、开发、使用过程中形成的,具有保存、利用价值的文件、图表、声像等资料,它记载着土地利用的全部过程,是一种重要的具有长期查考、利用价值的信息资源。近几年,随着菏泽市经济的快速发展,土地利用越来越多,形成的土地信息资源数量较大,目前,多数档案信息资源还未得到充分利用,