喜马拉雅山脉的地质地貌特征:来自SRTM数字高程模型和降水量数据的约束

利用GTOPO30和SRTM3数字高程(DEM)数据,提取了喜马拉雅山脉(造山带)的数字高程模型并对其进行了地质地貌的初步分析。从SRTM3数字高程数据提取出坡度数据,初步分析了喜马拉雅山脉坡度和高程的特征。数字高程和坡度图清楚地展现了喜马拉雅大型断裂带(构造边界)的空间分布特征。分析了中国气象局下属的西藏、青海、四川和云南4省区气象观测台站55年来的年平均降水量观测数据、喜马拉雅山脉南坡的年平均降水量数据、喜马拉雅DEM和裂变径迹数据,发现喜马拉雅山脉从东至西,年平均降水量逐渐减少,地形起伏逐渐变小,而高程渐次升高,与此同时剥蚀速率降低;从北至南,年平均降水量逐渐增加,地形起伏增大,高程快速降低,而剥蚀速率则急剧升高。这充分说明了喜马拉雅年平均降水量大的地区,地表剥蚀作用相对较强,年平均降水量小的地区,地表剥蚀作用则较弱,即:在喜马拉雅地区,长周期的地表剥蚀过程(可长达数个百万年时间尺度)和短周期(仅仅50年)的降水量观测是耦合的。     

Progress and prospect of research on forest landscape model

The Forest Landscape Model (FLM) is an efficiency tool of quantified expression of forest ecosystem''s structure and function. This paper, on the basis of identifying FLM, according to the stage of development, summarizes the development characteristics of the model, which includes the theoretical foundation of mathematical model, FLM of stand-scale, primary development of spatial landscape model, rapid development of ecosystem process model as the priority, and developing period of structure and process driven by multi-factor. According to the characteristics of different FLMs, this paper classifies the existing FLM in terms of mechanism, property and application, and elaborates the identifications, advantages and disadvantages of different types of models. It summarizes and evaluates the main application fields of existing models from two aspects which are the changes of spatial pattern and ecological process. Eventually, this paper presents FLM''s challenges and directions of development in the future, including: (1) more prominent service on the practical strategy of forest management''s objectives; (2) construction of multi-modules and multi-plugin to satisfy landscape research demand in various conditions; (3) adoption of high resolution''s spatial-temporal data; (4) structural construction of multi-version module; (5) improving the spatial suitability of model application.     

Landscape adaptation to climate change: Local networks,social learning and co-creation processes for adaptive planning

The development of legitimate, operative, and feasible landscape adaptation planning for climate change is dependent on the specific characteristics of the landscape and its inhabitants. Spatial patterns, culture, governance systems, socio-economic structures, planning methods, history, and collectively envisioned futures need to be accommodated. The literature suggests that landscape is a complex and dynamic socio-ecological system, the management and adaptation of which requires systemic and integrative approaches to respond to a wide variety of drivers of change, challenges, and interests. Based on activities developed in 15 European pilot landscapes, we identify some of the key factors and conditions affecting the generation of representative local networks for landscape adaptation to climate change. We illustrate how social learning and co-creation processes can be implemented in them and how their co-produced outcomes can help local communities overcome barriers and address critical issues in adaptive planning. Our results provide a framework for the creation of similar networks in other landscapes, exploring at the same time the interactions between the composition of networks, social learning, and the quality of the co-produced outputs as a fundamental step for the development of Landscape Adaptation Plans to Climate Change.     

Catchment scale spatial variability of soil salt content in agricultural oasis,Northwest China

Soil salinization is a serious environmental problem in the world, especially in arid and semi-arid regions. Therefore, estimating spatial variability of soil salinity plays an important role in environmental sciences. Aiming at the problem of soil salinization inside an oasis, a case study was carried out at the Sangong River catchment in Xinjiang province, northwest China. Methods of classical statistics, geostatistics, remote sensing (RS) and geographic information system (GIS) were applied to estimate the spatial variability of soil salt content in the topsoil (0–20 cm) and its relationship with landscape structure at catchment scale. The objective of this study was to provide a scientific basis to understand the heterogeneous of spatial distribution of soil salt content at a large scale. The results revealed that (1) elevation of landform was a key factor for soil salt content’s spatial variability, and soil salt content had a strong spatial autocorrelation, which was mainly induced by structural factors. (2) Mapping of soil salt content by Kriging and comparing it with landscape maps showed that area of soil salinization in old oasis was smaller than that in new oasis, and degree of soil salinization in old oasis was also lower than that in the new one. Among all landscapes, cropland was mostly affected by salinity, with 38.8% of the cropland in new oasis moderately affected by soil salinity, and 8.54% in old oasis.     

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.     

Where can pixel counting area estimates meet user-defined accuracy requirements?

Pixel counting is probably the most popular way to estimate class areas from satellite-derived maps. It involves determining the number of pixels allocated to a specific thematic class and multiplying it by the pixel area. In the presence of asymmetric classification errors, the pixel counting estimator is biased. The overarching objective of this article is to define the applicability conditions of pixel counting so that the estimates are below a user-defined accuracy target. By reasoning in terms of landscape fragmentation and spatial resolution, the proposed framework decouples the resolution bias and the classifier bias from the overall classification bias. The consequence is that prior to any classification, part of the tolerated bias is already committed due to the choice of the spatial resolution of the imagery. How much classification bias is affordable depends on the joint interaction of spatial resolution and fragmentation. The method was implemented over South Africa for cropland mapping, demonstrating its operational applicability. Particular attention was paid to modeling a realistic sensor's spatial response by explicitly accounting for the effect of its point spread function. The diagnostic capabilities offered by this framework have multiple potential domains of application such as guiding users in their choice of imagery and providing guidelines for space agencies to elaborate the design specifications of future instruments.     

湿地景观保育关键技术体系的构建:以九寨沟为例

湿地是九寨沟水体景观的主要载体,保护好湿地就是保护好九寨沟的景观资源。通过30余年的发展历程,九寨沟走出了一条"保护促发展,发展促保护"的可持续发展之路,在湿地景观保育方面采取了有效的保育措施,并开展了相关课题攻关研究,使九寨沟水体依然美丽,湿地生态系统良好。梳理了九寨沟湿地景观面临的威胁及导致其退化的关键驱动因子,分析了现有的湿地景观保育技术,构建的湿地景观保育技术体系将为九寨沟科学管理景区提供理论支撑,也可为其他湿地景区景观保育提供参考。     

我国东北地区某些荒芜土地的景观生态建设

我国东北地区荒芜土地的主要问题是:①土地自然生产力得不到充分发挥;②土地退化。本文根据景观生态学关于人与自然共同创造的思想及生物控制共生与自然界等级组织理论,主张在东北区域的沙地上建立林、草、田复合生态系统,在沙垅间长洼地上节节修筑沙坝,控制7—8月暴雨径流,再按不同生境种植水稻、芦苇及红麻,既适应环境,又提高生产力。     

欧洲景观生态学研究展望

随着土地利用变化的加剧以及社会经济体制的改变，欧洲传统景观生态学近切需要改革和创新。如何保持景观生态学在未来社会中的重要地位并发挥它解决实际问题的作用是摆在欧洲景观生态学家面前的迫切课题。介绍了欧洲景观生态学目前的研究热点，对未来欧洲景观生态学的发展趋势、研究框架和主要研究领域进行了展望，以期对中国景观生态不的发展有所借鉴。     

A local landscape in transition between production and consumption goals: can new management arrangements preserve the local landscape character?

Around towns in the Alentejo region, the landscape is dominated by a characteristic agricultural small-scale mosaic. These areas are central in the region landscape character – even if the large-scale latifundia landscape of the extensive silvo-pastoral systems is most commonly associated with the region. In the last two decades, these parcels became extremely attractive for new comers, who settle in the rural context as residents, week-end visitors, being often also lifestyle farmers. The paper presents a case study landscape, in Montemor-o-Novo, a small town 100 km from Lisbon, highly subject to the pressure for consumption uses, by urban users. The study shows that the new owners, even if they have settled in the area due to the tranquility and social bindings of the rural, end up doing farming, with new or reshaped production objectives, markets and models, but at the same time maintaining the traditional farm systems. Thus, the landscape character is maintained, so far. Nevertheless, the role of these neo-rurals and lifestyle farmers is still an unseen role, both by the agriculture and the planning sectors. And thus the question is, whether the combination of actors and land management drivers will continue maintaining the landscape in the future.