Ecological evaluation and reconstruction of fine-scale rural landscape

Strong demands for rural landscape development have taken into account of environmental issues related to sustainable development. The objective of this paper was to evaluate the main ecological effects of fine-scale rural landscape construction projects. Local landscapes boundaries, land uses and attributes were identified in a field survey with the help of high-resolution satellite images. Landscapes with least edge length over 2 m were classes as patches. These landscapes contained eight land use types, including farmlands, orchards, forests, grass, construction lands, roads, waters and others. Landscapes with least edge length between 0.5 m and 2 m were classed as linear landscapes. Such landscapes included vegetations, field roads, field ridges and ditches. All the field survey data were digitalized into a database in ArcGIS. Evaluation of landscape patterns and attributes was based on the rural landscape database composed of patches and linear landscapes. Landscape attributes contained land pavement and vegetation. Vegetation improvement potential was analyzed in three scenario conditions - basic, standard and optimal scenarios. Case studies were conducted in Daxing Region of Beijing City, Quzhou County of Hebei Province and Changshu City of Jiangsu Province. The study showed that current rural landscape construction projects seldom considered environment issues and had caused negative effects on landscape patterns and attributes. Simple block landscape patterns built in rural landscape construction projects eliminated landscape characteristics among different regions, forming similar landscapes in different areas. Field roads, ditches and field ridges were important linear landscapes with high densities in all three areas. Management patterns of shelterbelts were bad as interval distances between main shelterbelts were always larger than required optimal length for wind prevention. Over use of impervious surface pavements was a critical environmental risk in rural infrastructure construction. This risk was more serious in rural areas with strong economic support than in areas with weak economic investment. Excessive impervious surface pavements such as roads had reached 28.46% and 56.19% in Daxing Region and Changshu City, respectively, while it was only 5.6% in Quzhou County. Based on the evaluation of wood-cover and live vegetation volume, linear shelterbelt was nearly as importance as wood-plots at the local scale. Shelterbelts faced risks of simple vegetation structure, low tree species diversity and missing shelterbelt in range of 18% 38%. Simulation of the basic, standard and optimal scenarios showed a large potential for the improvement of wood-cover and live vegetation volume in rural areas through planting linear vegetation. Land use pressure was not simulated for linear vegetation distributions in marginal lands along roads, ditches and river banks. Through legitimate and appropriate planning and construction, wood-cover potentially increased by 0.58% 1.16% while live vegetation volume increased by 2.22% 19.59% under the standard scenario. Furthermore, the optimal scenario had higher growth of wood-cover and live vegetation volume. It was important to pay more attention to linear vegetation, including shelterbelt, in rural landscape planning for purpose of ecological improvement. The study revealed that evaluation at local scale was efficient in quantitatively identifying the shortcomings of current local landscape in terms of ecological conservation.