The Dynamics And Topographic Variation Study On Landscape Pattern Of Zhifanggou Watershed

To reveal the landscape spatial pattern of the comprehensive management in loess hilly and gully watershed, to supply the reference for further optimization of the watershed landscape. In this study, the Zhifanggou watershed landscape was field delineated based on the topographic map in 2009. The field delineation results were digitized using geographic information system software ArcGIS. The landscape types were classified according to the landscape function, land use type and constructive species of the eco-protective vegetation type. The landscape indices which could reflect the landscape composition and the features were selected. with the FRAGSTATS 3.3, analyzed the status landscape, landscape dynamic process in the past 30 years and the relationship between the landscape spatial pattern and the topography Zhifanggou watershed. The way of further optimize the landscape pattern of Zhifanggou watershed was proposed. The main results were as follows:1) Researched on the status landscape pattern of the Zhifanggou watershed, and the results showed that the general characteristics of watershed landscape pattern were high heterogeneity, concentrated and uniform distribution, the eco-protection landscape was the dominant landscape type in the watershed. The ecological protection was the dominant landscape type among the three landscape function types in the watershed; it had 21 types with an area of 81.97% of the total area. Ecological landscape types such as Robinia pseudoacacia, Caragana microphlla, Bothriochloa ischcemum, Artemisia giraldii+Stipa bungeana had important location, and their area was 52.56% of the total area, which could play an effective role in the water conservation benefits. Human dominated landscapes had significant advantage.2) Researched on the dynamic process of watershed landscape function in the past near 30 years, the results showed that the Zhifanggou landscape pattern was in continuous optimization process. Changes of the whole landscape pattern in the watershed were that the landscape patch richness and landscape diversity increased, landscape composition became more complex. The ecological protection landscape significantly increased in the patch number and area. However, the economic production landscape decreased, and the life-service landscape had little change. ecological protection landscape always was the dominant landscape in the watershed, the human jamming getting less and less and the vegetation restoration been in the self-renewal stage. The economic production landscapes and life-service landscape still interference by the continued human activities.3) The topographic variation played the major guiding role on the landscape heterogeneity in the Zhifanggou watershed. There was a complex topography in the Zhifanggou watershed, and most of the area easy to be soil erosion, so the soil and water conservation was still a challenge task in the watershed. Slope is the most important factor among the 3 topographic factors, the slope degree impact directly on soil erosion level in the loess hilly and gully region. The soil erosion level increased with the slope degree increase, and the interference of human activities on the landscape decreased a little, at the same time, the economic production landscape would gradually transform into ecological protection.4) Researched the status, dynamics and the landscape heterogeneities of the Zhifanggou watershed, and the results showed that the further optimization of watershed landscape pattern should follow: the key point of the vegetation landscape optimization would optimize the unreasonable spatial distribution of artificial or recession communities, Ensure that each landscape patch could play their ecological functions. The key of the landscape optimization and management of the watershed is to define the watershed as the agricultural economy ecosystem, on the basis of vegetation improvement, make the agricultural eco-cycle development play an important role, so as to achieve the sustainable development of ecological, agriculture and human.