| China is the country with large population and limited land resource. With the development of urbanization, industrialization and the continued growth of population, the area of cultivated land continues to decrease so that the contradictions between people and land have become increasingly prominent. The practical situations of unreasonable land use, the overall poor quality and small quantity of cultivated land urgently require the country attach great importance to the work of land consolidation. Land consolidation is the important measures and means to achieve dynamic balance of cultivated land and keep 18 million mu of cultivated land in our current and future long period of time. At the same time, it also has great significance to ensure food security, alleviate the contradiction between people and land, and promote the process of urbanization and socio-economic development. However, land consolidation is the process of reconfiguration of the original landscape pattern and it has changed the original land use way, land use structure and land cover of project area because of the use of a series of engineering measures. Strong interference from human factors into farmland ecosystems caused large-scale changes to the existing landscape structure surface in the project area, resulting in the major changes of the structure of land ecosystem composition, nutrient cycling and energy flow. While, inappropriate engineering measures of land consolidation have certain negative effects about soil properties, biodiversity, land ecosystem stability, decrease the soil nutrients such as available phosphorus, potassium, active organic matter and so on and soil microbes, reduce environmental degradation of farmland habitat and decline the ability to buffer and compensate, resist disasters and adapt to the environment of agricultural ecological system.The effects on the farm landscape and its ecological impacts caused by land consolidation as an important human land use activities have been more concerned by experts and scholars. In the feature, we should change the one-sided understanding that the main goal of land consolidation is to increase the cultivated land area, and pay more attention to landscape ecological effects of land consolidation, leading to the sustainable development of land resources.This paper takes the Caoyuan land consolidation project district and the Lijiazhai land consolidation project district as the object of study, combined with principles of landscape ecology, and use the method of landscape pattern analysis to analyze the landscape pattern characteristics of the plain and hilly two different types of land consolidation project district and the different effects on landscape ecological processes between them. It also analyzes the deficiencies of both in the landscape ecological construction, and try to promote some recommendations of landscape in order to provide references for the landscaping designing and ecological construction of the different types of land consolidation project in the future. This paper selects the more commonly used landscape indices to analyze the landscape pattern of land consolidation project district. Taking into account large quantity, certain correlation and different scale effects of the landscape indices which will affect the comprehensiveness of the analysis of landscape pattern, it's important to choose small independent or related landscape indices witch can explain the different aspects of landscape information and analyze landscape pattern based on the appropriate grain size in order to accurately reflect the real landscape pattern changes, but at this stage the researches on the appropriate selection of landscape indices and small size for the landscape pattern analysis of different types of land consolidation project district are not more. Therefore, this paper analyzes the landscape pattern grain size effects and the correlation of the landscape indices before the analysis of different types of land consolidation project districts in order to selection the appropriate landscape indices and grain size of land consolidation and improve the accuracy of overall landscape pattern analysis, so as to provide scientific basis for landscape pattern analysis and the planning of land consolidation in the future.Through the analysis of grain size effect and the landscape pattern of the existing land consolidation project, this paper draws the following aspects:(1)The landscape pattern grain size effects of land consolidation project district are obvious, and there are not only the similarities but also the differences between plain and hilly types of land consolidation.By the grain size effect of plain and hilly types of land consolidation, from the point of view of the proportion of landscape types, both plain and hilly areas, there are the following:①The responses of landscape types presented on grain size are not synchronized;②The responses of the same landscape type before and after presented on the grain size are also not synchronized and different in the sensitivity;③When the grain sizes are more large, the non-dominant(small percentage) landscape types before and after land consolidation may disappear from the landscape completely on the different grain sizes, and the sensitivities of the non-dominant landscape types are greater than the one of the dominant landscape;④corridor landscapes (the land for irrigation, ridge, traffic) are greater sensitive to grain size changes;⑤The mutation is more prevalent in the landscape, caused by the reasons of changes of the patch shape, partition or fusion of small patches, and even complete disappearance of some landscape types.Studying from the other landscape indices, plains and hilly landscape indices can be divided into three types:(a) Some ones show the consistent response to the changes of grain sizes and have no obvious turning point before and after land consolidation, including NP, PD, TE, ED, LSI, SHAPE_MN, FRAC_MN; (b) Some ones show different responses to changes of grain sizes before and after land consolidation, witch a part of them show the consistent rule, but another part show inconsistent rule, and they all have the turning points witch appear in different grain sizes, including AREA_CV, AREA_MN, CONTAG, PR, SHDI, AI; (c) Another one has no obvious rule of the response to changes of grain size and has no turning point, including LPI.Overall, whether plain or hilly areas, the landscape indices related to strong trend have the same or similar features of grain size effects. The stronger correlation between the landscape indices, the trends of the grain size effects are of the more similar. So,16 landscape indices in this paper were grouped into five categories, from witch when we select the landscape indices respectively.Meanwhile, there are also differences of the responses to changes of grain sizes between the plain and hilly types of land consolidation. Whether studying from the proportion of landscape types, or from other landscape indices, the grain size effects of hilly landscape are larger and more sensitive than the ones of plain landscape, because the overall boundaries, patch shape of the hilly land consolidation project district are so much more complicated than plain land consolidation project districts'.(2) Both plain and hilly land consolidation project districts can use PD, FRAC_MN, CONTAG, SHDI and AREA_CV to analyze their landscape patterns. Due to the grain size effects of hilly type is more sensitive than the plain type, the former choice of the appropriate particle size is smaller than the latter.(3) There are different changes of the landscape pattern between the plain and hilly land consolidation project district, and there are both positive and negative landscape and ecological effects.After Land consolidation, the positive effects of the plain land consolidation project district are the increases of patch area and the decreases of fragmentation and the negative effect is the degradation on landscape diversity; on the contrary, the fragmentation degree of the hilly land consolidation project district is enhanced and landscape diversity is increased.(4)There are some deficiencies of the landscape ecological construction both in the plain and hilly land consolidation project districts. So it is necessary to strengthen the landscape ecological construction in land consolidation. |
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