关键词: 生境质量, 地类斑块, 格网尺度, 尺度转换, 空间自相关, 黄山市

Abstract:

Grid cell is the basic spatial unit to analyze the habitat quality based on remote sensing imagery. The choice of suitable grid size is very important for different regions, as the resolution must be fine enough to ensure the accuracy of habitat quality assessment. The purpose of this study is to identify differences in the habitat quality assessed at different grid scales, and to provide a basis for selecting appropriate spatial scales to analyze habitat quality in different regions, so as to improve the assessment accuracy. Taking Huangshan City as the example, this paper evaluated its comprehensive habitat quality in 2017 based on the model of ecosystem service value, habitat quality index consisting of NPP and NDVI, and InVEST habitat quality assessment model. With 30 m as the base scale and employing the elastic coefficient and spatial autocorrelation method, this paper assessed how changing grid sizes affect the habitat quality assessment results. The findings are as follows. (1) in 2017, the original assessment result of Huangshan's total habitat quality was 2.02×10¹⁰ yuan, with an average of 21126.1 yuan/hm². And the last adjusted total habitat quality was 1.84×10¹⁰ yuan, with an average of 18627 yuan/hm². (2) With the increase of pixel's side length, the total value of the comprehensive habitat quality assessment result decreased in the zigzag form. (3) The grid size effects on different land uses showed that the results of the habitat quality assessment were much more accurate when the scale of change was an odd multiple of the base scale, i.e., 30 m. And it was much clearer for the elevation range of 0~200 m and 200~400 m. (4) In terms of the elasticity coefficient of habitat quality calculated for scale change from one grid size to another, the coefficient was larger for the scale changes from 150m to 180 m, 270 m to 300 m and above 900 m. With the base scale as a reference, the elasticity coefficient of the habitat quality would decrease in the power-function form with increasing grid size. And the change of the habitat quality would be most sensitive when grid size changed from 30m to 60m. While the value of habitat quality change was relatively insensitive as the grid size changed from 30m to 210m. (5) The spatial distribution of habitat quality in Huangshan City showed a significant positive autocorrelation. With increasing grid size, the index of Moran's I decreased in a waving manner, and the Z value of the normal distribution also decreased in the power-function form. Our fidings can provide theoretical support for the selection of suitable grid sizes for habitat quality analysis in different places.

Key words: habitat quality, land use type, grid size, scaling, spatial autocorrelation, Huangshan City