Land suitability evaluation using niche model for rural settlements in typical county in the upper reaches of Minjiang River

Abstract: Land suitability for rural settlements can greatly contribute to revealing the matching between human activities and the ecological environment, as well as social economy. Taking Li County in the uppers reaches of the Minjiang River as the study area; a systematic evaluation of land suitability was conducted using rural geography, landscape ecology, and niche model. A GIS spatial analysis was also performed on the landscape pattern using remote sensing images, socioeconomic statistics, and land use multi-source data, particularly considering the geographical scale of rural settlements and the degree of suitability between humans and natural environmental conditions. Firstly, the optimal scale was identified for land suitability of rural settlements in the study area. Secondly, the representative indicators were selected to construct an evaluation index system, according to the status quo of the region. Finally, a niche suitability model was used to evaluate the land suitability for the rural settlements. The results were as following: 1) The optimal scale was supposed to be 60 m in the study area, where the suitable scale ranging from 50-60 m in the first scale domain of landscape indices. The changes of landscape indexes were also obtained in the 8 rural settlements response to 20 rural settlement scales. 2) Each evaluation index was quantified to obtain the current restrictive conditions at the optimal scale of 60 m, such as forbidden construction area, water source protection area, and nature reserve. GIS spatial overlay function was also utilized to evaluate the land suitability of rural settlements. The suitable land area for rural settlement only accounted for 4.58% of the whole area. Specifically, the area of low suitable zone accounted for 0.52%, whereas, the moderate and highly suitable areas accounted for 4.06%, mainly distributing in the eastern and northeastern towns and the lower reaches of the Zagunao River Basin, along the National Highway 317. 3) The low unsuitable area was 4 116.03 km2 harsh for sustainable survival and development, mainly located in the water source and ecological protection areas prone to geological disasters. The moderately suitable areas presented outstanding characteristic industries and great potential to develop modern agriculture, in terms of natural resources and local conditions. The highly suitable areas behaved obvious advantages in terms of location, economy, natural and cultural resource conditions, indicating a relatively complete rural function and high level of economic development. It was supposed to be the main gathering area of rural population and industries. The moderate and highly suitable areas gained relatively distinct potentials for economic and social development. Therefore, the main space for rural revitalization can be concentrated on the moderate and highly suitable areas of rural settlement in the future. Additionally, it should be properly considered to explore the impact of industrial and commercial enterprises, public service facilities, and other land-use types on the land suitability of rural settlement against the requirements of rural revitalization strategy. This finding can provide a sound scientific basis to reconstruct the rural settlements for the optimization of territory space.