基于生态位理论的东北黑土区耕地整治适宜性评价——以公主岭市为例

耕地整治是保护耕地的重要举措,耕地整治适宜性评价则是开展耕地整治的重要前提和基础。本研究以生态位理论为基础,以吉林省公主岭市为例,从自然条件、基础设施条件、生态可持续性和空间稳定性4个维度选取14个指标,采用Delphi与AHP相结合的方法确定指标权重,在评判影响耕地整治的各项指标实际值(现实生态位)与耕地整治在理想条件下各项指标能够达到的最佳状态(最适生态位)的贴近程度的基础上,确定了3种类型指标的评价模型,并通过加权求和模型计算各评价单元耕地整治生态位适宜度,最终通过Ward聚类法将公主岭市耕地整治适宜性划分为4个等级,同时引入障碍性因素模型,定量确定不同等级区域耕地整治的障碍性因素,并提出整治的方向和对策。研究结果表明,研究区可分为4个整治区,Ⅰ级高度适宜区生态位适宜度大于0.75,耕地面积13 799.89 hm2,占总耕地面积的4.16%,主要障碍性因素为农田防护林覆盖率、道路通达度和田块规整度;Ⅱ级中度适宜区生态位适宜度在0.70到0.75之间,耕地面积77 754.36 hm2,占总耕地面积的23.41%,主要障碍性因素为灌溉条件、道路通达度和农田防护林覆盖率;Ⅲ级轻度适宜区生态位适宜度在0.61到0.70之间,耕地面积177 192.38 hm2,占总耕地面积的53.36%,主要障碍性因素为土壤有机质含量、距主交通干线距离和土壤pH;Ⅳ级不适宜区生态位适宜度小于0.61,耕地面积63 325.61 hm2,占总耕地面积的19.07%,主要障碍性因素为土壤质地、灌溉条件和耕层厚度。研究基于生态位适宜度模型对耕地整治适宜性进行评价,丰富了耕地整治适宜性评价方法,同时评价结果为耕地整治分区建设以及整治方向提供了科学依据。

Evaluation of cultivated land consolidation suitability in Northeast China black soil zone using niche-fitness model: A case study of Gongzhuling City

Cultivated land consolidation is a good protection measure of land resources, while land suitability evaluation forms the prerequisite and basis for cultivated land consolidation. Niche theory is generally used in ecological studies. Niche-fitness can be used to characterize the suitability of species to habitat conditions, which is increasingly applied on landscape studies. Similarly, it can be used to characterize the suitability of cultivated land consolidation index. With Gongzhuling City as the case study, this paper used niche theory and 14 indicators of four index layers (natural condition, infrastructure condition, ecological sustainability and spatial stability) to establish the suitability evaluation index system of cultivated land consolidation,. The Delphi method was then used in combination with Analytic Hierarchy Process (AHP) to determine the index weight. While the actual ecological niche of cultivated land consolidation was defined as the real index value, optimal ecological niche was defined as the ideal index value. Thus the evaluation models for the three index types (positive index, negative index and moderate index) were determined on the basis of the match degree between actual and optimal ecological niche. Based on this approach, the weighted sum of matching degree was calculated as the niche-fitness value of each evaluation unit. Finally, using the Ward method, the suitability of cultivated land consolidation were divided into 4 grades to evaluate cultivated land consolidation regions. Meanwhile, the optimal niche was proposed as a standard of cultivated land consolidation to establish the diagnosis model of obstacle indicators, clarifying the priority and orientation on cultivated land consolidation in different regions, searching countermeasures and valid paths. The results showed that the natural condition of cultivated land in Gongzhuling City was good and that cultivated land consolidation could be prioritized in the Southwest and North. About 13 799.89 hm² of land was highly suitable for cultivated land consolidation, which accounted for 4.16% of the total cultivated land. This area was restricted by farmland shelter belt ratio, road accessibility and the degree of field regularity. About 77 754.36 hm² of land was moderately suitable for cultivated land consolidation, accounting for 23.41% of the total cultivated land. The land was restricted by irrigation condition, road accessibility and farmland shelter belt ratio. About 177 192.38 hm² of land was mildly suitable for cultivated land consolidation, accounting for 53.36% of the total cultivated land. The land was restricted by soil organic matter content, distance from main traffic line and soil pH. The area unsuitable for cultivated land consolidation was 63 325.61 hm², accounting for 19.07% of the total cultivated land area. And the restrictive factors were soil texture, irrigation condition and topsoil thickness. It was suggested that the relevant departments should carry out corresponding measures of cultivated land consolidation in different regions and orderly implement the measures in the future. In conclusion, the application of the niche-fitness model in the evaluation of cultivated land consolidation suitability extended the application range of the theory of ecological niche. This provided the scientific basis for site selection and consolidation direction of cultivated land consolidation projects.