Changes in ecosystem services associated with planting structures of cropland: A case study in Minle County in China

摘要

The cropland ecosystem provides essential direct and indirect products and services to mankind such as food, fiber, biodiversity and soil conservation. A change of crop planting structure can change the ecosystem services of cropland by affecting land use type. In recent years, under the influence of regional comparative advantage and consumer demand changes, the crop planting structure in China has changed rapidly. However, there is still a lack of deep understanding on the effect of such a change in planting structure on the ecosystem services of cropland. Therefore, this research selected Minle County in the Heihe River Basin, which has small scattered croplands and a complex planting structure, as a study area. Based on the key time phase and optimal threshold of the normalized difference vegetation index (NDVI) data of the Thematic Mapper and Enhanced Thematic Mapper Plus (TM/ETM+) images, this study used the decision tree algorithm to classify and extract the crop planting structure in Minle County in 2007 and 2012 and to analyze the changes in its temporal and spatial patterns. Then, the market value method was adopted to estimate the effect of the change in crop planting structure on the ecosystem services of the cropland. From 2007 to 2012, the planting area of corn and rapeseed in Minle County increased by 5.86 x 10(3) ha and 5.10 x 10(3) ha, respectively. Conversely, the planting area of wheat and barley was reduced by 3.26 x 10(3) ha and 6.34 x 10(3) ha, respectively. These changes directly caused the increase of the ecosystem services value of corn and rapeseed by 1062.82 x 10(4) USD and 842.54 x 10(4) USD, respectively. The resulting reduction in the ecosystem services value of wheat and barley was 488.24 x 10(4) USD and 828.29 x 10(4) USD, respectively. Besides, the total ecosystem services value of cropland increased by 1564.98 x 10(4) USD. Further analysis found that the change in the crop planting structure caused an increase in the ecosystem servi