[Effects of Different Climatic Conditions on Vegetation-soil Coordination Relationship in Inner Mongolian Grasslands]

Abstract

Climate change and human activities are key factors in grassland degradation. The trend of grassland degradation has improved with the development of grassland conservation policies and the increase in the awareness of conservation； however, the mechanism of climate change remains unclear. The typical grassland of Inner Mongolia was used as the study area, and 19 typical sample plots were selected from east to west, and eight different climate change regions were divided according to the distribution of temperature and precipitation, which were mean annual rainfall （MAP）： 100-200 mm and mean annual temperature （MAT）： 2-4℃； MAP： 200-300 mm MAT： 0-2, 2-4, and 4-6℃； and MAP： 300-400 mm MAT： 0-2, 2-4, 4-6, and 6-8℃. Through the measured vegetation and soil characteristics in 2022 and 2023 and analyzing their changing rules, an evaluation index system consisting of six vegetation factors and four soil factors was established to analyze the impact of different climate zones on grassland vegetation-soil. The results showed that in different climate zones, except for the total nitrogen of soil factor in 2022, significant differences were present in the vegetation and soil factors. In 2022, total soil nitrogen and Shannon-Wiener diversity index, richness index, and cover were significantly and positively correlated （P<0.05）, and in 2023, evenness index and soil water content, soil pH, soil organic carbon, and total soil nitrogen were significantly correlated （P<0.05）. In two years, the coupling and coordination relationship of vegetation-soil in MAP： 300-400 mm and MAT： 0-2℃ climate zones was relatively good but also belonged to the endangered dysfunctional development mode, whereas all other climate zones were in the mild or moderate dysfunctional development modes. By studying the law of climate change on vegetation-soil coupling, we can not only provide scientific and accurate theoretical basis for grassland restoration and management but also predict the potential impact of future climate change on grassland ecosystems, so as to formulate countermeasures in advance.

Keywords: Inner Mongolia grasslands; climatic conditions; coupled coordination; species diversity; vegetation-soil systems.