基于格网的南四湖流域土地利用碳排放与其生态系统服务价值时空关系分析

Spatio-temporal relationship of land-use carbon emission and ecosystem service value in Nansi Lake Basin based upon a grid square

社会发展引起的土地利用变化对生态系统服务和碳排放有显著影响,探讨碳排放与生态系统服务价值(ESV)的时空关联规律,对促进区域低碳绿色发展提供重要的理论和实践借鉴。为揭示土地利用变化下碳排放与ESV的时空关系,以南四湖流域为研究对象,利用2000—2018年5期土地利用数据,采用土地转移矩阵和空间自相关等方法,并引入了碳源、碳汇、净碳排放量、碳排放强度和ESV强度作为研究变量,探索了ESV和碳排放的时空演变特征及其空间关联规律。研究结果表明:19年内流域内各地类间发生了程度不同的转移,其中耕地和建设用地是变化最大的类型;ESV随土地间的相互转化而波动变化,但整体上是增加的,水体面积的增加是导致其增加的决定性原因。ESV强度呈现“东高、西低,湖区不变”的分布特点,这与土地利用方式有关,受自然和社会等多因素影响;流域的碳汇量要远低于碳源量,净碳排放量呈稳定增长态势,其中建设用地的碳排放起着主导作用,因此建设用地在碳减排方面具有较大潜力。碳排放强度在研究期间发生了明显的时空变化,最大值从21.61 t/hm^(2)增长到101.42 t/hm^(2),增长了4.69倍,工业化和城镇化是其增长的驱动因素;碳排放强度和ESV强度具有空间负相关性,局部聚集现象明显,以高低聚集区为主转变为以低低聚集区为主,与地类面积和建设用地的碳排放系数有关;低高聚集区的范围和分布变化不大。总之,该流域在整体上面临着ESV和碳排放增加的趋势,根据它们之间的空间关联性,流域应采取有效措施来防止碳排放快速增长对周围区域生态环境带来负面影响,并构建生态良好的循环系统,以实现流域低碳经济。

Land-use change caused by social development significantly affects ecosystem services and carbon emissions. Exploring the spatio-temporal correlation between carbon emissions and ecosystem service value(ESV) can provide important theoretical and practical significance for promoting regional low-carbon and green development. To reveal the spatio-temporal relationship between carbon emissions and ESV under land-use change, this study took Nansi Lake Basin as the research object and adopted land transfer matrix and spatial autocorrelation methods based on land-use data of five periods from 2000 to 2018. Carbon sources, carbon sinks, net carbon emissions, carbon emission intensity, and ESV intensity were introduced as research variables. The spatio-temporal evolution characteristics and spatial correlation of ESV and carbon emissions were explored. The results showed that the changes of different land-use types in the basin occurred in different degrees during the 19 years, and changes of the cultivated land and construction land were the most significant. The ESV fluctuated with the transformation of land, but it increased on the whole, and the increase of water area was the decisive reason for its increase. The distribution of ESV intensity was “high in the east and low in the west, and remained unchanged in the lake area”, which was related to land use patterns and influenced by natural and social factors. The carbon sink of the basin was much lower than the carbon source, and the net carbon emissions increased steadily, among which the carbon emissions of construction land played a leading role, so the construction land had great potential for carbon emission reduction. The maximum carbon emission intensity increased from 21.61 t/hm^(2) to 101.42 t/hm^(2), an increase of 4.69 times. Industrialization and urbanization were the driving factors of carbon emission intensity growth. There was a negatively spatial correlation between carbon emission intensity and ESV intensity. The local aggregation phenomenon was obvious, from high-low cluster to low-low cluster, which was related to land type area and carbon emission coefficient of construction land. The range and distribution of low-high cluster areas did not change much. In conclusion, the basin as a whole is facing the trend of the increasing ESV and carbon emissions. According to the spatial correlation between carbon emission intensity and ESV intensity, effective measures should be taken to prevent the negative impact of the rapid growth of carbon emission on the surrounding regional ecological environment, and to build a good ecological circulation system, so as to realize the low carbon economy of the basin.