黑龙江省冻融侵蚀强度分级评价及空间分布特征

    Classification evaluation and spatial distribution characteristics of freeze-thaw erosion intensity in Heilongjiang Province of China

    • 摘要: 黑龙江省肩负维护国家生态安全、保障国家粮食安全的重任,近年来因冻融侵蚀影响,自然环境和黑土资源受到严重威胁。为了定量揭示黑龙江省冻融侵蚀强度的空间异质性及其影响因素,该研究选取10个冻融侵蚀强度评价指标,并确定其权重。通过构建多元回归模型得到冻融侵蚀下限,将权重和赋值结果代入综合评价指数模型,利用自然断点法对冻融侵蚀强度进行分级。研究结果表明:1)黑龙江省冻融侵蚀总面积为1.917×105 km²,占全省面积的40.53%,其中强烈和极强烈侵蚀分别占冻融侵蚀总面积的20.66% 和10.54%。2)黑龙江省中度冻融侵蚀以上的区域呈现三区一带的特征。三区分别为大兴安岭地区、小兴安岭地区和张广才岭地区;一带为西北—东南走向的“三岭一平原”廊道。3)黑龙江省冻融侵蚀强度在空间上表现出明显的正相关和集聚性特征,强度相近的冻融侵蚀区在空间上积聚,高强度和低强度的冻融侵蚀区在空间上分异,产生了多个高强度和低强度的冻融侵蚀区。4)植被覆盖度的增加可以降低冻融侵蚀强度,在植被覆盖度小于20%的地方,冻融侵蚀尤为剧烈;冻融侵蚀主要发生在土壤含水量为0.2~0.3 m3/m3的区域,而极少发生在土壤水分含量小于0.2 m3/m3的区域。研究结果通过对比验证显示出较高的可靠性,可为该地区冻融侵蚀的防护和管理提供依据,并为类似区域提供借鉴方法和技术参考。

       

      Abstract: Freeze-thaw erosion has occurred mostly in the alpine areas of the Qinghai-Tibet Plateau and the high-latitude area of Northeast China. Among them, Heilongjiang Province can be primarily responsible to maintain the national ecological and food security in the northeast region at present. However, the freeze-thaw erosion has seriously threatened to the natural environment and black soil resources in recent years. This study aims to quantitatively reveal the spatial heterogeneity of freeze-thaw erosion intensity and its influencing factors in Heilongjiang Province. 10 evaluation indexes of freeze-thaw erosion intensity were selected to determine their weights. The lower limit of freeze-thaw erosion was obtained to construct the multiple regression model. Finally, the distribution range of freeze-thaw erosion was drawn in the study area. The weight and assignment were then substituted into the comprehensive evaluation index model. The natural breakpoint was used to classify for the distribution map of freeze-thaw erosion intensity. The results showed that: (1) The distribution range of freeze-thaw erosion was located between 121°E-135°E and 47°N-54°N, in the north isoline of average annual ground temperature of 3℃, and about 2 latitudes lower than the southern boundary of permafrost probability. The total area of freeze-thaw erosion was 1.917×105 km2, accounting for 40.53% of Heilongjiang Province. The intense and extremely erosion were accounted for 20.66% and 10.54% of the total area of freeze-thaw erosion, respectively. (2) There was the spatial heterogeneity in the distribution of freeze-thaw erosion in the study area. The area above moderate freeze-thaw erosion presented the distribution of three areas and one belt. Specifically, the three areas were Daxinganling, Xiaoxing 'anling and Zhangguangcailing forest area; The belt was a corridor of "three ridges and one plain" from northwest to southeast. (3) The intensity of freeze-thaw erosion showed the outstanding positive correlation and agglomeration in spatial distribution. Areas with similar erosion intensity were tended to cluster spatially. By contrast, the high and low erosion intensity exhibited the spatial differentiation, leading to the multiple areas with the high and low intensity of frozen-thawed erosion. In addition, the high-low (HL) concentration areas were widely distributed in Xiaoxing 'anling area, high values of which were surrounded by low ones. (4) Freeze-thaw erosion was depended mainly on many factors, where the vegetation coverage and soil water content were contributed greatly. The increasing vegetation coverage was reduced the intensity of freeze-thaw erosion, especially where the vegetation coverage was less than 20%. The area proportion of mild, moderate, and intense erosion decreased with the increase of vegetation coverage. The freeze-thaw erosion occurred mainly in the areas with the soil water content of 0.2-0.3 m3/m3, but rarely occurred in the areas with the soil water content of less than 0.2 m3/m3. Therefore, the proportion of moderate and intense erosion increased with the increase of soil water content. These findings can provide the technical reference to protect and manage the frozen-thawed erosion in the similar areas.

       

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