呼伦贝尔草原风蚀坑植物分布空间异质效应

Distribution characteristics of vegetation around blowout in the Hulun Buir Glassland

风蚀坑是草原常见的风蚀地貌类型,其发生风蚀同时伴随不同程度的沙埋作用,造成其不同区域植被生长及分布存在一定差异。为明晰草原风蚀坑不同区域的植被组成特征与分布规律,本研究以呼伦贝尔草原处于活跃发展阶段的风蚀坑为研究对象,调查风蚀坑5个不同区域(沙坑、上风向区、左积沙区、右积沙区、下风向区)植物种类及其生长情况,并以周边天然草地为对照(CK),分析风蚀坑对植物空间分布的异质效应,拟为草原风蚀坑发展机制研究及其植被恢复技术提供重要依据。研究表明:(1)风蚀坑与CK相比植物种类显著增加,植物种类达到了42种,隶属于13科34属,CK为17种,隶属于8科16属,但增加的植物种多为沙蓬、兴安虫实等沙生植物。(2)风蚀坑不同区域植物种存在显著的异质性,沙坑主要植物种为菊科,植物种数量较CK分别减少85.42%。上风向处、左积沙区、右积沙区等区域植物种以苋科为主,下风向处以禾本科植物为主,分别增加了47.05%、117.75%、35.29%、29.17%。(3)不同区域植物长势存在较大差异,沙坑、下风向区较CK差异最显著,植株密度降低了99.63%、89.73%,植被盖度降低了84.48%、69.06%,地上生物量降低了93.15%、56.78%。(4)下风向区沙埋覆盖草地面积最大,随着沙坑边缘经过积沙区向草地延伸,植物种类数量逐渐接近CK,重合度可达到52.63%,苍耳、沙蓬等植物消失。

Blowouts are a common type of wind erosion landform in grasslands,and their occurrence is accompanied by different degrees of sand burial,resulting in specific variations in vegetation growth and distribution among different areas.This study focused on the blowouts in the active development stage of the Hulun Buir grassland as the research object to clarify the characteristics and distribution of vegetation in various areas of grassland blowouts.We investigated plant species and their growth in five different areas of the blowouts(sand pit,upwind,left sand accumulation,right sand accumulation,and downwind).The study also analyzed the heterogeneous effect of blowouts on the spatial distribution of plants in the blowout without being affected by sand burial in the upper wind direction as CK.This study aims to provide an essential basis for studying the development mechanisms of grassland blowouts and vegetation restoration technology.The results showed the following:(1)Compared with CK,the plant species of the wind erosion crater increased significantly,with 42 species belonging to 13 families and 34 genera,while CK had only 17 species belonging to eight families and 16 genera;most of these species were psammophytessuch as Agriophyllum squarrosum and Corispermum chinganicum insects.(2)There was marked heterogeneity in plant species from different areas of the blowout;the main species in the pit belonged to Asteraceae,and the number of species decreased by 85.42%compared with CK;the number of plant species in the upwind direction,and the left and right sand accumulation areas were dominated by those from Amaranthaceae;grasses were the primary plants in the downwind direction;and the number of species enhanced by 47.05%,117.75%,35.29%,and 29.17%,respectively,compared with CK.(3)The plant growth varied remarkably in the different regions,most significantly between the sand pit and downwind area compared with CK;plant density declined by 99.63%and 89.73%,vegetation coverage by 84.48%and 69.06%,and aboveground biomass by 93.15%and 56.78%.(4)The area of the sand-buried grasslands in the downwind area was the largest;the number of species gradually approached that of CK as the sand pit edge extended to the grasslands through the sandy area;the coincidence degree reached 52.63%;and plants such as Xanthium sibiricum and Agriophyllum squarrosum disappeared.