对河西走廊荒漠植物的群落类型、盖度、密度、重要值、地上生物量等进行了调查,收集整理各区域的气候资料,对它们的关系进行了初步研究。结果显示:(1)物种种类组成、总密度与海拔、经度呈正相关,与纬度呈负相关,在走廊的东南→西北方向上呈递减趋势。(2)在活动积温(〉10℃)〉3 200℃的荒漠地区,灌木(包括半灌木)在群落中占有绝对优势,其重要值可达到100;当活动积温在3 000℃左右时,群落往往是一些过渡类型,或以草本为优势种、以半灌木或灌木为伴生种,或以半灌木为优势种、以多年生草本为伴生种。(3)在年降水量110 mm以上的荒漠地区,植物群落生活型主要为半灌木或多年生草本;在年降水量110 mm以下的地区,生活型主要为小灌木或一年生草本;在年降水量小于50 mm的极端干旱地区,只有在雨季时有一年生草本生长。表明荒漠生态系统植被稀疏,生物量小,对气候因子,特别是降水变化敏感,对其保育显得尤为重要。
Types, coverage, density, appearance, important value, and aboveground biomass of the desert plant community in the Hexi Corridor region in northwestern China were investigated,and meteorological factors of the investigated place were collected, and their relationships were statistically analyzed. The results showed that the composition of plant species and the total density in Hexi Corridor region positively correlated with the elevation and the longitude, but negatively correlated with the latitude, and decreased from southeast to northwest in this region. In the desert regions with an accumulated temperature of 10℃ being greater than 3 200℃,the shrubs (included semi-shrubs) occupy dominant positions in the communities, and the importance values reaches 100 ; when accumulated temperature is about 3 000 ℃, the communities are often some type of transition, either with herbage being the dominant species ,and some semishrubs or shrubs being companion species, or dominant species are semi-shrub and some perennial herbage as companion species. In the desert communities with an annual precipitation of over 110 mm the plant main life forms are semi-shrubs or perennial herbs ; while less than 110 mm the plant main life forms are dwarf shrub or annual herbs. In the extreme arid region with annual precipitation around 50 mm in the northwestern part of the Hexi Corridor only some annual herbage grows just during the rainy season. Desert ecosystem takes on sparse vegetation and small biomass,changes with climate factors especially sensitive in precipitation, and it is particularly important for its conservation.