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机构地区:[1]石河子大学,新疆石河子832000 [2]书国科学院新疆生态与地理研究所,新疆乌鲁木齐830000
出 处:《中国沙漠》2013年第6期1803-1809,共7页Journal of Desert Research
基 金:国家自然科学基金项目(41361097);中国科学院“西部之光”博士专项基金(XBBS201103)资助
摘 要:古尔班通古特沙漠生物结皮占该沙漠总面积的30%左右,苔藓结皮是其中的优势者,在防风固沙、捕获隐匿降水和水土保持方面发挥着重要的生态作用。自然状态下,该沙漠苔藓结皮多以镶嵌式或纯群状斑块分布,本文从斑块尺度出发,以斑块面积为指标,分析了该沙漠藓类结皮斑块的分布格局和特征。结果表明:(1)在调查的7372个藓类结皮斑块中,有6930个斑块的面积在100CIIl。以内,占总斑块数目的94%,面积在100Clll。以上的斑块约为442个,占总斑块数的6%。(2)本研究共调查了143223c2苔藓结皮,其中100cm2以下的小斑块面积约为57289m2,占总调查面积的40%;其次是大小在100~200c2的斑块,面积约为32941Cm2,占总调查面积的23%;大小在200crn。以上的斑块面积约为50128c2,占总面积的35%。面积较大的斑块主要分布在沙漠东南部,西北部藓类结皮斑块面积较小,这一变化特征与苔藓结皮在区域尺度的优势发育区一致。(3)藓类结皮斑块面积大小与粒径在0.2mm以下的土壤含量正相关,大粒径的土壤不利于藓类结皮形成较大的斑块。(4)藓类结皮斑块面积与主要灌丛盖度呈微弱负相关,与土壤有机质、全氮、速效钾、可溶性钙含量显著正相关,这与区域尺度的报道一致。Biological soil crusts takes up 30% area of the Gurbantunggut Desert, moss crusts are the domi nant species, they are very important in the prevention of wind and sand, promoting dew capture. In natu ral condition, moss crusts are distributed in the form of different size patches. In this study, we researched moss crusts from the point of patch size and analyzed the size characteristics and environmental factors that influence the patch size. Our results indicated that: (1) there were 6 930 patches with area less than 100 cm2, and accounted for about 94 % of total surveyed moss crust patches; patches with area over 100 cm2 took up 6% of total surveyed patches. (2) in this study total surveyed area of moss crust were 143 223 cm2, total area of the patches with area less 100 cm2 were 57 289 cm2 and took up 40 % of total area; the second rank were those patches with area of 100200 cm2, the total area of 100200 cm2 patches were 32 941 cm2and took up 23% of total surveyed moss crust; the area of those patches with area over 200 cm2 was 50 128 cm2 and took up 35% of total surveyed moss crust. On the whole, big size patches mainly occurred in the south east and small size patches were found in the northwest of the desert, this pattern was consistent with the distribution of moss crust on the regional scale. (3) there was positive effect of soil particles with diameter less than 0.2 mm on the patch size, soil particles with the diameter more than 0.2 mm were not in favor of big size patches. (4) the shrub canopy area were weak negatively related with the moss crust patch size, and organic matter, total nitrogen, available potassium and soluble calcium were positive related with patch size, these were similar to the results of regional scale.
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