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以仅见于黄土高原半干旱区局部地段的黄土藻类群落为对象,分别从植被类型、坡向、坡度、地貌部位、干扰程度等方面对其分布规律进行系统地研究。通过调查,测定了藻类结皮在不同立地条件下的结皮厚度、植被分布、结皮盖度等指标。结果表明:①不同植被类型对藻类结皮盖度和厚度的影响呈现出不同的规律性。植被类型不同,藻类结皮盖度不同,荒坡>樟子松林>油松林。但结皮厚度表现出相反的特点,即油松林>樟子松林>荒坡地。②坡向对藻类结皮分布有明显影响。阴坡藻类结皮盖度和厚度均大于阳坡。③坡度对藻类结皮分布的影响是在多种因素的共同作用下形成的,不同坡度对藻类结皮盖度的影响差异不显著;但影响结皮厚度,即平缓坡>缓坡>陡坡>极陡坡。④地貌部位对藻类结皮分布有明显影响,在林地里,结皮盖度表现为坡上部>坡中部>坡下部。结皮厚度无显著差异。⑤干扰程度对藻类结皮分布具有明显影响,干扰程度弱,藻类结皮盖度和厚度均大,反之则小。
The distribution of loess algae communities in the semi-arid area of the Loess Plateau was systematically studied from the aspects of vegetation types, aspect, slope, topography and disturbance level. Through investigation, the crust thickness, vegetation distribution and crust coverage of algal crusts were measured under different site conditions. The results showed that: ① different types of vegetation algal crust cover and thickness showed a different regularity. Different types of vegetation, algal crust coverage of different slopes> Pinus sylvestris> Pinus tabulaeformis forest. However, the crust thickness showed the opposite characteristics, ie, Pinus tabulaeformis> Pinus sylvestris forest> wasteland. ② aspect of the algal crust distribution has a significant impact. The coverage and thickness of shady algal crusts were both greater than the sunny slopes. The effect of slope on the distribution of algal crust was formed under the combined action of many factors. The effect of different slopes on algal crust coverage was insignificant, but the effect of crust thickness, ie, gentle slope> gentle slope> steep slope> pole steep slope. ④ The topography of the algae had a significant effect on the distribution of algal crusts. In the woodland, the crust coverage showed the upper part of the slope> the middle part of the slope> the lower part of the slope. Crust thickness no significant difference. ⑤ The degree of disturbance has a significant effect on the distribution of algal crusts, and the degree of disturbance is weak. The coverage and thickness of algal crusts are both large and vice versa.