古尔班通古特沙漠南缘典型沙垄藻类的时空分布

Spatio-Temporal Distribution of Algae Relating to Biological Soil Crusts in the Gurbantunggut Desert,Xinjiang,China

通过研究春、夏、秋3季古尔班通古特沙漠典型沙垄藻类物种多样性、种类组成和生物量的变化,分析了典型沙垄中藻类的时空分布特征。结果表明:①地貌部位和不同土层对物种多样性指数影响极显著(P<0.01);在垂直层次中,藻类物种多样性指数由表及里逐渐降低。②在不同地貌部位和季节中,藻类的种类组成亦表现出一定的差异。垄间低地和背风坡球形藻类和丝状藻类丰富,迎风坡以丝状藻类占优势,垄顶藻类的种类和数量都有明显的下降。③地貌部位、垂直层次和季节对藻类生物量的影响均极显著(P<0.01)。藻类在沙漠典型沙垄的分布具有空间异质性,将影响到生物结皮的发育,使其处于不同的发育阶段,而它们在生物结皮中的地位和作用亦不同。

In spring,summer and autumn of 2007,soil samples were colleted,cultured and identified in the different locations of sand dunes in the Gurbantunggut Desert,northern Xinjiang of China.Algae biomass of soil samples was measured.The spatio-temporal distribution of algae was determined by species diversity,species composition and biomass.The results indicated that：（1） Species diversity was significantly affected by locations of sand dunes and soil layers with different depth（P0.01）.Species diversity of algae in windward and leeward of sand dunes were the most abundant,followed by inter-dune areas,and in top of sand dunes was the lowest.In vertical layers of all sand locations,species diversity of algal declined with the deepening of soil layer.（2） Some differences were observed for algal composition in different locations of sand dunes and in seasons.In inter-dune areas and leeward,coccoid and filamentous algae were abundant;in windward,only filamentous algae were dominant.However,taxa and number of algae decreased obviously in the top of sand dunes.In some locations of sand dunes,some algae were found in different seasons,otherwise,the number of the algae was different,which led to changes of dominant species and common species.Microcoleus vaginatus was the main dominant species in different sand locations.The other dominant species changed in different locations of sand dunes and in seasons.（3） Sand dune locations,layers with different depth and seasons had highly significant effects on algal biomass（P0.01）.For algal biomass,no seasonal changes were observed in the top of sand dunes.However,there were obvious seasonal changes for algal biomass in other sand locations.There was spatio-temporal heterogeneity for algal distribution in sand dunes.Heterogeneity of algal distribution may have some effects on the development of biological soil crusts（BSCs）,which may make BSCs be different developmental stages.Algal distribution in different BSCs made the role and status of algae changed.