世界自然遗产地陆生藻类物种多样性比较研究

Terrestrial algae diversity of the two world natural heritage sites in China

藻类是真核生物进化、植物起源与进化、生物地理学研究的良好材料,研究藻类物种多样性对理解生命起源与早期进化,探明地球地质地貌演化有着非常重要的意义。以两世界自然遗产地施秉云台山白云岩喀斯特、赤水丹霞的陆生藻类为研究对象,通过G-F多样性指数、Jaccard相似性系数、Bray-Curtis矩阵比较分析了不同地质地貌的两世界自然遗产地陆生藻类的物种多样性及种组特征,结果如下:(1)两地陆生藻类丰富,均以蓝藻为优势,共有优势科为色球藻科Chroococcaceae、颤藻科Oscillatoriaceae,施秉云台山还具伪枝藻科Scytonemataceae、念珠藻科Nostocaceae优势,优势属为粘球藻属Gloeocapsa、色球藻属Chroococcus,赤水丹霞仅以粘球藻属Gloeocapsa为优势。(2)施秉云台山G-F多样性指数高于赤水丹霞。(3)两地陆生藻类泛热带成分明显,施秉云台山中国特有成分较赤水丹霞丰富;两地科、属、种相似性系数依次为:56.25%、44.05%、37.62%,科的相似性达到中度水平,与同纬度范围其它地区的Bray-Curtis矩阵聚类结果显示不同地质地貌的两地首先聚为一类。从陆生藻类多样性组成上,初步反映两世界自然遗产地的地质历史、地层岩性及地理位置的异同。

Algae have been regarded as very useful materials for the research of eukaryote evolution,plant origin and evolution,and biogeographic changes.Thus,their diversity profiles are essential in understanding life′s origin and early evolutionary development and exploring the earth′s geology and geomorphology structure.We studied the terrestrial algae of Shibing Yuntai Mountain(SYM)and Chishui Danxia(CD)in Guizhou,the two world natural heritage sites in China representing dolomite karst and danxia landforms,respectively.G-F diversity index,similarity index,and Bray Curtis were used to compare their species composition.The results indicate that:(1)the algae are abundant in both heritage sites,featured with dominant cyanobacteria species,especially the families of Chroococcaceae and Oscillatoriaceae.The SYM,however,is rich in Scytonemataceae and Nostocaceae,with more abundance of Gloeocapsa and Chroococcus,which is different from CD with abundant genus Gloeocapsa.(2)SYM′s G-F diversity indices are greater than CD′s.Thus,the species diversity of SYM is higher than that of CD.This phenomenon may be related to the factor that the alga-promoting effect of the dolomite soil and the alga-suppressing effect of the red layer soil containing rich Fe and Mn.The predominance of nitrogen-fixed cyanobacteria in Scytonemataceae and Nostocaceae reflects the dolomite karst′s environmental characteristics:rich in calcium and magnesium but poor nutrition.The species of Gloeocapsa in CD are more abundant,which are related to the silicate minerals in sandstone,besides the dry and hot climate.(3)The algae analyzed in both sites have significantly tropical and subtropical compositions and are endemic to China,especially regarding SYM.The similarity coefficients of families,genera,and species between the two sites are 56.25%,44.05%,and 37.62%.Family similarity reaches a moderate level.The Bray-Curtis results show that the two sites are clustered into the same category despite their different geological and geomorphological features.The shared similarity at family and genus levels of the algae implies that the two sites maybe have diverged from the same aquatic environments.However,the heterogeneity at the species level between the sites maybe have resulted from their different terrestrial geographic landscapes,which shaped the algae alternatively under natural selection and environmental adaptation principles.We find the characteristic algae that can prove the landform′s development from different compositions of the existing algae at the two sites.Thus,this preliminary study integrally and systematically analyzes terrestrial algae′s diversity,heterogeneity,and similarity,and geographic varieties in evolutionary development,stratigraphic lithology,and structure of the two heritage sites in China.