基于排序分析法的北大港古泻湖湿地植被成带现象研究

Study on Vegetation Zonation Characteristics in Beidagang Ancient Lagoon Wetland Based on Ordination Analysis

北大港古泻湖湿地植被群落成带现象明显,利用DCA对群落成带规律进行研究,同时采用CCA确定影响该现象的主要环境因子.结果发现,植被"岸带成带"现象在空间上反映了植被的演替情况,植被类型按水生植被-湿生植被-中生植被-旱生植被进行变化,植被由聚盐植被变化到拒盐植被.通过DCA排序,北大港湿地植被呈现明显的6条分带,分别是芦苇-扁秆藨草群落、芦苇-碱菀群落、芦苇-盐地碱蓬群落、芦苇-碱蓬群落、芦苇-柽柳群落、猪毛蒿-黄花蒿群落.其中芦苇伴生在大部分的植物群落周围,具有非常宽的生态位,起到了良好的水土保持作用.外部因素是驱动群落成带分布的主要原因,通过CCA排序,土壤的含水量、含盐量、有机质含量都是影响植被分布的重要因素,而生境因子中,坡度对群落分布有较大影响.北大港湿地植被组成较为单一,以盐生草本植被为主,为了增强水土保持效果形成草-灌-乔稳定的群落结构,应该采取合理措施,加速演替的进行.

The phenomenon of＂vegetation zonation＂was very obvious in Beidagang wetland,DCA was used to analyze the characteristics of zonation,and CCA was used to analyze the main effecting factors.The results showed that the phenomenon of ＂vegetation zonation＂reflected the community succession spatially,the types of plants changed from aquatic plants,humidogene plants,mesophyte plants to xerophytic plants,vegetation changed from salt-gathering plants to salt-refusal plants.The vegetation patterns presented obvious zoning phenomenon with six zones based on DCA,they were Phragmites australis-Scirpus planiculmis community,Phragmites australis-Tripolium pannonicum community,Phragmites australis-Suaeda salsa community,Phragmites australis-Suaeda glauca community,Phragmites australis-Tamarix chinensis community,Artemisia scoparia-Artemisia annua community.The Phragmites australis associated around most of the vegetation communities,it had the widest ecological niche and played an important role in soil and water conservation.By CCA analysis,the factors of wc,sc,org were all main soil factors,while the slope gradient was also an important habitat factor,for it influenced the change of soil factors.External factors were the main factors to form the vegetation zonation.The species of vegetation were very single,especially dominated by coastal saline herbaceous plants,so more reasonable measures should be taken to accelerate succession proceed to form stable vegetation structure.