泥质海岸生物护坡植物群落演替过程研究

Research on Floral Succession in Plants Protecting Engineer of Muddy Sea Wall

以天津淤泥海挡植物防护工程为例,对利用碱渣、海底淤泥等废弃物质作为种植基质,通过工程脱盐后种植耐盐和盐生植物,同时在高潮线以下低潮位浅滩种植互花米草群落,从而形成的泥质海岸特定功能的植物群落进行多年观测。发现互花米草促淤的过程是创造生境的过程,其群落的演替过程也是造陆过程,演替方向是向退潮方向逆行演替,3年淤积厚度达30 cm,出现次生裸地,次年盐生植物迁入其间,形成盐地碱蓬、碱蓬、中亚滨藜、獐毛、芦苇、白刺、狐米草等盐生植物群落带。随着地势继续抬升,超高潮带(包括海挡下部高程2.8～5.5 m的坡面)的地下水位和土壤盐分的下降,种植耐盐性强、护坡固土能力强的灌木柽柳,构成迎风潮坡面护堤海挡植物,使其向潮间带重盐碱地演替或向坡顶轻盐碱堤上扩展,形成茂密的灌木林防护带。当海挡上部土壤含盐量下降至0.6%以下,种植毡毛梣、沙枣、臭椿、刺槐、柽柳、紫穗槐等多种耐盐乔、灌木植物,从而形成多层多种的海防林演替顶极乔木群落。

Take example for plants protecting engineer of muddy sea wall in Tianjin, using caustic sludge and brackish dredged sediment as medium, salt-tolerance plants and halophyte were planted after scientific manufacture and desalting treatment. At the same time, the ecological population of Spartina alterniflora was also planted in low tide shallows below high tide line; then, the plant community which had special functions in muddy sea wall was developed, and it was observed for many years. It was found that succession process of Spartina alterniflora was a process of land production, the succession direction converses the direction of tide ebbing. After 3 years, the thickness of deposition came to 30 cm, and there emerged secondary bare ground where halophyte immi- grated in next year, the halophyte biotic community with Suaeda salsa, Suaeda glauca, A triplex centralasialica, A eluropus sinensis, Phragmites communis, Nitraria sibirica, Spartina patens and so on was formed. With land rising, the groundwater level and salt content began to decline. Tamarix chenensis which had high tolerance to salt and ability of protecting earth was formed protection plant in slope of windward tide. Its successions direction was worst salt-affected soils in tide beach or saline-alkali soil at the top of slope. So, the thick spinney protection belt was formed. When soil salt content declined below 0.6%, the shrubs community was developed by planting Fraxinus velutina, Elaeagnus angustifolia, Ailanthus altissima, Robinia pseudoacacia, Tamarix chenensis, Amorphafruticosa and so on.