北仑河口的红树林及其生态恢复原则

The Mangroves and Their Ecological Restoration Principles of Beilun Estuary, Guangxi, China

关键词:  红树林  生长与生境  恢复原则  北仑河口

Key words:  mangroves  growth and habitats  restoration principles  Beilun Estuary

摘要:

以东兴河桥为起点,1km为单位尺度,将北仑河口岸线划分为12个岸段,其中第12岸段长为2km。在各岸段进行优势群落样方调查,同一群落选3个样方,每样方面积16m²。用取土器钻取各群落20cm~40cm土层土壤3份,用于测定土壤含水量、全N和全P。广西北仑河口的红树林由7种红树植物和6种群落类型组成。与广西其它海岸相比,老鼠簕和卤蕨群落在该河口发育良好。严重的滩涂侵蚀、红树林生境的破碎和土壤养分的明显缺乏是北仑河口次生红树林自然恢复困难的主要原因。不同的红树植物生长在不同的岸段是对盐度响应的结果。北仑河口13km长的岸线可大体上划分为内河(2km)、河口(5km)、近海河口(2km)、近海(3km)4个生态区间。应用工程的方法提高滩涂的高程,引入红树林新品种是北仑河口红树林生态恢复的关键。

Abstract:

The coastline of Beilun Estuary,Guangxi,China was divided into 12 sections starting from Dongxing Bridge in field survey. Each section is 1 km except that Section 12 is 2 km.Three sampling spots were selected in each dominant community,and each spot is 16 m². Three duplicates of soil samples were collected at the soil of 20 cm to 40 cm depth in each dominant community for determining water content, whole N and whole P of the soil. Seven mangrove species with six types of communities were identified for the mangroves along coasts of Beilun Estuary. The communities of Acanthus illicifolius and Acrostichum aureum develop better in this estuary than the other coasts of Guangxi. The severe erosion of intertidal lands, fragmentation of habitats and the obvious deficiency in soil nutrients are responsible for difficultly natural restoration of the secondary mangroves. The growth patterns of mangroves in the coastal sections are sensitive to salinity. The 13 km long coastline could be roughly divided into four ecological intervals of freshwater(2 km), estuary(5 km), inshore estuary(2 km) and inshore(3 km). To more protect the remaining mangroves, the increase of elevation of eroded intertidal lands by engineering means and the introduction of new mangrove species would be critical for the ecological restoration of Beilun mangroves.