广西海岸沙滩红树林的生态研究Ⅰ:海岸沙丘移动及其对白骨壤的危害

Ecological Studies on Sandy Mangroves along Guangxi Coast Ⅰ: the Movement of Coastal Sand Dune and Its Damages to Avicennia marina (Forsk) vierh

关键词:  海岸沙丘  移动  危害  红树林

Key words:  coastal sand dune  movement  damage  mangrove

摘要:

广西北海大冠沙红树林为开阔沙滩白骨壤林。为了解沙丘移动的规律及其对红树林的危害,从1992年4月到1995年7月对一处于发育初期的活跃沙丘进行实地观测。结果表明,30多年前沙丘才开始在林内发育和移动。沙丘高可达88cm,每年移动12.64m,在4~7月大潮期移动尤其迅速。沙丘在3.25年面积扩大了2.44倍。研究样地白骨壤植株高49.5~67.9cm,86%的植株因被沙丘埋没而死亡。在埋没过程中存活下来的植株继续受侵蚀、呼吸根上的固着动物和人为活动的危害。沙丘的移动引起白骨壤林的明显退失和生境的分化。

Abstract:

The mangrove at Daguansha, Beihai, Guangxi is an Avicennia marina forest growing at open sand beach. From 1992 to 1995, field observations were conducted on a junior active sand dune to understand its movement laws and the damages to mangroves. It was indicated that some 30 years ago, sand dune began to develop and move within the forest. The sand dune could reach 88 cm high and moved 12.64 m annually, and being more rapid from April to July when the spring tides undergo. The area of sand dune enlarged 2.44 times in period of 3.25 years. 86% of plant individuals died of the sand bury because of Avicennia tree height frequently rangig from 49.5 to 67.9 cm. The individuals that survived from the bury went on by further damages of erosion, fauna encrusting on the pneumatophores and human interventions. As results of the movement of sand dune, the forest considerably retreated and the habitats were differentiated.