中国红树林蛀木团水虱危害分析研究

Analytic Study on the Damages of Wood-boring Isopod,Sphaeroma,to China Mangroves

关键词:  红树林  团水虱  危害规律  管理建议

Key words:  mangrove  wood-boring isopod  regular of endangering  management suggestion

摘要:

[目的]蛀木团水虱是近年来危害中国红树林的一个新情况,已导致海南和广西部分红树林的死亡。为了防控团水虱,本文总结团水虱对中国红树林的危害情况,分析团水虱爆发的可能原因,提出一些管理策略。[方法]在海南和广西三处红树林团水虱危害地实地调查资料及生石灰消杀与鱼类捕食控制实验的基础上进行分析。[结果]调查表明,2010至2013年海南东寨港受团水虱攻击而死亡的红树林面积的平均连年增长率为66.4%。危害中国红树林的蛀木等足类生物主要为有孔团水虱和光背团水虱,前者是危害海南东寨港红树林的关键物种。受害的红树林都分布于人为干扰强烈且有机污染严重的海区。生长在污染物扩散通道潮沟边缘或污染物沉积区中的林子是团水虱的集中攻击对象。处于地带性演替后期、相对高大的成熟林易遭受团水虱危害。团水虱对红树植物的选择性攻击序列为:海莲、木榄 > 尖瓣海莲、角果木 > 白骨壤、秋茄 > 桐花树。由于潮差不同,中国大陆沿海红树林可受团水虱攻击的地上部高度为海南岛的2倍以上。在实验室中,1:1配比的石灰水90min就可达到50%的团水虱消杀效果。中华乌塘鳢单位时间的吞食量较稳定,24h内平均可捕食42只团水虱。[结论]推测在海区环境退化的背景下放养家鸭,虾塘排放有机物和消毒剂,人为捕获经济动物很可能是团水虱爆发的触发因子,建议将红树林团水虱危害纳入相关的海洋生态环境监测与评价体系,建立以化学手段为应急,物理措施为辅助,生态保育为长效的红树林团水虱防控机制。

Abstract:

[Objective] Damages to mangroves due to the presence of wood-boring isopod of Sphaeroma are newly found in China.Aiming to control the isopod disaster, this paper evaluates the status of isopod damages to China mangroves, analyzes the possible causes and puts forward some management tactics, and some scientific issues about massive occurrence of Sphaeroma in China are discussed.[Methods] Analyses were made on the information from field surveys conducted at three damaged mangrove sites in Hainan and Guangxi province, and the tests of isopod controls by calcium oxide killing and fish feeding.[Results] Field surveys revealed that areas of destructive mangroves in Dongzhaigang, Hainan increased at a mean continuous rate of 66.4% annually mangroves from 2010 to 2013. The major mangrove wood-boring isopods in China are Sphaeroma terebrans and Sphaeroma retrolaeve, of which the former is the key species found in Dongzhaigang. All of the mangroves damaged by borers distribute in the sea regions suffering serious anthropogenic disturbance and contamination. The attack of borers focuses on the forests growing across the creeks delivering pollutants and at the habitats depositing pollutants. Mature mangrove forests, being high relatively and in late successional stage of zonality, are vulnerable to the damage. Mangrove species preferred by the borers can be ranked in an order:Bruguiera sexangula, Bruguiera gymnorrhiza > B.s. var. rhynchopetala, Ceriops tagal > Avicennia marina, Kandelia obovata > Aegiceras corniculatum. Attributing to different tide amplitude, the height of above ground part of mangroves which the borers are able to attack is more than two times along China mainland coast than in Hainan Island. Laboratory test showed that 50% isopod individuals can be killed by calcium oxide at the weight concentration of 1:1 to water through 90 minutes treatment. The feeding rate of fish, Bostrichthys sinensi, on isopod is relatively stable at unit time, and 42 isopod individuals as a mean can be consumed by a fish in 24hours.[Conclusion] It is presumed that under the background of environmental degradation, duck patrol, drain of organic matter and disinfectors from shrimp pond and human collecting goods are likely to be the trigger of borer's boom.It is suggested that isopod should be an indicator included in marine monitoring and assessment system, and a mechanism be established to control isopod promptly by using chemical methods, additionally by physical methods, and permanently by ecological conservation.