广西植物2016，Vol.36Issue(7)：882-889,8.DOI:10.11931/guihaia.gxzw201412033
濒危海草贝克喜盐草在海南东寨港的分布及其群落基本特征
Distribution and community characteristics of threatened seagrass Halophila beccarii in Dongzhai Harbor, Hainan
摘要
Abstract
Recent mangrove surveys have discovered a seagrass bed of Halophila beccarii within Dongzhaigang National Natural Reserve, Hainan that have not previously been reported. The distribution, basic biological traits of the seagrass bed and associated habitat ( sediment and sea water) were studied in the paper. H. beccarii is among one of the ten <br> seagrass species which are at elevated risk of extinction in the world, and it was listed as‘Vulnerable’ by the Interna-tional Union for Conservation of Nature ( IUCN) under criterion B2. It is generally hard to be found in the field due to its very tiny leaves and its shoots are easily buried by sediment. In addition, this species has a very narrow, restricted depth range right at the intertidal zone ( usually mud flat or seaward mangrove areas ) , where is submersed tidally every day. Moreover, rapid population turnover and low awareness of seagrass do not facilitate the discovery of this species in China. Until today, very limited H. beccarii resources have been reported along the coast of Fujian, Taiwan, Guangdong, Hong Kong, Guangxi and Hainan, with an estimation of total area of less than 200 hm2 in China. In this study, we used a hand-hold GPS to map the extent of seagrass distribution in the study area. Besides, we sampled seagrass plants, asso-ciated sediment and seawater for analysis in the lab. Compared with other H. beccarii sites in China, the area in Dong-zhaigang was relative big, with a total area of 15.4 hm2 and intermediate density of (10 394 ± 576) shoots.m-2, rank-ing the second largest H. beccarii bed in China according the published data. However, the biomass ( 9. 225 ± 1. 151 gDW.m-2 ) and percent coverage ( 5. 0% ± 1. 1 %) at this site was very low partly due to its pretty small leaf [ leaf length:(4.83 ± 0.87) mm;leaf width:(1.44 ± 0.21) mm]. The ratio of above-to below-ground biomass was also very low (0.34), with (2.339 ± 0.245) gDW.m-2 of above-ground biomass and (6.886 ± 1.055) gDW.m-2 of below-ground biomass. No flower and fruit of the plant was found during our survey, but an intermediate density (2 105 ± 664 seeds.m-2 ) of seeds in the sediment was found. The organic carbon content and bulk density of sediment in the study area was (2.08 ± 0.13) %[0-10 cm:(2.42 ± 0.03) %;10-20 cm:(2.17 ± 0.03) %;20-30 cm:(1.65 ± 0.20) %and (0.98 ± 0.01) g.cm-3. 0-10 cm: (0.93 ± 0.01) g.cm-3; 10-20 cm: (0.97 ± 0.01) g.cm-3; 20-30 cm:(1.02 ±0.02) g.cm-3] respectively. In addition, (6.67 ± 0.24)‰of salinity, (7.33 ± 0.03) of pH, (-1.53 ± 1.85) mV of oxidation reduction potential (ORP) and (6.65 ± 0.31) mg.L-1 of dissolved oxygen (DO) of overlying water in the study area was measured in situ. On the other hand, (1.90 ± 0.03) mg.L-1 of total nitrogen content (TN), (0.13 ± 0.01) mg.L-1 of total phosphorus content (TP) and (5.89 ± 0.06) mg.L-1 of organic carbon content (Corg) of sam-pled-seawater during high tide in the study area was detected in the lab. A certain level of pollution in sea water of the site was demonstrated, which was consistent with the previous research in the same study area. We suggest that the seagrass plants and their associated habitats should also be listed in the key protection objects by the Management Bureau of Dongzhaigang National Natural Reserve besides mangrove ecosystem.关键词
海草生物地理学/东寨港红树林/海草保护/IUCN/土壤种子库Key words
seagrass biogeography/Dongzhaigang mangrove/seagrass conservation/IUCN/seed bank分类
农业科技引用本文复制引用
邱广龙,苏治南,钟才荣,范航清..濒危海草贝克喜盐草在海南东寨港的分布及其群落基本特征[J].广西植物,2016,36(7):882-889,8.基金项目
广西“红树林和海草系统保育与生态监测”特聘专家岗位基金 （）
广西红树林保护与利用重点实验室系统性课题( GKLMC-14A02) （ GKLMC-14A02）
广西青年科学基金(2012GXNSFBA053141) （2012GXNSFBA053141）
北部湾经济区优秀中青年专业技术人才培养工程(2014-2015)[Supported by Guangxi Distinguished Experts Post （2014-2015）
Guangxi Mangrove Conservation ＆ Utilization Key Lab ( GKLMC-14A02) （ GKLMC-14A02）
Guangxi Science Foundation (2012GXNSFBA053141) （2012GXNSFBA053141）
Outstanding Middle-young Aged Professional and Technical Talents Training Project of the Beibu Gulf Economic Zone (2014-2015)]。 （2014-2015）
