First quantification of subtidal community structure at Tristan da Cunha Islands in the remote South Atlantic: From kelp forests to the deep sea
First quantification of subtidal community structure at Tristan da Cunha Islands in the remote South Atlantic: From kelp forests to the deep sea
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DOI：
10.1371/journal.pone.0195167
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发表时间：
2018-03-29
期刊：
影响因子：
3.7
通讯作者：
Sala, Enric
中科院分区：
文献类型：
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作者：
Caselle, Jennifer E.;Hamilton, Scott L.;Sala, Enric
特里斯坦-达库尼亚群岛是一个由四个多岩石的火山岛组成的群岛，位于南大西洋和联合王国海外领土的一部分，是一个相对不受影响的温带海洋生态系统的罕见例子。我们对近岸海藻森林、近海远洋水域和深海栖息地进行了首次定量调查。海带森林的生物多样性和物种丰富度很低，但这些物种的生物量和丰富度很高。北部三个岛屿和南部高夫岛之间近岸鱼类和无脊椎动物/藻类的群落结构的空间结构差异最大，那里的海洋温度平均低3-4度。尽管龙虾渔业为特里斯坦群岛提供了大部分收入，但龙虾的数量和生物量与世界其他地区的许多海洋保护区相当或更高。远洋相机调查记录了近海丰富的生物多样性，包括大量的幼年蓝鲨，Prionace gluca。深海的物种丰富度和丰度与坚硬的岩石底物呈正相关，40%的深海相机部署中存在海笔、海百合、鞭状珊瑚和柳珊瑚等生物栖息地。我们观察到类似于750米水深的深水鱼类群落在上面和下面有明显的差异。同时进行的海洋采样显示，在这个深度，温度和盐度不连续。虽然特里斯坦的海洋生态系统目前健康，但也不是没有潜在的威胁：导致沉船和物种引进的航运交通，将捕捞努力增加到超过可持续水平的压力，以及气候变化的影响，这些都可能在未来几年增加。联合王国已承诺保护包括特里斯坦-达库尼亚在内的联合王国全境的海洋环境，这些结果可用于为未来的管理决定提供信息，并为今后的监测提供基准。
Tristan da Cunha Islands, an archipelago of four rocky volcanic islands situated in the South Atlantic Ocean and part of the United Kingdom Overseas Territories (UKOTs), present a rare example of a relatively unimpacted temperate marine ecosystem. We conducted the first quantitative surveys of nearshore kelp forests, offshore pelagic waters and deep sea habitats. Kelp forests had very low biodiversity and species richness, but high biomass and abundance of those species present. Spatial variation in assemblage structure for both nearshore fish and invertebrates/algae was greatest between the three northern islands and the southern island of Gough, where sea temperatures were on average 3-4 degrees colder. Despite a lobster fishery that provides the bulk of the income to the Tristan islands, lobster abundance and biomass are comparable to or greater than many Marine Protected Areas in other parts of the world. Pelagic camera surveys documented a rich biodiversity offshore, including large numbers of juvenile blue sharks, Prionace glauca. Species richness and abundance in the deep sea is positively related to hard rocky substrate and biogenic habitats such as sea pens, crinoids, whip corals, and gorgonians were present at 40% of the deep camera deployments. We observed distinct differences in the deep fish community above and below similar to 750 m depth. Concurrent oceanographic sampling showed a discontinuity in temperature and salinity at this depth. While currently healthy, Tristan's marine ecosystem is not without potential threats: shipping traffic leading to wrecks and species introductions, pressure to increase fishing effort beyond sustainable levels and the impacts of climate change all could potentially increase in the coming years. The United Kingdom has committed to protection of marine environments across the UKOTs, including Tristan da Cunha and these results can be used to inform future management decisions as well as provide a baseline against which future monitoring can be based.