Abundance and dispersal of drifting kelp Macrocystis pyrifera rafts in the Southern California Bight
Abundance and dispersal of drifting kelp Macrocystis pyrifera rafts in the Southern California Bight
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DOI：
10.3354/meps195101
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发表时间：
2000-01-01
影响因子：
2.5
通讯作者：
Hobday, AJ
中科院分区：
文献类型：
--
作者：
Hobday, AJ
当附着的植物与基质分离时，就会形成巨囊藻的漂流筏。这些海带筏有可能将动物群分散到孤立的海带森林中；然而，这种分散机制的成功将受到木筏数量和分散路径的影响。南加州八区（SCB）海带筏的丰度是根据附着植物的损失以及对海上筏的直接观察来估计的。 1988年至1998年期间，2个沿海海藻床内的7个地点的附着成体植物损失在冬季最高（23%），秋季最低（8%）。1995年至1997年期间，4次航行的海上筏密度有所不同，范围为0.78至6.96 km(-2)（平均3.02 km(-2)）。在 SCB 中，这些密度对应于 39 000 至 348 000 个漂流筏的瞬时丰度。使用卫星跟踪的漂流者评估了潜在的筏扩散路径和海带森林之间的交换频率。一年中的所有月份都观察到远离海岸的向南扩散。沿海岸和远离海岸向北扩散最有可能在七月至一月（夏季至冬季）之间，而沿海岸向南扩散则可能在一月至八月（冬末和早春）之间。采用了“成功连接事件”的定义，该定义是基于漂流者从距海岸不到 10 公里的地方出发并在距海岸不到 5 公里的地方结束的。根据这个定义，所有漂流者的释放中有 45% 是成功的。对大陆与大陆成功的时间模式和漂移轨迹的分析表明，Pt。受孕始终是南北连接的边界，但在秋季和冬季（十月至一月）期间对南北连接开放。漂流者被释放并留在铂族北部或南部。全年受孕都很成功。无论从任何成功标准来看，连接距离发布区域都不超过 300 公里。这项研究的结果表明，虽然筏可以漂流很长的距离，但通过海带筏成功连接海带森林仅限于较短的距离。
Drifting rafts of Macrocystis pyrifera are formed when attached plants are separated from the substrate. These kelp rafts have the potential to disperse fauna among isolated kelp forests; however, the success of this dispersal mechanism will be influenced by the abundance and the dispersal paths of the rafts. The abundance of kelp rafts in the Southern California Eight (SCB) was estimated from the loss of attached plants, and by direct observation of rafts at sea. Loss of attached adult plants was highest in winter (23%) and lowest in fall (8%) at 7 sites within 2 coastal kelp beds over the period of 1988 to 1998. Raft density at sea differed among 4 cruises in the period from 1995 to 1997, and ranged from 0.78 to 6.96 km(-2) (average 3.02 km(-2)). In the SCB these densities correspond to an instantaneous abundance of between 39 000 and 348 000 drifting rafts. The potential raft dispersal paths and the frequency of exchanges among kelp forests were evaluated using satellite-tracked drifters. Southward dispersal away from the coast was observed in all months of the year. Dispersal north, both along the coast and away from the coast, was most likely between July and January (summer-winter), while dispersal south along the coast was likely between January and August (late winter and early spring). A definition of a 'successful connection event' was adopted, based on a drifter starting less than 10 km and ending less than 5 km from the coast. Under this definition, 45% of all drifter releases were successful. Analysis of the temporal pattern and drift trajectories of the mainland-mainland successes revealed that Pt. Conception was always a boundary for north to south connections, but was open to south to north connections between fall and winter (October to January). Drifters released and remaining north or south of Pt. Conception were successful throughout the year. Connections were not made more than 300 km from a release region, under any criteria for success. The results of this study indicate that while rafts may drift long distances, successful connection of kelp forests through kelp rafts is limited to shorter distances.