2006 Tweedy et al. Salcombe Sargassum muticum records

The first reports of Sargassum muticum occurring in British waters coincided with a warning that this invasive alga may replace seagrass beds, particularly those of Zostera marina. Initial fears were allayed when subsequent research suggested that both species required different attachment substrata, and, therefore, S. muticum would be unable to replace Zostera beds on soft sediments. Here, however, we present evidence supporting the original warning: contrary to previous research we found that S. muticum is able to successfully colonise soft sediments and, furthermore, that the presence of Z. marina may aid attachment. The majority of S. muticum plants within Zostera beds studied at Salcombe, SW England, were found attached within the soft sediment; outside of the seagrass bed, however, this occurred in greatly reduced numbers. Therefore, we suggest that the presence of Z. marina may actually enhance S. muticum colonization of soft sediments, trapping drifting fragments and allowing viable algae to settle on the seagrass matrix in an otherwise unfavorable environment. The consequences for the invasion of seagrass beds by S. muticum may therefore be more severe than previously thought.英国水域首次记录到匍枝马尾藻（Sargassum muticum）时，伴随的预警指出该入侵藻类或可取代海草床，尤以大叶藻（Zostera marina）群落为甚。后续研究显示二者所需附着基质存在差异，因此初期的担忧一度得到缓解——人们认为匍枝马尾藻无法在软质沉积物上取代大叶藻床。但本研究提供的证据支持了最初的预警：与既往研究结论相悖，我们发现匍枝马尾藻能够成功定植于软质沉积物中，且大叶藻的存在反而可助力其附着。在英格兰西南部萨尔特科姆（Salcombe）的研究海草床内，多数匍枝马尾藻个体均附着于软质沉积物中；而在海草床外，此类附着个体的数量则大幅减少。据此我们认为，大叶藻的存在或可增强匍枝马尾藻在软质沉积物上的定植能力：其可截留漂流的藻体片段，使具有活力的藻类能够在原本不适宜的环境中，于海草基质上完成定殖。因此，匍枝马尾藻对海草床的入侵后果或比此前预想的更为严重。