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.

首次在英国水域发现Sargassum muticum的报告与一项警告不谋而合，该警告指出这种入侵性藻类可能会取代海草床，尤其是Zostera marina的海草床。最初的担忧在后续研究中得到了缓解，研究指出这两种物种需要不同的附着基质，因此S. muticum将无法在软质沉积物上取代Zostera海草床。然而，在此，我们提供了支持原始警告的证据：与先前的研究相反，我们发现S. muticum能够成功地在软质沉积物上定殖，并且，Z. marina的存在可能有助于附着。在英国西南部萨姆布里奇的海草床中研究的S. muticum的大部分植物都发现在软质沉积物上附着；然而，在海草床之外，这种现象发生的数量大大减少。因此，我们提出，Z. marina的存在实际上可能增强了S. muticum对软质沉积物的殖民，通过捕获漂浮碎片，使可行的藻类在原本不利的环境中能够在海草基质上定居。因此，S. muticum对海草床的入侵可能比之前所想的后果更为严重。