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.

首次报道Sargassum muticum在英国水域出现之际，伴随着对该入侵性藻类可能取代海草床，尤其是对Zostera marina海草床的警告。起初的忧虑在后续研究提出这两种物种需要不同的附着基质，因此S. muticum无法取代Zostera在海绵沉积物上的海草床之后得以缓解。然而，在此，我们提供了支持原始警告的证据：与先前研究相反，我们发现S. muticum能够成功殖民海绵沉积物，而且Zostera marina的存在可能有助于附着。在英国西南部Salcombe研究的Zostera海草床中的大多数S. muticum植株均被发现附着在海绵沉积物上；然而，在海草床之外，这种现象数量大幅减少。因此，我们提出Zostera marina的存在实际上可能增强了S. muticum对海绵沉积物的殖民，捕捉漂浮的碎片，并允许可行的藻类在原本不利的环境中在海草基质上定居。因此，S. muticum对海草床的入侵后果可能比先前预想的更为严重。