A non-native amphipod consumes eelgrass inflorescences in San Francisco Bay.
A non-native amphipod consumes eelgrass inflorescences in San Francisco Bay.
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旧金山湾的一种非本地片脚类动物以鳗草花序为食。
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
K. Boyer
中科院分区：
文献类型：
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作者：
Laura K. Reynolds;Lindsey A. Carr;K. Boyer
摘要/ ABSTRACT摘要：强烈的草食会改变生境特征，对生殖结构的放牧会降低植物的适应性和种群的长期稳定性。对海草的食草性通常限于附生植物；然而，最近在几个系统中观察到直接放牧。在加利福尼亚的旧金山湾，我们记录了大叶藻的叶子受到了广泛的损害，尤其是与非本地片脚类动物Ampi开花同时发生的大叶藻花序。实地调查发现，大叶藻在开花时丰度最高，开花时丰度高于营养芽，在发育后期（果实成熟或种子释放后）的生殖结构（路径）上丰度特别高。实验室实验表明，金银花消耗叶片和芽组织（以及整个果实），但通常更喜欢芽而不是叶。小路结构复杂，可能提供更好的栖息地，增加消费机会。低场藻类丰度并不能完全解释大叶藻的食草性，因为片脚类动物即使在提供藻类的情况下也会大量吃大叶藻。当出示来自片脚类动物的原生（弗吉尼亚州）和入侵范围（加利福尼亚州）的大叶藻时，后者的消耗率明显更高。营养成分和酚类物质含量都不能充分解释组织偏好。体型较大的加州鳗草可能促进了在用作栖息地的小路上偶然取食，但并不能解释加州鳗草在食用结构简单的叶子时的偏好。野外密度和实验室消耗率表明，这种非本地片脚类动物可以在1 - 3周内清除加利福尼亚鳗鱼草甸的所有种子，从而对遗传多样性的维持和草甸的长期持久性构成挑战。毕业论文关键词：海草·海苔·沙蚤·草食性·种子捕食
ABSTRACT: Intense herbivory can alter habitat characteristics, and grazing on reproductivestructures can reduce plant fitness and long-term population stability. Herbivory on seagrasses isoften limited to epiphytes; however, direct grazing has been observed recently in several systems.In San Francisco Bay, California, we documented extensive damage to leaves and especially inflo-rescences of eelgrass Zostera marina concurrent with blooms of the non-native amphipod Ampi -thoe valida. Field surveys found peaks of A. valida abundance when eelgrass was flowering, andgreater abundance on flowering than vegetative shoots, with particularly high abundances onreproductive structures (spathes) in late developmental stages (with ripe fruits or post seedrelease). Laboratory experiments showed that A. valida consumed leaf and spathe tissue (as wellas whole fruits), but usually preferred spathes to leaves. Spathes are structurally complex andlikely provide better habitat, increasing opportunity for consumption. Low field algal abundancesdo not fully explain eelgrass herbivory, as amphipods grazed eelgrass substantially even whenoffered algae. When presented with eelgrass from both the amphipod’s native (Virginia) andinvaded range (California), the latter was consumed at significantly higher rates. Neither nutrientnor phenolic content adequately explain the tissue preference. Greater size of California eelgrassmay have promoted incidental feeding on spathes used as habitat, but does not explain a Califor-nia bias during consumption of structurally simple leaves. Field densities and laboratory consump-tion rates suggest that this non-native amphipod could remove all seeds in a California eelgrassmeadow in 1−3 wk, thus challenging maintenance of genetic diversity and long-term meadowpersistence.KEY WORDS: Seagrass · Zostera marina · Ampithoe valida · Herbivory · Seed predation