美国东北大学理学院最新研究发现，食物链最低端稀有物种的减少会给生态系统的健康稳定带来很大影响。相关研究成果发表在《生态学快报》（Ecology Letters）在线版上。
该大学海洋科学中心的研究人员在马萨诸塞州岩岸多样的生物中模拟自然发生的变化，经多次实验分析移走海藻和固着动物（固着于他物而生活的动物）如贻贝和藤壶所带来的影响。
研究人员说，调查结果令人吃惊。这些极为稀有的物种的减少，会导致螺、蟹和其它移动动物的数量和多样性的锐减，而在食物链的底部总共显示为不到10%的海藻和动物生物量。
此前的研究专注于特定生态系统中高端食肉动物（通常指关键物种）的灭绝，及其对食物链低端动植物的影响。而现在的实验表明，食物链的基层，即被称为“基石”的稀有物种的减少，也会改造海洋生态系统。
物种下降出现在实验仅进行到三个星期时。研究人员对残余物又进行了五周的研究后表示：“以前的研究显示，稀有肉食动物的灭绝会在几个月甚至几年之后对生态系统产生很强的影响。而我们的研究发现，稀有海藻物种的减少仅在几个星期后即会造成很大影响。”（生物谷Bioon.com）
doi: 10.1111/j.1461-0248.2012.01758.x
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Realistic losses of rare species disproportionately impact higher trophic levels
Bracken, Matthew E. S.; Low, Natalie H. N.
Predicting the consequences of changes in biodiversity requires understanding both species’ susceptibility to extirpation and their functional roles in ecosystems. However, few studies have evaluated the effects of realistic, non-random biodiversity losses, severely limiting the applicability of biodiversity research to conservation. Here, we removed sessile species from a rocky shore community in a way that deliberately mimicked natural patterns of species loss. We found that the rarest species in the system act from the bottom up to disproportionately impact the diversity and abundance of consumers. Realistic losses of rare species in a diverse assemblage of seaweeds and sessile invertebrates, collectively comprising <10% of sessile biomass, resulted in a 42–47% decline in consumer biomass. In contrast, removal of an equivalent biomass of dominant sessile species had no effect on consumers. Our results highlight the ‘cornerstone’ role that rare species can play in shaping the structure of the community they support.
