美國東北大學(xué)理學(xué)院最新研究發(fā)現(xiàn),，食物鏈最低端稀有物種的減少會(huì)給生態(tài)系統(tǒng)的健康穩(wěn)定帶來很大影響。相關(guān)研究成果發(fā)表在《生態(tài)學(xué)快報(bào)》（Ecology Letters）在線版上,。
該大學(xué)海洋科學(xué)中心的研究人員在馬薩諸塞州巖岸多樣的生物中模擬自然發(fā)生的變化，經(jīng)多次實(shí)驗(yàn)分析移走海藻和固著動(dòng)物（固著于他物而生活的動(dòng)物）如貽貝和藤壺所帶來的影響,。
研究人員說,，調(diào)查結(jié)果令人吃驚。這些極為稀有的物種的減少,，會(huì)導(dǎo)致螺,、蟹和其它移動(dòng)動(dòng)物的數(shù)量和多樣性的銳減，而在食物鏈的底部總共顯示為不到10%的海藻和動(dòng)物生物量。
此前的研究專注于特定生態(tài)系統(tǒng)中高端食肉動(dòng)物（通常指關(guān)鍵物種）的滅絕,，及其對(duì)食物鏈低端動(dòng)植物的影響,。而現(xiàn)在的實(shí)驗(yàn)表明，食物鏈的基層,，即被稱為“基石”的稀有物種的減少,，也會(huì)改造海洋生態(tài)系統(tǒng)。
物種下降出現(xiàn)在實(shí)驗(yàn)僅進(jìn)行到三個(gè)星期時(shí),。研究人員對(duì)殘余物又進(jìn)行了五周的研究后表示：“以前的研究顯示,，稀有肉食動(dòng)物的滅絕會(huì)在幾個(gè)月甚至幾年之后對(duì)生態(tài)系統(tǒng)產(chǎn)生很強(qiáng)的影響。而我們的研究發(fā)現(xiàn),，稀有海藻物種的減少僅在幾個(gè)星期后即會(huì)造成很大影響。”（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.
