一項(xiàng)研究發(fā)現(xiàn),，原生海灘草的分布控制著沿海受風(fēng)暴侵害的脆弱性。Orencio Duran 和Laura Moore利用數(shù)學(xué)建模研究了植被與沙的相互作用如何形成了面向海的沙丘,。海灘植物幫助俘獲沙,，因此也就積累和穩(wěn)定了沙丘。這些沙丘反過來又作為天然屏障,，保護(hù)內(nèi)陸生態(tài)系統(tǒng)不受海洋和風(fēng)暴的沖擊,。這組科研人員確定了植被的類型以及它的分布影響著沙丘的尺寸，一些植物的分布形成了與海岸平行的長沙丘脊,，另一些植物形成了更具流動性,、較不連續(xù)的沙丘，而還有一些植物妨礙沙丘的形成,。這些植物的動態(tài)再加上風(fēng)流和地貌,，限制了面向海洋的沙丘的增長。這組作者報告說,，大型沙丘傾向于在遠(yuǎn)離水邊的平坦的細(xì)沙丘上形成,，因?yàn)榭拷叄罄烁蓴_了植物,，讓沙丘的形成偏向陸地,。相反，小型沙丘傾向于在更接近水邊的陡峭的粗砂灘上出現(xiàn),，在那里海浪較小,。在風(fēng)暴中，沙丘的尺寸影響著侵蝕,。這項(xiàng)研究發(fā)現(xiàn)通過控制沿海沙丘的最大尺寸,，植物在修改棲息地和改變沿海脆弱性方面起到了比以前認(rèn)為的更積極的作用,。(生物谷 Bioon.com)

生物谷推薦的英文摘要

PNAS  doi: 10.1073/pnas.1307580110

Vegetation controls on the maximum size of coastal dunes

Orencio Durán1,2 and Laura J. Moore

Coastal dunes, in particular foredunes, support a resilient ecosystem and reduce coastal vulnerability to storms. In contrast to dry desert dunes, coastal dunes arise from interactions between biological and physical processes. Ecologists have traditionally addressed coastal ecosystems by assuming that they adapt to preexisting dune topography, whereas geomorphologists have studied the properties of foredunes primarily in connection to physical, not biological, factors. Here, we study foredune development using an ecomorphodynamic model that resolves the coevolution of topography and vegetation in response to both physical and ecological factors. We find that foredune growth is eventually limited by a negative feedback between wind flow and topography. As a consequence, steady-state foredunes are scale invariant, which allows us to derive scaling relations for maximum foredune height and formation time. These relations suggest that plant zonation (in particular for strand “dune-building” species) is the primary factor controlling the maximum size of foredunes and therefore the amount of sand stored in a coastal dune system. We also find that aeolian sand supply to the dunes determines the timescale of foredune formation. These results offer a potential explanation for the empirical relation between beach type and foredune size, in which large (small) foredunes are found on dissipative (reflective) beaches. Higher waves associated with dissipative beaches increase the disturbance of strand species, which shifts foredune formation landward and thus leads to larger foredunes. In this scenario, plants play a much more active role in modifying their habitat and altering coastal vulnerability than previously thought.