Seed ecology of Mediterranean hind dune wildflowers

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• 作者：Stefano Benvenuti ^{stefano.benvenuti@unipi.it" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Dune ecosystem ; Sand burial ; Seed bank ; Seedling emergence ; Germination
• 刊名：Ecological Engineering
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：91
• 期：Complete
• 页码：282-293
• 全文大小：4116 K

文摘

There is an increasing need for the landscape conservation of the threatened biodiversity of coastal ecosystems. This work studies the seed ecology (germination, dormancy, self-burial, seedlings emergence and seed bank disposition) of various Mediterranean hind dune wildflowers in a perspective of landscape protection and restoration. The deep dormancy of most species (overall Fabaceae, Brassicaceae and Calystegia soldanella) was eliminated or reduced after some seed treatments selected to simulate some natural events (washing, cold stratification, scarification, etc). “In situ” seed bank analysis was carried out by collecting sand samples in different dune ecosystems of Tuscany and Sardinia.

Indeed the seed vertical distribution plays a crucial role in the germination dynamics on buried seeds. The vertical distribution of the seed bank of 20 selected species was confined to the upper 0–12 cm layer of sand dune. Their burial depth was found to be inversely related to the 1000 seed weight of the different species ranging by 0.01 g of Centaurium maritimum to 47.58 of C. soldanella. Roughly 80% of the seed bank is accumulated in the shallowest sand layer (0–3 cm) and the only very little seeds of C. maritimum and Silene colorata were capable to reach the deeper layer of 9–12 cm. Seedling emergence from increasing burial depth has been studied in pots “ex situ”. In spite of the respective seed dormancy-breaking treatments, their germination was progressively inhibited by burial depth increasing in the sand matrix. Calculation of the depth able to halve emergence established an inverse relationship between seed weight and depth-mediated inhibition. In addition, the ex situ capacity for self-burial (mediated by winter rains), ranging between 1 and 3.5 cm, showed a similar, but inverse, relationship between seed weight and self-burial performance. Seed bank of herbaceous perennial species appears to be a good indicator of an ecosystem's health and the perspective of environmental restoration, by using native wildflowers, should be carried out by sowing treated seeds, with a light burial, behind the natural or artificial foredunes.