Mammalian seed dispersal in Cantabrian woodland pastures: Network structure and response to forest loss

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• 作者：Andr¨¦s Peredo ; Daniel Mart¨ªnez ; Javier Rodr¨ªguez-P¨¦rez ; Daniel Garc¨ªa
• 关键词：Ecosystem service ; Fleshy-fruited plants ; Functional complementarity ; Mutualistic networks ; Northern Spain ; Plant&ndash ; animal interactions
• 刊名：Basic and Applied Ecology
• 出版年：2013
• 出版时间：August, 2013
• 年：2013
• 卷：14
• 期：5
• 页码：378-386
• 全文大小：734 K

文摘

We evaluated the role of wild large mammals as dispersers of fleshy-fruited woody plants in woodland pastures of the Cantabrian range (N Spain). By searching for seeds in mammal scats across four localities, we addressed how extensive seed dispersal was in relation to the fleshy-fruited plant community, and applied a network approach to identify the relative role of mammal species in the seed dispersal process. We also tested the response of mammalian dispersers to forest availability at increasing spatial scales. Five carnivores and three ungulates dispersed seeds of eight fleshy-fruited trees and shrubs. Mammalian seed dispersal did not mirror community-wide fruit availability, as abundant fruiting trees were scarce whereas thorny shrubs were over-represented among dispersed species. The dispersal network was dominated by bramble (m>Rubus ulmifoliusm>/m>fruticosusm>), the remaining plants being rarer and showing more restricted disperser coteries. Fox (m>Vulpes vulpesm>), badger (m>Meles melesm>), and wild boar (m>Sus scrofam>) dispersed mostly bramble, whereas martens (m>Martesm> sp.) dispersed mostly wild rose (m>Rosam> sp.). Ungulates occasionally dispersed holly (m>Ilex aquifoliumm>) and hawthorn (m>Crataegus monogynam>). The empirical network reflected a skewed distribution of interactions and some functional complementarity (as judged from the low levels of connectance and nestedness), but also some degree of specialization. Mammals overused uncovered microsites for seed deposition, and increased their disperser activity in those landscape sectors devoid of forest. Combined with previous findings on avian seed dispersal, this study suggest a strong functional complementarity coming from the low overlap in the main plant types that mammals and birds disperse - thorny shrubs and trees, respectively - and the differential patterns of seed deposition, with mammals mostly dispersing into deforested areas, and birds into forest-rich landscapes.