The consequences of species extinctions in ecological communities may be buffered through the rearrangement (rewiring) of the interactions between the remaining species. The structural and functional consequences of such extinctions can be explored by means of computer simulations that try to predict secondary extinctions and the degradation of ecosystem services. However, to improve the accuracy of these simulations, it is pivotal to evaluate their performance in predicting changes observed in natural communities. In this study, we first described the avian seed dispersal networks in 17 sites throughout Portugal, and found that blackberry (Rubus ulmifolius) was the most dispersed species in 13 out of the 17 sites. Second, we performed a manipulative experiment to evaluate the effect of removing the most dispersed plant species and compared the observed outcome in the structure of the network with computer simulations with and without rewiring. Observed changes were consistent with some rapid network rewiring, with dispersers shifting to alternative fruit species. Although the observed network topology after the

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& Context The Iberian cork oak Quercus suber montados are dynamic agro-silvo-pastoral systems, contrasting with the abandonment trend of other Mediterranean forested areas. & Aims We aimed to identify the effect of management type and vegetation features on breeding insectivorous birds and leaf-chewing defoliator insects. & Methods In central Portugal, we selected two groups of 20 sites: dense montados (DM, high cover of cork oaks and low cattle impact) and sparse montados (SM, low cover of oaks and high cattle impact). We collected variables associated with vegetation features, bird community and chewing defoliators. & Results The two systems differed significantly in oak trunk diameter, oak and shrub cover, tree and shrub diversity. Ground bird densities were higher in SM with fragmented shrub cover. In DM, higher woody vegetation cover and diversity can promote shrub birds and leaf warblers.Oak defoliation was mainly attributed to the sawfly Periclista andrei. Sawfly defoliation was significantly higher in SM and negatively correlated with shrub cover. & Conclusions Our results highlight (1) the relevance of management activities conducted at the shrubby layer, (2) the need of an increase in tree diversity and density and (3) the maintenance of a mosaic landscape in order to improve the bird community richness and reduce the defoliation impact in montado system.

& Context The remaining riparian stretches are often the unique suitable habitats for forest breeding birds in Mediterranean landscapes undergoing long-term changes. Understanding the interactions between riparian zones and their surroundings is critical to establish successful management actions. & Aims We assessed the influence of surrounding matrix on riparian bird communities and the use of riparian galleries as surrogate habitats for the forest passerine communities of southwestern Iberia. & Methods We used point counts in three simultaneous sampling stations, one in the riparian gallery and two in the adjacent matrix. Three matrix types were selected with a decreasing tree density gradient: dense montado,s p a r s e montado, and open agricultural areas. Data were analysed with redundancy analysis and differences in species' occurrences were tested with one-way ANOVA. & Results In riparian galleries, we found bird species belong to three ecological guilds: riparian, woodland, and edge guilds. The richness of bird guilds and the occurrence of some species depended on the surrounding matrix type. Riparian bird richness was constant in all surrounding matrices, woodland bird guild was richer in galleries embedded in dense montados, and edge guild in riparian galleries surrounded by sparse montados. Five among 19 assessed species were influenced by matrix type, within particular a few strictly riparian species. Species richness increased close to riparian galleries, due to the increase in habitat heterogeneity and resource availability for birds in densely vegetated riversides. However, the occurrence of some bird species differed according to the type of surrounding matrix. & Conclusion The matrix type explained most of the variance in riparian bird assemblages. Some woodland birds have used riparian galleries as surrogate habitat. Our study suggests that land use in the surrounding matrices must be taking into account for the management and rehabilitation of watercourses and bird conservation actions.

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