Early dynamics of natural revegetation on roadcuts of the Salamanca province (CW Spain) Ruth C. Martín-Sanz a , Belén Fernández-Santos b , Carolina Martínez-Ruiz a, * a Sustainable Forest Management Research Institute UVa-INIA, Área de Ecología, E.T.S. de Ingenierías Agrarias de Palencia, Universidad de Valladolid, Campus La Yutera, Avda. de Madrid 44, 34071 Palencia, Spain b Área de Ecología, Facultad de Biología, Universidad de Salamanca, Campus Miguel de Unamuno, 37071 Salamanca, Spain A R T I C L E I N F O Article history: Received 11 November 2013 Received in revised form 11 November 2014 Accepted 28 November 2014 Available online xxx Keywords: Dry Mediterranean climate Local environmental factors Species-pool effect Surrounding woody vegetation Species colonization patterns Species traits A B S T R A C T In order to reconcile conventional and emergent goals in restoration ecology, the knowledge of community assembly during succession at roadsides is crucial. With a chronosequence design, our study assesses the pathway and speed of vegetation succession on roadcuts under different specific site conditions, relating environmental factors to species cover by means of a combination of multivariate analyses and Huisman–Olff–Fresco (HOF) modeling. We want to ascertain to what extent environmental factors control primary colonization, establishment and early dynamics of vegetation on dry Mediterranean roadcuts. We found that changes in floristic composition during natural succession on roadcuts are mostly determined by the species-pool effect at different scales (landscape, regional, and local); particular site conditions of roadcuts (slope length, steepness) are also influential factors at a local scale. We also found a shift in the dispersal mode of plant species, from anemochory to zoochory, during succession on tertiary sediments and slates, and a tendency for life-form replacement, from pterophytes to hemicriptophytes, during succession on tertiary sediments. Competitive species are primarily circumscribed to tertiary sediments where succession is not so limited by environmental carrying capacity. Natural colonization is less active on granites, and hence succession is slower. Our results indicate that, in a relatively short time, vegetation communities spontaneously installed under roadcut’s environmental harshness are rich in species whether an adjacent seed source is present in remnant patches of natural vegetation. In particular, surrounding woody vegetation favors zoochory dispersion and the early arrival of late-successional species. ã 2014 Elsevier B.V. All rights reserved. 1. Introduction Increasing environmental degradation due to increasing worldwide road construction has resulted in an increasing ecological importance of vegetation in roadside restoration approaches (Bochet et al., 2007a; Mola et al., 2011). With regard to roadside revegetation practice, conventional reclamation goals, such as soil stabilization, erosion control, and aesthetic improve- ment, prevail against other more long-term ecological ones related to the characteristics of the plant community, such as biodiversity conservation (de la Riva et al., 2011; Mola et al., 2011). However, recent studies have demonstrated that many efforts to promote a fast and dense vegetation cover may well result in plant communities impoverished through the filtering effect of compet- itive exclusion, whereas unproductive roadslopes could act as refugia for a regional species pool that, from a global change perspective, may enable subsequent reconstruction of neighboring ecosystems (de la Riva et al., 2011; Mola et al., 2011). In order to reconcile conventional and emergent goals in restoration ecology, the knowledge of community assembly during succession at roadsides is crucial (de la Riva et al., 2011; Mola et al., 2011), and particularly under the environmental harshness of roadcuts (see Bochet and García-Fayos, 2004; Jiménez et al., 2013). It has been reported that plant establishment on recently exposed roadcuts (constructed by excavation) follows a process of primary succession (Jiménez et al., 2013; Mola et al., 2011). On roadcuts, all the biological structures that could act as local foci for vegetation development have been lost, and plant colonization and Abbreviations: AIC, akaike information criterion; CCA, canonical correspon- dence analysis; DCA, detrended correspondence analysis; HOF, Huisman–Olff– Fresco; SD, standard deviation; WRB-FAO, the world reference base-food and agriculture organization. * Corresponding author. Tel.: +34 979 108321; fax: +34 979 108440. E-mail address: caromar@agro.uva.es (C. Martínez-Ruiz). http://dx.doi.org/10.1016/j.ecoleng.2014.11.057 0925-8574/ ã 2014 Elsevier B.V. All rights reserved. Ecological Engineering 75 (2015) 223–231 Contents lists available at ScienceDirect Ecological Engineering journal homepage: www.else vie r.com/locat e/e coleng