Despite noticeable concern about the deforestation rate worldwide, the forest surface in Europe has considerably expanded over the past centuries as a consequence of the rural exodus and abandonment of agrarian practices. Tree recruitment associated with forest regrowth is a multi-stage process influenced by several biotic and abiotic factors. Yet, it is uncertain whether their influence on recruitment patterns and dynamics varies along a gradient of forest expansion. Similarly, for dioceious species, the influence of tree sex in recruitment is not entirely un-derstood. Here, we aim to elucidate what drives Spanish juniper recruitment in expanding forests. Specifically, we hypothesized that facilitation by conspecifics and heterospecific woody species would occur at the expanding front, where environmental conditions are harsher and that recruitment would be preferably associated to female trees because of the likelihood of mature cones produced by them germinating in the nearby area. The study was conducted in Mediterranean forests of Juniperus thurifera in central Spain. A total of 17 plots were delimited along a gradient of forest expansion including three stages: i) old forests, ii) an intermediate zone and iii) novel forests at the expanding front. Within each plot all J. thurifera individuals (saplings and adults) were mapped. We also recorded bio-volumetric characteristics and tree sex for all adult trees and estimated the percentage of cover of heterospecific woody species within the area of influence of each adult individual. We analysed the spatial pattern of J. thurifera individuals for each stand (plot). Using a novel spatial approach, we evaluated how conspecific (female and male tree sizes) and heterospecific (woody cover) vegetation influenced sapling density along a forest expansion gradient. We also studied the effects of the stage of the forest expansion gradient and the sex of adult trees on the spatial association between adults and saplings. Our results showed that sapling recruitment was negatively influenced by conspecific adult size along the whole gradient, while the effect of heterospecific woody vegetation was always positive. Conspecific facilitation of recruitment in J. thurifera forests occurred at their expanding front where saplings were associated to male adult trees. Despite having been overlooked in conservation policies, recently colonised areas in extreme environments are key targets to implement management measures aimed at achieving forest restoration, which aligns with the Aichi targets and the biodiversity policies of the European Union.

Abstract European forests are expanding and becoming denser following the widespread abandonment of farmland and rural areas. Spontaneous forest regrowth provides a cost‐effective opportunity to restore ecosystems, enhance multifunctionality and sustainability and mitigate climate change. Yet, little is known about the goods and services that such forests provide to people. We assessed the changes in nature's contributions to people (NCP) from spontaneous forest regrowth, i.e. forest expansion and densification, in South‐West Europe. We investigated 65 forest plots in four different landscapes with contrasting ecological and societal contexts. Two landscapes are located in rural areas undergoing human exodus and forest expansion and densification; the other two, in peri‐urban areas with intense land use and forest densification but negligible expansion. For each forest plot, we estimated variables related to ten out of the 18 main NCP defined by the Intergovernmental Science‐Policy Platform on Biodiversity and Ecosystem Services (IPBES). Regulating and material NCP were addressed using variables measured in the field as proxies. Non‐material NCP were studied through stakeholder interviews. Our results show across the cases that forest expansion and densification are generally associated with greater climate regulation and energy provision. Changes in other NCP, especially in non‐material ones, were strongly context‐dependent. The social perception of spontaneous forest regrowth was primarily negative in rural areas and more positive in peri‐urban landscapes. Passive restoration through spontaneous forest expansion and densification can enhance regulating and material NCP, especially when adaptive management is applied. To optimise NCP and to increase the societal awareness of and interest in spontaneous forest regrowth, the effects of this process should be analysed in close coordination with local stakeholders to unveil and quantify the many and complex trade‐offs involved in rural or peri‐urban social perceptions. A free Plain Language Summary can be found within the Supporting Information of this article.

Libro de resumenes de las comunicaciones presentadas en la III Jornada del Departamento de Biogeografia y Cambio Global ((Museo Nacional de Ciencias Naturales (Madrid), 22 de enero de 2018)

The Anthropocene as a distinct geological era has been the subject of active discussion within the scientific community. This era includes the notion that Homo sapiens has had a large impact on global planetary processes. Here, we aim at connecting the notion and nature of the Anthropocene with the social-economic success and the unexpected or unplanned environmental impacts of the anthropogenic activity. Some of the main achievements along the history of humankind have been important developmental steps for many human civilisations but they have also had undesired results that we could not foresee, including the rise of greenhouse gases emissions, the shifts in the area of species distributions or the affection of all major biogeochemical cycles. Increasing human life expectancy and health has promoted an exponential population growth, which together with the increased environmental footprint per capita has pushed many core variables for Earth functioning (e.g. biodiversity, nitrogen cycle, climate change) out of their safety limits. We illustrate examples of many ecosystems that have collapsed around the world because we have crossed the limits of their sustainable exploitation. Paradoxically, it is humanity itself who is pushing the Planet to conditions in which our own survival will unlikely be possible. The reason behind such a strong ecological and functional impact on the Planet within a relatively short space of time is an unsustainable economic system based on the assumption that a perpetual economic growth is not only possible but also desirable. Our awakening should lie on a global framework aimed at changing our relationship with the Planet.

Planting of woody species is a commonly used method to restore road embankments. Given the importance of road verges as potential corridors and refuge for biodiversity, natural plant regeneration processes may also play an important role in establishing vegetation into these novel landscape elements. Most studies on woody colonization of roadsides have considered only a few sites covering a very limited environmental range. Therefore, it is unclear whether or not there are general patterns that may explain the development of woody vegetation. We analyzed woody vegetation colonization in embankments over a large and heterogeneous territory, using aerial photographs, available repositories of environmental and land management data sets and some embankment features. We addressed the following questions: (1) To what extent does the presence of planted woody plants influence patterns of natural recruitment in road embankments? and (2) What are the key factors underlying natural/passive plant colonization in road embankments? We used Multi-Model Inference (MMI) analysis to model woody vegetation cover. According to our results, woody-planted vegetation does not have a facilitating effect on natural colonization, questioning the efficiency of reforestation measures in the ecological integration of areas affected by road construction. Passive natural plant colonization occurs spontaneously in road verges and shows a highly site-dependent pattern, driven mainly by the age of embankments and the immediate surrounding vegetation. Therefore, we suggest that natural succession may be sufficiently effective as a passive restoration measure on embankments in the long term. (C) 2015 Elsevier B.V. All rights reserved.

Questions: How does the response to environmental filters change across the life cycle of pioneer plants through the early process of community assembly? Is there a threshold at any of the life-history stages during roadcut primary colonization?Location: A very steep, sun-exposed, low-fertility and low water retention roadcut in a Mediterranean continental site in Madrid, central Spain.Methods: We tracked density of individuals, plant cover, species richness and community composition throughout the sequential process of primary colonization of a newly-exposed roadcut surface. We monitored from seed arrival to seedling emergence, seedling survival and plant growth across species over two growing seasons. We manipulated the intensity of environmental filters in 12 experimental plots (10 x 8 m) following a full-factorial design of two treatments (topsoil spreading and shallow tillage).Results: The response to environmental filter manipulation varied throughout the individual life cycle. Under an equal seed rain, the higher carrying capacity caused by topsoil spreading gave rise to the emergence of a larger number of species, which either persisted or occasionally appeared in some of the stages of the early community assembly. Further, topsoil spreading enhanced seedling survival across species, as well as subsequent plant growth. We therefore detected two life-history stages acting as thresholds in plant community assembly due to an ontogenetic niche shift across species. The first, at seedling emergence, in response to environmental cues with lasting consequences in community composition and species richness; and the second, at the transition to the adult stage in response to local resource availability, with consequences in subsequent plant growth and community cover.Conclusions: During primary colonization, ontogenetic development of pioneers was paralleled by the action of environmental filters throughout the community assembly process. On roadcuts, the confluence of both processes gives rise to a community ontogeny marked by two thresholds determining community richness and cover under Mediterranean conditions. Our findings shed light on the underlying mechanisms involved in technical solutions, such as topsoil spreading, and provide a more efficient approach to roadside restoration.

Earth movements for road construction give rise to nutrient-poor anthrosols. Early onset of soil processes in these environments has been reported on the basis of plant cover establishment. Evidences of full soil functionality, however, would reveal the emergence of a self-sustainable ecosystem on these manmade substrates. The aims of the present study involved (1) assessing soil functionality on six-year-old road embankments by means of the QBS index, based on microarthropod communities (2) elucidating soil properties responsible for the composition of soil microartrhopod communities, and (3) exploring the practical implications of soil quality for road embankment management. Road embankments were functional with QBS values comparable to those found in natural systems (> 100). Soil quality in these environments depended on soil organic carbon dynamics. Among the 36 arthropod groups found, Acari and Collembola dominated the soil community. Variation in microarthropod community composition was best explained by higher abundances of Brachypilina (Oribatida, Acari) and Symphypleona (Collembola). These trends in soil community structure were intimately linked to soil organic carbon content, clay content and humidity. Given its relevance, the acknowledgment of the early functionality attained by these roadside anthrosols should lead to the revision of current protocols for roadslope monitoring and management. (C) 2013 Elsevier B.V. All rights reserved.