Spontaneous forest regrowth in South‐West Europe: Consequences for nature's contributions to people

Can natural forest expansion contribute to Europe's restoration policy agenda? An interdisciplinary assessment

Natural forest expansion (NFE), that is, the establishment of secondary forest on non-forested land through natural succession, has substantially contributed to the widespread expansion of forests in Europe over the last few decades. So far, EU policies have largely neglected the potential of NFE for meeting policy objectives on restoration. Synthesising recent interdisciplinary research, this paper assesses the challenges and opportunities of NFE in view of contributing to European forest and ecosystem restoration. Specifically, we discuss the potential for supporting climate change mitigation and adaptation, biodiversity conservation, and forestry and economic use, summarize the current knowledge about societal perceptions and the policymaking on NFE, and make policy recommendations to better use the potential of NFE. We conclude that NFE has the potential to contribute to the European restoration policy agenda if local contexts and possible trade-offs are properly considered.

The Renaissance of Mixed Forests? New Insights Into Shifts in Tree Dominance and Composition Following Centuries of Human-induced Simplification of Iberian Forests

Anthropic activities have modelled and simplified southern European forest landscapes for centuries. Over recent decades, new drivers related to human-mediated global change have induced the redistribution of tree species and an increase in more complex forests. However, the current large-scale patterns and drivers of these changes are yet to be fully described for the Mediterranean Basin. In this frame, this work identifies and examines changes in dominance and composition from pure to mixed forests across bioclimatic gradients and forest types in Iberian forests over recent decades based on data from the Spanish National Forest Inventory from 1960 to 2020. Then, considering different environmental, anthropic, and disturbance variables we also identify some of the most important drivers associated with the shifts observed from 1986 to 2020. Our results confirm an ongoing increase in mixed forests involving the replacement of conifers by broadleaved species. These shifts are greater in the Atlantic biogeoregion and in pure broadleaved deciduous forests. Climate warming-associated disturbances such as drought severity together with land use legacies and forest types showed the strongest relationships with the observed changes in the studied forests. Our results support the premise put forward by palaeoecologists which states that the increase in tree mixtures is a natural process reversing the historical human-induced simplification of Iberian forests. The increasing importance of mixed forest in southern Europe makes decisive the revision of forest classifications as well as forest management and conservation plans in order to include these increasingly abundant novel stands in forest policies.

Early Differentiation of the Phenotypic Space and Performance of Juniperus thurifera Across Woodland-Expanding Areas

Forest expansion after rural abandonment is changing landscapes, bringing new challenges and opportunities. Juvenile performance has an effect in the establishment of new forests and the subsequent acclimation of adult trees. However, most studies have focused on the performance of adult trees. Here, we analysed differences in the phenotypic trait space of juveniles across gradients of Juniperus thurifera woodland expansion and explored which traits shape juveniles’ performance, seeking specific drivers of such differentiation and the role of the ontogeny. Thus, we surveyed functional leaf and plant-size traits in 180 juveniles growing in 18 plots at three different tree density stages (mature woodland, recently established area and a transition zone between both) and recorded local environmental conditions around each individual. We also estimated their radial growth and resilience to drought (in terms of resistance, recovery and resilience) as performance indicators. We found no relevant effects of the study environmental variables, but we did find a shift in the phenotypic space among juveniles across the gradient, with taller crowns and higher amount of leaf N and δ13C at the expanding edge. This trait differentiation across the gradient implied higher performance of young trees growing in old agricultural fields, both in growth rate and drought resilience terms. Our results showed a relevant land-use legacy on early trait differentiation that shapes more efficient phenotypes in the expanding edge compared to those in mature woodlands, suggesting that the future of these new forests is not compromised under current conditions.

Collaborative agent-based modeling for managing shrub encroachment in an Afroalpine grassland

We co-designed an agent-based model of an Afroalpine grassland in Ethiopia that is experiencing unwanted shrub encroachment. The goal was to enable managers of a community conservation area to better understand the drivers of shrub encroachment and to test possible management actions for controlling shrubs. Due to limited site-specific data, we parameterized this model using insights from published literature, remote sensing, and expert opinion from scientists and local managers. We therefore sought to explore potential future scenarios rather than make highly accurate predictions, focusing on facilitating discussions and learning among the diverse co-management team. We evaluated three social-ecological scenarios with our model, examining: (1) the impact of changing precipitation regimes on vegetation, (2) whether changing the frequency of guassa grass harvests would improve the long-term sustainability of the grassland, and (3) whether the combination of grass harvest and shrub removal would affect shrub encroachment. We found that the model was highly sensitive to the amount of grass harvested each year for local use. Our results indicate that the guassa grass was more resilient than shrubs during persistent dry climatic conditions, whereas a reduction in only the early spring rains (known as the "belg") resulted in considerable loss of grass biomass. While our modeling results lacked the quantitative specificity desired by managers, participants in the collaborative modeling process learned new approaches to planning and management of the conservation area and expanded their knowledge of the ecological complexity of the system. Several participants used the model as a boundary object, interpreting it in ways that reinforced their cultural values and goals for the conservation area. Our work highlights the lack of detailed scientific knowledge of Afroalpine ecosystems, and urges managers to reconnect with traditional ecological management of the conservation area in their pursuit of shrub encroachment solutions. The decline or absence of the belg rains is becoming increasingly common in the Ethiopian highlands, and our results underscore the need for more widespread understanding of how this changing climatic regime impacts local environmental management. This work lays a foundation for social-ecological research to improve both understanding and management of these highly threatened ecosystems.

Large Wood Debris Contributes to Beach Ecosystems but Colombian Beachgoer’s Do Not Recognize It

Large Woody Debris (LWD) accumulation serves essential ecological functions and benefits society’s coastal ecosystems (e.g., beaches). Thus far, the ecosystem services perspective has paid little attention to LWD. Therefore, we aim to contrast social perceptions on LWD and its ecological significance in Puerto Velero beach, Caribbean, Colombia. In consequence, the contribution of LWD to the conformation and creation of Puerto Velero beach was analyzed, as well as how beachgoers perceive the importance of LWD and if they were willing to pay to remove LWD in this beach. To achieve this, a quantitative convergent approach was then proposed using GIS analysis and remote sensing to understand the contributions of LWD to the Puerto Velero beach ecosystem; and in addition, a survey was performed to determine how beachgoers perceived LWD and how they valued the phenomenon. Results indicate that LWD contributed to beach maintenance; nevertheless, most people neglected LWD values because of its lack of visual attractiveness. As such, ecosystem services targets become conflicted because people positively perceived ecosystem services provided by beaches, but they did not assign importance to the beach dynamics they deemed unattractive, regardless of their vast importance.

Counterurbanization: A neglected pathway of forest transition

Human settlement into rural areas (counterurbanization) is generating new patterns of reforestation, with distinctive features compared to the previously considered pathways of forest transition through "economic development" and "forest scarcity". Here, we discuss the specific features of this neglected pathway of forest recovery and describe the process with the support of study cases around the world. This pathway includes specific motivations (e.g., natural amenities, outdoor recreation), particular socio-economic processes, conflicts between newcomers and locals, and specific ecological outcomes (e.g., a larger proportion of non-native species in the new forests). Although this pathway locally affects small areas, as a widespread and expanding process around the world, counterurbanization could have a growing global effect, with the potential to modify biodiversity, ecosystem services, and cultural values. These novel characteristics should be further explored to better understand the patterns and processes of forest transitions in a context of a globally connected world.

Managing Wildfire Risk in Mosaic Landscapes: A Case Study of the Upper Gata River Catchment in Sierra de Gata, Spain

Fire prevention and suppression approaches that exclusively rely on silvicultural measures and containment infrastructure have become increasingly ineffective in stopping the spread of wildfires. As agroforestry landscape mosaics consisting of a mix of different land cover and use types are considered less prone to fire than forests, approaches that support the involvement of rural people in agriculture and forestry activities have been proposed. However, it is unknown whether, in the current socio-economic context, these land-use interventions will nudge fire-prone landscapes towards more fire-resistant ones. We report on a case study of the Gata river catchment in Sierra de Gata, Spain, which is a fire-prone area that has been a pilot site for Mosaico-Extremadura, an innovative participatory fire-risk-mitigation strategy. Our purpose is to assess the efficacy of project interventions as “productive fuel breaks” and their potential for protecting high-risk areas. Interventions were effective in reducing the flame length and the rate of spread, and almost 40% of the intervention area was in sub-catchments with high risk. Therefore, they can function as productive fuel breaks and, if located strategically, contribute to mitigating wildfire risk. For these reasons, and in view of other economic and social benefits, collaborative approaches for land management are highly recommended.

Complete mitogenomes reveal limited genetic variability in the garden dormouse Eliomys quercinus of the Iberian Peninsula

The garden dormouse Eliomys quercinus is a poorly known Western Palearctic species experiencing a global decline. Even though the availability of genetic information is key to assess the driversunderlying demographic changes in wild populations and plan adequate management, data on E. quercinus are still scant. In this study, we reconstructed the complete mitogenomes of four E. quercinus individuals from southern Spain using in–solution enriched libraries, and found evidence of limited genetic variability. We then compared their cytochrome b sequences to those of conspecifics from other countries and supported the divergent but genetically depauperate position of this evolutionarily significant unit (ESU). The information produced will assist future conservation studies on this little–studied rodent.

An Analysis of the Worldwide Research on the Socio-Cultural Valuation of Forest Ecosystem Services

The socio-cultural valuation of forest ecosystem services is a useful tool to generate knowledge and help balance the different interests of stakeholders with respect to the management of these services. The aim of this study is to analyse the evolution of global research on the economic valuation of forest ecosystem services through a review of the existing literature on this topic. The results show that socio-cultural valuation has gained importance in recent years. There is a wide disparity between the countries conducting the research and those being studied. Inconsistency has been observed in the definition and classification of services provided by forests, as well as a lack of unanimity on the reference framework to be applied. The main methodological approaches in the socio-cultural valuation of forest services are participatory mapping, social media analysis, the Q method and free listing. For the collection of primary information, the dominant methodologies are focus groups, semi-structured interviews and online surveys. Finally, this study demonstrates that socio-cultural valuation has great potential to improve the legitimacy of forest ecosystem management decisions and to promote consensus building.