Beyond one-size-fits-all: Refining forest restoration indicators for the Mediterranean context based on expert knowledge

Abstract

Global and European forest restoration initiatives such as the European Nature Restoration Regulation (NRR) have set ambitious targets, but ensuring that restoration efforts translate into effective socioecological outcomes requires robust monitoring frameworks with appropriate indicators. However, the NRR’s proposed indicators for forest restoration have raised concerns regarding the lack of socioeconomic considerations and their applicability across diverse forest contexts, including the Mediterranean. This study evaluates expert perceptions of thirty-four indicators (NRR, scientific literature, and socioeconomic ones) through a Delphi consultation with over sixty forest restoration experts from diverse disciplinary and sociodemographic backgrounds in Spain. Our findings reveal that deadwood (both lying and standing) accumulation was deemed the least relevant NRR indicator by experts (mean ± SD: 3.3 ± 1.2 on a Likert scale) due to concerns about increased wildfire risk, whereas native tree species dominance (4.3 ± 0.8) and tree species diversity (4.3 ± 0.9) were the most highly rated ones. Additionally, 93 % of experts agreed that socioeconomic indicators should be incorporated into restoration monitoring, with positive public perception of restoration (4.5 ± 0.8) being the most valued metric. Experts also highlighted the need for indicators assessing ecosystem resilience, such as natural regeneration, fire risk and soil erosion, which are currently absent from the NRR. Building on these insights, we propose a flexible, goal-oriented framework for selecting restoration indicators, balancing harmonization with regional adaptation, and highlighting indicators that evaluate multiple restoration goals. This approach aims to enhance the effectiveness of forest restoration monitoring in Spain and other southern European regions while contributing to the development of national restoration plans.

his study was conducted as part of the REFORADAPT project, supported by the Biodiversity Foundation, of the Spanish Ministry for Ecological Transition and the Demographic Challenge, through the grant program for projects that contribute to the implementation of the Spanish National Climate Change Adaptation Plan (2021–2030). A.A. is funded through an Investigo Programme contract under the European Union’s Next Generation EU initiative. RNC and GPR are funded through DesFutur project, which has the support of the Biodiversity Foundation of the Ministry for the Ecological Transition and the Demographic Challenge (MITECO) of the Government of Spain, within the framework of the Recovery, Transformation and Resilience Plan (PRTR), funded by the European Union – NextGenerationEU. RNC and GPR are funded through DesFutur project, which has the support of the Biodiversity Foundation of the Ministry for the Ecological Transition and the Demographic Challenge (MITECO) of the Government of Spain, within the framework of the Recovery, Transformation and Resilience Plan (PRTR), funded by the European Union – NextGenerationEU. We extend our sincere gratitude to all the experts who generously contributed their knowledge and experience during the workshops. Special thanks to ICIFOR-INIA (CSIC), Forestal Catalana SA, Boumort National Game Reserve (Generalitat de Catalunya) and the University of Córdoba for their invaluable support in organizing the in-person workshops.