European, and especially Mediterranean, agri-food systems in marginal rural areas  (e.g. mountain agro-pastoral systems; extensive traditional systems etc.), face important drivers of change, mainly climate change, aging populations associated with outmigration of young people and a fragile socio-economic system, hit by the recent economic crisis (EC APP briefs nº7 2012). These drivers seriously increase social key risks, which may include disruption to local livelihoods, failure of food security (availability, access, use, stability of food), loss of common-pool resources and traditional knowledge and practices, or even increase of mortality and morbidity in cases of extreme heat (IPCC, 2014). To deal with such challenges, rural areas need to develop adaptation strategies that reduce their vulnerability, and in the case of agri-food systems, some authors suggest the need to re-think the way they are defined, assessed and managed (Rivera-Ferre et al. 2013). Recent research highlights the relevance of alternative agri-food systems organization (e.g. agroecological systems, short-food chains, new networks and partnerships along the agri/food activities etc.) to face climate change challenges and increase adaptive capacity (UNCTAD 2013). The purpose is thus to promote changes towards transformational adaptation for social-ecological sustainability, that is, adaptation that changes the fundamental attributes of the system (IPCC 2014: Glossary), which includes, among other options, the introduction of new technologies or practices and knowledge, and the formation of new institutions or systems of governance with the final purpose of achieving social needs (i.e. social innovation according to Westley et al. 2013). In order to reach transformational adaptation, the IPCC calls for addressing climate change research as related to food and agriculture under a systemic perspective (Porter et al. 2014). Accordingly, following Ostrom’s framework (2009), agrifood systems are here conceptualized as complex socio-ecological systems (SES), as adapted by Vallejos-Rojas et al. (2015), analyzing the dynamic and vulnerable interactions among the components (ecological, actors and knowledge, institutions) and interactions between activities along the food chain (production, transformation, distribution, consumption) in the face of short-term shocks and long-term stresses, and formulating diverse strategies according to the social, cultural and environmental context (Ericksen 2008; Rivera-Ferre 2012). Though climate change is a global problem that needs solutions at different geographic scales, in transformational adaptation the understanding of local context is of extreme importance (Agrawal, 2010) both in understanding the key risks of populations and the potential factors that may facilitate or be barriers for successful adaptation options. The IPCC (2014) stresses the need to pay more attention to local experiences, knowledge systems, institutions and practices to respond to climate change. Innovative research on climate change thus calls for re-focusing the study of how to support adaptive capacity. However, some research gaps should be approached.

First, while some studies have shown the relationship between adaptive capacity and institutions (Gupta et al 2010), an examination of if and how the set of knowledge systems, practices and technologies and institutional arrangements (Ostrom 1999) enhances adaptive capacity and contributes to decrease risks and sustainably manage of local agri-food systems in the context of climate change is overlooked. This set is conceived as the basis for local-level decision-making in many rural communities and has been highlighted by the IPCC as a potential tool to promote adaptation to climate change and by the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) as complementary and enriching to other knowledge systems (Diaz et al. 2015; Tëngo et al. 2014). Understanding what is driving changes and increasing risk in vulnerable local agrifood systems, what are the complex interactions between components (social and ecological) within a agrifood system and how to link to adaptive capacity and resilience is a urgent priority of systemic agrifood research. Second, empirical exploration is still incipient in social innovation, understood as mechanisms of social change and social learning processes. Understanding how to overcome barriers and catalyze diffusion of successful experiences. Recent studies have demonstrated that novelty in socio-economic strategies, management technology and practices, and institutional solutions may lead to more multifunctional forms of land use and more resilient agrifood systems (Horlings and Marsder, 2014). This novelty shows great potential for overall sustainability of marginal rural areas in Europe, but it is not clear what are such