Tarrasón D., Ravera F., Reed M.S., Dougill A.J., Gonzalez L. (2016) Land degradation assessment through an ecosystem services lens: Integrating knowledge and methods in pastoral semi-arid systems. Journal of Arid Environments. 124: 205-213.EnllaçDoi: 10.1016/j.jaridenv.2015.08.002
This paper develops and applies an integrated and participatory methodological framework to assess land degradation in pastoral systems through an ecosystem services (ES) lens in a semi-arid region of northern Nicaragua. We initially integrated local and scientific knowledge to assess ecological changes and understand the links with ecosystem services supplied by the local grazing system. Hence, we discuss land degradation features and test a state-and-transition ecological model, that is, we developed jointly with local farmers the hypotheses to understand transitions between ecological states and these hypotheses were then evaluated through an inventory of vegetation and an assessment of soil properties and seed bank composition. The assessment reveals that shifts in ecological state do not cause permanent soil properties changes, but that at a landscape scale they can limit production, affecting local livelihoods. The framework proposed provided local farmers with relevant information and facilitated communication with researchers, enabling them to use the co-constructed knowledge to implement adaptive management strategies to improve local productive systems. © 2015 Elsevier Ltd.
Ravera F., Tarrason D., Espelta J.M. (2014) Land use change trajectories, conservation status and social importance of dry forests in Nicaragua. Environmental Conservation. : 0-0.EnllaçDoi: 10.1017/S0376892914000186
Interdisciplinary studies have proved the interconnectedness of history and ecology relevant to forest conservation proposals and management policies. Engaging local views and concerns in the evaluation and monitoring process can lead to more robust knowledge in the pursuit of effective conservation. This study aimed to assess the degree to which land use change trajectories influence the state of tropical dry forest conservation, as evaluated by scientists and local people. Focusing on northern Nicaragua, the research identified three historical trajectories for types and magnitude of forest disturbance. The assessment process included inventorying sites under different trajectories and integrating ecological and social indicators (namely local perceptions of biodiversity value and concern over species threat). The different land use change trajectories had no influence on the present structure of the dry forest, but strongly affected species diversity, composition and their social importance. The study provided evidence of positive species selection by farmers, which suggested a feedback loop between ecological conditions, social value and awareness of conservation. Copyright © Foundation for Environmental Conservation 2014.
Ravera F., Tarrason D., Siciliano G. (2014) Rural change and multidimensional analysis of farm's vulnerability: A case study in a protected area of semi-arid northern Nicaragua. Environment, Development and Sustainability. 16: 873-901.EnllaçDoi: 10.1007/s10668-014-9531-z
This paper presents an empirical research in a protected area of northern Nicaragua, aimed at: (a) classifying predominant narratives surrounding present and future pathways of the local rural system, drivers of change, features of livelihoods' vulnerability; (b) understanding current functioning of local metabolic patterns of rural systems by developing a typology of farms and (c) comparing types' vulnerability to current drivers of change. To achieve these objectives, we integrated qualitative and quantitative analytical approaches. The different visions of rural spaces, which emerge from the analysis of the narratives, and the five types of farms, characterized by specific land-time budget and energy and monetary flows, suggest two emerging dynamics of local restructuration in protected areas: (1) a dominant land re-concentration process which is generating increasing inequality in access to resources and a progressive marginalization of the self-sufficient economy of landless and subsistence households; (2) an emergence of a paradigm of 'environmentalization' of rural spaces together with a valorization of small and medium-scale diversified economies. Moreover, the vulnerability assessment focuses on multidimensional features of types' sensitivity to crisis, i.e. risk unacceptability, production instability, economic inefficiency, food and exosomatic energy dependency, as well as capacity to buffer and adapt to change, i.e. access to assets, including labour for men and women, social safety nets and degrees of economic diversification. The discussion highlights the occurrence of trade-off between the solutions adopted by farms within different development paths, suggesting the relevance of the proposed framework of analysis at the interface between science and policy. © 2014 Springer Science+Business Media Dordrecht.
Tarrason D., Ojeda G., Ortiz O., Alcaniz J.M. (2014) Can organic amendments be useful in transforming a mediterranean shrubland into a dehesa?. Restoration Ecology. 22: 486-494.EnllaçDoi: 10.1111/rec.12092
Transforming a shrubland into a dehesa system may be useful for recovering certain productive and regulatory functions of ecosystems such as grazing potential, soil erosion control, and also for reducing the risk of wildfire. However, the productivity of the herbaceous cover and tree development in the transformed system may be limited by soil fertility, especially after wildfire events. Previous studies have shown that adequate doses of sewage sludge may improve soil fertility and facilitate plant recovery, but few studies have focused on plant biodiversity assessment. Here, we compare the effects of sewage sludge that has undergone different post-treatments (dewatering, composting, or thermal drying) as a soil amendment used to transform a fire-affected shrubland into a dehesa, on tree growth and pasture composition (vegetation cover, species richness, and diversity). In the short term, sewage sludge causes changes in both pasture cover and tree growth. Although no major differences in vegetation species richness and composition have been detected, fertilization using sewage sludge was shown to modify the functional diversity of the vegetation community. Rapid replacement of shrubs by herbaceous cover and ruderal plants (e.g. Bromus hordeaceus and Leontodon taraxacoides) and of the three grass species sown (Festuca arundinacea, Lolium perenne, and Dactylis glomerata) was observed, whereas N-fixing species (leguminous) tended to be more abundant in nonfertilized soils and soils amended with composted sludge. These results indicate that sewage sludge modifies the functionality of vegetation when applied to soils, and that the response varies according to the treatment that the sludge has undergone. © 2014 Society for Ecological Restoration.
Andrés P, Tarrasón D, Ravera F, Espelta JM, López K, Urrutia, JT, Rocha J (2012) La construcción de conocimiento complejo para la restauración de territorios económica y ambientalmente degradados. Un caso de aplicación a áreas ganaderas del trópico seco. (Ponencia por invitación) En: Simposio Internacional de Restauración Ecológica. Retos y Estrategias de Restauración en el Caribe Colombiano. Universidad del Atlántico. Barranquilla (Colombia). 25-27 de julio de 2012.
Andrés P, Mateos E, Tarrasón D, Cabrera C, Figuerola B (2011) Effects of fresh, composted, and thermally dried sewage sludge on soil microbiota and mesofauna. Applied Soil Ecology 48: 236-242.
Ravera F., Hubacek K., Reed M., Tarrasón D. (2011) Learning from experiences in adaptive action research: A critical comparison of two case studies applying participatory scenario development and modelling approaches. Environmental Policy and Governance. 21: 433-453.EnllaçDoi: 10.1002/eet.585
This paper contributes to the emerging debate on participatory modelling at the core of adaptive action research. We compare and reflect upon lessons learned from two projects in very different bio-physical and socio-economic contexts, the UK and Nicaragua, and outline a shared theoretical and methodological framework to assist researchers and local stakeholders to jointly assess, monitor and adapt to climatic and other changes. We discuss opportunities and obstacles, specifically: (1) incorporating uncertainty and surprises; (2) combining epistemologies; (3) dealing with representativeness and power dynamics; (4) creating opportunities for improving stakeholders' agency; and (5) facilitating dialogue and negotiation by using models as heuristics. Our analysis emphasizes the importance of dealing with unavoidable trade-offs when engaging in participatory and interdisciplinary research in complex and uncertain decision-making contexts. The participatory modelling experiences show that stakeholders' involvement throughout the process, epistemological plurality, flexibility and sensitivity to context-dependent socio-cultural processes need to be considered by researchers who wish to enhance the adaptive capacity of the communities they work with. © 2011 John Wiley & Sons, Ltd and ERP Environment.
Tarrasón D, Ojeda G, Ortiz O, Alcañiz JM (2010) Effects of Different Types of Sludge on Soil Microbial Properties: A Field Experiment on Degraded Mediterranean Soils. Pedosphere 20: 681-691.
Tarrasón D., Urrutia J.T., Ravera F., Herrera E., Andrés P., Espelta J.M. (2010) Conservation status of tropical dry forest remnants in Nicaragua: Do ecological indicators and social perception tally?. Biodiversity and Conservation. 19: 813-827.EnllaçDoi: 10.1007/s10531-009-9736-x
Intensive deforestation is reducing dry tropical forest areas worldwide and increasing its fragmentation. Forest remnants can be the basis for the future recovery of this forest type if appropriate management practices are applied. This requires a better knowledge of their conservation status and the assessment of their perceived value by land users. In this study we compare the structure, species richness and diversity of different types of tropical dry forest remnants in Nicaragua and we assess their conservation status based on a new index: Social simplified Importance Value Index (SsIVI). This index summarizes both ecological indicators and the perception by local stakeholders of the conservation status of the tree species present. Results show that gallery and hillslope forest remnants have higher species richness and diversity than isolated vestigial patches. In all remnants, species richness and diversity is higher in the tree layer than in the regeneration layer. No differences are observed in valorisation among different types of remnants either for the tree layer or for the regeneration layer. In the hillslope forests, where several degrees of disturbance are present, the valorisation decreases with increasing degradation. Results of species composition and forest structure indicate a strong degradation of dry tropical forest remnants in Nicaragua. However, the similar social valorisation of the three types of remnants suggests that they face similar threats but also similar opportunities to be preserved. A decrease in valorisation with increasing degradation warns about the potential loss of the most degraded areas, unless forest restoration is applied. © Springer Science+Business Media B.V. 2009.
Klaus H, Beharry N, Bonn A, Burt T, Holden J, Ravera F, Reed M, Stringer L, Tarrasón D (2009) Ecosystem services in dynamic and contested landscapes: the case of UK uplands. In: Winter, Michael and Matt Lobley (eds). Land Use and Management: The New Debate Earthscan.
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