Le rôle des forêts et des arbres dans l'adaptation sociale à la variabilité et au changement climatiques

Les écosystèmes fournissent d'importants services qui peuvent aider les populations à s'adapter à la variabilité et au changement climatiques. Reconnaissant ce rôle des écosystèmes, plusieurs organisations internationales et non gouvernementales ont encouragé une approche de l'adaptation basée sur les écosystèmes (ABE). Dans cet article, nous examinons la littérature scientifique portant sur le rôle des arbres et des forêts dans l'ABE et présentons cinq cas de figure dans lesquels ils peuvent soutenir l'adaptation : (1) les forêts et les arbres qui fournissent des biens aux communautés locales confrontées à des menaces climatiques ; (2) les arbres qui régulent l'eau, les sols et le microclimat dans les champs agricoles pour une production plus résiliente ; (3) les bassins versants forestiers qui régulent l'eau et protègent les sols afin de réduire les effets du climat ; (4) les forêts qui protègent les régions côtières contre les menaces liées au climat ; et (5) les forêts et les arbres urbains qui régulent la température et l'eau pour rendre les villes résilientes. La littérature montre que l'ABE à l'aide des forêts et des arbres peut réduire la vulnérabilité sociale aux risques climatiques ; toutefois, des incertitudes et des déficits de connaissances demeurent, concernant en particulier les services de régulation dans les bassins versants et les régions côtières. Peu d'études ont spécifiquement été entreprises sur l'ABE, mais l'abondante littérature relative aux services écosystémiques peut servir à combler les lacunes dansles connaissances. De nombreuses études évaluent les multiples bénéfices des écosystèmes pour l'adaptation ou le bien-être des populations, tout en reconnaissant qu'il faille élaborer des compromis entre les services écosystémiques fournis. Une meilleure compréhension de l'efficience, des coûts, des bénéfices et des compromis de l'adaptation fondée sur les écosystèmes des forêts et des arbres est nécessaire. Les projets pilotes en cours de mise en oeuvre pourraient servir de sites d'apprentissage et les informations existantes pourraient être systématisées et révisées à travers le prisme de l'adaptation au changement climatique. (Résumé d'auteur

Bosques y árboles para la adaptación social al cambio y la variabilidad del clima

CIFOR Working PaperLos ecosistemas proporcionan servicios importantes que pueden ayudar a las personas a adaptarse a la variabilidad y cambio climáticos. Reconociendo este papel de los ecosistemas, varias organizaciones internacionales y no gubernamentales han promovido un enfoque para la adaptación basado en los ecosistemas. En este artículo se revisa la literatura científica referente a la adaptación basada en los ecosistemas (ABE) con bosques y árboles, y se resaltan cinco casos en que los bosques y los árboles pueden apoyar a la adaptación: (1) bosques y árboles que proveen bienes a las comunidades locales que enfrentan amenazas climáticas, (2) árboles en los campos agrícolas que regulan el agua, el suelo y el microclima para una producción más resiliente, (3) cuencas hidrográficas boscosas que regulan el agua y protegen los suelos reduciendo los impactos climáticos, (4) bosques que protegen zonas costeras de amenazas relacionadas con el clima, y (5) bosques urbanos y árboles que regulan la temperatura y el agua para ciudades más resilientes. La literatura proporciona pruebas de que la ABE con bosques y árboles puede reducir la vulnerabilidad social a los riesgos climáticos, sin embargo, todavía quedan las incertidumbres y brechas de conocimiento, sobre todo para regular los servicios de las cuencas hidrográficas y las zonas costeras. Se han realizado pocos estudios sobre la ABE específicamente, pero se puede utilizar la abundante literatura que existe sobre los servicios ecosistémicos para llenar los vacíos de conocimiento. Muchos estudios evalúan los múltiples beneficios de los ecosistemas para la adaptación humana y el bienestar, pero también reconocen compensaciones entre los servicios ecosistémicos. Se requiere una mejor comprensión de la eficiencia, los costos y beneficios, y las compensaciones de la ABE con bosques y árboles. Los proyectos piloto en ejecución pueden servir como sitios de aprendizaje y la información existente puede ser sistematizada y abordada de nuevo con un enfoque de adaptación al cambio climático

Absence of curli in soil-persistent Escherichia coli is mediated by a C-di-GMP signaling defect and suggests evidence of biofilm-independent niche specialization

peer-reviewedEscherichia coli is commonly viewed as a gastrointestinal commensal or pathogen although an increasing body of evidence suggests that it can persist in non-host environments as well. Curli are a major component of biofilm in many enteric bacteria including E. coli and are important for adherence to different biotic and abiotic surfaces. In this study we investigated curli production in a unique collection of soil-persistent E. coli isolates and examined the role of curli formation in environmental persistence. Although most soil-persistent E. coli were curli-positive, 10% of isolates were curli-negative (17 out of 170). Curli-producing E. coli (COB583, COB585, and BW25113) displayed significantly more attachment to quartz sand than the curli-negative strains. Long-term soil survival experiments indicated that curli production was not required for long-term survival in live soil (over 110 days), as a curli-negative mutant BW25113ΔcsgB had similar survival compared to wild type BW25113. Mutations in two genes associated with c-di-GMP metabolism, dgcE and pdeR, correlated with loss of curli in eight soil-persistent strains, although this did not significantly impair their survival in soil compared to curli-positive strains. Overall, the data indicate that curli-deficient and biofilm-defective strains, that also have a defect in attachment to quartz sand, are able to reside in soil for long periods of time thus pointing to the possibility that niches may exist in the soil that can support long-term survival independently of biofilm formation

Antifungal activity of extracts of Ocimum gratissimum and Aframomum danielli against moulds isolated from stored rice

The fungitoxic effect of extracts of Ocimum gratissimum and Aframomum danielli on some moulds isolated from rice grains were determined in vitro. Aqueous extracts of Aframomum danielli inhibited the radial growth of the moulds at different levels between 46.4 - 56.7%. Aspergillus niger (56.7%) was the most sensitive to Aframomum danielli while Cladosporium sphaerospermum (46.4%) was the least sensitive. Ocimum gratissimum extract inhibited the radial growth of the moulds between 46.4 – 59.7% with Penicillium citrinum showing the highest sensitivity and C. sphaerospermum being the least sensitive. There was no significant difference (p>0.05) in the effect of Ocimum gratissimum and Aframomum danielli on all the moulds. Ocimum gratissimum showed the greater antifungal activity against the storage fungi (mean = 53.4%) compared to Aframomum danielli (mean = 51.9%). However, there was no significant difference (p>0.05) in the effect  of Ocimum gratissimum and Aframomum danielli on the storage fungi. Both plant products showed varying levels of fungitoxic activities and could be potentially used in the storage of Ofada and Abakaliki rice against moulds. Keywords: Plant extracts, Antifungal activity, Storage fungi, Moulds, Ric

Catalytic steam reforming of syngas hydrocarbons to maximise hydrogen production - a thermodynamic study

Hydrogen is an energy source of the future. It is imperative to develop competitive hydrogen production technology from renewable sources such as biomass. The biomass can be converted to hydrogen through gasification to produce syngas, a mixture of hydrogen, tar, methane, carbon monoxide, carbon dioxide and other hydrocarbon gases. Tar has been a challenge as it easily condenses at lower temperatures and may severely block equipment. However, tar and other hydrocarbons present in syngas could be catalytically reformed to produce hydrogen and thus maximise hydrogen production, which can be subsequently separated from other syngas species. Current reforming catalysts suffer from deactivation caused by sulphur present in syngas; this worsens the gasification process performance and often causes unwanted side reactions. Sulphur deactivation could occur through mechanisms of sulphidation, alteration and coke formation. To develop a solution for preventing sulphur deactivation, a novel catalyst composition NixCo(1-x)CeO3 is proposed and formulated. A thermodynamic simulation of syngas reforming was conducted to gain a foundation reference indicating the novelty of the catalyst performance, and the novel catalyst considers sulphur resistance being rendered by labile lattice oxygen which oxidises chemisorbed sulphur to gaseous sulphur oxides. Further kinetic modelling has been performed using kinetic data for existing catalysts, it was found to be operating at 44% of thermodynamic hydrogen production rate, meaning there is a significant performance gap the catalyst in this research needs to cover. Thermodynamic simulation predicted ideal reforming temperature of 650-700oC for maximum conversion. Important parameters (e.g., steam to carbon ratio, gas hourly space velocity) and insights have been obtained for use in next phase of the research work on assessing catalyst performance. Figure 1 below illustrates the proposed mechanism for the novel catalyst resistance to sulphur and coke, and Figure 2 shows the results of the thermodynamic and catalytic simulation for syngas reforming

Governing Congo Basin forests in a changing climate: actors, discourses and institutions for adaptation and mitigation

Governing Congo Basin Forests in a Changing Climate: Actors, Discourses and Institutions for Adaptation and Mitigation OA Somorin Abstract The thesis deals with the central question of the governance processes of making tropical forests deliver climate change adaptation and mitigation outcomes of sustainable livelihoods, biodiversity conservation and enhanced carbon stocks. Using the case of the Congo Basin forests, it analyzes the nexus between forest and climate change, particularly on the governance processes of using the forests to respond to climate change. The thesis questions the dominant frames and discourses shaping the policymaking processes of adaptation and mitigation strategies in the Congo Basin. The research is informed by past (and still current) debates among different actors on the forms of institutional and policy frameworks required for policy making on adaptation and mitigation in the Congo, given the region’s context of weak human and governance capacities. Drawing from the theoretical perspective of discursive institutionalism which takes into account the institutional context in which discourses emerge and the way in which they are institutionalized in social practices. Conceptually, the thesis employs the analytical elements of discursive institutionalism: discourses, actors and institutions in terms of their consequences for governance process analysis. The focus is to understand the types of actors involved along with their capacity and competence to contribute to the policy processes; the overarching global to local discourses on the issues; and the institutional structures considered relevant for adaptation and mitigation in the Congo Basin. Despite the framing of adaptation as a priority for the Congo Basin region due to the high vulnerability (and low adaptive capacity) of the population to climate risks, the thesis finds more significant policy attention is rather given to mitigation. The dominance of the mitigation discourses is largely due to elements of financial resources, knowledge and influence employed by their actor coalitions to advance the policymaking process. While mitigation policy debates among state and non-state actors on institutional and governance frameworks exist at the national level, adaptation strategies including sustaining food security, income generation and livelihood diversification, are already in practice at the local levels. Ultimately, policy actors’ interest to match the multiple opportunities that mitigation offers with the priorities of adaptation underlines the deliberate actions towards fostering synergy. The thesis concludes that the future of the Congo Basin forests under a changing climate lies in how the actors are able to develop policy frameworks and governance arrangements to foster mitigative adaptation and adaptive mitigation. </p

Climate impacts, forest-dependent rural livelihoods and adaptation strategies in Africa : a review

This article reviews and analyzes the implication of impacts of climate variability and change on African societies. It focuses on the African forest sector, especially the livelihoods of forest-dependent rural populations. Increasing Africa’s adaptive capacity urgently requires commitment at local, national and international levels. Forest-use affects sustainability of livelihoods, alleviates poverty in a variety of ways, and supports economic, social, cultural and environmental development in rural areas

Life-cycle assessment of self-generated electricity in Nigeria and Jatropha biodiesel as an alternative power fuel

Insufficient available energy has limited the economic growth of Nigeria. The country suffers from frequent power outages, and inconvenient black–outs while residents and industries are forced to depend on self-generated electricity. Life-cycle assessment methodology was used to assess the environmental burdens associated with self-generated electricity (SGE) and proposed embedded power generation in Nigeria. The study shows that SGE from 5 kVA diesel generators contributes to greenhouse gas (GHG) emissions of 1625 kg CO2 eq./MWh, along with other environmental burdens. Based on a point estimate of diesel electric generators in Nigeria, SGE can contribute 389 million tonnes CO2 eq. to climate change every year. This can reposition Nigeria as one of the top 20 emitters of CO2 globally. A mandatory diesel fuel displacement with Jatropha biodiesel can reduce annual GHG emissions from SGE by 76% provided combined cycle power plants are adopted for embedded power generation. The magnitude of these benefits would depend on material inputs, seed yield as well as the environmental status of the reference fuel. Minimal use of fertilizers, chemicals and resources and fossil fuel substitution with renewable options can minimize adverse environmental burdens