Modelling and simulating change in reforesting mountain landscapes using a social-ecological framework

Natural reforestation of European mountain landscapes raises major environmental and societal issues. With local stakeholders in the Pyrenees National Park area (France), we studied agricultural landscape colonisation by ash (Fraxinus excelsior) to enlighten its impacts on biodiversity and other landscape functions of importance for the valley socio-economics. The study comprised an integrated assessment of land-use and land-cover change (LUCC) since the 1950s, and a scenario analysis of alternative future policy. We combined knowledge and methods from landscape ecology, land change and agricultural sciences, and a set of coordinated field studies to capture interactions and feedback in the local landscape/land-use system. Our results elicited the hierarchically-nested relationships between social and ecological processes. Agricultural change played a preeminent role in the spatial and temporal patterns of LUCC. Landscape colonisation by ash at the parcel level of organisation was merely controlled by grassland management, and in fact depended on the farmer's land management at the whole-farm level. LUCC patterns at the landscape level depended to a great extent on interactions between farm household behaviours and the spatial arrangement of landholdings within the landscape mosaic. Our results stressed the need to represent the local SES function at a fine scale to adequately capture scenarios of change in landscape functions. These findings orientated our modelling choices in the building an agent-based model for LUCC simulation (SMASH - Spatialized Multi-Agent System of landscape colonization by ASH). We discuss our method and results with reference to topical issues in interdisciplinary research into the sustainability of multifunctional landscapes

Patterns of ash (Fraxinus excelsior L.) colonization in mountain grasslands: the importance of management practices

International audienceWoody colonization of grasslands is often associated with changes in abiotic or biotic conditions or a combination of both. Widely used as fodder and litter in the past traditional agro-pastoral system, ash (Fraxinus excelsior L.) has now become a colonizing species of mountain grasslands in the French Pyrenees. Its present distribution is dependent on past human activities and it is locally controlled by propagule pressure and abiotic conditions. However, even when all favourable conditions are met, all the potentially colonizable grasslands are not invaded. We hypothesize that management practices should play a crucial role in the control of ash colonization. From empirical field surveys we have compared the botanical composition of a set of grasslands (present and former) differing in management practices and level of ash colonization. We have displayed a kind of successional gradient positively linked to both ash cover and height but not to the age of trees. We have tested the relationships between ash presence in grassland and management types i.e. cutting and/or grazing, management intensity and some grassland communities' features i.e. total and local specific richness and species heterogeneity. Mixed use (cutting and grazing) is negatively linked to ash presence in grassland whereas grazing alone positively. Mixed use and high grazing intensity are directly preventing ash seedlings establishment, when low grazing intensity is allowing ash seedlings establishment indirectly through herbaceous vegetation neglected by livestock. Our results show the existence of a limit between grasslands with and without established ashes corresponding to a threshold in the intensity of use. Under this threshold, when ash is established, the colonization process seems to become irreversible. Ash possesses the ability of compensatory growth and therefore under a high grazing intensity develops a subterranean vegetative reproduction. However the question remains at which stage of seedling development and grazing intensity these strategies could occur

FLUX DISTRIBUTIONS AND LEAKAGE CURRENTS FOR SRE, P-16

BS>Two-group, two-region criticality calculations were made for 10 and 11 ft diameter tanks. The 10 ft tank required a core radius of 102 cm and the 11 ft tank a core radius of 95 cm for criticality. In the calculations, the fluxes were assumed to go to zero at the edge oi the graphite reflector. The fast group of the two-group calculation was broken down into 3 fast groups. The leakage out of the core and reflector for the 4 energy groups is given. (M.C.G.

Shield for Water Boiler

Siimplified shielding calculations indicating the proposed design for the water boiler assembly will reduce the radiation at normal operaton to values well below those which are considered tolerable

Public policies and management of rural forests : lasting alliance or fool's dialogue ?

Most people in forest and rural areas manage trees as part of their livelihood systems. The resulting "domestic" or "rural" forests are distinct from conventional forest. They have historically been overlooked by the forestry sector and impacted by forest policies and regulatory frameworks. These forests presently encounter requalification and valuation dynamics, fueled by a sustainable development ideology, and induced by both public powers and local communities. These dynamics move in two different directions: the naturalization of rural forests by policy makers, and their politization by rural people. We draw on long-term research experiences in France, Morocco, Southeast Asia, and Africa on forests managed by "farmers", among which some are analyzed in the Ecology and Society Feature, Public policies and management of rural forests: lasting alliance or fool's dialogue?. We first elaborate on domestication, analyzed at tree, ecosystems and landscape levels, as a concept allowing for a better understanding of the specific relationships developed between rural people and forests. We then engage in a critical review of how forest-related and sustainable development policies consider rural forests, and discuss how they address (or do not address) their specificity and encourage (or do not encourage) their development

Influence des modes d'exploitation sur les caractéristiques et l'évolution des surfaces pastorales : cas des Pyrénées centrales

International audienc

The multiple dimensions of rural forests : lessons from a comparative analysis

Rural forests are characterized by different levels of formal and nonformal appropriation by rural communities who have generally managed, shaped, or rebuilt these forest formations over many generations with refined local knowledge and practices related to their use and perpetuation. Rural forests are therefore social-ecological systems that contribute to ecosystem and landscapes configuration, definition of rural territories, and sustainability of local livelihoods. Although some studies have attempted to explain their specificities, in specific geographical and social contexts, their characteristics are not well defined as they encompass highly diversified situations. This lack of comprehension of the identity of rural forests is at the heart of the lack of dialogue between forestry policies and rural forest development. Our major aim is to identify universal characteristics of rural forests as well as specificities that can differentiate them. Eleven situations of rural forests were analyzed by means of detailed, harmonized monographs, from developing and developed countries, and localized within contrasting ecological environments (humid tropics, dry forests, temperate forests) and socio-economic and public policies contexts. Qualitative data were obtained through a common analytical framework and were encoded with an approach based on the collective appreciation of the group of researchers who developed case studies. These were pooled within a common analysis chart and were processed by means of multivariate analyses. Results were further discussed taking into consideration four major characteristics that emerged from this analysis, and which form the identity of rural forests. These are: 1) specific forest structures and levels of integration in agricultural matrices which are linked historically to overall agroecosystem approaches and practices, 2) a multiscale approach to domestication practices from landscape to individual trees inscribed in continuities between "nature" and "culture", natural processes and human techniques of control and transformation, 3) multiple uses of plant species which vary in relation to the commercial or noncommercial status of their products and a reversible nature of these use patterns accordingly, 4) the imbricate nature of rules of access and control between state and customary levels, and between individual and collective levels, requiring specific formal and informal arrangements. Typologies of rural forests can be drawn along each of these major characteristics and provide a reliable system to analyze and understand the functioning of rural forests. Forestry approaches in rural contexts, hence, need to consider variations along these major lines that form the identity cards of rural forests

Outcomes of high volume cataract surgeries in a developing country

Aim: To analyse the outcome of high volume cataract surgery in a developing country, community based, high volume eye hospital. Methods: In a non-comparative interventional case series, the authors reviewed the surgical outcomes of 593 patients with cataract operated upon by three high volume surgeons on six randomly selected days. There were 318 female (54%) and 275 male (46%) patients. Their mean age was 59.57 (SD 10.13) years. The majority of the patients underwent manual small incision cataract surgery (manual SICS). Extracapsular cataract extraction with posterior chamber intraocular lens (ECCE-PCIOL) and intracapsular cataract extraction (ICCE) were also done on a few patients as clinically indicated. Results: Best corrected visual acuity of ⩾6/18 was achieved in 94% of the 520 patients who could be followed up on the 40th postoperative day (88% follow up rate). Intraoperative and immediate postoperative complications as defined by OCTET occurred in 11 (1.9%) and 75 (12.6%) patients, respectively. Average surgical time of 3.75 minutes per case (16–18 cases per hour) was achieved. Statistically significant risk factors for outcomes were found to be age >60, sex, and surgeon. Conclusion: High volume surgery using appropriate techniques and standardised protocols does not compromise quality of outcomes