Impacts des activités d'extraction de gravier au Sud du Bénin et leur perception par la population locale

Impacts of gravel extraction activities in Southern Benin: Residents' perception. Gravel extraction activities in Southern Benin are carried out without formal license from the state authorities. The majority of sites are rented from landowners and located near other forms of land use including human settlements. This study aims at assessing the perception by the residents of these gravel extraction operations. The results show the social services and damages of this industry. An ordinal logit regression revealed significant influences of the respondents' ethnic group, occupation, education level, marital status and age on the perception of road infrastructure, dust pollution, loss of agricultural land and school drop-out. Therefore, it is important that the local authorities undertake mitigation actions in particular in order to prevent road dust occurrence and to restore abandoned sites so that these sites are again available for agriculture

Forest fragmentation: causes, ecological impacts and implications for landscape management

In order to enable the development of appropriate landscape management plans, the causes and impacts of fragmentation should be fully understood. A new definition, incorporating the key aspects cited in landscape ecological literature since the 1980s, is proposed in order to shed light on the matter of fragmentation. By means of two case studies in the Democratic Republic of the Congo (Oriental Province) and in North Benin, the key role of anthropogenic activities in landscape fragmentation is evidenced; the spatial dispersion of forest vegetation is linked to population density and land use change. The potential impact of fragmentation on biodiversity is shown by an analysis of forest diversity in Ivory Coast (Tanda region), and by a study of edge effects on two rodent species in the Democratic Republic of the Congo (Kisangani). The chapter is concluded by an study on how planned corridors, assuming a spatial regrouping of existing teak plantations, could contribute to the conservation and management of remaining natural forest patches in the Atlantic Department in Benin

Effet de lisière sur la productivité du teck (Tectona grandis L.f.): étude de cas des teckeraies privées du Sud-Bénin

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Caractéristiques structurelles et écologiques des phytocénoses de sous-bois des plantations privées de teck du département de l’Atlantique (Sud-Bénin, Afrique de l’Ouest)

Structural and ecological characteristics of private Teak plantations in the Atlantic Department, South Benin, were studied according to the synusial approach of phytosociology in order to contribute to the sustainable management of the plantations. The study of dendrometric characteristics of Teak plantations was done by establishing two temporal plots, each of 1 are. In each plot, the stem girth of the trees and the total height of three mean trees were measured. A total of 99 vegetal synusias has been described, then combined into 18 phytocoenoses. Ecological characteristics are also studied.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Structural characteristics and forest sites identification in Pahou forest reserve, South-Benin

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Anhydrous Monoalkylguanidines in Aprotic and Nonpolar Solvents: Models for Deprotonated Arginine Side Chains in Membrane Environments

In this study, the synthesis of crystalline dodecylguanidine free base and its spectroscopic characterization in nonpolar environments are described. IR as well as ¹H and ¹⁵N NMR spectra of the free base dissolved in aprotic solvents are substantially different from the previously reported spectra of arginine, or other monoalkylguanidinium compounds, at high hydroxide concentrations. The current results provide improved modeling for the spectroscopic signals that would be expected from a deprotonated arginine in a nonpolar environment. On the basis of our spectra of the authentic dodecylguanidine free base, addition of large amounts of aqueous hydroxide to arginine or other monoalklyguanidinium salts does not deprotonate them. Instead, hydroxide addition leads to the formation of a guanidinium hydroxide complex, with a dissociation constant near ∼500 mM that accounts for the established arginine p<i>K</i> value of ∼13.7. We also report a method for synthesizing a compound containing both phenol and free-base guanidine groups, linked by a dodecyl chain that should be generalizable to other hydrocarbon linkers. Such alkyl-guanidine and phenolyl-alkyl-guanidine compounds can serve as small-molecule models for the conserved arginine–tyrosine groupings that have been observed in crystallographic structures of both microbial rhodopsins and G-protein-coupled receptors

Tree plantation will not compensate natural woody vegetation cover loss in the Atlantic Department of southern Benin

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