Yvonne Bachmann

Ecological Factors Influencing Physical Soil Degradation in the Atacora Mountain Chain in Benin, West Africa

Abstract This study analyzed the ecological factors influencing soil degradation in the Atacora Mountains in northern Benin, which harbor two endemic species, Thunbergia atacorensis and Ipomoea beninensis. Data were collected along line transects from plain to summit within 22 plots of 30 m × 30 m. Indicators of physical soil degradation (extent of organic layer, color of topsoil, compactness of soil, presence and extent of rills, and occurrence of sheet erosion) and environmental factors (canopy and ground cover, topography, occurrence of flooding, and slope) were assessed. Cluster analysis identified 4 soil degradation classes: light, moderate, high, and extreme. Discriminant and multivariate variance analyses identified canopy and ground cover as the 2 main ecological drivers of soil degradation. Plant, litter, and stone cover were found to decrease as soil degradation increased. The parts of the Atacora Mountains with high elevation and steep slope were found to be less degraded than areas with low slopes, which are easily accessible for human activities. Policies to mitigate soil degradation should prioritize practices with low impact on vegetation cover and promote soil protection practices such as tree planting and mulching.

The impact of land use on species composition and habitat structure in Sudanian savannas — A modelling study in protected areas and agricultural lands of southeastern Burkina Faso

Abstract Schmidt, M., E. Mbayngone, Y. Bachmann, K. Hahn, G. Zizka & A. Thiombiano (2016). The impact of land use on species composition and habitat structure in Sudanian savannas — A modelling study in protected areas and agricultural lands of southeastern Burkina Faso. Candollea 71: 265–274. In English, English abstract. Sudanian Savannas are under high agricultural pressure and are therefore changing rapidly. Due to high population densities and an increasing need for food and cash crops, the mosaic of traditional agroforestry systems, fallows and savanna is being transformed into intensively used croplands and savannas only remain in protected areas. The focus of this study is to characterize the differences in plant diversity and composition between protected areas and surrounding agricultural lands and to identify areas most important for plant conservation. Building on observation and collection records, we modelled distributions of individual plant species and summarized these. We mapped the species richness of vascular plants in general, of woody plants, graminoids and forbs, the share of weeds and the average size of grasses and trees and calculated means for the reserves and outside areas. Distinct differences between protected areas and agricultural lands have been found in the richness of herbs (both forbs and graminoids) and weeds as well as in the size of grasses: Woody species seem to be less affected by human impact in the agricultural lands concerning both species richness and plant size. Weeds are playing an important role in the higher species richness of the agricultural lands. Received: May 24, 2016; Accepted: July 20, 2016; First published online: August 2, 2016

Mangroves in Benin, West Africa: threats, uses and conservation opportunities

Mangrove ecosystems constitute valuable resource all over the world. They provide habitats for flora and fauna species, protect the coast against erosion and supply various products for local communities. Currently, mangroves are overused and degraded. Up to now, perceptions of local communities on the dynamic of mangrove forest and their acceptable participation forms for mangroves restoration have not been entirely understood. This study was undertaken in order to assess human pressure on mangroves from user perspective and to provide baseline information for its sustainable management in three districts (Grand-Popo, Ouidah and Sèmè-Kpodji) located in the coastal area of Benin. Structured and semi-structured questionnaire surveys regarding perceptions of mangrove forest dynamic, causes of mangrove forest degradation, indigenous restoration strategies and forms of participation were conducted among randomly selected informants. It has been reported that Beninese mangrove ecosystems supply timber and non-timber forest products, rich fishing grounds and salt for local communities. Local communities are aware of the need of restoring and ensuring sustainable conservation of mangrove ecosystems. Dominant measures for restoration and conservation indicated by informants for mangrove users include the reintroduction of traditional rules, avoidance of uncontrolled settlements, planting of mangrove trees, planting alternative fuelwood, use of solar energy for salt production and creation of alternative income generating activities. Planting mangrove trees and alternative cooking energy sources supplying to local communities to avoid mangrove destruction are urgent needs for the coastal area of Benin.