André Lindner

Bee pollination increases yield quantity and quality of cash crops in Burkina Faso, West Africa

Mutualistic biotic interactions as among flowering plants and their animal pollinators are a key component of biodiversity. Pollination, especially by insects, is a key element in ecosystem functioning, and hence constitutes an ecosystem service of global importance. Not only sexual reproduction of plants is ensured, but also yields are stabilized and genetic variability of crops is maintained, counteracting inbreeding depression and facilitating system resilience. While experiencing rapid environmental change, there is an increased demand for food and income security, especially in sub-Saharan communities, which are highly dependent on small scale agriculture. By combining exclusion experiments, pollinator surveys and field manipulations, this study for the first time quantifies the contribution of bee pollinators to smallholders’ production of the major cash crops, cotton and sesame, in Burkina Faso. Pollination by honeybees and wild bees significantly increased yield quantity and quality on average up to 62%, while exclusion of pollinators caused an average yield gap of 37% in cotton and 59% in sesame. Self-pollination revealed inbreeding depression effects on fruit set and low germination rates in the F1-generation. Our results highlight potential negative consequences of any pollinator decline, provoking risks to agriculture and compromising crop yields in sub-Saharan West Africa.

Management Effects on Woody Species Diversity and Vegetation Structure of Coffee-based Agroforestry Systems in Ethiopia

The effect of Ethiopian coffee production systems on the diversity and composition of woody species and vegetation structure was studied along a management gradient ranging from low to intensive, namely forest coffee, semi-forest coffee, semi-plantation coffee and plantation coffee. Data were obtained from a field survey and secondary sources. A reduction of species diversity and a shift in species composition were found over the range of low, moderate to intensive management systems, together with dominance of a few pioneer tree species in the two most intensively cultivated systems. There was also a structural variation along the management gradient and within semi-forest coffee though not consistent over variables and sites. The dominance of pioneer species can serve as an indicator of ecological status (e.g. a loss of species or a reduction of refuges for forest dwelling organisms) and productivity of such systems because long-term coffee productions and resilience against disturbances (e.g. climate change) can be negatively affected by management intensity.

Prospects for Forest-Based Rural Development

This synopsis provides an outlook for the complex issue of tropical forestry and rural development. It is based on the previous chapters, and incorporates historical facts, rural development politics and policies, and management systems and instruments. The mix between factual and instrumental aspects rules out a simple conceptual framework. In this synopsis the co-evolution model presented at the outset is taken up, to represent the complex reality of tropical forestry and rural development (Fig. 13.1). The highly dynamic and action-oriented character of this outlook is rooted in the discussion of paradigm changes, leading to design elements for a prospective tropical forestry and rural development theory.

The Challenges Facing Forest-Based Rural Development in the Tropics and Subtropics

In spite of decades of unprecedented exploitation of resources, rural areas in the tropics and subtropics still possess vast human, biological, mineral, land, forest and other natural resources that potentially represent a primary source of human and economic development. However, the benefits produced by past development programs and policies often bypassed rural areas. The apparent failure of societies to develop rural areas to the same extent as their urban and metropolitan centers has largely been attributed to a complex set of factors at the level of the natural and the social sub-system at local, national and global scales. In this chapter the authors attempt to provide a comprehensive review of the manifold dimensions of the rural development challenge in forest areas of tropical and subtropical countries. In so doing, the authors draw heavily on empirical evidence published in the pertinent scientific literature.