Alfred Oteng-Yeboah

Science for managing ecosystem services: Beyond the Millennium Ecosystem Assessment

The Millennium Ecosystem Assessment (MA) introduced a new framework for analyzing social–ecological systems that has had wide influence in the policy and scientific communities. Studies after the MA are taking up new challenges in the basic science needed to assess, project, and manage flows of ecosystem services and effects on human well-being. Yet, our ability to draw general conclusions remains limited by focus on discipline-bound sectors of the full social–ecological system. At the same time, some polices and practices intended to improve ecosystem services and human well-being are based on untested assumptions and sparse information. The people who are affected and those who provide resources are increasingly asking for evidence that interventions improve ecosystem services and human well-being. New research is needed that considers the full ensemble of processes and feedbacks, for a range of biophysical and social systems, to better understand and manage the dynamics of the relationship between humans and the ecosystems on which they rely. Such research will expand the capacity to address fundamental questions about complex social–ecological systems while evaluating assumptions of policies and practices intended to advance human well-being through improved ecosystem services.

Chemical constituents and antimicrobial activity of medicinal plants from Ghana: Cassia sieberiana, Haematostaphis barteri, Mitragyna inermis and Pseudocedrela kotschyi

The antimicrobial activity of the sequential n‐hexane, acetone and 50% aqueous methanol extracts of leaves, stem bark and roots of four species of medicinal plants, Cassia sieberiana DC. (Leguminosae), Haematostaphis barteri Hook. f. (Anacardiaceae), Mitragyna inermis (Willd.) O. Kuntze (Rubiaceae) and Pseudocedrela kotschyi (Schweinf.) Harms (Meliaceae), from Ghana were tested against Bacillus subtilis, Pseudomonas syringae and Cladosporium herbarum using TLC direct‐autobiographic methods. Extracts from leaves, stem bark and roots of the four species gave a positive result against at least one test organism. Twelve of the 36 extracts were active against B. subtilis, four extracts were active against P. syringae and six were active against C. herbarum. Preliminary chemical analysis revealed the presence of flavonoids, stilbenes and alkaloids. This is the first report of a stilbene from the Anacardiaceae. Copyright

The Unique Character of Traditional Forest-Related Knowledge: Threats and Challenges Ahead

This chapter reflects on the major findings of the lead authors of this book regarding traditional forest-related knowledge (TFRK) using five criteria for distinguishing the unique character of traditional knowledge: (1) its attention to sustainability; (2) relationships to land; (3) identity; (4) reciprocity; and (5) limitations on market involvement. Following an explanation of these criteria, we discuss the definition of “traditional forest-related knowledge,” with some remarks about its resilience. We then consider threats to the maintenance of TFRK, how other definitions of sustainability differ from that used in TFRK, and how relationships that holders of this knowledge have to their land have been weakened and their identities challenged. We highlight how the key role of reciprocity, or the sharing of the utilization of land, is undermined by individualistic motives which are promoted by the global expansion of modern markets (for commodities, ecosystems services and for knowledge itself), which also challenge the policies of traditional knowledge holders to keep market influences under control. We then focus on two notable, but often ignored, contributions of TFRK (and the holders of this knowledge) to forest management today, specifically the preservation of biodiversity, and traditional knowledge-based shifting cultivation practices and their importance for both sustainable management of forests and food security. Finally, we consider enabling conditions for the preservation and development of TFRK, and examine the role of the scientific community in relation to TFRK and principles for successful collaboration between traditional knowledge holders and scientists.

(E)-Anethole as a Major Essential Oil Constituent of Clausena anisata

ABSTRACT In the course of our comprehensive investigation of the oils of the leaves of Clausena anisata from three West African countries, we have observed that, on the basis of its oil constituents, C. anisata can be classified into three major chemovarieties. Two of these chemovarieties have been observed in collections in Ghana, Togo and Benin. One contains mainly methyl chavicol (80–100%), and between one and ten other constituents, while the other contains a large number of constituents (up to 50), varying in concentration from 0.2% to about 20%. These include limonene, β-phellandrene, β-caryophyllene, α-humulene and germacrene D. However, there is a third collection in Ghana, positively identified as C. anisata, which yields between 85–100% of(E)-anethole as its major essential oil constituent. The chemovariation does not appear to be dependent on seasonal or geographical factors. The plants containing either methyl chavicol or (E)-anethole give very high yields of oil while those with several const...

(E)- and (Z)-foeniculin, constituents of the leaf oil of a new chemovariety of Clausena anisata

Abstract The leaf oils of Clausena anisata Hook. f. collected from Pokuase, Ghana, were found to contain (E)-foeniculin as a major constituent (>78%) in 17 of 19 samples. (E)-anethole was the major constituent of the two other samples (57% and 67%) with (E)-foeniculin as the second most important compound (38% and 29%). The identity of the new natural product (Z)-foeniculin, present in small amounts (0.2-1.4%), was based on a comparison of retention indices and mass spectra with those of a synthesized sample whose spectroscopic data, reported here for the first time, are in agreement with the proposed structure. Two other minor constituents were identified as the rarely encountered natural products dictagymnin (1-20%) and 4-(3-methyl-2-butenyl)oxybenzaldehyde (0-0.2%).