Tree diversity in cocoa agroforestry in Ghana

Samuel Kudjo Ahado

Master's thesis

Abstract:

Cocoa cultivation that maintains higher proportions of shade trees in a diverse structure (cocoa agroforestry) is gradually being considered as a sustainable land-use practice that complements the conservation of biodiversity. Our basic hypothesis was that cocoa agroforestry systems can support relatively high tree diversity compared to primary and secondary forest. The objective of this study was to assess the impacts of forest conversion on tree communities by comparing tree species richness, diversity and composition between natural primary and secondary forest and cocoa agroforestry systems. In all we collected data in 15 (25 x 25 m) plots on three land-use systems (5 in cocoa agroforestry 5 in secondary forest and 5 in primary forest) in Bedum in the Western region of Ghana. All trees were identified to species and their height and DBH recorded. Cocoa farmers were also interviewed to ascertain their knowledge about association of cocoa with trees. Our results support the hypothesis that cocoa agroforestry contains relatively high tree species richness and diversity comparable to secondary forest. Although we found higher tree density in primary and secondary forest compared to cocoa agroforestry. The species richness was found the highest in the primary forest. Per the species diversity indexes the species composition of cocoa agroforestry is higher than in secondary forest. Farmers have very good and extensive knowledge about advantages that trees provide for cocoa soil improvement and biodiversity conservation. However we also find that tree species cultivated in cocoa agroforestry are not very different from the species found in primary forest so that seems to partially answer the question "if the relatively high tree diversity and richness can support some of the original faunal diversity found in natural forest". In this context our study forms a good scientific background for the further monitoring of ecological changes in human modified landscape in the Western region of Ghana.

Keywords

Cocoa agroforestry, Cocoa, Ghana, primary forest, secondary forest, species richness, species diversity, biodiversity, tropical rainforest

Language used: English

Date on which the thesis was submitted / produced: 19. 4. 2017

Thesis defence

• Supervisor: doc. Ing. Bohdan Lojka, Ph.D.

Czech University of Life Sciences Prague

Faculty of Tropical AgriSciences

Master programme / field:
Engineering Ecology / Nature Conservation