Woody species diversity and important value indices in dense dry forests in Abdoulaye Wildlife Reserve (Togo, West Africa)

Johannes Dietrich Merkel

Abstract

Dry forests are seriously under threats, mostly linked to human disturbance. In Togo where continuous deforestation is ongoing, it important to assess woody species diversity that maintain forest structure and functions. In that concern, this study was carried out in Abdoulaye Wildlife Reserve (AWR) with a specific objective to assess woody species diversity. A total of 258 plant species belonging to 119 genera and 63 families were found in AWR dry forests. Of this total, 67 woody species with 903 individuals and 52 genera were recorded. The highest relative frequencies were recorded by Anogeissus leiocarpa (83.37%), Pouteria alnifolia var. alnifolia (73.37%), Cola gigantea (50%), Diospyros mespiliformis (50%) and Dialium guineense (40%). The lianas species are dominated by Rourea coccinea, Dioscorea dumetorum, Cissus populnea, Dioscorea burkilliana whereas the dominated herbaceous of the undergrowth layer were Anchomanes difformis, Chromolaena odorata, Olyra latifolia and Oplismenus hirtellus. Three stand groups were revealed and the study highlighted trees bushfire and breakage as main threats on species diversity. These human pressures were highest in GIII. Globally, Pielou’s index varied from 0.78 to 0.85. All these groups were dominated by A. leiocarpa. The study suggests conservation strategies to protect woody species against anthropogenic pressures (for example, protection from or reducing the frequency and/or intensity of disturbance, especially woodcutting and bushfires).