Tree species diversity and abundance in coffee farms adjacent to areas of different disturbance histories in Mabira forest system, central Uganda

Samson Gwali,David Hafashimana,Hillary Agaba,Paul Balitta,Fabrice Pinard,Anne Kuria,Joseph Nkandu,Fergus Sinclair

doi:10.1080/21513732.2015.1050607

Abstract

Coffee production in Uganda is done on small-scale farms containing a very significant tree component. However, there is little information on how tree species abundance, richness and diversity change in coffee farms as distance from forest changes. The main objectives of this study, therefore, were to assess (a) abundance and (b) diversity of tree species in the coffee production systems in proximity to disturbed and undisturbed forest around Mabira forest, one of Uganda’s Robusta coffee-growing areas. Seventy-nine 0.1 ha plots were established in nine villages close to undisturbed and disturbed forest, and over 5 km from the forest. A total of 875 trees belonging to 63 species were recorded. There was significant similarity in species composition among the three study sites (analysis of similarity R = 0.09, p < 0.01; analysis of variance: F3,12 = 0.353, p = 0.79). Non-metric dimensional scaling supported these findings (stress value = 0.224 at k = 2) and showed that tree species composition in the three proximity categories was very similar. These results demonstrate that tree species composition and diversity is similar in coffee farms regardless of their distance from the nearest natural forest and forest exploitation history.

Highlights

The practice of tree integration in coffee production systems plays a very important role in biodiversity conservation (Perfecto et al 1996; Albertin & Nair 2004; Rice 2008; Correia et al 2010)
52% of the species recorded occurred inside Mabira forest, comparing closely with a similar study by Boffa et al (2008) who recorded 46% of woody species that occurred both in Mabira forest and surrounding coffee farms
There were no species in the coffee farms that can be considered endemic to Mabira forest

Summary

Introduction

The practice of tree integration in coffee production systems plays a very important role in biodiversity conservation (Perfecto et al 1996; Albertin & Nair 2004; Rice 2008; Correia et al 2010). Farmers maintain some indigenous and grow exotic tree species to minimize competition with coffee plants while helping to ameliorate climate changes, maintain soil fertility and provide important goods such as timber, fuel wood and fruit (Beer et al 1997; Albertin & Nair 2004; Bandeira et al 2005; Soto-Pinto et al 2007) These ecosystem goods and services help to lower the cost of production as well as diversify farm production and benefits (Beer et al 1997; Peeters et al 2003; Albertin & Nair 2004; Soto-Pinto et al 2007; Méndez et al 2007; Ipulet & Kasenene 2008; Isabirye et al 2008; Rice 2008)

Objectives

Methods

Results

Discussion

Conclusion