Integrating local knowledge with tree diversity analyses to optimize on-farm tree species composition for ecosystem service delivery in coffee agroforestry systems of Uganda

Abstract

Coffee agroforestry systems deliver ecosystem services (ES) critical for rural livelihoods like food but also disservices that constrain livelihoods like fostering coffee-pests. Since such ES are treebased, maximizing ES and limiting constraints requires knowledge on optimizing on-farm tree composition especially trees adapted to local conditions. The study was in three sites along a rainfall gradient in Central Uganda where we: assessed tree diversity in coffee agroforestry; ranked tree suitability for providing ES according to farmers' knowledge; and then proposed an approach for optimizing on-farm tree composition for delivery of ES. We collected data on tree diversity and, farmers' knowledge of tree species and the ES they provide. Farmers ranked ES in order of importance to their livelihoods ('Needs rank') and ranked trees according to suitability for providing ES. Using Bradley Terry modeling, we grouped trees into 'ES groups' according to suitability for providing different ES and ranked 'ES groups' according to tree diversity ('Diversity rank'). Tree-suitability for providing ES and importance of ES to farmers varied with rainfall regime but tree diversity did not match farmers' needs for ES. We propose the FaD-FaN (matching farm tree diversity to farmers' needs) approach for optimizing tree species composition with respect to tree-suitability for farmers' priority ES. Farmers locally prioritize ES needed and identify trees that best serve such ES. The approach then focuses on modifying on-farm tree diversity to match/suit 123Agroforest Syst https://doi.org/10.1007/s10457-017-0172-8 farmers' priority ES. The FaD-FaN approach caters for varying socio-ecological conditions; it's adaptable for other coffee and cocoa-growing areas worldwide.

Ecosystem Services and Importance of Common Tree Species in Coffee-Agroforestry Systems: Local Knowledge of Small-Scale Farmers at Mt. Kilimanjaro, Tanzania

“…Kilimanjaro. Similar studies have been conducted in other East African countries and the differences in findings [15,16,24,25] demonstrate the importance of locally specific investigations.…”

“…Some other studies also show the importance of shade tree species for coffee production is matched with their planting densities [36,42]. Bukomenko, et al [24], however, found a mismatch between ESs that are important for respondents and the trees they have on their fields. Graefe, et al [30] used a similar methodology for cocoa production in Ghana and also reported disparities between higher ranked tree species suitable for cocoa intercropping and their abundance in the northern part of the cocoa belt with marginal conditions for cocoa production.…”

“…At Mt. Elgon (Uganda), farmers rather prioritized ESs such as mulch provision, erosion control and temperature regulation [16], coffee yield, soil moisture enhancement, and quick leaf decomposition in Central Uganda [24]. Differences in the importance of ESs may reflect differences in environmental conditions, as well as market access [16,30].…”

“…This species is favored by farmers in Ethiopia [41,42]. Other Albizia species are considered important for providing multiple ESs in East Africa, such as, but not limited to, mulch, shade, improvement of microclimate, coffee yield and soil moisture in Uganda [16,24]. Unfortunately some Albizia species are also alternative hosts for black coffee twig borer in the closely related Robusta coffee (Coffea canephora Pierre ex Froehn.)…”

Influence of shaded systems on Xylosandrus compactus infestation in Robusta coffee along a rainfall gradient in Uganda

“…Therefore, removing A. chinensis from coffee plots and increasing the density of sap exuding trees should reduce X. compactus infestations, although this is not without caution: removing one host to a generalist pest such as X. compactus , which thrives on many hosts, may not significantly affect their population (Ratnadass et al ., ). Nonetheless, farmers choosing to eliminate A. chinensis should aim to replace it with suitable trees that provide similar ecosystem services and preferably exude sap (Bukomeko, ).…”