Indigenous knowledge on shade tree in coffee farms of Zegie Peninsula and nearby islands of Lake Tana, Ethiopia: Implications for sustainable agroforestry and biodiversity conservation

Background : Indigenous knowledge underpins the sustainability of coffee-based agroforestry systems through informed shade tree selection and management. However, such knowledge remains insufficiently documented in northwestern Ethiopia, particularly in culturally protected landscapes such as the Zegie Peninsula and the monastic islands of Lake Tana. This study was designed to explore indigenous knowledge on shade tree selection among coffee producers and assess future implications for sustainable agroforestry and biodiversity conservation. Methods : Ethnobotanical data were collected from January to June 2024 using semi-structured interviews, focus group discussions, guided field walks, and participant observation. A total of 130 informants, including farmers, monks, and priests, were involved. Free listing, pairwise ranking, preference ranking, and direct matrix ranking were applied to identify priority species, selection criteria, and management practices. The collected data were analyzed using descriptive statistics and qualitative content analysis by using Microsoft Excel 2013. Results : Farmers applied multiple ecological and cultural criteria when selecting shade trees. The most frequently cited criteria were effects on coffee yield and quality (86%), litter contribution to soil fertility (78%), and canopy characteristics for light regulation (73%). Albizia schimperiana , Ehretia cymosa , Cordia africana , and Millettia ferruginea were the most preferred species due to their moderate shade, rapid litter decomposition, and low belowground competition. Croton macrostachyus and Celtis africana were widely avoided because of perceived negative effects on coffee health. Shade tree preferences varied by gender, age, and site, reflecting differences in livelihood priorities and ecological knowledge. Indigenous management practices, including pruning, pollarding, coppicing, and retention of sacred trees, were widely practiced. Monasteries functioned as key custodians of indigenous tree species through long-standing religious norms. Conclusions : Indigenous knowledge in the Zegie Peninsula represents a context-specific and ecologically robust foundation for coffee agroforestry. Integrating producers’ knowledge into extension services and conservation planning can enhance sustainable coffee production and biodiversity conservation in Afromontane landscapes.