RESUMO
Agroforestry has been recognized as an effective circa citum conservation strategy in Ethiopia. Despite progress in the recent past, there has been very little research characterizing the management strategies of farmers for agroforestry practices (AFP) and quantifying their contribution to biodiversity conservation. We (i) characterized the management strategies of farmers for agroforestry practices and (ii) assessed the floristic composition, diversity, and structure of woody species in agroforestry practices in Northwestern Ethiopia. We interviewed farm owners to gather information on the management strategies of agroforestry practices. We also collected biophysical data using quadrats established in 126 fields selected from homegardens (HG), coffee-based (CS), and Rhamnus prinoides (Locally Gesho)-based practices. A total of 83 trees and shrubs (76 % native and 24 % non-native) from 40 families and 47 genera recorded in the study area. The results indicate that AFPs represent diverse vertical and horizontal management strategies, and plant functions, which vary among AFPs and wealth status. The results suggest the potential of agroforestry practices for supporting livelihoods and biodiversity conservation. Farmers' management practices and strategies affect the species diversity of AFPs. The mean height (m), basal area (m2 ha-1), and diameter at breast height (cm) varied among AFPs. The average stem density ha-1 as well as species richness per farm significantly varied among AFPs and wealth status. Richness, Shannon, and Simpson's diversity varied among HGs in the study sites. In the Lay Armachiho district, species richness, Shannon, and Simpson's diversity significantly varied (P < 0.05) among agroforestry practices. Our study suggests management strategies and household wealth status that affect the diversity of woody plants in AFPs should be consider to improve biodiversity conservation in agricultural landscapes. Since AFPs play a vital role in biodiversity conservation that is part of a bigger conservation strategy, the suggestion of AFPs to apply in Ethiopia is proposed. To advance the overall contribution, further studies on the optimization of technical, socio-economic and environmental (including density and diversity) performance of agroforestry practices is needed.
RESUMO
BACKGROUND: Agroforestry (AF) is an ancient tradition in Ethiopian dryland farming system. Several studies have examined system design, soil fertility management and system interactions, but the biodiversity and mitigation aspects of climate change have received less focus. We assessed the diversity of woody species, biomass carbon (C), and soil organic carbon (SOC) stock associated with indigenous dryland AF practices. A total of 197 smallholder farmers representing four AF practices (home garden, parkland, boundary plantation, and woodlot) from lowland, midland, and highland areas were systematically selected. The inventory of woody species was carried out on each farm's randomly formed plot. RESULTS: We identified a total of 59 woody species representing 48 genera and 32 families. Shannon diversity index (H') was highest in home garden and parkland AF, while woodlots had the highest mean total stock of biomass C (31 Mg C ha-1). C stocks for smallholding systems (total biomass C and SOC 0-60 cm) ranged from 77-135 Mg ha-1. Total biomass C stocks were significantly correlated with abundance (Spearman r = 0.333; p = 0.002) but biomass components were not significantly correlated with H'. SOC soil depth stock (0-60 cm) was positively and significantly associated with H' (Spearman r = 0.291 & 0.351; p < 0.01). CONCLUSIONS: We report greater species richness in home garden and parkland AF systems than in woodlots. While parkland AF produce lower biomass and SOC stock relative to other AF systems. The strategic use of home gardens and boundary planting can improve tree diversity and carbon storage in Ethiopian dryland ecosystems.
