Plant Diversity and Carbon Storage Potential in Coffee Agroecosystems of Western Ethiopia

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Date

2019-11-11

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Addis Ababa University

Abstract

Human mismanagement of natural habitats caused the great loss of biodiversity and ecosystem because of their conversion into agricultural landscape. An approach to conserve biodiversity only in protected areas was found to be ineffective. The agricultural matrix also plays great complementary roles for conserving biodiversity. The main objective of this study was to assess the diversity of woody species, vascular epiphytes, and carbon stocks in three coffee management systems across an increasing farmers’ management intensity in selected research areas of Western Wollega, Ethiopia. A total of 72 samples (24 per each management systems) were purposively selected for collecting data on woody species, vascular epiphytes, and soil parameters. Plants were collected following standard herbarium technique and identified in the field and at national herbarium. Diameter at breast height, height, crown diameter and soil data were measured by using different devices. Socio-economic data were collected using a semi-structured questionnaire. Descriptive statistics such as mean, percentage, and standard deviation were used to present the results. A total of 50 woody species and 10 true vascular epiphytes were identified. Cordia africana was found as the most abundant shade tree in coffee agroecosystems. Diversity of woody species was significantly different among the coffee management systems (P <.0001) and altitude ranges (P <.0001), while the pattern was insignificant among the age groups (P=0.7154). Density, basal area, and shade significantly reduced along the increased coffee management intensity. Total carbon stored in garden coffee system was significantly lowest (P=0.036). Carbon stocks stored in soil varied significantly across the increased management and altitude ranges. Stored carbon decreased downward in soil depth. The study found evidence that the intensification of coffee management was not always the source of biodiversity loss; rather, it is an opportunity for conservation of the endangered higher plants and host specific epiphytes. Carbon stock is not always higher in soil, but also in plant biomass of less intensively managed coffee system. Coffee agroecosystems have an intermediate carbon storage potential based on farmers management strategies as long as the preservation of large canopy trees and soil management practices. Therefore, the national and regional governments should recognize the coffee agroecosystems in the design of climate change adaptation and mitigation strategies.

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Keywords

Biomass Carbon, Ecosystem Services, Epiphytes, Management Practices, Shade Trees, Soil Carbon

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