Changes in Regulating Ecosystem Services following Establishing Exclosures on Communal Grazing Lands in Ethiopia: A Synthesis

Wolde Mekuria

doi:10.1155/2013/860736

Abstract

In four separate studies undertaken in the northern highlands of Ethiopia, changes in regulating ecosystem services, economic viability, and the perception of local communities following establishing exclosures on communal grazing lands were investigated. Replicated 5-, 10-, 15-, and 20-year-old exclosures were selected and paired each exclosure with an adjacent grazing land. All exclosures displayed higher ecosystem services than communal grazing lands. Differences between exclosures and grazing lands varied between 29 (±4.9) and 61 (±6.7) Mg C ha−1 for ecosystem carbon stock (ECS), 2.4 (±0.6) and 6.9 (±1.8) Mg ha−1 for total soil N stock, and 17 (±3) to 39 (±7) Kg ha−1 for the available P stock, and all differences increased with exclosure duration. Differences in plant species richness and biomass between an exclosure age and communal grazing land were higher in oldest than in youngest exclosures. Over a period of 30 years, sequestered carbon dioxide was 246 Mg ha−1, total soil nitrogen increased by 7.9 Mg ha−1, and additional available phosphorous stocks amounted to 40 kg ha−1. The Net Present Value of exclosures ecosystem services under consideration was about 28% (837 US$) higher than alternative wheat production indicating that exclosures are competitive to alternative land uses. There are substantial opportunities to mobilize the local communities in efforts to establish exclosures, given that more than 75% had a positive view on exclosures effectiveness to restore degraded ecosystems. Establishing exclosures on communal grazing lands can be effective for restoring degraded ecosystems and the services that they provide.

Highlights

Land degradation, a decline of the biological or economic productivity of land resources resulting from land uses or processes arising from human activities, has a strong impact on ecosystem’s services [1]
This paper presents a synthesis of the regulating ecosystem services of exclosures based on four independent studies that are conducted in the northern highlands of Ethiopia
The results of the present study confirm that establishment of exclosures on degraded communal grazing lands in the Northern highlands of Ethiopian is a viable option to restore ecosystem carbon stock (ECS), soil properties and nutrients and degraded native vegetation

Summary

Introduction

A decline of the biological or economic productivity of land resources resulting from land uses or processes arising from human activities, has a strong impact on ecosystem’s services [1]. Land degradation may have impact on ecosystem’s services through either land use conversion and/or inappropriate land management practices [2]. As part of the efforts to restore degraded ecosystems and improve the services that they provide, communities in the highlands of Ethiopia started to establish exclosures on communal grazing lands about three decades ago [4]. Exclosure management and protection have proven to be effective because of the participation of the local communities in the establishment of exclosures and the responsibility of local authorities for management and control of the area [6, 7]. Farmers’ motivation for establishing exclosure and Journal of Ecosystems devising bylaws for managing exclosures in the northern highland of Ethiopia is deeply rooted in the political struggle of the Tigray People Liberation Front (TPLF) and follows a participatory process in most cases [9, 10]. The size of an exclosure ranges from as small as 1 ha up to 700 ha [5]

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Conclusion