Protecting habitats in low-intensity tropical farmland using carbon-based payments for ecosystem services

Robert W Davies,Ieuan Lamb,Oscar Morton,Kwame Boafo,David P Edwards,David Lawson,Luke Nelson,John W Mallord

doi:10.1088/1748-9326/ac3030

Abstract

Tropical land-use change for agricultural expansion is the primary driver of global biodiversity decline. Efforts to stem this decline often focus on protecting pristine habitats or returning farmland to forest, yet such approaches fail to protect vulnerable taxa reliant on habitats within low-intensity farmland. We assess the economic viability of carbon-based payments for ecosystem services (PES) to protect farmland trees and fallowing in Ghana, which provide vital wintering sites for imperiled Afro-palearctic migrant birds and enhance landscape-level carbon storage. We estimate the carbon breakeven prices (BEPs) associated with alternative agricultural management scenarios that protect existing farmland trees. BEPs associated with tree protection on existing farmland were very low, ranging from US$2.49 to US$6.45 t−1 CO2. Extending and reintroducing fallow periods also carried competitive BEPs, US$4.67—US$15.45 t−1 CO2, when combined with the protection of 50 trees per hectare. Accounting for leakage and economic uncertainty increased BEPs considerably, but scenarios protecting farmland trees and extending fallow periods remained below EU Emissions Trading Scheme prices. Protecting low-intensity farmland habitats and associated biodiversity is cost-effective under carbon-based PES. Implementation should be combined with efforts to close yield gaps, providing greater local food security and resilience.

Highlights

Agricultural expansion is the greatest threat to global biodiversity (Laurance 2007)
We show that protecting existing farmland trees using carbon-based payments for ecosystem services (PES) schemes offers a cost-effective method to conserve important tropical farmland habitats
Encouraging the use of fallow periods and protecting farmland trees offers a win-win by protecting at-risk species and reducing carbon emissions associated with agricultural expansion and intensification

Summary

Introduction

Agricultural expansion is the greatest threat to global biodiversity (Laurance 2007). With global population and food demand projected to continue rising to at least 2050 (Tilman et al 2011), agricultural expansion and intensification will persist, largely to the detriment of global biodiversity (Laurance et al 2014). Conservation efforts often seek to prevent or reverse tropical agricultural expansion by prohibiting the clearance of forests (Peres 2005) or encouraging forest regrowth on abandoned agricultural land (Gilroy et al 2014). Sparing primary tropical forest from conversion or allowing secondary forest regrowth on abandoned farmland via agricultural intensification will conserve more biodiversity than protecting wildlife within farmland (land sharing) (Phalan et al 2011, Edwards et al 2021). In areas with a long history of human disturbance a hybrid ‘three-compartment’ approach, whereby some low-intensity farmland is retained alongside natural habitat on land that is spared as result of highintensity agriculture, allows the persistence of species reliant on both natural habitat and low-intensity farmland (Feniuk et al 2019)

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