Conserving the Birds of Uganda’s Banana-Coffee Arc: Land Sparing and Land Sharing Compared

Mark F Hulme,Juliet A Vickery,Ben Phalan,Derek E Pomeroy,Dan E Chamberlain,Dianah Nalwanga,David Mushabe,Rhys E Green,Simon Bolwig,Philip W Atkinson,Raymond Katebaka,Dorian Q Fuller

doi:10.1371/journal.pone.0054597

Abstract

Reconciling the aims of feeding an ever more demanding human population and conserving biodiversity is a difficult challenge. Here, we explore potential solutions by assessing whether land sparing (farming for high yield, potentially enabling the protection of non-farmland habitat), land sharing (lower yielding farming with more biodiversity within farmland) or a mixed strategy would result in better bird conservation outcomes for a specified level of agricultural production. We surveyed forest and farmland study areas in southern Uganda, measuring the population density of 256 bird species and agricultural yield: food energy and gross income. Parametric non-linear functions relating density to yield were fitted. Species were identified as “winners” (total population size always at least as great with agriculture present as without it) or “losers” (total population sometimes or always reduced with agriculture present) for a range of targets for total agricultural production. For each target we determined whether each species would be predicted to have a higher total population with land sparing, land sharing or with any intermediate level of sparing at an intermediate yield. We found that most species were expected to have their highest total populations with land sparing, particularly loser species and species with small global range sizes. Hence, more species would benefit from high-yield farming if used as part of a strategy to reduce forest loss than from low-yield farming and land sharing, as has been found in Ghana and India in a previous study. We caution against advocacy for high-yield farming alone as a means to deliver land sparing if it is done without strong protection for natural habitats, other ecosystem services and social welfare. Instead, we suggest that conservationists explore how conservation and agricultural policies can be better integrated to deliver land sparing by, for example, combining land-use planning and agronomic support for small farmers.

Highlights

Increases in human population and per capita consumption are likely to lead to greatly increased agricultural demand over at least the 40 years [1], which could lead to further habitat destruction, loss of ecosystem services, ecosystem simplification and species loss [2]
Land sparing gave higher total populations of more of the loser species than did land sharing at all production targets, but the proportion of loser species doing best with land sparing increased as the production target increased
Land sharing gave higher total populations of more of the winner species than did land sparing at all production targets

Summary

Introduction

Increases in human population and per capita consumption are likely to lead to greatly increased agricultural demand over at least the 40 years [1], which could lead to further habitat destruction, loss of ecosystem services, ecosystem simplification and species loss [2] This has raised the question of how food production and biodiversity conservation can best be reconciled [3,4,5]. Some studies have cast doubt on the effectiveness of land sharing initiatives, in both temperate and tropical areas [14,15,16] This is both because wildlife-friendly farmland often offers a poor substitute habitat, for the most sensitive species, and because it often entails a yield penalty and requires a greater area to produce any given amount of food (but see criticism of this interpretation of the evidence in [17])

Methods

Results

Discussion

Conclusion