Loss of Plant Species Diversity Reduces Soil Erosion Resistance

Frank Berendse,Jasper Van Ruijven,Saskia Keesstra,Eelke Jongejans

doi:10.1007/s10021-015-9869-6

Frank Berendse, Jasper Van Ruijven + Show 2 more

Open Access

https://doi.org/10.1007/s10021-015-9869-6

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Abstract

In many estuarine areas around the world, the safety of human societies depends on the functioning of embankments (dikes) that provide protection against river floods and storm tides. Vegetation on land-side slopes protects these embankments from erosion by heavy rains or overtopping waves. We carried out a field experiment to investigate the effect of plant species diversity on soil loss through erosion on a simulated dike. The experiment included four diversity treatments (1, 2, 4, and 8 species). In the third year of the experiment, we measured net annual soil loss by measuring erosion losses every 2 weeks. We show that loss of plant species diversity reduces erosion resistance on these slopes: net annual soil loss increased twofold when diversity declines fourfold. The different plant species had strongly diverging effects on soil erosion, both in the single-species and in the multi-species plots. Analysis of the dynamics of the individual species revealed that the main mechanism explaining the strong effects of plant species diversity on soil erosion is the compensation or insurance effect, that is, the capacity of diverse communities to supply species to take over the functions of species that went extinct as a consequence of fluctuating environmental conditions. We conclude that the protection and restoration of diverse plant communities on embankments and other vegetated slopes are essential to minimize soil erosion, and can contribute to greater safety in the most densely populated areas of the world.

Highlights

The Convention on Biological Diversity of Rio de Janeiro (1993) stressed the importance of biodiversity for ecosystem functions that are essential to mankind
It is important to answer the question of what the consequences of the worldwide losses of plant species diversity (Van Vuuren and others 2006) will be for the erosion resistance on man-made river and sea embankments, and on sloping pastures that provide a significant part of food production in many parts of the world (Pimentel and others 1987)
Our findings show that loss of plant species diversity has important effects on the erosion resistance of slopes

Summary

Introduction

The Convention on Biological Diversity of Rio de Janeiro (1993) stressed the importance of biodiversity for ecosystem functions that are essential to mankind. Examples of such functions are production of clean drinking water, erosion resistance, and regulation of the temperature on the Earth’s surface. Soil erosion resistance is an important feature of undisturbed, non-fertilized ecosystems. In undisturbed forests, erosion losses are 70–2000 times lower than those from arable land and 20–100 times lower than losses from fertilized pastures (Cerdan and others 2010; Kateb and others 2013). It is important to answer the question of what the consequences of the worldwide losses of plant species diversity (Van Vuuren and others 2006) will be for the erosion resistance on man-made river and sea embankments, and on sloping pastures that provide a significant part of food production in many parts of the world (Pimentel and others 1987)

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