Introduction

In Chapter 3, the variation in ecosystem processes and functions was described using the plant functional trait approach. Due to variability in plant functional traits and other environmental conditions, as well as variation in human influence on ecosystems, the supply of ecosystem services is not homogeneously distributed across space. Besides spatial variation in the supply of ecosystem services, spatial variation in socioeconomic conditions makes the demand of ecosystem services dependent upon location as well. To understand the role of this spatial variation many ecosystem service assessments use observations, measurements, and models to create ecosystem service maps. Especially in the last couple of years an exponential increase has been observed in research, papers, and reports focused on mapping of ecosystem services. Ecosystem services can be mapped using various methods, of which applicability depends upon data availability, scope of the study, and time constraints. Regulating services are most commonly mapped, followed by provisioning services. The most frequently studied individual ecosystem services are climate regulation and food production (Martínez-Harms and Balvanera, 2012), and when multiple ecosystem services are mapped food production is almost always included (Crossman et al., 2013). Moreover, these studies vary in their scale from the global to the local level, vary in the type and number of ecosystem services incorporated, and map supply, demand, or a combination of both.

Introduction

In this chapter we look at the costs and benefits of three possible interventions that would enhance the planet's biodiversity and improve its ecosystems over the next forty years. The results are based on a study carried out across four research institutes and coordinated by the Scottish Agricultural College (Hussain et al., 2011) that combined a global biophysical model (IMAGE-GLOBIO), which analyzed the biophysical impacts of different development scenarios compared to the counterfactual, with a set of valuation studies that placed monetary values on the outcomes resulting from the different policy options in terms of biodiversity and ecosystem services (ESSs).

While reference is frequently made in the popular press to biodiversity losses, in practice it is difficult to quantify and value them. There are several studies that attempt to do this in specific cases but no one has successfully estimated the value of the loss of biodiversity at a global level. This is because the links between biodiversity and biolo-gical systems and the economic and social values that they support are extremely complex. Even the measurement of biodiversity is problematic, with a multi-dimensional metric regarded as appropriate (Purvis and Hector, 2000; Mace et al., 2003), but with further work considered necessary to define the appropriate combination.