The vulnerability of ecosystem services to land use change

Abstract

Terrestrial ecosystems provide a number of vital services for people and society, such as biodiversity, food, fibre, water resources, carbon sequestration, and recreation. The future capability of ecosystems to provide these services is determined by changes in socio-economic characteristics, land use, biodiversity, atmospheric composition and climate. Most published impact assessments do not address the vulnerability of the human–environment system under such environmental change. They cannot answer important multidisciplinary policy relevant questions such as: which are the main regions or sectors that are vulnerable to global change? How do the vulnerabilities of two regions compare? Which scenario is the least, or most, harmful for a given region or sector?

The ATEAM project (Advanced Terrestrial Ecosystem Analysis and Modelling) uses a new approach to ecosystem assessment by integrating the potential impacts in a vulnerability assessment, which can help answer multidisciplinary questions, such as those listed above. This paper presents the vulnerability assessment of the ATEAM land use scenarios. The 14 land use types, discussed in detail by Rounsevell et al. (this volume), can be related to a range of ecosystem services. For instance, forest area is associated with wood production and designated land with outdoor recreation. Directly applying the vulnerability methodology to the land use change scenarios helps in understanding land use change impacts across the European environment. Scatter plots summarising impacts per principal European Environmental Zone (EnZ) help in interpreting how the impacts of the scenarios differ between ecosystem services and the European environments.

While there is considerable heterogeneity in both the potential impacts of global changes, and the adaptive capacity to cope with these impacts, this assessment shows that southern Europe in particular will be vulnerable to land use change. Projected economic growth increases adaptive capacity, but is also associated with the most negative potential impacts. The potential impacts of more environmentally oriented developments are smaller, indicating an important role for both policy and society in determining eventual residual impacts.

Introduction

Many aspects of our planet are changing rapidly due to human activities and these changes are expected to accelerate during the next decades (IPCC, 2001a, IPCC, 2001b, IPCC, 2001c). For example, forest area in the tropics is declining (Geist and Lambin, 2002), many species are threatened with extinction (Thomas et al., 2004), and rising atmospheric carbon dioxide results in global warming (IPCC, 2001a, IPCC, 2001b, IPCC, 2001c). Many of these changes will have an immediate and strong effect on agriculture, forestry, biodiversity, human health and well-being, and on amenities such as traditional landscapes (Watson et al., 2000, UNEP, 2002). Furthermore, a growing global population, with increasing per capita consumption of food and energy, are expected to continue emitting pollutants to the atmosphere, resulting in continued nitrogen deposition and eutrophication of environments (Galloway, 2001, Alcamo, 2002). In the face of these changes, it is important to integrate and extend current operational systems for monitoring and reporting on environmental and social conditions (cf. Kates et al., 2001). Over the last decades many people have become increasingly aware of these environmental changes, such that they are now commonly recognised as ‘global change’ (Steffen et al., 2001). Many research projects and several environmental assessments are currently addressing these concerns at all relevant scales, frequently in multidisciplinary collaborations. However, integrating this wealth of information across disciplines remains a considerable challenge (Millenium Ecosystem Assessment, 2003).

This paper aims to quantify global-change concerns, focusing specifically on changes associated with scenarios of land use change, by defining and estimating vulnerabilities. Both the vulnerability concept (Metzger et al., 2004, Metzger, 2005) and the land use change scenarios (Rounsevell et al., 2005, Ewert et al., 2005, Kankaanpaa and Carter, 2004; Rounsevell et al., this volume) described in this paper were developed as part of the ATEAM project (Advanced Terrestrial Ecosystem Analysis and Modelling). Detailed information about the project can be found on its website (http://www.pik-potsdam.de/ateam).

Amongst the many aspects of global change, land use change has been highlighted as a key human-induced affect on ecosystems (Turner et al., 1997, Lambin et al., 2001). Land use has been changing since people first began to manage their environment, but the changes in Europe over the past 50 years have been especially important. An increasingly urbanised society has led to the major development of settlements, improved technology to a changing role for agriculture and new aspirations have lead to land being used for recreation and leisure. Such land use change directly influences the provision ecosystem services (e.g. provision of food and timber, climate regulation, nutrient cycling, and cultural identity) (Daily, 1997, Millenium Ecosystem Assessment, 2003, Reid et al., 2005). In the vulnerability concept used in this paper, the sustainable supply of ecosystem services is used as a measure of human well-being under the influence of global change threats, as indicated by the Millenium Ecosystem Assessment (2003). This is similar to the approach used by Luers et al. (2003) in looking at the vulnerability of Mexican farmers to decreasing wheat yields arising from climate damage and market fluctuations.

The Synthesis chapter (Smith et al., 2001) of the Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report (TAR) recognised the limitations of traditional impact assessments, where a few climate-change scenarios are used to assess the response of a system at a future time. Smith et al. (2001) challenged the scientific community to move toward more transient assessments that are a function of shifting environmental parameters (including climate) and socio-economic trends, and explicitly include the ability to innovate and adapt to the resulting changes. A step towards meeting this challenge is their definition of “vulnerability”:

Vulnerability is the degree to which a system is susceptible to, or unable to cope with, adverse effects of climate change, including climate variability and extremes (IPCC TAR).

Although this definition addresses climate change only, it already includes susceptibility, which is a function of exposure, sensitivity, and adaptive capacity. The vulnerability concept developed for ATEAM is a further elaboration of this definition and was developed especially to integrate results from a broad range of models and scenarios. Projections of changing supply of different ecosystem services and scenario-based changes in adaptive capacity are integrated into vulnerability maps for different socio-economic sectors (agriculture, forestry, water management, energy, and nature conservation) (Schröter et al., 2005a, Metzger et al., 2004). These vulnerability maps provide a means of making comparisons between ecosystem services, sectors, scenarios and regions to tackle questions such as:

• Which regions are most vulnerable to global change?

• How do the vulnerabilities of two regions compare?

• Which sectors are the most vulnerable in a certain region?

• Which scenario is the least harmful for a sector?

The term vulnerability was thus defined in such a way to include both the traditional elements of an impact assessment (i.e. potential impacts of a system to exposures), and adaptive capacity to cope with the potential impacts of global change (Turner et al., 2003, Schröter et al., 2005b).

The following sections first summarise the concepts of the spatially explicit and quantitative framework that was developed for a vulnerability assessment for Europe. It is explained how various land use changes were coupled to changes in ecosystem service provision, and the findings are discussed per principal European Environmental Zone.