ABSTRACT
The Conceptual Framework of the Millennium Assessment (MA, 2003) distinguishes between different sets of driving forces that influence changes in ecosystems and their services and therefore also impact on human well-being. These include both direct and indirect drivers, and both exogenous and endogenous drivers. Understanding the different characteristics of these factors is an important step towards devising options for responding to the observed ecosystem change. Biodiversity and ecosystem services are affected by both direct and indirect
drivers. A driver is a natural or human-induced factor that directly or indirectly causes a change in ecosystem services. Direct drivers are those that directly impact on biodiversity and ecosystems, for example, land-use conversion, overexploitation, introduction of invasive species, pollution and climate change. Indirect drivers are those that influence the direct drivers of change, for example, economic and population growth resulting in an increased demand for food, fibre, water and energy and agricultural subsidies that promote increased agricultural production. Consequently, it is important to understand the relationship between the indirect and direct drivers of change, which can combine in different ways. Decision-makers need to be able to identify the drivers that operate in a
system in order to understand conditions and trends of ecosystem services, consequences for ecosystems and human well-being, and possible directions these trends might take in the future, and they also need to be able to identify response options. Understanding the factors that cause changes in ecosystems and their services is essential to the design of interventions that enhance positive and minimize negative effects. Each driver has a spatial and temporal scale over which it changes and over which it has an effect on ecosystem services and
human well-being. Climate change may operate on the spatial scale of a large region; political change may operate at the scale of a nation or a municipal district. Social-cultural change typically occurs slowly, on a timescale of decades, while economic forces tend to occur more rapidly. Because of the variability in ecosystems, their services and human well-being in space and time, there may be mismatches or lags between the scale of the driver and the scale of its effects on ecosystem services. Drivers, which are largely scale-dependent, can be controlled to varying
degrees by decision-makers. Endogenous drivers are largely under the direct control or influence of a decision-maker. Exogenous drivers are largely beyond the direct control or influence of a decision-maker. The most common localscale endogenous drivers are land use and land cover change, introduction of new technology and invasive species. Local-scale exogenous drivers are more varied, ranging from natural drivers (such as climate) to economic policy to infrastructure development. Drivers that are exogenous at one particular scale may be endogenous at another (usually coarser) scale. For example, prices for a particular commodity are usually an exogenous factor for a farmer that he or she has little control over, while a national government can influence the prices the farmer receives by regulating the market for this commodity. Processes and structures can influence the effects of drivers on ecosystem
services. These include natural phenomena as well as social, political and economic factors. The effect of an international trade agreement on food availability, for example, might be changed by national-level agricultural policies or the practices of local institutions. Understanding drivers, their interactions and their consequences for
ecosystem services and human well-being is crucial to the design of effective responses. Drivers often operate within sets of other drivers creating interwoven causal processes of ecosystem change. Causal processes of ecosystem change interact with each other, often in synergistic ways. Although many responses target specific problems with ecosystem services, the nature of complex systems means that such responses can have unintended consequences for the multiple interacting drivers that operate in the system and their effects on ecosystem services. Individual drivers may be difficult to affect without impacting on others, and therefore intervening in interactions between drivers is often a more direct way to achieve a desired outcome and enables a more integrated and holistic approach to ecosystem service management. Actors that effect biodiversity and ecosystem services over a range of spatial
scales need to work together, including:
1. Individuals and communities at the field level; 2. Public and private decision-makers at the local and national levels; and 3. Public and private decision-makers at the regional (for example, the European Union (EU)) and international level, through international conventions and multilateral environmental agreements (for example, the Convention on Biological Diversity (CBD), Ramsar, Cites and the United
Nations Framework Convention on Climate Change (UNFCCC)) and international trade agreements (for example, the World Trade Organization (WTO)).
