Chapter 3 Measuring biophysical quantities and the use of ... - TEEB

Figure 6:Water availability in Southern Africa expressed as relative to demand for waterSource: Scholes and Biggs 2004Both of these examples reflect the importance of thresholds highlighted in the MA. Ecosystemservice change is seldom linear or independent and can often be accelerating, abrupt andpotentially irreversible (MA 2005b). The loss of biodiversity and increasing pressures fromdrivers of ecosystem change increase the likelihood of these non-linear changes. While science isincreasingly able to predict some of these risks and non-linearities, predicting the thresholds atwhich these changes will happen generally is not possible. Users of indicators and assessments ofecosystem change and its consequences need to bear this in mind, and where possible to reflectknown or possible ecological and social thresholds and not to assume linear relationships betweenbiodiversity loss and its consequences.4 Link to valuation and further workThe flow of ecosystem services from point of production to point of use is influenced by bothbiophysical (e.g. currents, migration) and anthropogenic (e.g. trade, access) processes whichinfluence the scale of service flow from locally produced and used services (e.g. soil production)to globally distributed benefits (e.g. carbon sequestration for climate regulation). The flow ofbenefits and scale of flows influences the value of the service due to changes in demand andsupply which vary spatially and temporally. Use of the service is intrinsically a human centeredprocess relying largely on socio-economic data and to a lesser degree on biophysical information.Information will include the distribution of users, the socio-economic circumstances of users,37