By affecting evapotranspiration and influencing how water is routed and stored in a basin, forests, wetlands and floodplains play a crucial role in the hydrological cycle. Although they are widely attributed a major role in regulating flows (i.e., both attenuating floods and maintaining flow during dry periods), these services are rarely factored into the planning and management of water resources. One reason for the failure to include them is lack of understanding. Very often the extent to which natural regulating functions really occur is unclear. Against this background, this report describes a simple, pragmatic approach for quantifying the flow regulating functions of natural ecosystems. The method has been applied at 14 locations in the Zambezi River Basin.

This synthesis focuses on estimates of biodiversity change as projected for the 21st century by models or extrapolations based on experiments and observed trends. The term "biodiversity" is used in a broad sense as it is defined in the Convention on Biological Diversity to mean the abundance and distributions of and interactions between genotypes, species, communities, ecosystems and biomes. This synthesis pays particular attention to the interactions between biodiversity and ecosystem services and to critical "tipping points" that could lead to large, rapid and potentially irreversible changes. Comparisons between models are used to estimate the range of projections and to identify sources of uncertainty. Experiments and observed trends are used to check the plausibility of these projections.

One of the major innovations of the Millennium Ecosystem Assessment is the incorporation of local and regional assessmentsù33 in allùin a global portrait of the planetÆs health. It is the first global assessment of ecosystems to include not only a diversity of ecosystems, but to draw on a wide range of cultural orientations and intellectual traditions, including those of indigenous peoples. The Sub-global Assessments Working Group integrated information from multiple sources and found that biophysical factors such as land-use change, climate change and variability, pollution, and invasive species have a significant effect on human well-being across cultures. For example, in places where there are no other social safety nets, diminished human well-being tends to increase immediate dependence on ecosystem services, which can damage the capacity of those local ecosystems, which in turn appears to increase the probability of natural disaster or conflict. Representing the baseline and framework for ongoing assessments of ecosystem and human well-being on a variety of scales around the world, Multiscale Assessments provides students, researchers, and policy-makers with the most comprehensive methodology for assessing ecosystems at local, national, and regional scales.