For forests and other terrestrial habitat types the patch size distribution of habitats may be derived from vegetation information systems. For river fragmentation, defined as the interruption of a rivers natural flow by dams, inter-basin transfers or water withdrawal, fragmentation can be assessed based on number, placement and amount of water stored behind dams. Description: The fragmentation of habitats caused by human activities has significant, largely negative implications for their native biodiversity, through the effects of area reduction, edge exposure and isolation, as well as through interruption of ecosystem processes and associated ecosystem degradation.