Comment:

Ecosystems provide a range of potential hazard mitigation services. These can derive from ecosystem processes in situ at the sites where risk occurs or elsewhere (e.g. upstream). The hazard mitigation services currently considered by Co$tingNature are landslide/erosion control, coastal protection, flood storage/mitigation, flow regulation). Landslide/erosion control is considered to be provided by the presence of vegetation, especially trees and by regulated land use . Therefore the landslide/erosion control service is assumed to scale with the proportion of upstream land that is tree-covered (Copernicus, 2015) or protected (WDPA, 2016). The upstream tree cover index is also assumed to control the flow regulation service at a point. Flood control is assumed to be provided by the upstream fractional cover of water bodies (Mulligan, 2010), wetlands (Mulligan, 2010), floodplains (Mulligan, 2010) and tree canopies (Mulligan, 2010), all of which provide storage capacity for flood waters. Coastal protection is assumed to be provided in coastal areas (within 2000m of the coast and from 0-30m above mean sea level) by the cover of mangroves (Spalding et al., 1997) and by wetlands (Lehner et al., 2004) in those areas. Total potential hazard mitigation services is thus the sum of coastal protection, flood protection, flow regulation and soil erosion/landslide control mitigation services.