Using Googleearth, a virtual imaging platform, for ecosystem services-based river assessment.

A methodology for reach-based river ecosystem service assessment of eight ecosystem functions using remote sensing via Google Earth is presented. The number of publications addressing Google Earth and ecosystem services has grown significantly since 2005, yet this powerful remote sensing platform remains under-used in river science. Theoretical linkages between 18 riverscape fluvial features, attributes and land cover types, observable and measurable on Google Earth, and resultant river ecosystem service delivery are central to the methodology. Using this framework, we build on earlier ecosystem service conceptual models to develop a rules-based scoring approach and apply it to three rivers of differing size and character from source to mouth. The aim was to devise a robust ecosystem service assessment tool applicable to any ecoregion and to rivers of any size, degree of human modification and character. Reach or sector scales are river length dependent. The minimum reach scale recommended is 500 m, and a 10 km sector length was used on the longest of our three rivers. Two key metrics, the individual ecosystem service score and the total ecosystems service score, are derived at the river reach scale from source to mouth. Scoring is on a 0–3 scale with 0 representing an absent or virtually no ecosystem service value and 3 an optimal or maximum value. Output is best expressed in score per kilometre of river length. The exercise showed the tool to be applicable across two ecoregions and to rivers of varying size, level of human modification and character. While requiring further refinement, the approach shows that ecosystem service assessments based on virtual globes can be universally applied providing valuable information on riverscape ecosystem service delivery. key words: Google Earth; remote sensing; ecosystem services; virtual globe; rivers; river assessment