|Title||Distribution of runoff and rivers related to vegetative characteristics, latitude, and slope: A global perspective|
|Publication Type||Journal Article|
|Year of Publication||1997|
|Journal||Journal of the North American Benthological Society|
|Keywords||rivers, Runoff, streams, Terrestrial systems, vegetation|
The geographic distribution of streams on earth can be associated with terrestrial vegetation, slope, and latitude, among other factors. Classifying flowing water habitats by associated vegetative cover is useful because factors such as downstream transport of organic carbon (C), sediments, nutrients, and other dissolved or suspended materials are influenced heavily by the vegetative characteristics of the watershed. Global datasets with 1-degree spatial resolution were analyzed to characterize both volume of runoff and number of mapped rivers associated with each of 14 classes of vegetation, and how runoff is influenced by latitude and slope. The vegetation classes (land cover) were ranked in decreasing order with respect to runoff. About 30% of the global runoff originates from broadleaf evergreen forest, followed by wooded C4 grassland (14.8%), cultivated land (8.9%), coniferous forest and woodland (8.3%), ice (7.8%), wooded C3 grassland (6.0%), mixed coniferous and broadleaf deciduous forest (5.4%), C3 grassland (5.3%), tundra (4.5%), high latitude deciduous forest and woodland (3.9%), broadleaf deciduous forest and woodland (2.3%), C4 grassland (1.7%), shrubs and bare ground (1.4%), and desert and bare ground (0.5%). Numbers of mapped rivers followed a similar pattern, except that broadleaf evergreen forests did not dominate, and tundra habitats were much more important. Counts of intermittent rivers were generally highest in the areas with the lowest runoff. River counts are likely to be less reliable than runoff estimates because they rely upon the subjective judgment of cartographers. Equatorial and northern temperate regions accounted for the greatest proportion of total runoff. A weak positive relationship occurred between slope and runoff. This analysis may assist investigators in determining how well their results can be extrapolated beyond regional scales.