Land use and topography bend and break fractal rules of water body size-distributions

The size-distributions of inland water bodies (WB) within different regions often poorly conform to geophysically based theoretical models (power-law: y = axβ); however, the causes of these deviations remain unknown. Therefore, we compared WB abundance and size-distribution parameters (slope [β] and model fit [r2]) in 164 regions in the United States with varying topography, climate, and agricultural intensity. We found all three factors influenced WB size-distributions and their fit to expected models. WB size-distributions in steeper terrain had more small WB and better fit power-law models, while regions with flatter terrain and greater precipitation had poorer fits. Extensive agriculture increased the proportion of small WB, causing distributions in some regions to fall outside theoretically predicted limits (βCDF < −1). Regional variation of WB size-distributions can help develop and test integrated theory that accounts for geophysical and anthropogenic drivers of WB sizes, which is essential for scaling biogeochemical processes in aquatic systems.

Duke Scholars

Author James Brendan Heffernan Environmental Sciences and Policy