Scale-dependence of land use effects on water quality of streams in agricultural catchments.

摘要: The influence of land use on water quality in streams is scale-dependent and varies time space. In this study, cover patterns stocking rates were used as measures agricultural development two pasture one native grassland catchment New Zealand related to various orders. amount per subcatchment correlated well total nitrogen nitrate turbidity phosphorous the other catchment. Stocking only but showed stronger correlations ammonium, Winter spring floods significant sources nutrients faecal coliforms from catchments into a wetland complex. Nutrient coliform concentrations better predicted by pastural fourth-order than second-order streams. This suggests that upstream more influential larger streams, while local factors may be important smaller These temporal spatial scale effects indicate water-monitoring schemes need scale-sensitive.