Patterns and drivers of spatio-temporal variability of suspended sediment in the Waikato lakes, New Zealand

Quantifying and interpreting variability in ecological systems allows us to better understand the driving forces that determine ecosystems functioning. We utilised earth observation-based remote sensing to determine total suspended sediment (TSS) concentrations for 109 lakes over 16 years. The coefficient of variation (CV) was used to quantify variability of TSS at three temporal scales (monthly, annual and long-term) and at the horizontal spatial scale. CV values varied between 0.14 and 1.09. Drivers of observed variability patterns were explored using five lake morphological and catchment characteristics. Lake area was the most important variable to predict variability of TSS. De-vegetated lakes displayed significantly higher TSS concentrations than vegetated lakes; however, aquatic vegetation was found to moderate only spatial variability of TSS. As spatio-temporal variability can be assumed to drive key ecosystem functions, determining characteristic variability patterns for various attributes should be a prerequisite when setting management goals and developing monitoring regimes.