Relating landscape to stream nitrate-N levels in a coastal eastern-Atlantic watershed (Portugal)
We apply a linear regression mixed effects model to explore the influence of landscape factors on nitrate-N concentrations in a coastal watershed of Portugal. Landscape composition and configuration metrics, together with variables assessing the physical characteristics of the study area, were used. The analysis was performed using seasonal data from the years 2001 and 2006. The seasonal influence was included as a random effect to account for temporal correlations. Together, the fixed and the random factors explain 78% of the variance, whereas the fixed factors alone explain 10%.