Dr. Jane M Caffrey

Changes in landscape composition and configuration can profoundly influence water quality. Many studies have investigated the impact of landscape composition on water quality whereas the attention given to quantifying the effects of landscape configuration on water quality is limited. However, it is vital to understand the association of water quality with changing patterns of both land-use types and their configuration. This study conducted a comprehensive investigation of how landscape composition and configuration patterns affected the water quality in the Pensacola Bay system. The catchment was divided into 26 sub-catchments. Data describing seasonal (July to September) water quality variables at the outlet of each sub-catchment were obtained from the Water Quality Portal. Land cover rasters of the catchment at seven-time intervals between 2001 to 2019 were acquired from the US Geological Survey’s National Land Cover Database and the spatial configuration of each map was extracted using FRAGSTATS 4.3 software. The correlation and association of each landscape composition and configuration variable to water quality variables were analyzed using a Partial Least Square Regression model. The interaction between landscape compositions and configurations accounted for most of the variation in water quality parameters. The water quality of the catchment was affected both negatively and positively; however, the magnitude and direction were not consistent across spatial scales, and observed impacts were amplified at a smaller spatial scale. Although both landscape composition and configuration impacted water quality, significant changes were best explained by the composition. While changes in land cover such as increased evergreen forest and increased urban development were correlated with increased nutrient concentrations at multiple locations, reduced concentrations were also observed in other sub-catchments. The findings of this study provide key information for improved land-use planning and protection of water quality at multiple spatial scales.