The Florida Everglades ecosystem has been impacted by hydrologic modifications, landscape fragmentation, increased nutrient inputs, and altered fire regime. These natural and anthropogenic forcing functions cause shifts in pedo- and biodiversity. Our goal was to gain a better understanding of the variability of physico-chemical soil properties along gradients of impacted and unimpacted zones throughout the Everglades. Our objectives were to identify the magnitude and scale at which soil properties account for variability and map the distribution of this variability. We used a spatial principal component analysis on 11 soil physico-chemical properties that were mapped at 1,328 sites spatially-distributed throughout the Everglades. Principal component (PC) factors scores were identified. A PC can also be considered as a regionalized variable (RV). The magnitude and scales of variation for each RV, identified from semivariograms of PCs, were used to characterize the variability of soil properties. Ordinary kriging and splines were used to interpolate the PCs across the study area.

The first four components accounted for 88% of the total variability of the dataset. The first PC accounted for 46% of the variance including most of the variation in loss on ignition, total carbon, total nitrogen and total phosphorus suggesting that ecological variation in the Everglades is mainly caused by anthropogenic nutrient gradients and subsequent transformations (C, P, N-cycles). The second PC accounted for about 20% of the total variance and had negative loadings on aluminum, iron, total phosphorus and total inorganic phosphorus. This may point to the importance of metal complexation with phosphorus and organic matter. Our spatial analyses characterized the spatial variability of soil properties, reduced the complexity of spatial soil signatures through PC mapping, and provided linkages to underlying factors.