Biogeochemical Study of the Pinelands in Everglades National Park, Florida

Jackson, Larry; Briggs, Paul; Gough, Larry; Stolte, Kenneth

This report presents the study design, sampling methods, and chemical analysis procedures and results for a cooperative biogeochemical study between the National Park Service and the U.S. Geological Survey in the pinelands of Everglades National Park (EVER). This study was conducted to help determine baseline ranges and spatial variability in element concentrations in South Florida slash pine (Pinus elliottii Engelm. var. densd) and the associated rockland soils. The study focused on a grid sampling of pines and soils from Long Pine Key in EVER. Long Pine Key is the principal remnant of the subtropical pinelands within South Florida. Throughout Long Pine Key, the largely second growth pines are relatively uniform in trunk diameter, but vary somewhat in canopy height. Understory height within the key varies greatly depending upon fire history. Soils throughout the pineland exhibit little development and are present as a thin veneer or in solution pockets in the oolitic limestone. Samples were collected from 76 grid locations (grid cells were 0.75 km on a side) within Long Pine Key and neighboring pinelands in March-May 1989 (grid design). The total number of samples of each sample media was 105 which included within grid, within site, and laboratory replicates. Summary statistics and baseline 95 percent expected element concentration ranges are reported for major, minor, and trace elements in slash pine needles and rockland soils. A subset of 20 pine and soil samples from Long Pine Key were analyzed for arsenic, mercury, and stable sulfur isotope ratios (barbell design) and summary statistics are reported similarly to the grid sampling design. The results of the smaller barbell sampling design appear to be reasonably representative of the larger population of pine needles and soils within EVER. Analysis of variance results from both designs indicated that the majority of the element concentration variance was attributable to localized differences at distances of 10's to 100's of meters. This was particularly true for elements in the soils. However, normalization to aluminum content helped reduce the localized variability. Based on the analysis of variance results from the barbell design, there was little indication of significant east-west element concentration trends within the relatively small area of Long Pine Key. Principal component models indicated that macro and micro nutrients accounted for most of the variability in pine needle chemistry, whereas elements associated with alumino-silicates and carbonates explained a majority of the variability in soil chemistry. Contour maps of element concentrations in pine needles and element to aluminum ratios in soils are presented. Whereas the contour maps generally indicate that the element concentrations in the pines and soils are fairly uniform throughout Long Pine Key, there are some manifestations of edge or ecotonal effects at the boundaries of the key. For example, slightly higher phosphorous concentrations in pine needles and soils along the northern edge of Long Pine Key may be from agricultural/urban runoff. The former farming activity along the southern edge of the key does not appear to have influenced the pine or soil chemistry in any detectable way. No significant correlations were found between fire history and pine or soil chemistry. In general, the pinelands do not appear to be highly contaminated with any element that was determined in this study.

Biogeochemical Study of the Pinelands in Everglades National Park, Florida

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