Characterization of the spatial distribution of soil properties in water Conservation Area 2A, Everglades, Florida

摘要

Wetland soils are heterogenous in nature, and biogeochemical properties show different spatial autocorrelation structures that translate into fine- and coarse-scale spatial patterns. Understanding these patterns and how they relate to other ecosystem properties (e.g., vegetation) is critical to restore wetlands impacted by nutrient influx. Our goal was to investigate Water Conservation Area 2A, a wetland in the Florida Everglades, that has been impacted by nutrient influx and incursions of cattail as well as biogeochemical cycling of nutrients, hydrologic manipulation, and natural events (fire, hurricanes, and tropical storms). The objective of this study was to characterize the spatial patterns of soil and floc/detritus total phosphorus (TP), total inorganic phosphorus (TPi), bulk density (BD), total nitrogen (TN), total calcium (TCa), total carbon (TC), and floc depth in Water Conservation Area 2A. A total of 111 sites were sampled at three different depths (floc, 0- to 10-cm, and 10- to 20-cm depth). Geostatistical techniques were used to estimate and map soil properties across the wetland. Observed TP ranged from 155 to 1702 mg kg-1 (0-10 cm) with a mean of 551 mg kg-1 and showed strong spatial autocorrelation extending over long distances of 6864 m (10-20 cm) and 9669 m (floc). The nugget-to-sill ratio was less than 25% for all observed properties except for TN, indicating strong spatial dependence. This spatially explicit study provided insight into the variability of soil properties generated by external and internal factors and establishes a baseline framework for future management decisions involving the restoration of this wetland.