『Abstract
Documenting local change of soil properties over longer periods
of time is critical to assess trends along trajectories. We present
two types of temporal trajectories that document change in soil
phosphorus (P) and pedo-patterns in Water Conservation Area 2,
a subtropical wetland in the Everglades, Florida. Our specific
objectives were to (i) quantify the spatial distribution of total
P (TP) in floc and topsoil at two time periods (1998 and 2003),
(ii) create TP change maps using a crisp, geospatial mapping approach,
(iii) analyze relationships between floc/soil TP temporal trajectories
and vegetation, and (iv) describe change in pedo-patterns using
fuzzy sets to account for the uncertainty inherent in crisp soil
property mapping. The median TP in floc was 730 mg kg-1
in 1998 and increased to a median of 751 mg kg-1 in
2003; whereas the median in soil was 485 mg kg-1 in
1998 that decreased to 433 mg kg-1 in 2003. Floc TP
change trajectories varied between 0-990 mg kg-1 (increase)
and 0-2900 mg kg-1 (decrease); and soil TP change trajectories
varied between 0-370 mg kg-1 (increase) and 0-1439
mg kg-1 (decrease). Phosphorus-enriched sites were
associated with nutrient influx via surface waters and showed
linkages to expanding Typha domengensis vegetation. The
temporal trajectories of pedo-patterns provided pixel-specific
signatures of ecosystem processes such as P enrichment, organic
matter turnover, hydrologic shifts, and fire in form of fuzzy
membership values. The fuzzy set-based temporal trajectory maps
provided a holistic approach documenting shifts in this ecosystem
due to external environmental drivers and biogeochemical processes
within a 5-year period.
Keywords: Change analysis; Temporal trajectories; Geospatial analysis;
Fuzzy modeling; Crisp modeling』
1. Introduction
2. Methods and materials
2.1. Study area
2.2. Sampling and analytical analysis
2.3. Geospatial analyses and fuzzy c-mean classification
3. Results and discussion
4. Summary and conclusions
Acknowledgements
References