Old-growth longleaf pine savannas are characterized by diverse ground-layer plant communities comprised of graminoids, forbs, and woody plants. These communities co-exist with variable-aged patches containing similar-aged trees of longleaf pine (Pinus palustris Mill.). We tested the conceptual model that physical conditions related to the cycle of longleaf pine regeneration (stand structure, soil attributes, fire effects, and light) influence plant species’ composition and spatial heterogeneity of ground-layer vegetation. We used a chrono-sequence approach in which local patches represented six stages of the regeneration cycle, from open areas without trees (gaps) to trees several centuries old, based on a 40-year population study and increment cores of trees. We measured soil characteristics, patch stand structure, fuel loads and consumption during fires, plant productivity, and ground-layer plant species composition. Patch characteristics (e.g., tree density, basal diameter, soil carbon, and fire heat release) indicated a cyclical pattern that corresponded to the establishment, growth, and mortality of trees over a period of approximately three centuries. We found that plants in the families Fabaceae and Asteraceae and certain genera were significantly associated with a particular patch stage or ranges of patch stages, presumably responding to changes in physical conditions of patches over time. However, whole-community-level analyses did not indicate associations between the patch stage and distinct plant communities. Our study indicates that changes in composition and the structure of pine patches contribute to patterns in spatial and temporal heterogeneity in physical characteristics, fire regimes, and species composition of the ground-layer vegetation in old-growth pine savanna.

A silvicultural chronosequence was studied in upland pine stands of Fort Benning, Georgia, to assess understory vegetation and soil characteristics following silvicultural disturbance activities. Hypotheses regarding patterns of understory vegetation distribution and abundance, and the impact of disturbance on soil properties were evaluated in 32 forest stands. The chronosequence encompassed various times following clear-cut regeneration: stand age (0–3 yrs), (8–10 yrs), (18–20 yrs), and (30–80 yrs). Soil pH, total carbon (C) and nitrogen (N) contents, soil texture, and bulk density were used to characterize soil conditions across the chronosequence. Foliar cover by species was used to characterize vegetation across this same chronosequence. Canonical correspondence analysis (CCA) was performed to determine the relationship between understory vegetation pattern and measured soil gradients and stand age. CCA identified stand age as the most important factor influencing distribution and abundance o...

Published by the UF/IFAS Florida Sea Grant College Program, this manual provides an overview of the coastal ecosystems along the Florida Panhandle and shows how dunes can be restored and enhanced in this region of the Northern Gulf of Mexico. In addition to direct experience acquired over many years of field work and experimentation, authors Chris Verlinde, Mack Thetford, and Debbie Miller consulted peer-reviewed academic journals, government documents, and various online resources to create the manual. Undergraduate and graduate students from the University of Florida and local professionals worked together with the UF/IFAS researchers to develop and test practical restoration techniques for Florida’s dunes. http://edis.ifas.ufl.edu/sg156