Year

2009

Paper Type

Master's Thesis

College

College of Arts and Sciences

Degree Name

Master of Science in Biology (MS)

Department

Biology

First Advisor

Dr. Anthony Rossi

Second Advisor

Dr. Daniel Moon

Third Advisor

Dr. Kerry Clark

College Dean

Dr. Barbara Hedrick

Abstract

As the human population in Florida continues to expand, development follows, and tree farms give way to homes and businesses. As parks are established, restoration of these semi-natural plantations may provide critical habitat for species conservation. This study evaluates vegetation response to restoration treatments at two study sites, formerly tree farms, now preserves in NE Florida. Treatments included thinning, clearing, or control (no treatment) within 10m^2 plots. Thinning reduced tree canopy to 20% (2-3 pines/plot) and removed all other vegetation; clearing treatments removed all biomass to bare soil; no herbicides were used. Within these plots richness and abundance was assessed by establishing two parallel transects and counting ramets on a bi-annual basis. Tree diameter at breast height (dbh) was also measured (cm). It was hypothesized that release of resources (thinning and clearing) would increase overall diversity (more so in graminoids and forbs), and encourage more robust tree growth versus control groups. Diversity ANOVA (Simpons & Shannon indices) showed significant differences due to survey date (p< 0.05) at the McGirts Creek site and a significant (p= 0.056) effect for the interaction term at the Tigers Point site. Tree dbh also increased at a significantly greater rate in thinned, versus control groups at the Tigers Point site (p= 0.03) perhaps due to higher initial tree density, but not at the McGirts Creek site (p= 0.85). Placing species into guilds revealed both sites reflected high levels of graminoids in cleared plots, which is consistent with early successional species (pioneer plants). McGirts followed hypothesis as forbs and graminoids were dominant in both thinned and cleared plots and the Tigers Point site had higher levels of vines and shrubs than expected. Restoration goals of increasing vegetative diversity, especially in r-selected species, and robust growth can be met by techniques used in this study.

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