The University of West Florida campus ecosystem study: the college/university campus as a unit for study of the ecology of longleaf pine

Abstract

College and university campuses comprise a unique urban interface. Property used to establish the University of West Florida (UWF) in Pensacola, Florida, contained numerous ecological features, including natural areas with remnant longleaf pine stands that had undergone recovery from extensive regional logging. The two most prominent of these were studied to quantify the effects of chronic fire exclusion on longleaf pine stands. We addressed these questions: (1) how does composition and structure vary between areas? (2) how do soil characteristics vary between areas and change under fire exclusion? (3) what is the size structure of longleaf pine on the UWF campus? (4) how does the status of longleaf pine at the UWF campus compare to campuses of other colleges/universities within the nature range of longleaf pine? Fifteen 0.04 ha circular plots were established in each area to assess composition and structure and sample mineral soil. All live stems ≥2.5 cm diameter at breast height (DBH) in each plot were identified to species and measured for DBH to the nearest 0.1 cm. Mineral soil was taken to a 5-cm depth, air dried, and analyzed for pH, organic matter, cation exchange capacity, extractable macro- and micronutrients, and extractable aluminum. Basal area and density were closely similar between the natural areas, as was canopy dominance (live oak and longleaf pine), but with contrasting sub-dominant species. Soil analyses revealed no significant differences between natural areas, but suggested that fire exclusion decreased soil organic matter and fertility with establishment of hardwood species. Diameter structure of longleaf pine contrasted sharply between natural areas and with the main campus, suggesting different land-use history. The wide array of approaches to longleaf pine ecology by colleges/universities within its natural range indicates the importance of establishing a longleaf pine consortium to coordinate information.