Temporal patterns of ground flora response to fire in thinned Pinus–Quercus stands

The ground flora stratum affects stand structure, resource acquisition, nutrient cycling, and taxonomic richness in forest ecosystems. Disturbances such as thinning and prescribed fire alter forest understory growing conditions that generally increase ground flora cover and richness. We studied annual changes in ground flora assemblages over three growing seasons after fire in thinned and frequently burned (3-year rotation) Pinus–Quercus stands. Our results corroborated trends from other studies that indicated greater ground flora richness and cover after thinning and burning compared with thin-only treatments. We also found that the stratum experienced relatively rapid succession between growing seasons that complimented the tolerance succession model. Forbs had reduced cover and richness from increasingly difficult growing conditions over time and were replaced by woody plants, shrubs, and seedlings. This likely occurred from changing competition dynamics that favored quick growth in the first growing season and long-term investment in vertical growth in the third growing season. The successful regeneration pathways also fit ground flora regeneration models and added a unique pathway to strengthen the predictive power of these models. As many stand management goals are focused towards improving biodiversity, prescribed fire and thinning may be used to increase understory richness in Pinus–Quercus stands.

Quantitative comparison of tree roosts used by red bats (Lasiurus borealis) and Seminole bats (L. seminolus)

We radio-tracked 11 red bats (Lasiurus borealis) and 5 Seminole bats (L. seminolus) to 64 and 34 day roosts, respectively. Individuals of both species were found roosting within the canopy of the roost trees, clinging to leaf petioles or the tips of small branches (<4 cm in diameter). Red bats roosted primarily in hardwoods (97%), whereas the roosts of Seminole bats were located primarily in pines (94%). Ten of the 16 roost-site variables examined differed significantly between red bats and Seminole bats: number of trees in the overstory, overstory height, understory richness and diversity, overstory richness, diversity, and evenness, roost-tree diameter, percent canopy closure, and percentage of conifers in the overstory. These differences were related directly to the differential use of roosting habitats by the two species. The roosts of red bats were located in pine - mixed hardwood communities and bottomland hardwood swamps, while the roosts of Seminole bats were located in communities dominated by pines. To examine within-stand roost selection, the diameter, height, and species composition of roost trees used by red and Seminole bats were compared with those of neighboring trees. Roost trees of red and Seminole bats had significantly larger diameters and were significantly taller than surrounding trees. Day roosts of red and Seminole bats were located in 18 and 5 tree species, respectively. The tree species used differed significantly from expected for the red bat but not for the Seminole bat.