Wet Flatwoods Research Articles

Mammals of Hazeldell Nature Preserve, Pulaski County, Kentucky: A Rare Highland Rim Ecosystem

Hazeldell Nature Preserve is a rare ecosystem on the Highland Rim of south-central Kentucky. It is the only state-protected site of its kind. This preserve is comprised of two distinct plant communities, including wet flatwoods and wet meadow. Despite its uniqueness, no ecological studies have been conducted on mammals in the past. Currently, two separate studies are underway on mammals. Here we present the results from the first of these that used camera traps set in the wet flatwoods community from 1 February to 28 March 2020. A total of 34,071 photos were taken with 553 having images of 12 species of mammals. The four most photographed species were eastern gray squirrel, Virginia opossum, white-footed deermouse, and white-tailed deer. These four species appeared in 91% of photos. The remaining 49 photos were of eight species including: eastern cottontail, coyote, bobcat, northern raccoon, striped skunk, southern flying squirrel, common gray fox, and eastern fox squirrel. Woodchuck and eastern chipmunk were not photographed during the study, yet each have ranges that include the preserve. These burrowers may avoid the preserve because of the secondary water table and saturated soil that occur during extended periods. The results of this study serve as baseline data for comparison to future camera trapping. Continued photo documentation will be used to identify changes in the mammal species composition of the preserve caused by species range changes in response to various factors, including habitat fragmentation and climate change.

Group selection silviculture for converting pine plantations to uneven-aged stands

Recent years have witnessed an increased interest in managing and restoring southern pine stands using uneven-aged silvicultural strategies, that rely on natural regeneration. Group selection harvests are regarded as an effective approach to induce natural regeneration and convert pine plantations to uneven-aged stands. In a wet flatwoods site in north-west Florida, we characterized natural regeneration (density, size, spatial distribution, hot spots) of slash pine (Pinus elliottii Englm.) eight years following group selection harvests and one year following prescribed fire in mature slash pine plantations. Our study utilized a long-term, operational scale experiment consisting of circular harvest group openings of four different sizes (0.1, 0.2, 0.4, 0.8 ha), each replicated three times. In all group openings, we stem mapped all regeneration > 1.37 m in height and measured their diameter at breast height (dbh) and total height. We also estimated understory shrub cover in the group openings. Overall, slash pine regeneration response was highly variable across group opening sizes and ranged between 150 (in 0.1 ha group openings) to 670 stems ha−1 (in 0.8 ha group openings). On average, 468 ± 105 (mean ± standard error) stems ha−1 were found in the group openings. Group opening size had no significant effect on regeneration density or size (ɑ =0.05). Position within group opening, however, had a significant effect on regeneration density and height, with higher density occurring in group opening centers and taller stems in northern positions. Shrub cover decreased with increasing group opening size and was lowest in northern positions. Dense shrub cover (60–100%) was associated with greater regeneration density. The areas with dense shrub cover appeared to have escaped prescribed fire and experienced lower seedling mortality. Spatial point pattern analysis showed aggregation of regeneration for all group sizes across all distances. Regeneration hotspots were mostly central and southern positions in group openings. Earlier observations of our study suggest that the group selection harvesting may be a suitable approach to regenerate slash pine and add an age-class (regeneration cohort) to even-aged stands in wet flatwoods sites.

Low‐dose Herbicide Effects on Tree Establishment and Soil Nitrogen Biogeochemistry within Pine Savannas

Core Ideas Imazapyr‐treated pines were larger than pines applied with other herbicides. Imazapyr‐treated pines had better survival when the treatment is applied during the second season. Imazapyr soils produced higher ammonification rates compared to the control. Sulfometuron methyl‐treated pines were smaller than control plot trees. Sulfometuron methyl‐treated soils had lower ammonification rates and microbial biomass. Longleaf pine (Pinus palustris P. Mill) survival and growth, net nitrogen mineralization, and soil microbial biomass, were evaluated after four growing seasons in a Florida wet flatwoods site following chemical vegetation control during the first year or second year after planting, or during both years. The four herbicide treatments included sulfometuron methyl at 0.26 ai kg ha−1, hexazinone (0.56 ai kg ha−1), sulfometuron (0.26 ai kg ha−1) plus hexazinone (0.56 ai kg ha−1) mix, and imazapyr at 0.21 ai kg ha−1. Imazapyr was the only treatment to significantly improve growth over the control in a single application. Consecutive annual applications of imazapyr and hexazinone on seedlings also improved growth rates compared to the control. Sulfometuron methyl‐treated pine trees had lower survival rates and were smaller than pines growing in the control plots after a single application. The survival and growth rates of imazapyr‐treated seedlings were improved when the chemical was applied during the second growing season after planting, instead of the first year. Imazapyr and hexazinone applications increased net nitrogen mineralization rates, but imazapyr was the only treatment to increase ammonification; compared to the control. Microbial and fungal biomass carbon showed no differences between treatments. The results did show that microbial biomass significantly increased with two consecutive years of herbicide applications over a single application. Imazapyr applied during the second growing season proved to be the best treatment for improving pine growth, controlling competitive vegetation, minimizing pine mortality, and to remain effective when soils are saturated.

Effects of conversion harvests on light regimes in a southern pine ecosystem in transition from intensively managed plantations to uneven-aged stands

Uneven-aged silviculture is increasingly viewed as ecologically and economically appropriate strategy to manage forest ecosystems. Consequently, there is interest in converting intensively managed pine plantations to uneven-aged stands in the southeastern United States. Understanding biophysical factors that determine performance and growth of desirable species is critical to success of such conversions. We initiated a replicated, long-term, operational-scale stand conversion experiment in mature slash pine (Pinus elliottii Engelm.) plantations in mesic-wet flatwoods sites in northwest Florida, and examined how five conversion harvests (shelterwood, group selection, staggered third row thin, third row thin, cut 2 leave 3 thin harvests), in addition to an uncut control, affected understory light availability in these forests. Light availability was measured in terms of leaf area index, sky, and fractions of Absorbed Photosynthetically Active Radiation (both direct and diffuse). The values of these variables were derived by analyzing a total of 880 (450 in the harvest treatment plots and additional 430 in the gaps of group selection) Digital Hemispherical Photographs using image analyzing software CAN-EYE. We found that shelterwood harvest resulted in highest light availability, whereas greatest variability in light conditions was observed following group selection harvests. Among the four circular gap sizes (0.1, 0.2, 0.4 and 0.8 ha) we studied, gaps of larger sizes had greater light availability. Light availability increased as the distance from the gap edge increased and was highest either in the center of the gap or slightly towards northern and western sides of the gap center. Variability in light availability increased as gap size increased from 0.1 to 0.4 ha but was reduced in the 0.8 ha gap. In shade-intolerant species like slash pine in wet flatwoods-- where soil moisture and nutrients are generally not limiting-- light availability could be the most critical factor determining the success of regeneration and stand conversion. Overall, the results indicated that shelterwood harvest resulted in highest average light availability which would be conducive to slash pine regeneration while group selection harvest created the most diverse light environment during the stand conversion which may promote a broader diversity of groundcover species. Long-term monitoring of regeneration growth and recruitment following prescribed burning and over multiple cutting cycles will determine if slash pine can be sustainably managed using uneven-aged silviculture.

The Ecological Classification of Coastal Wet Longleaf Pine (Pinus palustris) of Florida from Reference Conditions

Tropical storms, fire, and urbanization have produced a heavily fragmented forested landscape along Florida’s Gulf coast. The longleaf pine forest, one of the most threatened ecosystems in the US, makes up a major part of this fragmented landscape. These three disturbance regimes have produced a mosaic of differently-aged pine patches of single or two cohort structures along this coastline. The major focus of our study was to determine reference ecosystem conditions by assessing the soil biochemical properties, overstory stand structure, and understory plant species richness along a patch-derived 110-year chronosequence in order to accurately evaluate on-going longleaf pine restoration projects. This ecological dataset was also used to classify each reference patch as mesic flatwoods, wet flatwoods, or wet savanna. All of the reference locations were found to have similar soil types with no significant differences in their soil biogeochemistry. Mean diameter-at-breast height (DBH), tree height, and patch basal area increased as mean patch age increased. Stand growth reached a plateau around 80-90 years. Shrub cover was significantly higher in the matureaged patches (86-110 years) than in the young (6-10 years) or mid-aged (17-52 years) patches, despite prescribed fire. Plant species diversity as indicated by the Shannon-Wiener index decreased with patch age. Soil biogeochemical properties, forest structure, and understory species composition were effective for ecologically classifying our pine patches as 55 % mesic flatwoods, 20% wet flatwoods, and 25% wet savanna. Florida’s Gulf coastal wet longleaf pine flatwoods attain a structural and plant species equilibrium between 80-90 years.

Timing Constraints on Remote Sensing of Wildland Fire Burned Area in the Southeastern US

Remote sensing using Landsat Thematic Mapper (TM) satellite imagery is increasingly used for mapping wildland fire burned area and burn severity, owing to its frequency of collection, relatively high resolution, and availability free of charge. However, rapid response of vegetation following fire and frequent cloud cover pose challenges to this approach in the southeastern US. We assessed these timing constraints by using a series of Landsat TM images to determine how rapidly the remotely sensed burn scar signature fades following prescribed burns in wet flatwoods and depression swamp community types in the Apalachicola National Forest, Florida, USA during 2006. We used both the Normalized Burn Ratio (NBR) of reflectance bands sensitive to vegetation and exposed soil cover, as well as the change in NBR from before to after fire (dNBR), to estimate burned area. We also determined the average and maximum amount of time following fire required to obtain a cloud-free image for burns in each month of the year, as well as the predicted effect of this time lag on percent accuracy of burn scar estimates. Using both NBR and dNBR, the detectable area decreased linearly 9% per month on average over the first four months following fire. Our findings suggest that the NBR and dNBR methods for monitoring burned area in common southeastern US vegetation community types are limited to an average of 78–90% accuracy among months of the year, with individual burns having values as low as 38%, if restricted to use of Landsat 5 TM imagery. However, the majority of burns can still be mapped at accuracies similar to those in other regions of the US, and access to additional sources of satellite imagery would improve overall accuracy.

Persea palustris, Swamp Bay

FOR 260, a 2-page fact sheet by Michael G. Andreu, Melissa H. Friedman, Mary McKenzie, and Heather V. Quintana, describes this native evergreen found in swamps, wet flatwoods, and on the edges of canals and marshes, whose fruit is a good food source for birds and mammals, and whose leaves are eaten by larvae of the swallowtail butterfly — scientific and common names, description, allergen, and applications. Includes references. Published by the UF School of Forest Resources and Conservation, June 2010. FOR 260/FR322: Persea palustris, Swamp Bay (ufl.edu)

Floristic Inventory of Tiger Creek Preserve and Saddle Blanket Scrub Preserve, Polk County, Florida

A floristic inventory of vascular plants for The Nature Conservancy's Tiger Creek Preserve and Saddle Blanket Scrub Preserve, on the Lake Wales Ridge, Polk County, Florida, was conducted from August 2004 through February 2008. The 2308 combined hectares of the Preserves yielded 553 taxa, of which 54 are non-native, 37 are at or near the southern or northern limits of their ranges in Florida, and 24 are new Polk County records. Fifty-five taxa endemic to Florida were found, of which 27 are restricted to Florida peninsular scrubs or scrub/sandhill ecotonal habitats. Nine of these taxa are restricted to four or fewer counties. Twenty-seven are listed in Florida as endangered, threatened, or of management concern, and 18 are listed federally. Twelve plant communities are characterized: scrub, scrubby flatwoods, sandhill, xeric hammock, mesic flatwoods, wet flatwoods, bayhead, seepage slope, depression marsh, floodplain wetlands, blackwater stream, and ruderal. Descriptions and photographs of the plant communities are provided.

Conclusion: An action plan for coastal plain wetland conservation. Toward a continental conservation strategy

Coastal plain wetlands support some of the greatest concentrations of rare plants in eastern North America, and yet the rate of habitat destruction resulting from ,drainage, damming, filling, and water quality degradation appears to be out-pacing current protection efforts. To reverse this trend, advances need to be made on several t¥onts: (1) intensify inventories of rare species and exemplary natural communities to determine rangewide status and distribution; (2) use status and location information to establish site protection priorities; (3) protect critical sites from existing threats; (4) increase public awareness of coastal plain resources; and (5) conduct ecological research and monitoring to guide successful management. Fhe goal of this broad-based integrated effort is to protect a full measure of the biological and ecological .diversity represented in coastal plain wetlands. Before we address each conservation action in greater detail, a working definition of the term 'coastal plain wetlands' is needed. Our definition is rather restrictive, connoting natural freshwater oligotrophic wetlands which contain, at least, a modest complement of plants confined to, or characteristic of, the Atlantic coastal plain physiographic region (Canadian Maritime Provinces to the Gulf Coast of Texas). Coastal plain wetlands usually have both strongly acidic soils and pronounced water level fluctuations to which the coastal plain flora and fauna have become adapted. Seasonal ponds, lake shores, peatlands, wet flatwoods, and some river shores support coastal plain wetland vegetation. Wetlands in Ontario, Michigan, and elsewhere can be characterized as coastal plain wetlands if they support disjunct populations of plants typically found on the coastal plain. Excluded by this working definition are eutrophic to mesotrophic wetland communities such as tidal marshes and bottomland hardwood forests.