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Prior to European settlement, the portion of north and central Florida corresponding to the historic range of longleaf pine (Pinus palustris) was dominated by fire-dependent, herbaceous and open woodland plant communities. Economic development coupled with fire suppression lead to a drastic decline in the abundance, contiguity and integrity of these natural communities. We present a classification and description of natural, fire-maintained pineland communities of this highly fragmented landscape. Plot locations were stratified by region and topographic position to assure comprehensive coverage of compositional variation associated with local and regional gradients of environmental and geographic variation. Our focus was description of groundcover vegetation, which harbors most of the plant diversity. We censused all plant species within 293 vegetation plots of 1,000 m2. We then developed a comprehensive vegetation classification based on floristic similarity using K-means cluster analysis and ordination. Sixteen distinct “communities” are recognized, corresponding to plant assemblages that we deem readily discernable in the field. These communities were grouped into five ecological “series” corresponding to those of Peet: Xeric Sandy Uplands (2 communities), Subxeric Sandy Uplands (2 communities), Silty Uplands (2 communities); Flatwoods (3 communities); and Wetlands (7 communities). For each community we summarize species diversity, woody plant structure, diagnostic (indicator) species, and environmental and physiographic characteristics. Floristic variation within and between series is described relative to geographic variation and edaphic characteristics.
Conseola corallicola is a rare cactus that is known from just two islands in Florida, Little Torch Key and Swan Key. The appearance of the cactus-eating moth, Cactoblastis cactorum, in the 1980s, threatened its survival. Outplantings at various locations were made in the 1990s and early in the 21st century to try to boost population sizes in the field and to determine optimal outplanting conditions. Here, I examine the survival of these cacti and compare it to the survival of volunteers around the bases of parent plants at Little Torch Key. I correlate percent survival in all locations with soil nutrients.
Survival of recruits in outplantings was lower than that of volunteers around parent plants. Transplant experiments showed the physical act of replanting did not reduce survival. Cacti planted close to individuals of prickly pear cactus, Opuntia stricta, suffered from attack by Cactoblastis as they spilled over from O. stricta onto C. corallicola outplantings. Survival of cacti planted far away from O. stricta was often low because of poor soil quality and high mortality from crown rot. Where cacti were not killed by Cactoblastis, survival was greatest where soil nutrient content and water content were highest. Soil fertilization did not increase survival rates, but did increase survivor growth. Future restoration of C. corallicola in the Florida Keys is likely to prove difficult. As Cactoblastis spreads throughout the United States and Mexico, these same issues will likely be faced by Cactoblastis-susceptible cacti in many other locations.
Thirty populations of Sandhills lily (Lilium pyrophilum) in North Carolina and Virginia were studied to understand the habitat requirements and develop search criteria to find new populations. In each population a study plot containing lily individuals was compared with a nearby plot lacking the lily. Lilium pyrophilum habitat occurred on floodplains and adjacent side slopes that supported four Coastal Plain plant community types and maintained rights-of-way and had an open canopy with an understory dominated by herbs and shrubs. Lily individuals occurred on a range of organic to mineral-organic soils but not on sandy soils and lily soils had higher sulfur levels. Relative to plots lacking lily individuals, Lilium pyrophilum plots had a higher wetness index. Since 97% of plots were in jurisdictional wetlands, a wetland indicator of FACW was recommended for L. pyrophilum. Search criteria for finding new populations were developed on the basis of the habitat features elucidated in this study.
Four study areas located within the Fraser fir (Abies fraseri)-red spruce (Picea rubens) forest on the summit of Mount Rogers in southwestern Virginia sampled originally in July 1982 were resampled during June 2007. Mount Rogers is the northernmost locality for Fraser fir, a species that has suffered serious damage over the past half century from the introduced balsam woolly adelgid (Adelges piceae). Both total basal area (m2/ha) and density (number/ha) of trees (≥10 cm DBH) increased during the 25 year interval between the two sampling dates, whereas basal area of small trees (≥2.5–9.9 cm DBH) increased and density decreased. Much of the change in overall composition was due to the decrease in importance of red spruce with a concurrent increase in importance of Fraser fir. The most striking differences were noted for saplings (stems ≥1 m but <2.5 cm DBH), with those of Fraser fir and red spruce decreasing from 5,725 to 550 and 475 to 0 stems/ha, respectively. In addition, cover of herbaceous plants declined during the 25 years while bryophyte cover increased. Mean age of representative larger red spruce and Fraser fir trees cored in 2007 (83 years) was comparable to the value recorded in 1982 (84 years). These data suggest that many of the older individuals present in the community in 1982 were no longer present in 2007.
This study evaluated the ability of bigtooth aspen (Populus grandidentata Michx.) patches to contribute to the understory diversity of southeastern Ohio's mixed oak forests by providing unique microenvironments embedded within the larger mixed vegetation matrix. Twenty bigtooth aspen patches and adjacent mixed oak forest were selected for study. Microenvironmental parameters were assessed in both the patch and surrounding matrix and included light, relative humidity, soil and air temperature, soil moisture, nitrate, texture, pH, O and A horizon depth, organic matter content, and cation (Mg, Ca, P, K, Al) availability. Spring and summer vegetation surveys were conducted to investigate differences in floristic composition between aspen patches and surrounding forest. A MANOVA revealed significant (P < 0.001) differences in the microenvironment between aspen patches and the oak matrix resulting from differences in soil texture, organic matter content, soil and air temperature, soil pH, magnesium, calcium, and aluminum availability. Vegetation surveys demonstrated that aspen patches had greater vegetative cover (P < 0.05) and species richness (summer survey only; P < 0.05) than the surrounding mixed oak forest. However, ordinations did not reveal distinct compositional differences based upon the presence or absence of aspen, suggesting that although community structure and environment differs between aspen patches and control forest, bigtooth aspen does not support a distinct and consistent flora beneath their canopy.
A calculation is presented that converts plant frequency per plot size sampled to expected frequency per any plot size of interest so as to compare studies that used different plot sizes or to assess degrees of spatial randomness in individual studies that used multiple plot sizes. Expected frequency is exponentially related to measured frequency, being dependent on plot size of interest relative to plot size from which measured frequency was obtained. Expected frequency per plot size of interest (Fe) may be expressed as Fe = 1 − (1 − Fs)r, where Fs is measured frequency per plot size sampled and r is the ratio of plot size of interest to plot size sampled. The calculation assumes that plants are randomly distributed, or approximately so, and criteria for presence of plants in plots are consistent in studies being compared.
Piedmont prairie communities of the southeastern United States were common prior to European settlement. Suther Prairie in Cabarrus County, North Carolina is among the best-known examples of such an ecosystem. This study provides a complete floristic list of species observed at the site from 1997–2007. Sampling over the 10 yr period included fixed transects and general floristic inventories. During the 2006–07 growing seasons, additional transects and 90 randomly placed 1 m2 quadrats were established for sampling species frequency. Soil in six of these random quadrats was sampled at three depths (0–10 cm, 11–20 cm, 21–30 cm) for pH, organic C, total N, and extractable P, K, Ca, Mg, Zn, Mn, Cu, B, and Na.
There were 208 species documented during the 10 yr sampling period. In 2006–07 142 new species were identified, but 49 previously documented species were not re-located. Of the 208 species, 66 were graminoids (36 grasses and 30 sedges/rushes). Ninety of these had previously been reported from prairie habitats. Obligate or facultative wetland species comprised 32% of the list. Thirteen species were rare, watch-listed, or uncommon for North Carolina. Big Bluestem (Andropogon gerardii) and Eastern Gamagrass (Tripsacum dactyloides var. dactyloides) had the highest frequency of occurrence during the 2006–07 sampling. Species richness was 6.8 species per m2. Levels of Ca and Mg were much higher than normal for Piedmont soils, and there was significant variation in soil C, N, P and Zn levels among the sampled depths.
A descriptive survey of the vascular plants was conducted on the Camp Nelson Quarry, a 2.3 ha limestone quarry, abandoned since 1991 in Garrard County, Kentucky. Collections made from this site during 1996, 1997, 2000, 2003, and 2004 resulted in an annotated plant list of 209 species in 155 genera from 61 families. The known vascular plants of the quarry included one species of Equisetophyta, one species of Pinophyta, and 207 species of Magnoliophyta (45 Liliopsida, 162 Magnoliopsida). A total of 137 taxa (65.55%) were native and 72 (34.45%) were non-native. Of the exotics, 34 are considered invasive pest plants in Kentucky. Thirty-four (16.27%) of the taxa were woody, while 175 (83.73%) were herbaceous. In 13 years of disuse, plants have colonized nine anthropogenic habitats in the quarry through progressive secondary succession: vertical highwalls, talus slopes, spoil heaps, dry quarry floor, old-field succession area, wet quarry floor, wet ditch border, seasonal pond area, and permanent pond area. Sørenson's Similarity Indices were significant between Camp Nelson Quarry and two older and smaller abandoned limestone quarries. Species richness is expected to increase in the quarry as more plants colonize and become established through progressive secondary succession and soil development.
This study was undertaken to document the vascular plant species of Sand Prairie Conservation Area, an 80 hectare site located at roughly 37°05′N; 89°30′W in Scott County, Missouri, during the growing seasons of 2007 and 2008. A total of 220 vascular plant taxa were collected from the Conservation Area: 55 Monocots, 162 Dicots, one Pteridophyte, and two Gymnosperms. Forty-one non-native taxa were documented, representing about 19 percent of the species collected. Notable collections include 10 Species of Conservation Concern and one state record. During the 2008 growing season, the distributions of the 10 Species of Conservation Concern found on Sand Prairie Conservation Area were mapped using GPS and GIS technologies. The assembled species list, along with known distributions of Species of Conservation Concern, will serve as baseline data for future management and restoration efforts.
Viburnum ozarkense was recently resurrected as a distinct species after having been synonymized with the related and partially sympatric Viburnum molle for much of the latter half of the 20th century. Presently, V. ozarkense is considered to be endemic to the Interior Highlands physiographic region of western Arkansas, southern Missouri, and eastern Oklahoma. However, this research suggests that although V. ozarkense is morphologically distinct from V. molle, it cannot be distinguished from V. bracteatum, a species found more than 500 km away in southeastern Tennessee, northeastern Alabama, and northwestern Georgia. Based on morphological and phytogeographical evidence, V. ozarkense is here considered to be conspecific with V. bracteatum. An overview of the expanded taxonomic concept, distribution, ecology and rarity of V. bracteatum is provided.