Genetic variation in Pueraria lobata (Fabaceae), an introduced, clonal, invasive plant of the southeastern United States

Pueraria lobata (kudzu), a clonal, leguminous vine, is invading the southeastern United States at a rate of 50 000 ha per year. Genetic variability and clonal diversity were measured in 20 southeastern U.S. populations using 14 allozyme loci. Within its U.S. range, 92.9% of the loci were polymorphic and overall genetic diversity was 0.290. Such high levels of genetic diversity are consistent with its history of multiple introductions over an extended period of time. The average proportions of polymorphic loci and genetic diversity within populations were 55.7% (range = 28.6–85.7%) and 0.213 (range = 0.114–0.317), respectively. The proportion of total genetic diversity found among populations was similar to species with equivalent life history characters (G_ST = 0.199). No regional patterns of variation were seen. The number of putative genotypes in each population ranged from 2 to 26. Mean genotypic diversity was 0.694, ranging from 0.223 to 0.955. Such high levels of genotypic diversity indicate that local sites are often colonized by several propagules (most likely seeds) and/or that sexual reproduction occurs within populations after establishment. An excess of heterozygosity was observed in populations with few unique genets, implying that selection for highly heterozygous individuals may occur in populations of P. lobata.     

Tricharia vezdae (Ascomycetes: Asterothyriaceae), a new lichen species from the southeastern United States

Tricharia vezdae is described as new from specimens collected in Tennessee, Louisiana and Florida. It is characterized by a corticolous habit, the presence of only a few sterile hairs, the unusual structure of the conidia-like hyphae on the hyphophores and of the ascospores.

     

Evidence of population bottleneck in Astragalus michauxii (Fabaceae), a narrow endemic of the southeastern United States

Genetic factors such as decreased genetic diversity and increased homozygosity can have detrimental effects on rare species, and may ultimately limit potential adaptation and exacerbate population declines. The Gulf and Atlantic Coastal Plain physiographic region has the second highest level of endemism in the continental USA, but habitat fragmentation and land use changes have resulted in catastrophic population declines for many species. Astragalus michauxii (Fabaceae) is an herbaceous plant endemic to the region that is considered vulnerable to extinction, with populations generally consisting of fewer than 20 individuals. We developed eight polymorphic microsatellites and genotyped 355 individuals from 24 populations. We characterized the population genetic diversity and structure, tested for evidence of past bottlenecks, and identified evidence of contemporary gene flow between populations. The mean ratios of the number of alleles to the allelic range (M ratio) across loci for A. michauxii populations were well below the threshold of 0.68 identified as indicative of a past genetic bottleneck. Genetic diversity estimates were similar across regions and populations, and comparable to other long-lived perennial species. Within-population genetic variation accounted for 92 % of the total genetic variation found in the species. Finally, there is evidence for contemporary gene flow among the populations in North Carolina. Although genetic factors can threaten rare species, maintaining habitats through prescribed burning, in concert with other interventions such as population augmentation or (re)introduction, are likely most critical to the long term survival of A. michauxii.     

Temperature adaptation in the freshwater snail, helisoma trivolvis (say), in an artificially heated reservoir in the southeastern United States

Snails from a heated zone of Par Pond of the U.S. Savannah River Plant were compared with conspecifies from an unheated area of the same reservoir. The heated area averaged 5°C warmer and was thermally more variabic than the control area. This situation has existed for about twenty years. Variation in metabolic response to temperature was observed according to season and heated vs unheated area. A laboratory rearing experiment indicated that part of the observed variation was environmetally induced.

Life cycle and growth rates were similar in the two collection areas. Three generations were produced annually in both areas and spawning was synchronous except that the summer spawning period was shorter in the heated area. Live weights expressed relative to shell size were also similar, and decreased in both areas during summer.

It appears from these results that metabolic compensation for temperature can serve as an indicator of general thermal adaptability, but only if the degree of environmental plasticity is known for the species.     

Molecular zoogeography of freshwater fishes in the southeastern United States

Restriction fragment length polymorphisms in mitochondrial DNA (mtDNA) were used to reconstruct evolutionary relationships of conspecific populations in four species of freshwater fish—Amia calva, Lepomis punctatus, L. gulosus, and L. microlophus. A suite of 14-17 endonucleases was employed to assay mtDNAs from 305 specimens collected from 14 river drainages extending from South Carolina to Louisiana. Extensive mtDNA polymorphism was observed within each assayed species. In both phenograms and Wagner parsimony networks, mtDNA clones that were closely related genetically were usually geographically contiguous. Within each species, major mtDNA phylogenetic breaks also distinguished populations from separate geographic regions, demonstrating that dispersal and gene flow have not been sufficient to override geographic influences on population subdivision.—Importantly, there were strong patterns of congruence across species in the geographic placements of the mtDNA phylogenetic breaks. Three major boundary regions were characterized by concentrations of phylogenetic discontinuities, and these zones agree well with previously described zoogeographic boundaries identified by a different kind of data base—distributional limits of species—suggesting that a common set of historical factors may account for both phenomena. Repeated episodes of eustatic sea level change along a relatively static continental morphology are the likely causes of several patterns of drainage isolation and coalescence, and these are discussed in relation to the genetic data.—Overall, results exemplify the positive role that intraspecific genetic analyses may play in historical zoogeographic reconstruction. They also point out the potential inadequacies of any interpretations of population genetic structure that fail to consider the influences of history in shaping that structure.     

Leptospiral antibodies in white-tailed deer of the southeastern United States

Serum samples from 1,544 white-tailed deer (Odocoileus virginianus) collected in nine southeastern states were examined for leptospiral antibodies. Significant titers of 1:100 or greater were found in 292 deer. The highest prevalence of leptospiral antibodies was in Virginia, where 108 of 351 deer had significant titers. The most frequently encountered serotypes of Leptospira interrogans were: grippotyphosa (210 positive), pomona (81), and canicola (26). Other serotypes disclosed were australis (15), icterohaemorrhagiae (10), pyrogenes (6), tarassovi (hyos) (5), georgia (4), ballum (4), sejroe (3), bataviae (2) and autumnalis (2).     

Gondysia preceded Neadysgonia (Lepidoptera, Erebidae, Erebinae), a new generic synonymy from southeastern United States

The recently proposed genus Neadysgonia Sullivan, 2010, was preceded in the literature by Gondysia Berio, 1955, a monotypic genus based on specimens without locality labels but presumed to be from Madagascar. The genus Gondysia replaces Neadysgonia and the species Gondysia pertorrida Berio, 1955, becomes a junior synonym of Gondysia consobrina (Guenée, 1852).     

Agglutinins from marine macroalgae of the southeastern United States

Protein extracts from 22 species of marine macroalgae from Florida and North Carolina were compared for their abilities to agglutinate sheep and rabbit erythrocytes. Protein extracts from 21 algal species agglutinated rabbit erythrocytes compared to 19 for sheep erythrocytes. However, agglutination by brown algal extracts was variable. The agglutination produced by protein extracts from Dictyota dichotoma could be blocked by addition of polyvinylpyrrolidone. Protein extracts from North Carolina macroalgae were also tested against five bacterial species. Three of these agglutinated bacterial cells. Ulva curvata and Bryopsis plumosa agglutinated all five species. Protein extracts from five species of Florida algae were tested for their effects on mitogenesis in mouse splenocytes and human lymphocytes. Gracilaria tikvahiae HBOI Strain G-5, Ulva rigida and Gracilaria verrucosa HBOI Strain G-16S stimulated mitogenesis in mouse splenocytes, while Gracilaria tikvahiae HBOI Strain G-16stimulated mitogenesis in human lymphocytes.     

Molecular phylogeny, biogeography, and systematics of Dicerandra (Lamiaceae), a genus endemic to the southeastern United States

Dicerandra, an endemic mint of the southeastern United States, comprises nine species, all of which are threatened or endangered and restricted to sandhill vegetation and a mosaic of scrub habitats. Molecular phylogenetic analyses of Dicerandra based on data from the nuclear and plastid genomes for all 13 taxa of the genus, identified two strongly supported clades, corresponding to the four annual and to the five perennial species of Dicerandra. However, the nuclear and plastid trees were incongruent in their placement of two perennial taxa, D. cornutissima and D. immaculata var. savannarum, perhaps due to ancient hybridization or to lineage sorting. Based on these analyses, the widespread D. linearifolia is not monophyletic, with populations of D. linearifolia var. linearifolia falling into either western or eastern clades. The western clade, comprising populations of D. linearifolia var. linearifolia and var. robustior, occurs in an area drained by rivers flowing toward the Gulf of Mexico, whereas the eastern clade, comprising populations of D. linearifolia var. linearifolia, D. densiflora, D. odoratissima, and D. radfordiana (i.e., all the annual species), occupies a region drained by rivers flowing to the Atlantic Ocean. Although this pattern of genetic differentiation between populations from these two river drainages has been documented in several animal species, it has not previously been reported for plants. A revised subgeneric classification is presented to reflect the annual and perennial clades.     

Phylogeography of the salamander genus Pseudobranchus in the southeastern United States

This study provides an extensive set of mitochondrial cytochrome b sequences for the salamander genus Pseudobranchus of the southeastern United States. These sequences were analysed by multiple phylogenetic methods that support a single set of major phylogeographic divisions for its two corroborated species (P. axanthus and P. striatus). These phylogeographic divisions overlap with the geographic breakpoints of other freshwater and terrestrial taxa in this region. Collectively, these overlapping patterns highlight the Central Highland and Tifton/Vidalia uplands as a significant barrier to Atlantic vs. Gulf coast groups, while reconfirming the phylogeographic significance of the Altamaha and Apalachicola river drainages. Despite their distinct phylogeographic split, P. striatus from west and east of these uplands are not currently recognizable as separate species according to the concordance principles for species definition.     

Diseases diagnosed in wild turkeys (Meleagris gallopavo) of the southeastern United States

Diagnostic findings are presented on 139 sick or dead wild turkeys examined during the period 1972 through 1984. Turkeys originated from eight southeastern states (Alabama, Arkansas, Florida, Georgia, South Carolina, Tennessee, Virginia, West Virginia) and included 31 turkeys categorized as capture-related mortalities and 108 turkeys categorized as natural mortalities. Frequent diagnoses (greater than or equal to 10% of case accessions) in the natural mortality group were trauma, avian pox, and histomoniasis. Less frequent diagnoses (less than or equal to 4% of case accessions) included malnutrition/environmental stress syndrome, coligranuloma-like condition, crop impaction, bumblefoot, organophosphate toxicosis, infectious sinusitis, a lympho-proliferative disease, salmonellosis, aspergillosis, toxoplasmosis, crop trichomoniasis, and melorheostosis.     

Blood parasites in wood storks (Mycteria americana) from the southeastern United States

Wood storks (Mycteria americana) are endangered throughout their breeding range in the United States. Because of this, researchers have had little opportunity to thoroughly examine the continental wood stork population for endoparasites. The blood protozoan Haemoproteus crumenium has been identified from several populations of wood storks in North America. However, there have been no reports of wood storks being infected with species of Plasmodium or Leucocytozoon. During 2003, 42 nestling wood storks were captured at sites in Georgia and 27 free-ranging wood storks were captured at postbreeding dispersal sites in Mississippi and Louisiana. Two thin blood smears were made from each bird, and they were examined for parasites. Haemoproteus crumenium was found in 5 wood storks (7.2%), whereas Leucocytozoon sp., Plasmodium sp., and microfilariae were not observed. Mean intensity of H. crumenium was 4.4 +/- 0.7 (SE) per 2,000 erythrocytes counted. All infected wood storks were subadult or adult and were from postbreeding dispersal sites in Mississippi.     

ABA-induced tolerance to ion leakage during rehydration following desiccation in the moss Atrichum androgynum

A simple ion leakage assay was used to investigate the effect ofabscisic acid (ABA) pretreatment on desiccation tolerance in the mossAtrichum androgynum. Results from experiments involvingtheapplication of the protein synthesis inhibitor cyclohexamide during desiccationor rehydration suggested that pretreatment with ABA does not facilitate theproduction of protection or repair proteins duringdesiccation or rehydration. Rather, ABA induces the synthesis of these proteinsduring pretreatment. The ABA-induced increase in tolerance was much less ifplants were pretreated in the dark. Exposure to red light could not substitutefor white light, suggesting that ABA action does not require phytochrome.Desiccating intact long stem segments or long segments separated into apicalandbasal parts had no effect on the desiccation tolerance of either plant part.This suggests that no movement of signals or protective molecules occurs fromthe stem bases to the apices during desiccation. Basal stem segments were muchmore sensitive to desiccation than apical regions, suggesting during senescencea breakdown in mechanisms that protect mosses from injury occurs. Theimplications of these findings for the water relations of A.androgynum are discussed.     

Bioenergy production and forest landscape change in the southeastern United States

Production of woody biomass for bioenergy, whether wood pellets or liquid biofuels, has the potential to cause substantial landscape change and concomitant effects on forest ecosystems, but the landscape effects of alternative production scenarios have not been fully assessed. We simulated landscape change from 2010 to 2050 under five scenarios of woody biomass production for wood pellets and liquid biofuels in North Carolina, in the southeastern United States, a region that is a substantial producer of wood biomass for bioenergy and contains high biodiversity. Modeled scenarios varied biomass feedstocks, incorporating harvest of ‘conventional’ forests, which include naturally regenerating as well as planted forests that exist on the landscape even without bioenergy production, as well as purpose‐grown woody crops grown on marginal lands. Results reveal trade‐offs among scenarios in terms of overall forest area and the characteristics of the remaining forest in 2050. Meeting demand for biomass from conventional forests resulted in more total forest land compared with a baseline, business‐as‐usual scenario. However, the remaining forest was composed of more intensively managed forest and less of the bottomland hardwood and longleaf pine habitats that support biodiversity. Converting marginal forest to purpose‐grown crops reduced forest area, but the remaining forest contained more of the critical habitats for biodiversity. Conversion of marginal agricultural lands to purpose‐grown crops resulted in smaller differences from the baseline scenario in terms of forest area and the characteristics of remaining forest habitats. Each scenario affected the dominant type of land‐use change in some regions, especially in the coastal plain that harbors high levels of biodiversity. Our results demonstrate the complex landscape effects of alternative bioenergy scenarios, highlight that the regions most likely to be affected by bioenergy production are also critical for biodiversity, and point to the challenges associated with evaluating bioenergy sustainability.