Infections of granulocytic ehrlichiae and Borrelia burgdorferi in white-tailed deer in Connecticut

Serum or whole blood samples, obtained from 141 white-tailed deer (Odocoileus virginianus) in Connecticut (USA) during 1980, 1991, and 1996, were analyzed to detect past or current infections of Ehrlichia phagocytophila genogroup organisms and Borrelia burgdorferi. When the BDS or NCH-1 strains of granulocytic ehrlichiae were used separately in indirect fluorescent antibody (IFA) staining methods, antibody positivity rates varied from 25 to 64% in 1991 and 1996, respectively. All 50 sera tested from 1980 collections were negative. Although percentages of sera with B. burgdorferi antibodies, as detected by an enzyme-linked immunosorbent assay, also differed (23 to 53%), there were coexisting antibodies to both bacteria in 20 (49%) of 41 sera. In tests on specificity, 19 deer sera with ehrlichial antibodies also were tested by IFA staining procedures for Anaplasma marginale antibodies; one serum with a titer of 1:5,120 to ehrlichial antigen reacted to A. marginale antigen at a serum dilution of 1:320. In parallel analyses of 69 sera, results of Western blot analyses for ehrlichial infections in deer were concordant (72% agreement) with those of IFA staining methods containing ehrlichial antigen. All positive immunoblots showed bands to peptides of the NCH-1 strain of the human granulocytic ehrlichiosis (HGE) agent having molecular masses of about 44, 105, or 110 kDa. In polymerase chain reaction (PCR) studies of blood samples from 63 deer, 11 (18%) specimens were positive for 16S ribosomal DNA of an Ehrlichia phagocytophila genogroup organism, whereas 23 (37%) samples were positive for the DNA of the 44 kDa gene of the HGE agent. White-tailed deer are exposed to different tick-borne bacteria in areas where Ixodes scapularis ticks are abundant and may, in some instances, have had concurrent infections.     

Comparative phylogeography of eastern chipmunks and white-footed mice in relation to the individualistic nature of species

Palaeoecological studies have demonstrated that ecological communities as a whole did not remain stable throughout the climatic fluctuations of the Quaternary. The result is that long-term associations of species cannot be inferred by contemporary associations in ecological communities. Therefore, the evolutionary significance of any contemporary ecological interactions among species and of the biotic community within which species have evolved also cannot be assumed from contemporary conditions. Comparative phylogeographic data provide a method to identify species within ecological communities that have shared biogeographic histories. We present an example of a long-term association between populations of two mammalian species, eastern chipmunks (Tamias striatus) and white-footed mice (Peromyscus leucopus), which are commonly associated with deciduous forest habitats. The distribution of mitochondrial DNA variation in T. striatus and P. leucopus from previously glaciated regions of the eastern United States support the hypothesis that, in at least part of their range, genetic lineages of the two species have expanded from similar population sources since the Last Glacial Maximum. In addition, the spatial concordance of genetic lineages of T. striatus and P. leucopus with the oak-savannah forest formations of Wisconsin and Illinois, suggest that populations associated with this community colonized the area in association with a set of arboreal species that comprise their deciduous forest habitat.     

Helicoverpa zea and Bt cotton in the United States

Helicoverpa zea (Boddie), the bollworm or corn earworm, is the most important lepidopteran pest of Bt cotton in the United States. Corn is the preferred host, but the insect feeds on most flowering crops and wild host plants. As a cotton pest, bollworm has been closely linked to the insecticide-resistance prone Heliothis virescens (F.), tobacco budworm. Immature stages of the two species are difficult to separate in field environments. Tobacco budworm is very susceptible to most Bt toxins, and Bt cotton is considered to be "high dose." Bollworm is less susceptible to Bt toxins, and Bt cotton is not "high dose" for this pest. Bt cotton is routinely sprayed with traditional insecticides for bollworm control. Assays of bollworm field populations for susceptibility to Bt toxins expressed in Bt cotton have produced variable results since pre-deployment of Bt cottons in 1988 and 1992. Analyses of assay response trends have been used by others to suggest that field resistance has evolved to Bt toxins in bollworm, but disagreement exists on definitions of field resistance and confidence of variable assay results to project changes in susceptibility of field populations. Given historical variability in bollworm response to Bt toxins, erratic field control requiring supplemental insecticides since early field testing of Bt cottons, and dramatic increases in corn acreage in cotton growing areas of the Southern US, continued vigilance and concern for resistance evolution are warranted.     

Antibodies to whole-cell or recombinant antigens of Borrelia burgdorferi, Anaplasma phagocytophilum, and Babesia microti in white-footed mice

Serum samples were obtained from white-footed mice (Peromyscus leucopus) in tick-infested areas of Connecticut during the period 2001 through 2003 and analyzed for antibodies to Borrelia burgdorferi, Anaplasma phagocytophilum, and Babesia microti. Emphasis was placed on the evaluations of highly specific recombinant VlsE or protein (p) 44 antigens of B. burgdorferi and A. phagocytophilum, respectively, in a newly developed enzyme-linked immunosorbent assay (ELISA) as well as testing sera with whole-cell antigens by conventional ELISA or indirect fluorescent antibody staining methods. Of the 414 mouse sera analyzed, 310 (75%) had antibodies to whole-cell B. burgdorferi, whereas 157 (38%) were positive to the VlsE antigen. The latter nearly equaled the overall antibody prevalence rate (37%) computed when sera were tested separately with the p44 antigen. Mice were exposed to these pathogens and B. microti (antibody prevalence = 25%) in extreme northern Connecticut as well as the southern coastal areas of the state, thus indicating further geographic expansion of these infections. Fifty-three (13%) sera from widely separated sites had antibodies to all three pathogens. With expression and immunological recognition of VlsE and p44 antigens in P. leucopus, separate incorporation of these fusion proteins in an ELISA was very helpful in confirming past or current infections and in identifying specific foci for B. burgdorferi and A. phagocytophilum.     

Sustained susceptibility of pink bollworm to Bt cotton in the United States

Evolution of resistance by pests can reduce the benefits of transgenic crops that produce toxins from Bacillus thuringiensis (Bt) for insect control. One of the world's most important cotton pests, pink bollworm (Pectinophora gossypiella), has been targeted for control by transgenic cotton producing Bt toxin Cry1Ac in several countries for more than a decade. In China, the frequency of resistance to Cry1Ac has increased, but control failures have not been reported. In western India, pink bollworm resistance to Cry1Ac has caused widespread control failures of Bt cotton. By contrast, in the state of Arizona in the southwestern United States, monitoring data from bioassays and DNA screening demonstrate sustained susceptibility to Cry1Ac for 16 y. From 1996-2005, the main factors that delayed resistance in Arizona appear to be abundant refuges of non-Bt cotton, recessive inheritance of resistance, fitness costs associated with resistance and incomplete resistance. From 2006-2011, refuge abundance was greatly reduced in Arizona, while mass releases of sterile pink bollworm moths were made to delay resistance as part of a multi-tactic eradication program. Sustained susceptibility of pink bollworm to Bt cotton in Arizona has provided a cornerstone for the pink bollworm eradication program and for integrated pest management in cotton. Reduced insecticide use against pink bollworm and other cotton pests has yielded economic benefits for growers, as well as broad environmental and health benefits. We encourage increased efforts to combine Bt crops with other tactics in integrated pest management programs.     

Antibodies to vesicular stomatitis virus in populations of feral swine in the United States

From 1979 to 1985, 941 feral swine (Sus scrofa) from 53 locations in 15 states were serologically tested for antibodies to vesicular stomatitis virus (VSV). Antibodies to New Jersey serotype VSV were present in 75 swine from five locations in Arkansas, Florida, Georgia, and Louisiana. Within these populations, antibody prevalences ranged from 10 to 100%. No antibodies to Indiana serotype were detected.     

Late Quaternary biomes of Canada and the eastern United States

Pollen data have been used to construct biome maps for today, 6000 ¹⁴C yr bp and 18,000 ¹⁴C yr bp for Canada and the eastern United States. The inferred modern biome distributions agree well with independent reconstructions of North American vegetation prior to European settlement. Some discrepancies between the pollen data and the modern potential vegetation are caused by post‐settlement clearing of the landscape and the consequent increase of herbaceous types in the recent pollen record. Biome distributions at 6000 ¹⁴C yr bp reflected the warmer and drier conditions then prevalent in the continental interior, but the overall position of biomes was similar to that of today. The boreal treeline in North America was not significantly north of its present position, in contrast to the 100–200 km shift reported for Siberia. At the last glacial maximum (18,000 ¹⁴C yr bp ), steppe and tundra were prevalent in the Midwest and north‐western Canada, and coniferous forests and woodlands grew in eastern North America. The open vegetation at 18,000 ¹⁴C yr bp was probably due to drier conditions and/or lower concentrations of atmospheric CO₂. The composition and physical structure of biomes is not constant over time. Mid‐Holocene biomes were similar in structure to those of today, but shifts in the relative importance of individual plant functional types are large enough that the physical properties of biomes, such as albedo, canopy conductance and surface roughness, are likely to have varied even during the Holocene. Last glacial maximum biomes were structurally different from their modern counterparts. The biome maps therefore may obscure significant vegetational changes in space and time during the late Quaternary. The difference between the highest and next highest affinity scores for each sample measures how strongly affinity scores discriminate among biomes. For many biomes, the difference is not large, and affinity score ties are not uncommon, highlighting the importance of tie‐break procedures when using the biomization method.     

Anisotropic spread of hemlock woolly adelgid in the eastern United States

Simple population models predict that the spread of an invading species through a homogenous habitat should be equal in all directions, but geographic variation in the habitat that affects either reproduction or movement could result in variable rates of spread. We analyse records of the historical range expansion of the hemlock woolly adelgid (HWA) (Adelges tsugae Annand) in the eastern United States from 1951 to 2006 to document that this species has spread in an anisotropic fashion. Furthermore, the magnitude and direction of this anisotropy has varied through time. We explore the extent to which this spatial and temporal variation in spread can be explained by geographical variation in climate and by the abundance of hosts, eastern hemlock (Tsuga canadensis L.) and Carolina hemlock (Tsuga caroliniana Engelm.). We found that a significant component of the spatial anisotropy in HWA spread rate can be explained by the geographical distribution of host trees. January temperatures were negatively associated with spread rates but this may be an artifact of the association between hemlock and cold climates. The current distribution of the adelgid in eastern N. America may be approaching the extent of its potential range to the south and west determined by availability of host hemlock and to the north determined by lethal cold winter temperatures.     

Xeric limestone prairies of eastern United States: Review and synthesis

Xeric limestone prairies (XLPs) are open, nonforested areas in which herbaceous plant communities occur on shallow, rocky soils derived from calcareous substrates. These grasslands are characterized by dominance of C₄ perennial grasses (particularlySchizachyrium scoparium) and are distributed in eastern United States from Missouri and Pennsylvania south to Arkansas and Georgia. XLPs occur in the Ozark Plateaus, Central Lowland, Interior Low Plateaus, Appalachian Plateaus, Ridge and Valley, and Coastal Plain physiographic provinces, and they are developed on Alfisols, Ultisols, Mollisols, Inceptisols, and Vertisols derived from Paleozoic limestones (also Eocene), dolomites, and calcareous shales. The C₄ perennial prairie grassS. scoparium is the characteristic dominant taxon in XLPs of eastern United States. However, C₃ perennial forbs are dominant in some sites, and C₄ annual grasses (Sporobolus spp.) may be locally dominant in shallow-soil-zone microsites. Thirteen taxa apparently are endemic, or nearly so, to this vegetation type, including eight in the Ridge and Valley in Alabama (Cahaba River valley), four in the Ozark Plateaus in Missouri and Arkansas, and one in the Ridge and Valley of West Virginia and Virginia. Various types of information are used to construct a conceptual model of the origin, maintenance, and successional dynamics of XLPs. Affinities of XLPs in eastern United States to other herbaceous vegetation types in eastern and western North America are discussed, and directions for future research are suggested.     

Tree mortality in the eastern and central United States: patterns and drivers

Substantial uncertainty surrounds how forest ecosystems will respond to the simultaneous impacts of multiple global change drivers. Long‐term forest dynamics are sensitive to changes in tree mortality rates; however, we lack an understanding of the relative importance of the factors that affect tree mortality across different spatial and temporal scales. We used the US Forest Service Forest Inventory and Analysis database to evaluate the drivers of tree mortality for eastern temperate forest at the individual‐level across spatial scales from tree to landscape to region. We investigated 13 covariates in four categories: climate, air pollutants, topography, and stand characteristics. Overall, we found that tree mortality was most sensitive to stand characteristics and air pollutants. Different functional groups also varied considerably in their sensitivity to environmental drivers. This research highlights the importance of considering the interactions among multiple global change agents in shaping forest ecosystems.     

Paleoenvironment of Late Mississippian fenestrate bryozoans, eastern United States

Fenestrate bryozoans in Chesterian rocks of the eastern United States are common to abundant in diverse carbonate platform lithologies but are not common in clastic deposits. Fenestella and Archimedes are the most abundant and widespread. Fenestella apparently tolerated a range of water agitation and lived on shoal margins as well as in more protected areas. Archimedes required quiet bottoms and was locally extremely abundant immediately leeward of shoals. Polypora and Septopora were less common than, but had a similar distribution to, Fenestella except that they apparently did not live on shoals. Lyroporella inhabited zones of pronounced current activity and fine quartz sand influx. Penniretepora and Ptylopora were least often encountered, restricted to fine-grained sediments deposited in protected regions.     

Landscape-scale drivers of fish faunal homogenization and differentiation in the eastern United States

Hydrobiologia - Establishment of nonnative fishes and extirpations of native fishes have homogenized freshwater fish faunas, yet our understanding of the drivers of this process remain limited. We...     

Prescribed take levels of downy and hairy woodpeckers in the eastern United States

Hairy (Dryobates villosus) and downy (Dryobates pubescens) woodpeckers occur in high densities in residential areas of the eastern United States. In many areas of their range, they cause damage to wooden structures through foraging, excavation of nesting cavities, and drumming behaviors, causing requests for allowable take permits. Both species hold year-round territories, which could make them vulnerable to local extirpation with excess take. To meet the requirements of the Migratory Bird Treaty act, the United States Fish and Wildlife Service (USFWS) requested scientifically informed evaluation of take to minimize population effects as part of its approach to reduce human–wildlife conflict. We used a prescribed take approach, which uses data from population, demographic, and management parameter estimates to determine the allowable take from Louisiana to Minnesota and all states east. Furthermore, we used 2 different methods of estimating growth rates to control for demographic uncertainties. The resulting estimates provide take at the state and USFWS regional scales to improve stakeholder choices when setting allowable take. Current authorized take (2016–2018) is below the take that could be sustained by current populations, and current rates of take are not likely to cause population-level effects. These results were largely consistent across methodologies for calculating the rate of growth for both species. Take still needs to be managed to prevent local extirpation of these resident species. Allowable take estimates should be periodically updated to reflect changing management and population needs for both species.     

Mineralogy of the rhizosphere in forest soils of the eastern United States

Chemical and mineralogical studies of forest soils from six sites in the northeastern and southeastern United States indicate that soil in the immediate vicinity of roots and fine root masses may show marked differences in physical characteristics, mineralogy and weathering compared to the bulk of the forest soil. Examination of rhizosphere and rhizoplane soils revealed that mineral grains within these zones are affected mechanically, chemically and mineralogically by the invading root bodies. In SEM/EDS analyses, phyllosilicate grains adjacent to roots commonly aligned with their long axis tangential to the root surface. Numerous mineral grains were also observed for which the edge abutting a root surface was significantly more fractured than the rest of the grain. Both the alignment and fracturing of mineral grains by growing roots may influence pedogenic processes within the rhizosphere by exposing more mineral surface to weathering in the root-zone microenvironment. Chemical interactions between roots and rhizosphere minerals included precipitation of amorphous aluminium oxides, opaline and amorphous silica, and calcium oxalate within the cells of mature roots and possible preferential dissolution of mineral grains adjacent to root bodies. Mineralogical analyses using X-ray diffraction (XRD) techniques indicated that kaolin minerals in some rhizosphere samples had a higher thermal stability than kaolin in the surrounding bulk forest soil. In addition, XRD analyses of clay minerals from one of the southeastern sites showed abundant muscovite in rhizoplane soil adhering to root surfaces whereas both muscovite and degraded mica were present in the immediately surrounding rhizosphere soil. This difference in mineral assemblages may be due to either K-enrichment in rhizoplane soil solutions or the preferential dissolution of biotite at the root-soil interface