Root-infecting fungi associated with a decline of longleaf pine in the southeastern United States

A 35-year-old longleaf pine stand exhibited trees in various stages of decline. A study was conducted to determine root-infecting fungi and other abnormalities associated with varying degrees of crown symptoms. A four-class crown symptom rating system was devised according to ascending symptom severity. Leptographium procerum and L. terebrantis were significantly associated with increasing crown symptom severity. Heterobasidion annosum was also isolated in higher frequency as crown symptoms increased. Also, evidence of insects on roots increased as did amount of resinosis observed. Edaphic and silvicultural factors may interact with these pathogens and insects to pose a pathological limitation on longer-term management objectives. Further research is needed to determine relationships among various edaphic, silvicultural, and biological factors associated with the decline syndrome on this site. This revised version was published online in June 2006 with corrections to the Cover Date.     

Fungal assemblages associated with sponges of the southern coast of Sakhalin Island

This paper examines the biodiversity of fungi associated with six species of sponges from the southern coast of Sakhalin Island. The species richness of fungal assemblages is represented by 78 species, mainly Anamorphic fungi. The diversity and numbers of fungi depend on the species of sponge, which is due to the rigidity of the skeleton and the morphological characteristics of the sponges.     

Occurrence of bluegreen algae (Cyanophyta) in the phytoplankton off the southeastern coast of the United States

Bluegreen algae are more common in the continental shelf watersoff the southeastern U.S. coast than previous reports indicate.Sixteen species have been noted in collections taken in 1973and 1978. These include both filamentous and coccoid forms,many of which are part of the nanoplankton component. The estuaryand coastal marsh systems are suggested as a source for manyof the bluegreen algae found in the shelf phytoplankton. A broaderrole in nutrient relationships of the shelf area is also suggestedfor this group.     

Ultrastructure of the body cavities in juveniles and adults of the appendicularian Oikopleura gracilis (Tunicata,Chordata) suggests how the heart may have evolved in tunicates

The organization of the body cavities is an important morphological trait that can be used for establishing the phylogenetic relationships between different groups of animals. In the present study, the hemocoel and coelomic systems of 10‐hr‐old juveniles and adults of the hermaphroditic oikopleurid Oikopleura gracilis were examined using light and transmission electron microscopy. The trunk hemocoel in 10‐hr‐old juveniles was represented by small clefts containing layers of extracellular matrix of adjacent tissues or interstices with migrating primordial germ syncytium. The wide hemocoel in the tail contained extracellular strands, subdividing the hemocoel into hemal sinuses. In adults, a large hemocoel appeared in the trunk and tail, and also contained extracellular strands. The hermaphroditic gonad was surrounded by its own lining, separating it from the hemocoel. The gamete‐filled cavity in the ovary and testis appeared only at late‐stage gonadogenesis, when the pre‐spawning reduction of syncytium occurred in the gonads. The true coelom in 10‐hr‐old juveniles and adults was represented by the pericardium. The lining of the pericardium consisted of myoepithelial and peritoneal cells. In the myoepithelial cells of 10‐hr‐old juveniles, myofibrils had been formed. The myoepithelial cells of adults had several parallel rows of completely differentiated myofibrils. The substantial reduction of the coelomic and circulatory systems in O. gracilis evidently results from the extreme shortening of ontogeny in appendicularians. Development in O. gracilis from early juvenile to adult involves the following steps, which also suggest how the tunicate heart may have evolved: a single‐layered coelomic sac gives rise to a grooved pericardium with an open hemal sinus (simple heart). In ascidians, this simple heart in turn gives rise to a closed tubular, double‐layered heart–pericardial complex, with a separate pericardial cavity and a closed heart, whose wall is formed by specialized myocardium.     

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.     

Seasonality of the copepod assemblages associated with interplay waters off northeastern Taiwan

This study investigated copepod assemblages in the regime around Turtle Island off northern Taiwan to trace South China Sea water (SCSW) flowing northward with the Kuroshio Current. Seasonal variations of copepod assemblages demonstrated a dynamic succession of changes in copepod populations; the average abundance for total copepods ranged from 102.58 ± 53.38 in December to 1669.89 ± 1866.17 in March (individuals m^?3). A total of 87 copepod species representing 36 genera and 21 families were identified. Among all samples, Temora turbinata dominated the copepods by a relative abundance (RA) of 26.89 %, followed by Paracalanus parvus (RA: 22.34 %) and Corycaeus (Ditrichocorycaeus) affinis (RA: 12.77 %). Only the Acrocalanus gracilis species was recorded in all samples. Results of one-way ANOVA revealed that the number of copepod species, indices of richness, evenness, and Shannon–Wiener diversity differed significantly in five different cruises. The density of five copepod species (Gaetanus minor, Calanus sinicus, Eucalanus elongates, Rhincalanus nasutus, and Rhincalanus rostrifrons) exhibited a significant negative correlation with seawater temperature. In contrast, the density of Canthocalanus pauper and Undinula vulgaris was significantly positively correlated with seawater temperature. The cold-water indicator species, C. sinicus, recorded in samples of March and May indicated the effect of China Coast Water (CCW) on copepod communities in the study area. Furthermore, the presence of Calanoides philippinensis in May samples strongly indicated that the SCSW may reach the Turtle Island area. Consequently, C. philippinensis and C. sinicus can be used to trace SCSW and CCW, respectively, in the study area.     

Large branchiopod assemblages common to Mexico and the United States

Cu, Cd, Zn and Pb concentrations in both dissolved andparticulate phase were assessed during 1995. DataQuality Assurance was an integral part of this studyand involved all major steps of the analysis proceduresuch as sampling, sample handling, preconcentrationand determination. Desorption and redox processes clearly control thedissolved Cu and Cd profiles. Mobilisation ofdissolved Zn is small and essentially restricted tothe low salinity area and the late spring survey.Dissolved Pb shows the clearest dilution pattern. Theparameters representative of these processes(dissolved oxygen and salinity) also correlate verywell with the particulate metal profiles. In addition, the plankton activity (expressed by thechlorophyll-a levels) may influence the dissolved andparticulate metal profiles. In combination withdesorption and redox processes, seasonal variationswere induced. This revised version was published online in July 2006 with corrections to the Cover Date.     

Argentine ant invasion associated with loblolly pines in the southeastern United States: minimal impacts but seasonally sustained

Invasive ants are notorious for directly displacing native ant species. Although such impacts are associated with Argentine ant invasions (Linepithema humile) worldwide, impacts within natural habitat are less widely reported, particularly those affecting arboreal ant communities. Argentine ants were detected in North Carolina mixed pine-hardwood forest for the first time but were localized on and around loblolly pines (Pinus taeda), probably because of association with honeydew-producing Hemiptera. We explored the potential impacts of L. humile on arboreal and ground-foraging native ant species by comparing interspersed loblolly pines invaded and uninvaded by Argentine ants. Impacts on native ants were assessed monthly over 1 yr by counting ants in foraging trails on pine trunks and in surrounding plots using a concentric arrangement of pitfall traps at 1, 2, and 3 m from the base of each tree. Of floristics and habitat variables, higher soil moisture in invaded plots was the only difference between plot types, increasing confidence that any ant community differences were caused by Argentine ants. Overall patterns of impact were weak. Composition differed significantly between Argentine ant invaded and uninvaded trunks and pitfalls but was driven only by the presence of Argentine ants rather than any resulting compositional change in native ant species. Native ant abundance and richness were similarly unaffected by L. humile. However, the abundance of individual ant species was more variable. Although numbers of the arboreal Crematogaster ashmeadi (Myrmicinae) declined on and around invaded pines, epigeic Aphaenogaster rudis (Myrmicinae) remained the most abundant species in all plots. Argentine ant densities peaked in late summer and fall, therefore overlapping with most native ants. Unexpected was their continued presence during even the coldest months. We provide evidence that Argentine ants can invade and persist in native North Carolina forests, probably mediated by pine-associated resources. However, their localized distribution and minimal impact on the native ant fauna relative to previously described invasions requires further resolution.     

The ecological condition of geographically isolated wetlands in the southeastern United States: The relationship between landscape level assessments and macrophyte assemblages

Geographically isolated wetlands (GIWs) are common features of the Dougherty Plain physiographic region in southwestern Georgia. Due to lack of protection at the state and federal levels, these wetlands are threatened by intensive agricultural and silvicultural land uses common in the region. Recently, the ecological condition of such GIWs was assessed for the southeastern United States using the Landscape Development Intensity Index (LDI), a practical assessment tool that relies on remotely sensed land use and land cover (LULC) data surrounding isolated wetlands to rapidly predict wetland condition. However, no assessments have been attempted for GIWs in the Dougherty Plain specifically. Our goal was to develop a framework to guide and refine remote assessment of wetland condition within this agriculturally intense region of the southeastern USA. In this study, we characterized human disturbances associated with isolated wetlands in the Dougherty Plain, and paired the rapid assessment of GIWs using LDI with an intensive assessment of wetland plant communities. Specifically, we: (1) examined how macrophyte assemblages and vegetation metrics vary across a human disturbance gradient in the Dougherty Plain; (2) compared multiple condition assessment outcomes using variations of the LDI method that differed in spatial extent and resolution of LULC categories; and (3) determined the predicted condition of GIWs in the Dougherty Plain as indexed by LDI and compared with region-wide assessments of GIWs of the southeastern USA. Generally, the relationship between wetland plant communities and surrounding land use supported the assumptions of the LDI index in that wetlands surrounded by agricultural land use classes featured distinct plant communities relative to those surrounded by forested land use classes. Our results indicated that finer spatial resolution of LULC data improved the predictive ability of LDI. However, based on incongruence between wetland vegetation composition and LDI scores in some forested landscapes, this study identified limitations of the LDI assessment method, particularly when applied in regions in which prescribed fire is an important ecological driver of vegetation and habitat. Thus, we conclude that LDI may be biased toward an overestimation of reference condition GIWs, even though the habitat may be functionally degraded by the absence of natural processes such as fire. Regardless, relative to the assessment of the entire southeastern US, a greater proportion of total GIWs of the Dougherty Plain were identified as impaired due to the intensity of irrigated agricultural land use.     

Taxonomic and Biological Characterization of Steinernema rarum Found in the Southeastern United States

Two Steinernema isolates found in Louisiana and Mississippi were later identified as isolates of S. rarum. DNA sequences of ITS regions of the United States isolates are identical with sequences of Argentinean S. rarum strains Samiento and Noetinger and differ by two bases from the Arroyo Cabral isolate from Córdoba, Argentina. SEM observations revealed several new structures in the isolates from the US: female face views have a hexagonal-star perioral disc and eye-shaped lips; some females do not have cephalic papillae; lateral fields of infective juveniles are variable; there are two openings observed close to the posterior edge of the cloaca. Virulence of the US isolates to Anthonomus grandis, Diaprepes abbreviatus, Solenopsis invicta, Coptotermes formosanus, Agrotis ipsilon, Spodoptera frugiperda, and Trichoplusia ni and reproductive potential were evaluated in comparison with other heterorhabditid and steinernematid nematodes. Results such as particularly high virulence to S. frugiperda indicate that the biocontrol potential of the new S. rarum strains merits further study.     

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.     

Black Scoter habitat use along the southeastern coast of the United States

While the Atlantic Coast of the United States and Canada is a major wintering area for sea ducks, knowledge about their wintering habitat use is relatively limited. Black Scoters have a broad wintering distribution and are the only open water species of sea duck that is abundant along the southeastern coast of the United States. Our study identified variables that affected Black Scoter (Melanitta americana) distribution and abundance in the Atlantic Ocean along the southeastern coast of the United States. We used aerial survey data from 2009 to 2012 provided by the United States Fish and Wildlife Service to identify variables that influenced Black Scoter distribution. We used indicator variable selection to evaluate relationships between Black Scoter habitat use and a variety of broad‐ and fine‐scale oceanographic and weather variables. Average time between waves, ocean floor slope, and the interaction of bathymetry and distance to shore had the strongest association with southeastern Black Scoter distribution.     

The diminutive supercolony: the Argentine ants of the southeastern United States

Native to Argentina and Brazil, the Argentine ant (Linepithema humile) is an invasive species that has become established on six continents and many oceanic islands. In several parts of its introduced range, including the western United States, southern Europe and Chile, the Argentine ant is unicolonial, forming extensive supercolonies. We examined population genetic structure and intercolony aggression in two regions of the introduced range of this species in the United States: California and the southeastern United States. Our results show that the southeastern L. humile population has high genotypic variability and strong intercolony aggression relative to the California population. In the California population, intercolony aggression was absent and 23 alleles were found across seven polymorphic microsatellite loci. However, in the Southeast, aggression between colonies was high and 47 alleles were present across the same seven loci in an equal number of colonies. We suggest that distinctly different colonization patterns for California and the Southeast may be responsible for the striking disparity in the genetic diversity of introduced populations. Southeastern colonies may have descended from multiple, independent introductions from the native range, undergoing a bottleneck at each introduction. In contrast, the California supercolony may have originated from one or more colonies inhabiting the southeastern United States, thus experiencing a double bottleneck. The differences in present-day distribution patterns between California and the Southeast may be due to the combined effect of two factors: lower winter temperatures in the Southeast and/or competition with another successful and widely distributed ant invader, the fire ant Solenopsis invicta.     

Survival and cause-specific mortality of male wild turkeys across the southeastern United States

Estimating survival and cause-specific mortality of male eastern wild turkeys (Meleagris gallopavo silvestris) is important for understanding population dynamics and implementing appropriate harvest management. To better understand age-specific estimates of annual survival and harvest rates, we captured and marked male wild turkeys with leg bands (n = 311) or bands and transmitters (n = 549) in Georgia, Louisiana, North Carolina, and South Carolina, USA, during 2014–2022. We fitted time to event models to data from radio-marked birds to estimate cause-specific mortality and annual survival. We used band recovery models incorporating both band recovery and telemetry data to further investigate harvest rates and survival. Annual survival from known-fate models in hunted populations was 0.54 (95% CI = 0.49–0.59) for adults and 0.86 (95% CI = 0.81–0.92) for juveniles. Cause-specific mortality analysis produced an annual harvest estimate of 0.29 (95% CI = 0.24–0.33) for adults and 0.02 (95% CI = 0.01–0.03) for juveniles, whereas predation was 0.15 (95% CI = 0.10–0.20) and 0.12 (95% CI = 0.08–0.17), respectively. Annual survival for adult males in a non-hunted population was 0.83 (95% CI = 0.72–0.97). Survival rate was negatively correlated with harvest rate, indicating harvest was an additive mortality source. Annual survival from band recovery models was 0.40 (95% CI = 0.37–0.44) for adults and 0.88 (95% CI = 0.81– 0.93) for juveniles, whereas annual harvest estimates were 0.24 (95% CI = 0.23–0.25) for adults and 0.04 (95% CI = 0.03–0.05) for juveniles. Both models suggested no differences in annual survival across years or among study areas, which included privately owned and public properties. Harvest was an additive mortality source for male wild turkeys, suggesting that managers interested in increasing annual survival of adult males could consider ways of reducing harvest rates.     

New species of Septobasidium from southern Costa Rica and the southeastern United States

New species are described in Septobasidium, a genus of urediniomycete parasites on scale insects. One new species, S. gomezii, is described from Costa Rica, and another, S. meredithiae, is described from Louisiana. S. gomezii is most similar to S. septobasidioides, but macroscopic and microscopic differences support it being a distinct species. S. meredithiae is similar to S. alni and S. castaneum but differs from these species in several macroscopic and microscopic characters, especially when the species are observed on the same host tree and insect species. Another species collected only once in Costa Rica is listed with observations but it is not formally described here. This Septobasidium species shares some key characteristics with S. ramorum but combines a dense, compact, nearly black thallus and pigmented probasidia-like structures with spindle-shaped haustoria. Implications for taxonomy, morphological evolution and host specificity in Septobasidium are discussed.     

Antimicrobial activity of marine bacteria associated with sponges from the waters off the coast of South East India

Seventy-five marine bacterial strains associated with four species of sponges (Echinodictyum sp., Spongia sp., Sigmadocia fibulatus and Mycale mannarensis) were isolated from the Tuticorin coast, Gulf of Mannar region. The agar-overlay method was used to screen for antibiotic production by these strains against four bacteria, viz., Bacillus subtilis, Escherichia coli, Vibrio parahaemolyticus, and Vibrio harveyi and one fungal pathogen, viz., Candida albicans. Twenty-one per cent of the bacterial strains were found to be antibiotic producers and their activities ranged from broad spectral to species specific. A strain coded SC3 was found to be highly potent and was mass cultured. The ethyl acetate extract of the culture broth was further fractionated by reverse phase HPLC and the active fraction identified. In addition, SC3 was subjected to morphological and physiological characterization. The results of the tests showed SC3 to be a Gram-positive rod, sporulating, motile, catalase and oxidase positive. Phylogenetic analysis based on comparative analysis of sequenced 16s rRNA of the active strains indicated a preponderance of bacteria belonging to Vibrio and Bacillus genera with 95-99% sequence similarities. To our knowledge this is the first report on phylogenetic identification of antibiotic producing bacteria associated with sponges from Indian waters.     

Species richness of marine Bryozoa in the continental shelf and slope off Argentina (south-west Atlantic)

Abstract.  A total of 246 marine bryozoan species was recorded within an area of the south-west Atlantic between 35° and 56°S, and between the coast of Argentina and 50°W. The distribution pattern of benthic stations surveyed during the most important cruises in the area shows that the sampling effort has been biased towards southern shelf areas off Santa Cruz and Tierra del Fuego, as well as around the Malvinas (Falkland) islands. The littoral zone, Patagonian gulfs and the continental shelf off Chubut, Río Negro and Buenos Aires state received less attention, and should be surveyed more intensively in the future. Only 2% of the species can be regarded as non-indigenous, all of them inhabiting biofouling communities in harbour environments. With the exception of some thoroughly surveyed localities, the number of species recorded for different areas of the coast, shelf and slope is estimated to be just a small fraction of the actual number of species present. A distinct diversity gradient was found, with species-rich stations located only in the southern shelf. Highest diversity occurred in shelf areas dominated by coarse sediments, and along a high-productivity shelf-break front. A remarkable decrease in species richness was found in inner and middle shelf areas off Chubut, Río Negro and Buenos Aires state. This pattern may be related to the Pacific origin of the Magellanic fauna, since the diversity of bryozoans is higher in the Pacific than in the Atlantic Ocean. The trend of species richness is, however, overemphasized by the fact that the least diverse faunistic assemblage occurs in areas where surveys have been relatively less frequent. An up-to-date checklist of species recorded for the study area is included.