Investigating damselfly populations at springs in Banff National Park, Canada, with special focus on Argia vivida, Amphiagrion abbreviatum, and Ischnura cervula (Odonata: Coenagrionidae)

The objective of this study was to estimate Argia vivida (Odonata: Coenagrionidae) populations, identify breeding habitat, and investigate movement of adults within Banff National Park, Alberta, Canada, during the summer of 2003. Mark-recapture techniques and standardized dip-net surveys were used to monitor Argia vivida at various life stages. A reproductive index identified which sites Argia vivida recognized as suitable breeding habitat, and exuvia surveys confirmed breeding sites. The basic structure of emergent and surrounding vegetation was measured to investigate the importance of available ovipositing or roosting sites and the condition of the matrix habitat. Data was recorded for Amphiagrion abbreviatum and Ischnura cervula (both Odonata: Coenagrionidae) to determine if these spring-associated damselflies were successfully breeding within Banff National Park. Comparisons were made between the highly protected Middle Springs and the heavily altered Cave & Basin Springs. Additional surveys at the Vermilion Lake cool spring and Middle Springs Bog investigated their use as breeding habitat for Amphiagrion abbreviatum and Argia vivida, respectively. Results suggest the ecological value of thermal springs extends beyond their origin to outflows and downstream pools. Conservation of Argia vivida must recognize the value of unobstructed thermal outflows, and consider the condition of the forested habitat surrounding springs with regard to its potential use as nocturnal roosts and dispersal corridors. Amphiagrion abbreviatum was confirmed breeding within Banff National Park, while no sign of breeding activity was recorded for Ischnura cervula.     

Environmental Constraints Underpin the Distribution and Phylogenetic Diversity of <Emphasis Type="Italic">nifH</Emphasis> in the Yellowstone Geothermal Complex

Biological nitrogen fixation is a keystone process in many ecosystems, providing bioavailable forms of fixed nitrogen for members of the community. In the present study, degenerate primers targeting the nitrogenase iron protein-encoding gene (nifH) were designed and employed to investigate the physical and chemical parameters that underpin the distribution and diversity of nifH as a proxy for nitrogen-fixing organisms in the geothermal springs of Yellowstone National Park (YNP), Wyoming. nifH was detected in 57 of the 64 YNP springs examined, which varied in pH from 1.90 to 9.78 and temperature from 16°C to 89°C. This suggested that the distribution of nifH in YNP is widespread and is not constrained by pH and temperature alone. Phylogenetic and statistical analysis of nifH recovered from 13 different geothermal spring environments indicated that the phylogeny exhibits evidence for both geographical and ecological structure. Model selection indicated that the phylogenetic relatedness of nifH assemblages could be best explained by the geographic distance between sampling sites. This suggests that nifH assemblages are dispersal limited with respect to the fragmented nature of the YNP geothermal spring environment. The second highest ranking explanatory variable for predicting the phylogenetic relatedness of nifH assemblages was spring water conductivity (a proxy for salinity), suggesting that salinity may constrain the distribution of nifH lineages in geographically isolated YNP spring ecosystems. In summary, these results indicate a widespread distribution of nifH in YNP springs, and suggest a role for geographical and ecological factors in constraining the distribution of nifH lineages in the YNP geothermal complex.     

Linking microbial oxidation of arsenic with detection and phylogenetic analysis of arsenite oxidase genes in diverse geothermal environments

The identification and characterization of genes involved in the microbial oxidation of arsenite will contribute to our understanding of factors controlling As cycling in natural systems. Towards this goal, we recently characterized the widespread occurrence of aerobic arsenite oxidase genes (aroA‐like) from pure‐culture bacterial isolates, soils, sediments and geothermal mats, but were unable to detect these genes in all geothermal systems where we have observed microbial arsenite oxidation. Consequently, the objectives of the current study were to measure arsenite‐oxidation rates in geochemically diverse thermal habitats in Yellowstone National Park (YNP) ranging in pH from 2.6 to 8, and to identify corresponding 16S rRNA and aroA genotypes associated with these arsenite‐oxidizing environments. Geochemical analyses, including measurement of arsenite‐oxidation rates within geothermal outflow channels, were combined with 16S rRNA gene and aroA functional gene analysis using newly designed primers to capture previously undescribed aroA‐like arsenite oxidase gene diversity. The majority of bacterial 16S rRNA gene sequences found in acidic (pH 2.6–3.6) Fe‐oxyhydroxide microbial mats were closely related to Hydrogenobaculum spp. (members of the bacterial order Aquificales), while the predominant sequences from near‐neutral (pH 6.2–8) springs were affiliated with other Aquificales including Sulfurihydrogenibium spp., Thermocrinis spp. and Hydrogenobacter spp., as well as members of the Deinococci, Thermodesulfobacteria and β‐Proteobacteria. Modified primers designed around previously characterized and newly identified aroA‐like genes successfully amplified new lineages of aroA‐like genes associated with members of the Aquificales across all geothermal systems examined. The expression of Aquificales aroA‐like genes was also confirmed in situ, and the resultant cDNA sequences were consistent with aroA genotypes identified in the same environments. The aroA sequences identified in the current study expand the phylogenetic distribution of known Mo‐pterin arsenite oxidase genes, and suggest the importance of three prominent genera of the order Aquificales in arsenite oxidation across geochemically distinct geothermal habitats ranging in pH from 2.6 to 8.     

Evolutionary history of Ash Meadows pupfish (genus <Emphasis Type="Italic">Cyprinodon</Emphasis>) populations inferred using microsatellite markers

Pupfish (genus Cyprinodon) persist in a series of isolated warm springs in Death Valley. Here we describe an analysis of microsatellite variation at six loci for nine populations encompassing three distinct taxa. Levels of genetic variation within populations and the pattern of relatedness among populations are best explained by spring elevation. Springs at higher elevations harbored less variation and exhibited greater among population divergence than lower elevation springs. This pattern reflects regional paleohydrological history showing a declining water table over the last 20,000 years. Continuing decline of the water table, a trend accelerated by local ground water mining, portends a future of increasing isolation and declining within-population variation.     

Immigrant and native? The case of the swamp foxtail Cenchrus purpurascens in Australia

Aim

Spring wetlands in arid regions of Australia provide habitat for many highly endemic organisms, including fish, molluscs, crustaceans and plants, but these unique ecosystems have been under pressure since the arrival of Europeans about 250 years ago. Arguments over whether particular plant species are long‐term spring inhabitants or recent immigrants are confounding efforts to conserve spring flora. One such example is the swamp foxtail, Cenchrus purpurascens, a grass that is variably listed in the literature as being native to Australian wetlands or as being an introduced weedy species from Asia.

Location

Australia, China and Korea.

Methods

We use DNA sequences of the nuclear ITS and the chloroplast DNA regions trnL‐F and matK, complemented with newly designed simple sequence repeat (SSR) markers, to assess the native status of C. purpurascens in Australia and determine whether there is genetic differentiation among spring populations.

Results

We find that, although there has been gene flow between Asia and Australia in the geological past, the populations are now strongly differentiated: C. purpurascens has probably been present in Australia through the Pleistocene. In Australia, there is also strong genetic differentiation among populations from different springs, and between springs and non‐springs populations, indicating long‐term occupancy of some springs sites.

Main conclusions

Cenchrus purpurascens was present in Australia well before European colonization of the continent. The level of genetic differentiation among populations enhances the existing conservation values of Elizabeth Springs, Edgbaston, Doongmabulla and Carnarvon Gorge springs complexes within the Great Artesian Basin.

     

Nanoarchaeota,Their Sulfolobales Host,and Nanoarchaeota Virus Distribution across Yellowstone National Park Hot Springs

Nanoarchaeota are obligate symbionts with reduced genomes first described from marine thermal vent environments. Here, both community metagenomics and single-cell analysis revealed the presence of Nanoarchaeota in high-temperature (∼90°C), acidic (pH ≈ 2.5 to 3.0) hot springs in Yellowstone National Park (YNP) (United States). Single-cell genome analysis of two cells resulted in two nearly identical genomes, with an estimated full length of 650 kbp. Genome comparison showed that these two cells are more closely related to the recently proposed Nanobsidianus stetteri from a more neutral YNP hot spring than to the marine Nanoarchaeum equitans. Single-cell and catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) analysis of environmental hot spring samples identified the host of the YNP Nanoarchaeota as a Sulfolobales species known to inhabit the hot springs. Furthermore, we demonstrate that Nanoarchaeota are widespread in acidic to near neutral hot springs in YNP. An integrated viral sequence was also found within one Nanoarchaeota single-cell genome and further analysis of the purified viral fraction from environmental samples indicates that this is likely a virus replicating within the YNP Nanoarchaeota.     

Microbial diversity and autotrophic activity in Kamchatka hot springs

Microbial communities of Kamchatka Peninsula terrestrial hot springs were studied using molecular, radioisotopic and cultural approaches. Analysis of 16S rRNA gene fragments performed by means of high-throughput sequencing revealed that aerobic autotrophic sulfur-oxidizing bacteria of the genus Sulfurihydrogenibium (phylum Aquificae) dominated in a majority of streamers. Another widely distributed and abundant group was that of anaerobic bacteria of the genus Caldimicrobium (phylum Thermodesulfobacteria). Archaea of the genus Vulcanisaeta were abundant in a high-temperature, slightly acidic hot spring, where they were accompanied by numerous Nanoarchaeota, while the domination of uncultured Thermoplasmataceae A10 was characteristic for moderately thermophilic acidic habitats. The highest rates of inorganic carbon assimilation determined by the in situ incubation of samples in the presence of ¹⁴C-labeled bicarbonate were found in oxygen-dependent streamers; in two sediment samples taken from the hottest springs this process, though much weaker, was found to be not dependent on oxygen. The isolation of anaerobic lithoautotrophic prokaryotes from Kamchatka hot springs revealed a wide distribution of the ability for sulfur disproportionation, a new lithoautotrophic process capable to fuel autonomous anaerobic ecosystems.

     

Trumpeter Swan Abundance and Growth Rates in Yellowstone National Park

ABSTRACT Decreasing abundance of resident, nonmigratory trumpeter swans (Cygnus buccinator) in Yellowstone National Park (YNP), USA, raised concern that this population, which helped facilitate the restoration of the species across North America, may disappear. We quantified trends in abundance of resident and migratory trumpeter swans in YNP from 1967 to 2007 and investigated the potential mechanisms for declining population trends, including cessation of the supplemental feeding program and relocation programs outside of YNP, density dependence, and annual variations in environmental conditions. Estimated abundance of resident trumpeter swans in YNP ranged from 59 individuals in 1968 to 10 individuals in 2007. Using log-linear modeling, the best approximating model chosen from an a priori set of competing models estimated the annual growth rate (r) of resident swans from 1967 to 2007 was −0.036 (95% CI =−0.042 to −0.030, Akaike wt [w_i] = 0.44). A competing model provided evidence that decreases in abundance became more dramatic after supplemental feeding of grain outside of YNP was terminated in winter 1992–1993 (r̂_1967–1992 = −0.027, 95% CI = −0.039 to −0.015; r̂_1993–2007 = −0.053, 95% CI = −0.029 to −0.080; w_i = 0.42). There was little evidence of density-dependent effects on the resident population growth rates (βYNP_pop = 0.006, 95% CI = −0.017 to 0.007), but rates were lower following severe winters, wetter springs, and warmer summers. Our results indicate that the YNP population of trumpeter swans is decreasing and may act as a sink to surrounding populations. Thus, population levels of YNP trumpeter swans may depend on management outside the Park and we recommend the National Park Service collaborate with surrounding agencies in managing trumpeter swans throughout the Tri-state region where more productive habitats may exist.     

Molecular Community Analysis of Arbuscular Mycorrhizal Fungi in Roots of Geothermal Soils in Yellowstone National Park (USA)

To better understand adaptation of plants and their mycorrhizae to extreme environmental conditions, we analyzed the composition of communities of arbuscular mycorrhizal fungi (AMF) in roots from geothermal sites in Yellowstone National Park (YNP), USA. Arbuscular mycorrhizal fungi were identified using molecular methods including seven specific primer pairs for regions of the ribosomal DNA that amplify different subgroups of AMF. Roots of Dichanthelium lanuginosum, a grass only occurring in geothermal areas, were sampled along with thermal and nonthermal Agrostis scabra and control plants growing outside the thermally influenced sites. In addition, root samples of Agrostis stolonifera from geothermal areas of Iceland were analyzed to identify possible common mycosymbionts between these geographically isolated locations. In YNP, 16 ribosomal DNA phylotypes belonging to the genera Archaeospora, Glomus, Paraglomus, Scutellospora, and Acaulospora were detected. Eight of these phylotypes could be assigned to known morphospecies, two others have been reported previously in molecular studies from different environments, and six were new to science. The most diverse and abundant lineage was Glomus group A, with the most frequent phylotype corresponding to Glomus intraradices. Five of the seven phylotypes detected in a preliminary sampling in a geothermal area in Iceland were also found in YNP. Nonthermal vegetation was dominated by a high diversity of Glomus group A phylotypes while nonthermal plants were not. Using multivariate analyses, a subset of three phylotypes were determined to be associated with geothermal conditions in the field sites analyzed. In conclusion, AMF communities in geothermal soils are distinct in their composition, including both unique phylotypes and generalist fungi that occur across a broad range of environmental conditions. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Flow permanence and macroinvertebrate community variability in limestone spring systems

Limestone (karst) springs within the River Wye catchment (Derbyshire, U.K.) were investigated to examine the influence of physical and chemical characteristics and habitat variability on macroinvertebrate community composition. Flow permanence had a greater influence on the invertebrate community than any other physical or chemical variable examined. Clear differences in the macroinvertebrate community were observed between perennial (7) and intermittent springs (11) and the mainstem river. Springs support distinct communities, with some taxa exclusively recorded at the source or within the springbrook (e.g. Agabus guttatus [Paykull] and Micropterna lateralis [Stephens]). A degree of faunal overlap with the mainstem river occurred suggesting that perennial springs may form a refugium for many taxa and that intermittent springs are rapidly colonised by taxa from the mainstem river after the resumption of flow.     

Phenotypic and genetic differentiation among yellow monkeyflower populations from thermal and non-thermal soils in Yellowstone National Park

In flowering plants, soil heterogeneity can generate divergent natural selection over fine spatial scales, and thus promote local adaptation in the absence of geographic barriers to gene flow. Here, we investigate phenotypic and genetic differentiation in one of the few flowering plants that thrives in both geothermal and non-thermal soils in Yellowstone National Park (YNP). Yellow monkeyflowers (Mimulus guttatus) growing at two geothermal ("thermal") sites in YNP were distinct in growth form and phenology from paired populations growing nearby (<500?m distant) in non-thermal soils. In simulated thermal and non-thermal environments, thermal plants remained significantly divergent from non-thermal plants in vegetative, floral, mating system, and phenological traits. Plants from both thermal populations flowered closer to the ground, allocated relatively more to sexual reproduction, were more likely to initiate flowering under short daylengths, and made smaller flowers that could efficiently self-fertilize without pollinators. These shared differences are consistent with local adaptation to life in the ephemeral window for growth and reproduction created by winter and spring snowmelt on hot soils. In contrast, habitat type (thermal vs. non-thermal) explained little of the genetic variation at neutral markers. Instead, we found that one thermal population (Agrostis Headquarters; AHQ-T) was strongly differentiated from all other populations (all F (ST)?>?0.34), which were only weakly differentiated from each other (all F (ST)?相似文献   

Microbial community analysis of pH 4 thermal springs in Yellowstone National Park

Extremophiles - The pH of the majority of thermal springs in Yellowstone National Park (YNP) is from 1 to 3 and 6 to 10; relatively few springs (~5%) have a pH range of 4–5. We used 16S rRNA...