Taxonomic Membership Research Articles

Individual diet variability shapes the architecture of Antarctic benthic food webs

Antarctic biodiversity is affected by seasonal sea-ice dynamics driving basal resource availability. To (1) determine the role of intraspecific dietary variability in structuring benthic food webs sustaining Antarctic biodiversity, and (2) understand how food webs and the position of topologically central species vary with sea-ice cover, single benthic individuals’ diets were studied by isotopic analysis before sea-ice breakup and afterwards. Isotopic trophospecies (or Isotopic Trophic Units) were investigated and food webs reconstructed using Bayesian Mixing Models. As nodes, these webs used either ITUs regardless of their taxonomic membership (ITU-webs) or ITUs assigned to species (population-webs). Both were compared to taxonomic-webs based on taxa and their mean isotopic values. Higher resource availability after sea-ice breakup led to simpler community structure, with lower connectance and linkage density. Intra-population diet variability and compartmentalisation were crucial in determining community structure, showing population-webs to be more complex, stable and robust to biodiversity loss than taxonomic-webs. The core web, representing the minimal community ‘skeleton’ that expands opportunistically while maintaining web stability with changing resource availability, was also identified. Central nodes included the sea-urchin Sterechinus neumayeri and the bivalve Adamussium colbecki, whose diet is described in unprecedented detail. The core web, compartmentalisation and topologically central nodes represent crucial factors underlying Antarctica’s rich benthic food web persistence.

Evaluating the influences of temperature, primary production, and evolutionary history on bivalve growth rates

AbstractOrganismal metabolic rates reflect the interaction of environmental and physiological factors. Thus, calcifying organisms that record growth history can provide insight into both the ancient environments in which they lived and their own physiology and life history. However, interpreting them requires understanding which environmental factors have the greatest influence on growth rate and the extent to which evolutionary history constrains growth rates across lineages. We integrated satellite measurements of sea-surface temperature and chlorophyll-a concentration with a database of growth coefficients, body sizes, and life spans for 692 populations of living marine bivalves in 195 species, set within the context of a new maximum-likelihood phylogeny of bivalves. We find that environmental predictors overall explain only a small proportion of variation in growth coefficient across all species; temperature is a better predictor of growth coefficient than food supply, and growth coefficient is somewhat more variable at higher summer temperatures. Growth coefficients exhibit moderate phylogenetic signal, and taxonomic membership is a stronger predictor of growth coefficient than any environmental predictor, but phylogenetic inertia cannot fully explain the disjunction between our findings and the extensive body of work demonstrating strong environmental control on growth rates within taxa. Accounting for evolutionary history is critical when considering shells as historical archives. The weak relationship between variation in food supply and variation in growth coefficient in our data set is inconsistent with the hypothesis that the increase in mean body size through the Phanerozoic was driven by increasing productivity enabling faster growth rates.

The respiratory tract microbiome and its relationship to lung cancer and environmental exposures found in rural china.

We previously reported that bacterial diversity in sputum samples from never-smoking women in rural China varied by lung cancer status and household air pollution (HAP) exposure type. Here, we expand on our associations between environmental exposures and respiratory tract microbiota with an additional 90 never-smoking women from Xuanwei, China. DNA from sputum samples of cases (n = 45) and controls (n = 45) was extracted using a multistep enzymatic and physical lysis, followed by a standardized clean up. V1-V2 regions of 16S rRNA genes were Polymerase chain reaction (PCR) amplified. Purified amplicons were sequenced by 454 FLX Titanium pyrosequencing and high-quality sequences were evaluated for diversity and taxonomic membership. In our population of never-smokers, increased risk of lung cancer was associated with lower alpha diversity compared to higher alpha diversity (Shannon: ORhigh = 1.00 [reference], ORmedium = 3.84 [1.02-14.48], ORlow = 3.78 [1.03-13.82]; observed species: ORhigh = 1.00 [reference], ORmedium = 2.37 [0.67-8.48], ORlow = 2.01 [0.58-6.97]; Phylogenetic Diversity (PD) whole tree: ORhigh = 1.00 [reference], ORmedium = 3.04 [0.85-10.92], ORlow = 2.53 [0.72-8.96]), as well as a decreased relative abundance of Fusobacteria (ORhigh = 1.00 [reference], ORmedium = 1.24 [0.42-3.66], ORlow = 2.01 [0.63-6.44], ptrend = 0.03). Increasing alpha diversity was associated with smoky coal use compared to clean fuel use among all subjects (observed species, P = 0.001; PD whole tree, P = 0.006; Shannon, P = 0.0002), as well as cases (observed species, P = 0.02; PD whole tree, P = 0.03; Shannon, P = 0.03) and controls (observed species, P = 0.01; PD whole tree, P = 0.05; Shannon, P = 0.002). Increased diversity was also associated with presence of livestock (observed species, P = 0.02; PD whole tree, P = 0.02; Shannon, P = 0.03) in the home for cases. Our study is the first to report that decreased microbial diversity is associated with risk of lung cancer. Larger studies are necessary to elucidate the direct and indirect effects attributed to the disease-specific, HAP-specific, and animal-specific associations. Environ. Mol. Mutagen. 2019. © 2019 Wiley Periodicals, Inc.

IDENTIFICATION OF CONTAMINATION OF SALMON MEAT BY DNA FROM BACTERIA OF THE PSEUDOMONAS FLUORESCENS GROUP IN THE IMPLEMENTATION OF THE DNA BARCODING OF PRODUCTS OF JAPANESE CUISINE

DNA barcoding as a tool for genetic certification and identification of taxonomic membership of organisms has recently become very popular. We have applied DNA barcoding method for taxonomic identification of fish ingredients (salmon, tuna, flying fish roe, shark) in product of Japanese cuisine. We have analyzed 27 samples from 6 retail outlets and 3 restaurants of the city of Voronezh. It was found that for products designated as containing “salmon” in all selected outlets were used as a fillet of Atlantic salmon (Salmo salar), which is considerably less valuable than Pacific salmon. Results of DNA barcoding showed that one of the samples of «salmon» was in fact, yellowfin tuna, whereas one sample of “tuna” was a fillet of Atlantic salmon. However in general, the “salmon” and “tuna” samples were substituted infrequently. Analysis of “flying fish roe” samples revealed that only one sample from 6 was really Fourwing flyingfish (Hirundichthys affinis). The remaining samples were identified as DNA of capelin (Mallotus villosus). By analyzing the “double” sequences in 2 samples, we have found that two samples of «flying fish roe» were mixtures of Fourwing flyingfish roe and capelin roe. A sample labeled “shark” was identified as Mozambique tilapia. This species is a freshwater fish. Bacterium Pseudomonas fluorescens was identified in one of the “salmon” samples. Analysis of “double” sequences of “salmon” samples revealed presence of P. fluorescens DNA. Analysis of salmon meat with the use of species-specific primers for this bacterium revealed contamination of all samples by P. fluorescens. This bacterium causes the disease in salmon and can be harmful to patients with compromised immune systems. Primers used for DNA barcoding were shown to have high homology to DNA of bacterial group P. fluorescens.

Migration in the Anthropocene: how collective navigation, environmental system and taxonomy shape the vulnerability of migratory species.

Recent increases in human disturbance pose significant threats to migratory species using collective movement strategies. Key threats to migrants may differ depending on behavioural traits (e.g. collective navigation), taxonomy and the environmental system (i.e. freshwater, marine or terrestrial) associated with migration. We quantitatively assess how collective navigation, taxonomic membership and environmental system impact species' vulnerability by (i) evaluating population change in migratory and non-migratory bird, mammal and fish species using the Living Planet Database (LPD), (ii) analysing the role of collective navigation and environmental system on migrant extinction risk using International Union for Conservation of Nature (IUCN) classifications and (iii) compiling literature on geographical range change of migratory species. Likelihood of population decrease differed by taxonomic group: migratory birds were more likely to experience annual declines than non-migrants, while mammals displayed the opposite pattern. Within migratory species in IUCN, we observed that collective navigation and environmental system were important predictors of extinction risk for fishes and birds, but not for mammals, which had overall higher extinction risk than other taxa. We found high phylogenetic relatedness among collectively navigating species, which could have obscured its importance in determining extinction risk. Overall, outputs from these analyses can help guide strategic interventions to conserve the most vulnerable migrations.This article is part of the theme issue 'Collective movement ecology'.

DETERMINATION OF PHYLOGENETIC RELATIONSHIP OF YERSINIA PESTIS STRAINS FROM NATURAL PLAGUE FOCI OF THE CAUCASUS BY MULTI-LOCUS VNTR-ANALYSIS

Determination of the degree of phylogenetic relationship of Yersinia pestis strains iso- lated from the territories of natural foci of plague from the Caucasus using VNTR-typing by 25 loci (MLVA25). 26 strains of Y pestis from Russian natural foci of the Caucasus were used in the study. 25 loci of tandem repeats in Y pestis genome by Le Fleche scheme were used for execution of multi-locus VNTR-analysis. Deciphering of nucleotide sequences was carried out in automatic sequencer ABI 3130 Genetic Analyser. Analysis of confinement of clusters to certain territories, objects and time of isolation of strains was carried out. using Arc GIS 10.1 program. Groups of MLVA25-types of various levels of discrimination were formed: clusters, groups and subgroups. Clusters were formed by strains ofvarious taxonomic membership: main and subspecies of Y pestis. Subgroups reflect membership of strains in certain foci, and MLVA25-types - the degree of genetic relationship. Genetic <<portraits>> of plague causative agents obtained using MLVA25-types circulating in various natural-focal territories allow to solve problems ofboth theoretical and practical character: from interpretation of microevolution processes to the search of the source of infection and ways of its spread during possible epidemic complications.

Diagnostic and Prognostic Microbial Biomarkers in Inflammatory Bowel Diseases

The microbiome plays multifaceted roles in the pathogenesis of inflammatory bowel diseases (IBD). Accordingly, the clinical challenge of patient heterogeneity in disease phenotype and response to treatment should in part be addressed by biomarkers that detect the host response to microbiota, and the levels of microbial taxa and products eliciting the host response in susceptible individuals. Molecular analysis has revealed much evidence for microbial taxonomic membership and microbial products in association with IBD, but their utility as clinical biomarkers is still in its infancy. A rich area of progress has been the development and validation of host serologic microbial biomarkers, which have achieved a distinctive position in the diagnosis and prognosis in IBD, and as a template for defining other categories of microbial biomarkers in disease state and phenotype.

Floral Phenology of Bee Pasture Plants in Northwestern Cagayan (Phase 1)

Sufficient knowledge of floral phenology is the prerequisite to startbeekeeping. In August 2010 to July 2011, the researchers conducted a study inNorthwestern Cagayan to determine the existing bee flora and develop a floralcalendar in relation to pollen and nectar availability in the area. The study useddescriptive research utilizing quadrant method to obtain the data for this study.Analysis of data included frequency count. Based on ocular observations andsurvey, 55 plant species were highly abundant sources for honey and pollen.These species were identified as tree, palm, herb, and weeds. The study ascertains sixteen flowering plants as extremely important as those blossoms continually.The honey flow period is on March to May with the most number of bloomingplants like Artocarpus ovatus, Premna odorata, Antidesma bunius, Dipterocarpspp., Gliricidia sepium, Coffea sp., Diospyros philippinensis, Pterocarpus spp., Vitexparviflora, Melanolepis multiglandolosa and Ficus variegata. The dearth periodis July to September as Semaena saman, Terminalia microcarpa, and Portulaceaoleracea only bloom during these months. Northwestern Cagayan is suitable toinitiate bee farming. However, climatic factors restrict the phenological periodof most species. Plant attributes and taxonomic membership strongly relate toflowering phenodynamics in the different floras studied.Keywords: Ecology and conservation, floral phenology, bee flora, honey flow, dearthperiod, descriptive research, Philippines

The potential role of lung microbiota in lung cancer attributed to household coal burning exposures.

Bacteria influence site-specific disease etiology and the host's ability to metabolize xenobiotics, such as polycyclic aromatic hydrocarbons (PAHs). Lung cancer in Xuanwei, China has been attributed to PAH-rich household air pollution from burning coal. This study seeks to explore the role of lung microbiota in lung cancer among never smoking Xuanwei women and how coal burning may influence these associations. DNA from sputum and buccal samples of never smoking lung cancer cases (n = 8, in duplicate) and controls (n = 8, in duplicate) in two Xuanwei villages was extracted using a multi-step enzymatic and physical lysis, followed by a standardized clean-up. V1-V2 regions of 16S rRNA genes were PCR-amplified. Purified amplicons were sequenced by 454 FLX Titanium pyrosequencing and high-quality sequences were evaluated for diversity and taxonomic membership. Bacterial diversity among cases and controls was similar in buccal samples (P = 0.46), but significantly different in sputum samples (P = 0.038). In sputum, Granulicatella (6.1 vs. 2.0%; P = 0.0016), Abiotrophia (1.5 vs. 0.085%; P = 0.0036), and Streptococcus (40.1 vs. 19.8%; P = 0.0142) were enriched in cases compared with controls. Sputum samples had on average 488.25 species-level OTUs in the flora of cases who used smoky coal (PAH-rich) compared with 352.5 OTUs among cases who used smokeless coal (PAH-poor; P = 0.047). These differences were explained by the Bacilli species (Streptococcus infantis and Streptococcus anginosus). Our small study suggests that never smoking lung cancer cases have differing sputum microbiota than controls. Further, bacteria found in sputum may be influenced by environmental exposures associated with the type of coal burned in the home.

The Genetic Basis of Primate Behavior: Genetics and Genomics in Field-Based Primatology.

Recent advances in genetic and genomic techniques have led to explosive advances in the fields of biology and ecology. Perhaps nowhere is the stark difference between what was possible in genetics research 10 years ago compared to what can be done today as obvious as in field-based studies of animals. Whereas biologists of the past were severely limited by the costs of most genetic analyses, the biologists of today must cope with the timeand information-processing constraints associated with analyzing huge quantities of data—a privileged problem to be sure. This shift has been brought about most directly by the widespread use of massively parallel (or next-generation) sequencing, which has drastically reduced not only the costs of genotyping (a trend that continues), but also the quantity and quality of requisite DNA, as well as the amount of time required to complete genetics projects (Bradley and Lawler 2011; Perry 2014; Tung et al. 2010). These advances, in addition to the now commonplace presence of shared genomics infrastructure in research institutes and universities, have removed most of the major limitations to the use of genetic information by animal biologists. Scholars that study nonhuman primates are particularly well poised to take advantage and benefit from this new wave of genetics. Interests in primates from the biomedical community, which stem from our shared taxonomic membership (McClure 1984; Rogers and Hixson 1997; Watson and Platt 2012), have resulted in the fullgenome sequencing of a relatively large number of primate species. The full-genome sequence has been published or is underway for at least 23 primate species (Bradley Int J Primatol (2014) 35:1–10 DOI 10.1007/s10764-013-9732-6

Temporal stability of the mouse gut microbiota in relation to innate and adaptive immunity

Gut microbial community properties of mammals are thought to be partly shaped by a combination of host immunity and environmental factors, but their relative importance is not firmly established. To address this gap, we first characterized the faecal bacteria of mice with a functioning immune system (wild-type, WT), mice with defective immune responses (CD45), mice lacking an adaptive immune system (RAG), and mice with both immune dysfunctions (45RAG). Using fingerprinting of 16S rRNA genes, we observed significant differences in gut microbiota composition across all mouse strains (P < 0.001) and identified several mouse strain-specific genera via pyrosequencing, including Turicibacter sp. (in WT mice) and Allobaculum sp. (in CD45-deficient animals). To define the role of the host immune system in constraining gut microbiota stability after perturbation, we cohoused CD45-deficient and WT mice and monitored gut bacterial community dynamics during 8 weeks. Cohousing caused the WT bacterial communities to become indistinguishable from those of CD45 mice (P > 0.05). Time-series analysis indicated that the communities of cohoused mice changed directionally as opposed to the relatively stable communities of non-cohoused controls. When we considered only taxonomic membership, it was the communities of CD45 non-cohoused mice that experienced the highest rate of change. Rather than be governed by fluctuations in the relative abundance of taxa, we suggest that CD45-regulated immune responses either are stimulated by the presence of bacteria per se or promote temporal stability by selecting for the occurrence of specific taxa.

Barcoding Sponges: An Overview Based on Comprehensive Sampling

BackgroundPhylum Porifera includes ∼8,500 valid species distributed world-wide in aquatic ecosystems ranging from ephemeral fresh-water bodies to coastal environments and the deep-sea. The taxonomy and systematics of sponges is complicated, and morphological identification can be both time consuming and erroneous due to phenotypic convergence and secondary losses, etc. DNA barcoding can provide sponge biologists with a simple and rapid method for the identification of samples of unknown taxonomic membership. The Sponge Barcoding Project (www.spongebarcoding.org), the first initiative to barcode a non-bilaterian metazoan phylum, aims to provide a comprehensive DNA barcode database for Phylum Porifera.Methodology/Principal Findings∼7,400 sponge specimens have been extracted, and amplification of the standard COI barcoding fragment has been attempted for approximately 3,300 museum samples with ∼25% mean amplification success. Based on this comprehensive sampling, we present the first report on the workflow and progress of the sponge barcoding project, and discuss some common pitfalls inherent to the barcoding of sponges.ConclusionA DNA-barcoding workflow capable of processing potentially large sponge collections has been developed and is routinely used for the Sponge Barcoding Project with success. Sponge specific problems such as the frequent co-amplification of non-target organisms have been detected and potential solutions are currently under development. The initial success of this innovative project have already demonstrated considerable refinement of sponge systematics, evaluating morphometric character importance, geographic phenotypic variability, and the utility of the standard barcoding fragment for Porifera (despite its conserved evolution within this basal metazoan phylum).

Flowering phenology of co-occurring Asteraceae: a matter of climate, ecological interactions, plant attributes or of evolutionary relationships among species?

We analyzed the flowering phenodynamics of 43 Asteraceae species co-occurring in natural populations of Chaco Serrano forests in central Argentina. We explored the potential influence of factors such as photoperiod and climate (variations in temperature, rainfall, and frost), animal-plant interactions (richness of floral visitors, frequency of visits), some plant attributes (plant growth form, seed dispersal mechanism), and evolutionary relationships among species on flowering phenodynamics. Cluster Analysis (CA) and Principal Component Analysis (PCA) were the multivariate statistical methods used to analyze emerging patterns associated with these co-occurring species. Null-model analyses were used to evaluate whether flowering times are aggregated, segregated, or random. Results showed that flowering phenology was significantly correlated with the seasonal variation in temperature, photoperiod, rainfall, and frost. The multivariate statistical methods separated all the species in three groups: 1) species with short flowering time, large plant floral display, high frequency of visits by a large number of species of floral visitors, anemochorous fruits, and shrubby growth form, with a tendency to a segregated flowering pattern; 2) species with long flowering time, small plant floral display, low frequency of visits by few insect species, anemochorous fruits, and herbaceous growth form; and 3) species with long flowering time, small plant floral display, intermediate values for frequency of visits and number of species of floral visitors, seed dispersal mechanisms other than anemochory, and herbaceous growth form. In addition, all but one species belonging to early-branching tribes (tribes phylogenetically close to the root of the Asteraceae tree) were grouped together and clustered in the same region of the two-dimensional PCA ordination. All species belonging to the late-branching tribes (Asteroideae subfamily tribes) included in group 1 were separated from the other Asteroideae species in the PCA. In conclusion, it seems that climatic factors restrict the phenological period of most species, and that plant attributes and taxonomic membership are strongly related to flowering phenodynamics in this group of Asteraceae studied.

On taxonomic membership

Taxonomic membership frequencies exhibit distributions in which groups with few numbers of subtaxa are much more common in a clade than those with more subtaxa. Here, a “broken plate” model is developed to describe such taxonomic memberships; some higher taxonomic group (the plate) is randomly subdivided into intermediate taxonomic units (plate fragments), whose sizes are dependent on the number of taxonomic subunits that they each contain. Theoretical distributions of membership frequencies produced by this model yield a superior fit to data from both modern and fossil groups, as illustrated by classifications for primarily fossil brachiopods and entirely modern mammals. The nature of these distributions is consistent with the contention that Linnaean membership frequencies result from the random partitioning of taxonomic/morphologic space. Moreover, numbers of taxa contained within hierarchically equivalent groups are unrelated, as are membership numbers at taxonomically higher and lower levels of consideration. Agreement between observed taxonomic memberships and those anticipated from the random partitioning of diversity as described by the “broken plate” model bears directly on a number of fundamental questions including the significance of extreme polytypy and inferred causes of adaptive radiation within many taxonomic groups.

Classification of Genomic Sequences via Wavelet Variance and a Self-Organizing Map with an Application to Mitochondrial DNA

We present a new methodology for discriminating genomic symbolic sequences, which combines wavelet analysis and a self-organizing map algorithm. Wavelets are used to extract variation across various scales in the oligonucleotide patterns of a sequence. The variation is quantified by the estimated wavelet variance, which yields a feature vector. Feature vectors obtained from many genomic sequences, possibly of different lengths, are then classified with a nonparametric self-organizing map scheme. When applied to nearly 200 entire mitochondrial DNA sequences, or their fragments, the method predicts species taxonomic group membership very well, and allows the results to be visualized. When only thousands of nucleotides are available, wavelet-based feature vectors of short oligonucleotide patterns are more efficient in discrimination than frequency-based feature vectors of long patterns. This new data analysis strategy could be extended to numeric genomic data. The routines needed to perform the computations are readily available in two packages of software R.

Influence of phylogeny and ploidy on species ranges of North American angiosperms

Summary1. Species differ widely in the size and ecological characteristics of their geographic ranges. This variation reflects, in part, differences in ecological tolerance among taxa, but the influence of phylogeny and evolutionary divergence through genome duplication remains controversial.2. Here, we examine the evolutionary sources of variation in species range area, latitudinal position and overlap, and six range climatic variables (maximum, minimum and breadth of temperature and precipitation) for North American angiosperms. We sampled two diploid and one polyploid species from each of 144 genera and examined sources of variation in a nested taxonomic analysis and congeneric species pairs comparison.3. For all range characteristics studied, a significant portion of the variance among species (mean 53%, range 37–60%) was attributable to taxonomic membership above species (i.e. genus, family and order). Four of the seven range attributes were significantly correlated between diploid congeners (e.g. range arears = 0.65) and between heteroploid (diploid and polyploid) congeners (e.g. range arears = 0.62). The strength of correlations between heteroploid relatives was not consistently different than correlations between diploids.4. No differences in mean range breadth (range area, temperature breadth, precipitation breadth) or climatological position (minimum and maximum temperature and precipitation) were observed between diploid and polyploid congeners. Polyploids were not more likely to occupy northern latitudinal positions and were no more displaced from diploids than other congeneric diploids.5.Synthesis. Our results suggest that, at the scale of North America, the geographical and ecological aspects of species ranges are influenced by phylogenetic history. Furthermore, genome duplication does not cause or allow greater divergence in species range characteristics than occurs between related diploid species.

Effect of PCR amplicon size on assessments of clone library microbial diversity and community structure

PCR-based surveys of microbial communities commonly use regions of the small-subunit ribosomal RNA (SSU rRNA) gene to determine taxonomic membership and estimate total diversity. Here we show that the length of the target amplicon has a significant effect on assessments of microbial richness and community membership. Using operational taxonomic unit (OTU)- and taxonomy-based tools, we compared the V6 hypervariable region of the bacterial SSU rRNA gene of three amplicon libraries of c. 100, 400 and 1000 base pairs (bp) from each of two hydrothermal vent fluid samples. We found that the smallest amplicon libraries contained more unique sequences, higher diversity estimates and a different community structure than the other two libraries from each sample. We hypothesize that a combination of polymerase dissociation, cloning bias and mispriming due to secondary structure accounts for the differences. While this relationship is not linear, it is clear that the smallest amplicon libraries contained more different types of sequences, and accordingly, more diverse members of the community. Because divergent and lower abundant taxa can be more readily detected with smaller amplicons, they may provide better assessments of total community diversity and taxonomic membership than longer amplicons in molecular studies of microbial communities.

The Evolutionary Significance of Seed Germinability in an Alpine Meadow on The Eastern Qinghai-Tibet Plateau

In this study, we created a database of 633 species collected from alpine meadows on the eastern Qinghai-Tibet Plateau, and considered the correlation of interspecific seed germinability variation with ecological, life-history, and phylogenetic background. We found that taxonomic membership accounted for the majority of the weighted germination index (WGI) variation (71%). The strong taxonomic effect suggests that WGI variation within taxonomic membership is constrained, and a large proportion of WGI variation is explained by life-history traits also correlated with taxonomic membership. The overlap does not negate the adaptive significance of the relationship between these life-history traits and germinability. In addition, the altitudes and habitats when considered first had no significant effect on seed germinability variation, but we found that there were significant interactions between altitudes (or habitats) and some phylogenetic groups. Although their interactions were all less than the main effects of phylogenetic groups, they could explain that the effect of phylogenetic constraint on seed germination was also impacted by environmental factors. Thus, we could not exclude the effect of longtime selection by environmental factors on seed germination, and we think interspecific seed germinability variation was affected by phylogenetic, life-history, and ecological factors together.

The Evolutionary Significance of Seed Germinability in an Alpine Meadow on The Eastern Qinghai-Tibet Plateau

In this study, we created a database of 633 species collected from alpine meadows on the eastern Qinghai-Tibet Plateau, and considered the correlation of interspecific seed germinability variation with ecological, life-history, and phylogenetic background. We found that taxonomic membership accounted for the majority of the weighted germination index (WGI) variation (71%). The strong taxonomic effect suggests that WGI variation within taxonomic membership is constrained, and a large proportion of WGI variation is explained by life-history traits also correlated with taxonomic membership. The overlap does not negate the adaptive significance of the relationship between these life-history traits and germinability. In addition, the altitudes and habitats when considered first had no significant effect on seed germinability variation, but we found that there were significant interactions between altitudes (or habitats) and some phylogenetic groups. Although their interactions were all less than the main effects of phylogenetic groups, they could explain that the effect of phylogenetic constraint on seed germination was also impacted by environmental factors. Thus, we could not exclude the effect of longtime selection by environmental factors on seed germination, and we think interspecific seed germinability variation was affected by phylogenetic, life-history, and ecological factors together.

Biogeography of Stream Fishes in Connecticut: Defining Faunal Regions and Assemblage Types

Stream fish survey data were analyzed to describe patterns of fish distributions in wadeable streams (primarily 1st–4th order) in Connecticut. Species occurrence within the United States Geological Survey 8-digit hydrologic unit code watersheds were used to aggregate similar watersheds into stream fish faunal regions. Within each identified region, multivariate analyses were used to identify major fish assemblage types and associate stream habitat with assemblage types. The analyses revealed an eastern and western faunal region defined primarily by distribution of a few native species. Native species associated with the western watersheds were: Semotilus atromaculatus (Creek Chub), Exoglossum maxillingua (Cutlips Minnow), and Cottus cognatus (Slimy Sculpin). Native fishes associated with the eastern watersheds were: Erimyzon oblongus (Creek Chubsucker), Esox niger (Chain Pickerel), and Esox americanus (Redfin Pickerel). Inclusion of non-indigenous species in the analyses resulted in a similar east–west grouping of watersheds. Five and four assemblage types were identified in the eastern and western faunal regions, respectively. Both regions harbored 3 fluvial assemblages defined longitudinally from headwater streams to larger wadeable streams and a macro-habitat generalist assemblage inhabiting streams with proportionately more pool habitat, but taxonomic membership and indicator species rankings among assemblages were not necessarily identical between the regions. A distinct assemblage dominated by Redfin Pickerel was recognized only in the eastern region. Streams in the western region were generally higher in elevation and colder in water temperature. The discovery and description of eastern and western fish faunal regions and their fish assemblage types will be useful in stratifying the biological monitoring of streams and other aquatic resource management actions in Connecticut.