Levels Of Taxonomic Diversity Research Articles

Resistance against tree encroachment is driven by richness and identity of herbaceous resident species

AbstractAimsHerbaceous plant cover can be used to inhibit tree encroachment in many managed and semi‐natural grasslands. Ideally, herbaceous seed mixtures should reduce the establishment and growth of many invading tree species over several years. Theory predicts that invasion resistance can be maximized by both: (a) increasing the diversity (taxonomic and/or functional) of resident seed mixtures, and (b) including species that are especially efficient at blocking further colonizers. We established an experiment in a regularly mown old field within a deciduous forest region in southeastern Canada. Our overall goal was to examine the relative contribution of old field community composition and diversity (taxonomic and functional) to resistance against encroachment by two undesirable native tree species over time.LocationVarennes, southern Québec, Canada (45°37′01.24″ N, 73°23′03.57″ W).MethodsWe tested our hypotheses by seeding experimental plots with different levels of taxonomic diversity (from one to nine species) and functional group richness (grasses, legumes, and forbs). Our herbaceous species comprised four native species and five introduced and naturalized species. We then seeded the plots with two model tree colonizers, Acer rubrum and Betula populifolia, during three consecutive years. We also transplanted seedlings of Acer and Betula to determine the effect of herbaceous diversity on post‐emergence growth and seedling survival.ResultsOverall, herbaceous species identity (presence and absence) better predicted the resistance of resident herbaceous seed mixtures to tree encroachment than the other diversity measures assessed in our study. Fast‐growing herbaceous species, such as Lolium, substantially inhibit resistance to woody encroachment in the first year. Achillea millefolium and Solidago canadensis were by far the most efficient in blocking tree seedling establishment and growth, particularly during the second and third years. These effects highlight the potential for a combination of fast‐growing species, along with slower‐growing but highly inhibitive species, as a way to limit tree encroachment in real field applications. Functional group richness was a poor predictor of tree encroachment. Species richness reduced tree encroachment, especially when considering a multidimensional tree encroachment index integrating all aspects of tree establishment and growth over the three years of our experiment.ConclusionsSeeding highly inhibiting herbaceous species is the most efficient approach against specific tree invaders. However, it is difficult to implement in practice because it relies on a priori knowledge of the species’ inhibitory effects. In the absence of this knowledge, the taxonomic richness of seed mixtures should be increased to prevent tree encroachment.

Distribution, taxonomic diversity and ecology of paleogene <i>Bacillariophyta</i> in Ukraine

The geographic distribution, level of taxonomic diversity, and ecological preferences of Bacillariophyta complexes extracted from Paleogene deposits in various regions of Ukraine are characterized. The stratigraphic sequence of diatom assemblages, the relationship of the conditions of their formation to paleoceanological events in sedimentation basins, and the biostratigraphic significance are traced. The most taxonomically diverse (up to 250 species) associations of marine diatoms and silicoflagellates are found in the Middle to Upper Eocene deposits of the northeast margin of the Dnieper-Donetsk Depression, the northwest margins of the Donbas, and the slopes of the Voronezh Uplift. In Eocene-Oligocene deposits of the Ukrainian Shield, diatom complexes consist of over 60 marine and brackish taxa. Early Oligocene marine associations, widespread in the Sambir Carpathians and the eastern part of the Azov region, include over 130 species-level taxa. Changes in the proportion of ecological groups of diatom algae indicate their formation under different facies conditions and the transition from marine warm to more cold-water coastal-marine environments during the Eocene, with episodes of freshwater input in the Oligocene.

The role of macroinvertebrate taxonomic resolution in bioassessment of urban streams: A case study from the City of Lodz, Poland

Benthic macroinvertebrates were sampled at 28 sites situated on ten urban streams (Łódź, Poland) representative of a wide range of anthropogenic modifications of water chemistry and bed structure. A total of 5,043 individuals, comprising 121 species belonging to 37 families and 15 orders, were collected. Diptera (35.8 %) and Ephemeroptera (31.8 %) were dominant.The studied sites were grouped into clusters based on separately-analyzed environmental parameters, various levels of taxonomic diversity, and bioassessment variables. All analyses demonstrated similar trends of anthropogenic modification, intensifying concentrically from the suburbs towards the city centre. The first cluster included the upper section of streams; less polluted, richer in ecotone zones and natural stream bed substrate. The second cluster comprised streams demonstrating the influence of moderate human pressure. The third cluster included streams flowing through the city center in concreted beds and which were connected to a combined sewage system in which sewage and rain water are transported through a single canal system and enters the nearest stream. Modification of stream beds was significantly negatively correlated with the number of species, families and orders, but not with total abundance.The number of species, the number of families and the number of orders were highly mutually correlated. Moreover, they were similarly correlated with biodiversity and biotic indices, which are used to assess the ecological status of the aquatic environment. Hence, different levels of taxonomic identification demonstrate similar effectiveness in assessment, i.e. higher taxa of aquatic macroinvertebrates may be suitable for simplified ecological monitoring of urban watercourses.

Annotated list of the coastal habitats flora of the Southern Crimea and its brief analysis

The aim of this work is to assess the level of taxonomic diversity and to analyze the structure of the vascular flora of the coastal biotopes of the Southern Crimea. The work is based on the results of long standing field research, which was carried out by the traditional route-reconnaissance method, analysis of YALT herbarium materials and data from literary and Internet sources. Arealogical and biomorphological characteristics of the species are given according to "Biological Flora of Crimea" by V.N. Golubev, biotope coding – according to EUNIS habitat classification. The nomenclature of taxa corresponds to the "Spontaneuos flora of the Crimean peninsula" by A.V. Yena and international databases IPNI, Euro+Med PlantBase, The Plant List, Catalog of Life. 17 types of biotopes of the local, regional and European levels were identified in the coastal landscapes of the Southern Crimea according to the EUNIS habitat classification. An annotated list of vascular plants of coastal habitats has been compiled, which includes 334 species and subspecies from 223 genera of 58 families. The "core" of the studied flora has been identified, which includes 94 species most characteristic of it from 74 genera of 29 families. The analysis of the systematic, geographical and biomorphological structures of the flora and its sozological assessment are carried out. It has been established that the diversity of the coastal landscapes of the Southern Crimea is represented by 17 types of habitats, the flora of which includes 334 species and subspecies from 223 genera of 58 families of vascular plants. The most characteristic for the studied biotopes are 94 species from 74 genera of 29 families, which constitute the "core" of their flora. 14 coastal biotopes and 41 plant species have conservation status of different levels.

GEOGRAPHICAL RELATIONS OF DARKLING BEETLES (COLEOPTERA: TENEBRIONIDAE) OF THE PALAEARCTIC TETHYS DESERT-STEPPE REGION WITH THE HISTORICAL REVIEW

Aim. The aim of the work is to analyze the geographic relationships of the family Tenebrionidae, which should be the basis of faunogenesis of the Tethys region of Palaearctic. Methods. The work is based on the material collected by the authors in the various regions of the Caucasus, the south of the European part of Russia, Kazakhstan and North Africa during 50 years (from 1961 to 2016), as well as the extensive literature data. We used the cluster analysis based on the Jaccard similarity coefficient which considers the positive coincidences for analysis the Tethys region tenebrionid faunas. Invasive species are not included in the analysis. Results. Extensive review of the history of study of Western Palaearctic Tenebrionidae from the mid-19th Century to the present day is given. The main directions of contemporary research are marked. Four hundred three genera of darkling beetles are distributed in the Tethys region including dendrophilous groups with tropical origin, transpalaearctic and cosmopolitan species, that represent 63% of all known Palaearctic tenebrionid genera (640 genera). Three quarters of them (304 genera or 75%) combining 5674 species include mainly xerophilous genera that are not found outside the region or presented only by very small number of species in the neighboring territories. Evidences of a common historical development of tenebrionid fauna appear in the 24 common widespread Tethys genera, which may be slightly spread beyond the boundaries, but have a very high diversity of species and infrageneric (probably a center of the origin) diversity within the Tethys region. The significant part (61%) of common Tethys genera, the high diversity of large Palaearctic genera of Tenebrionidae in the western and eastern parts of Tethys region, as well as the presence of complex of supralittoral relics of marine paleobassins (Western Tethys and Eastern Paratethys) from the genus Ectromopsis, indicates a single area of faunogenesis of darkling beetles, which is historically related with epicontinental Paleogene Tethys Ocean. Two super-regions (with western Tethys and eastern Tethys complexis of taxa) are allocated. These two regions are divided on several subregions which differ by high level of taxonomic diversity. The division is based on the analyses of species and generic abudance and level of an endemism. Claster analyses of common to the region genera, Tethys genera, common to the region species and the genus Blaps shows similarity of Anatolia and the Balkan region faunas; the Caucasus is similar to Iran. Two early allocated super-regions are more or less clearly revealed on all dendrograms. The Arabian Peninsula and North Africa have ancient relations with both super-regions based on the analyses of Tethys genera, and the Arabian Peninsula and the Middle East have ancient relations with both super-regions using analyses of all tenebrionid species of the Tethys region. Conclusion. The faunogenesis of several subregions of the Tethys region was formed as island type. Analysis of the distribution and taxonomic diversity of darkling indicates a long-time development of the tenebrionid fauna in coastal and island ecosystems of the Tethys Ocean, and later an independent prime of this fauna in different areas of the Tethys desert-steppe region with the retreat of ocean water, aridity and orogeny. At the same time, faunistic elements of relic type of Paleogene origin are preserved and evoluted in the mountain island forests in Anatolia, the Middle East and the Atlas with the Late Tertiary relict flora.

The nematode assemblage of a coastal lagoon (Lake Varano, southern Italy): ecology and biodiversity patterns

This study was conducted in Lake Varano (southern Italy) in order to determine the environmental parameters that influence nematode taxonomic and functional diversity and how they influence them, and to classify for the first time the ecological quality status of a transitional environment. The general composition and level of taxonomic diversity were comparable with those reported for transitional environments worldwide. Principal component analysis revealed that the main environmental factors controlling the assemblages in terms of both composition and biological traits were grain size, organic matter, pollution load index and, only secondarily, salinity. Molgolaimus allgeni, Terschellingia longicaudata and Leptolaimus luridus showed higher values in relation to silt, organic matter and pollution load index, while Axonolaimus caudostriatus, Odontophora wieseri, Paramonhystera pellucida and Paracanthonchus longicaudatus showed higher values in relation to the redox potential and sand percentage. Salinity was detected as an influencing parameter only secondarily and particularly for Calomicrolaimus honestus, Daptonema normandicum, Thalassomonhystera parva and Sabatieria pulchra . With respect to functional traits, the trophic groups seemed to be mainly related to sediment type, which is in turn reflected by the nature of the available food. The maturity index, as well as c-p classes, did not always permit a clear interpretation of the interaction between anthropogenic and natural factors. However, the greater influence of the San Antonino and San Francesco Canals was perfectly revealed by the nematode assemblage. In accordance with the current ecological quality classes, Lake Varano can mainly be classified as having good to poor ecological quality status.

SPECIAL ISSUE HONORING THE MEMORY OF PROFESSOR JOHN H. WRENN - AN INTRODUCTION

This special issue of Palynology honors the memory of John H. Wrenn. Each contributed paper has been written by at least one author who regarded John as a colleague or friend. It is singularly fitting that AASP–The Palynological Society’s own journal should publish this collection of papers, as John was deeply committed to the American Association of Stratigraphic Palynologists (AASP, the previous name of our society) for much of his professional life. John’s involvement with AASP began in 1986 when he organized and chaired the First Symposium on Neogene Dinoflagellate Cyst Biostratigraphy during AASP’s 20th Annual Meeting in New York City. This was an inspired initiative as it launched the study of Neogene dinoflagellate cysts into the mainstream of palynological research. The accompanying proceedings (Wrenn et al., 1986), which were made available at the meeting, revealed a hitherto unappreciated level of taxonomic diversity for this time interval. During this same year, John took over the editorship of the AASP Newsletter (1986–1988), and in doing so began a life-long commitment to editing that included Palynos (the newsletter of the International Federation of Palynological Societies) from 1992 to 1996, and several books (Head and Wrenn, 1992a; Bryant and Wrenn, 1998; Wrenn et al., 1999) and conference proceedings. In addition to serving on numerous AASP committees, he was its President from 1991 to 1992, and in 1993 was appointed as the inaugural Director of the AASP Center of Excellence in Palynology which had been established at Louisiana State University (LSU) in Baton Rouge. It was testimony to John’s modesty that he soon had the name changed to Center for Excellence in Palynology, believing that the original name was presumptuous. His many contributions to this association were recognized in 1998, when AASP’s Distinguished Service Award was conferred upon him. John’s research interests …

Клавариодные грибы полуострова Ямал

51 species of clavarioid fungi (Basidiomycota) belonging to 14 genera, 7 families and 4 orders are reported from arctic and subarctic areas of the Yamal Рeninsula. The highest level of taxonomic diversity and richness (51 species) is recorded in the foresttundra, but highest level of dominance is characteristic of the arctic tundras having the lowest species diversity. The family Typhulaceae tends to decrease in species number from north to south of the peninsula, in contrast to the family Gomphaceae increasing in species number toward forest-tundra. All clavarioid fungi of Yamal are widely distributed, i. e. cosmopolitan, Eurasian or Holarctic. 14% species are common (more than 8 records), and 54% are rare (1–3 records). Saprotrophic fungi are dominating, especially growing on soil, rotten litter, dead herbs, leaves and wood. Only one species is a parasite on alive grasses.

Variation and diversity in Homo erectus: a 3D geometric morphometric analysis of the temporal bone

Although the level of taxonomic diversity within the fossil hominin species Homo erectus ( sensu lato) is continually debated, there have been relatively few studies aiming to quantify the morphology of this species. Instead, most researchers have relied on qualitative descriptions or the evaluation of nonmetric characters, which in many cases display continuous variation. Also, only a few studies have used quantitative data to formally test hypotheses regarding the taxonomic composition of the “ erectus” hypodigm. Despite these previous analyses, however, and perhaps in part due to these varied approaches for assessing variation within specimens typically referred to H. erectus ( sensu lato) and the general lack of rigorous statistical testing of how variation within this taxon is partitioned, there is currently little consensus regarding whether this group is a single species, or whether it should instead be split into separate temporal or geographically delimited taxa. In order to evaluate possible explanations for variation within H. erectus, we tested the general hypothesis that variation within the temporal bone morphology of H. erectus is consistent with that of a single species, using great apes and humans as comparative taxa. Eighteen three-dimensional (3D) landmarks of the temporal bone were digitized on a total of 520 extant and fossil hominid crania. Landmarks were registered by Generalized Procrustes Analysis, and Procrustes distances were calculated for comparisons of individuals within and between the extant taxa. Distances between fossil specimens and between a priori groupings of fossils were then compared to the distances calculated within the extant taxa to assess the variation within the H. erectus sample relative to that of known species, subspecies, and populations. Results of these analyses indicate that shape variation within the entire H. erectus sample is generally higher than extant hominid intraspecific variation, and putative H. ergaster specimens are significantly different from other specimens in H. erectus ( sensu lato). However, shape distances within geographical groups of H. erectus are also high, and OH 9 and Dmanisi 2280 are morphologically distinct from the Koobi Fora specimens that are sometimes classified as H. ergaster. These findings suggest that, although H. erectus may be composed of multiple species, the differentiation is complex, and specimens cannot easily be grouped geographically or chronologically. Consequently, more complicated scenarios seeking to explain the observed variation within H. erectus must be considered.

Assessment of Coastal Lagoon Quality with Taxonomic Diversity Indices of Fish, Zoobenthos and Macrophyte Communities

Lagoons and marshes account for more than 50% of the coastal area in the Languedoc Roussillon region (South of France, Mediterranean Sea). The lagoons are very different in their physical and chemical characteristics, eutrophication level and resource exploitation mode. In this study, different levels of taxonomic diversity and two indices (Δ+ and Λ+) based on macrophyte, zoobenthos and fish communities are used to compare three lagoons (Ingril, Prevost and Mauguio). Whilst the taxonomic diversity of the fish community seems not influenced by the lagoon characteristics, the benthos community is strongly related to their eutrophication status. With the same sampling effort we identified 7 benthic species in Mauguio, the most impacted lagoon, while 24 species were found in the Ingril lagoon, which is the less impacted one. Overall, the variance of taxonomic distinctness Λ+ appeared as the best indicator of the lagoon eutrophication level. This index is always highest for the Mauguio lagoon, whatever the biotic compartment considered. In a more stable environment like in the Ingril lagoon (lower variations of salinity, temperature or turbidity), Λ+ is low, i.e., the structure of the taxonomic tree is very regular with a relatively homogeneous partition of species among phyla. By contrast, when salinity variations are wide, like in the Mauguio lagoon, the taxonomic tree becomes irregular with some lineages less constrained (many species belonging to the same family), while others are more impacted with a limited number of species in these phyla.

The taxonomic diversity of quarry vegetation in northwest Siberia and Chukotka

Data on the floras of quarries from different sites in the Russian Far North are presented. Thirty‐two quarries with different substrate textures were studied (ranging from sandy‐loamy to stony) ‐17 in northwestern Siberia and 15 in Chukotka. The paper presents a complete list of vascular plants found in the quarries, and analyzes the taxonomic diversity of quarry vegetation and its relationship to disturbed‐area size, age since abandonment, and type of substrate texture. It appears that the highest level of taxonomic diversity is typical of quarries with rubbly substrates, and the lowest level with quarries with sandy surfaces.

Population genetics of four species of Ordovician bryozoans: stereology and jackknifed analysis of variance

Collections of four Ordovician bryozoan species from habitats of differing levels of taxonomic diversity were examined in order to assess the effect of environmental conditions on intraspecific and interspecific morphologic patterns. Up to 20 morphometric characteristics were measured for each species from populations in both high-diversity and low-diversity settings. Character means and the levels of character variability differ between populations in different diversity zones. Across species, mean character values differ significantly in 41 percent of the total comparisons, permitting intraspecific and interspecific multivariate discrimination of populations from the two diversity zones.The partitioning of clonal morphologic variability into within-colony (nonheritable) and among-colony (potentially heritable) components reveals that habitat conditions favoring high diversities appear to promote a greater proportion of potentially heritable genetic variation both within- and among-species than do low-diversity settings wherein a larger percentage of variation is ecophenotypic, or nonheritable, plasticity. Although the actual percentages vary from species to species, this pattern is obtained for representatives of four different trepostome bryozoan families and therefore is robust. Variability of this sort, if unrecognized, could lead to taxonomic oversplitting along ecologic gradients. These local, facultative adjustments to environmental conditions may be indicative of processes involved in the reactions of populations to selective pressures.Analyses such as this, coupled with examinations of character covariances, may permit the recognition not only of environmentally-induced morphologic plasticity and the proportions of potentially heritable and nonheritable variability, but also provide evidence for intraspecific changes in the rates and timing of developmental events (i.e., across-population or facultative heterochrony).

STUDIES ON BLOOD GROUPS IN THE AMERICAN BISON (BUFFALO)

The antigenic characteristics of red cells provide unusual advantages for the analysis of genetic similarities and differences among related species. This opportunity has been most extensively exploited in the analysis of relationships among various species of pigeons and doves (cf. Irvin, 1953) and in ducks (McGibbon, 1944). Rather numerous studies have been made also of the occurrence of antigenic factors related to those found in human blood, as they occur in other animals (cf. Wiener, 1943). The most common experience in such studies has been to find that antigenic materials similar to, but often not identical with, the antigens segregating or fixed in a given species are either segregating or fixed in a related species. There has been little basis for evaluating the degree of such relationships in terms of the evolutionary affinities of the populations concerned. Some years ago, we undertook to capitalize on the availability of a large battery of antibody reagents distinguishing individual differences in cattle, for the investigation of this kind of problem. Several levels of taxonomic diversity were subjected to study, beginning with differ-