Taxonomic and functional homogenisation of macroinvertebrate communities in recently intermittent Alpine watercourses

1. Mountain streams in southwestern European Alps are currently shifting from perennial to intermittent flow due to the combined effects of climate change and local anthropogenic pressures. Given that flow intermittency is a recently documented phenomenon in the Alps, only scattered studies have investigated functional and taxonomical diversity of benthic invertebrate communities in recently intermittent Alpine streams.
2. We used a hierarchical sampling design to investigate patterns in taxonomic and functional diversity of benthic invertebrate communities in 13 recently intermittent Alpine streams in north-west Italy. in April 2017, we sampled benthic communities in two reaches of each stream with different hydrological conditions: a control reach, with permanent flow; and an intermittent reach, which recently experienced non-flow periods in summer.
3. We tested for the response of taxonomic richness at multiple spatial scales by partitioning total diversity into the average richness of local communities and the richness due to variation among local communities both within and among reaches. By partitioning total diversity (γ) into its local (α) and turnover (β) components we showed a decrease in local and regional species richness both within and among reaches, whereas variation among communities was significantly lower in intermittent reaches at the reach scale only.
4. The analysis of multidimensional trait space of macroinvertebrate communities in reaches with different hydrological conditions revealed a significant reduction of functional diversity, dispersion, and evenness in intermittent reaches. There was trait overdispersion in intermittent reaches, as these hosted both typical Alpine taxa and organisms adapted to flow intermittency. In particular, we observed the replacement of taxa with aquatic respiration and those preferring medium- to fast-flowing oligotrophic waters by taxa adapted to lentic habitats, air breathing and with larval dormancy phases.
5. These results indicate that recent flow intermittency has caused drastic changes in benthic invertebrate communities in Alpine streams. Our work highlights the importance of integrating taxonomic and functional diversity to thoroughly assess the impacts of flow intermittency.

     

Tropical and Temperate: Evolutionary History of Páramo Flora

Biogeography of the tropical alpine flora of South and Central America, the páramo flora, has been studied by dividing genera into tropical, temperate, and cosmopolitan chorological flora elements. Published molecular phylogenies of páramo genera are reviewed to summarize knowledge about evolutionary history of the páramo flora and to assess congruence between chorological and phylogenetic approaches. Molecular phylogenies suggest that both the tropical and temperate regions have been important source areas for evolution of the páramo flora. Conclusions derived from chorological patterns regarding origin of genera in páramo are mostly supported by phylogenetic data. Nevertheless, in Chuquiraga, Halenia, Huperzia, and Perezia the chorological scenario is rejected, and in Chusquea-Neurolepis, Elaphoglossum, Gunnera, Halenia, Jamesonia-Eriosorus, and Lasiocephalus independent colonization events from one or several source areas are suggested. Tropical and temperate genera contributed equally to modern species richness of the páramo flora. Among temperate genera, the northern hemisphere genera gave rise to more species in páramo than did genera from the southern hemisphere. So far, no unequivocal evidence has been provided for migration of páramo genera to the temperate zones.     

Subsistence strategies of two Bronze Age hill-top settlements in the eastern Alps—Friaga/Bartholomäberg (Vorarlberg, Austria) and Ganglegg/Schluderns (South Tyrol, Italy)

Up to now, archaeobotanical investigations of prehistoric sites in the eastern Alpine region have been rare. Recent palaeoethnobotanical investigations of carbonised plant remains from two Bronze Age hill-top settlements, one located north and the other south of the main Alpine range, contribute essentially to the knowledge of subsistence strategies and husbandry regimes in the Alps in prehistoric periods. The principal cereals were Hordeum vulgare (hulled barley), Triticum dicoccon (emmer) and Panicum miliaceum (broomcorn millet). In general, hulled barley was the most important cereal crop in the eastern Alps. Legumes such as Vicia faba (horse bean) and Pisum sativum (pea) also occurred regularly in both hill-top settlements. In addition to these field crops, a large variety of wild plants was still gathered and contributed considerably to the daily diet. The arable weed flora suggests that crops were sown in spring and autumn and it indicates crop rotation in this period. The results of the plant macrofossils imply a complex pattern of plant resource utilisation in the Alpine area during the Bronze Age.     

Beitrag zur Kenntnis der GattungHieracium L. in den Kaukasusländern

Taxonomic and chorological remarks on theHieracium flora of the Caucasian countries are given. A list contains localities of 28 taxa of the genusHieracium (incl.Pilosella) from Georgia and Armenia.H. piloselloides (sensu auct. medioeurop.) is new for the Soviet part of Transcaucasia.     

Chironomids from Southern Alpine Running Waters: Ecology, Biogeography*

The chironomid fauna living in running waters in the Southern Alps was investigated from an ecological and biogeographical point of view: 202 species were identified (not including terrestrial species). It must be emphasised that species identification is tentative within some genera, especially those awaiting revision (e.g., Boreoheptagyia, Chaetocladius). Although much taxonomic work was done in the past on the chironomid Alpine fauna, there are still many unsolved problems. Most of the species found are widespread in the Palearctic Region, with no evidence of bio-geographical barriers separating different Alpine sectors. Really a relatively high number of species reported from the northern and western side (France, Switzerland, Austria) of the Alps was not captured on the southern side (Italy), whereas most species found on the southern side are also present on the northern one. Very few species are reported from southern side only. Lack of sampling, imperfect taxonomic knowledge and different environmental conditions between the northern and southern sides may be responsible of this result. A comparison of the fauna of the southern Alps with the fauna of the Apennines suggests that the differences are probably more related to ecological conditions (lack of glaciers in the Apennines) than to biogeographical barriers. Different chironomid assemblages colonise manifold habitat types: strict cold-stenothermal species tolerating high current velocity (e.g., Diamesa latitarsis – steinboecki group) are almost the sole inhabitants of kryal biotopes, while other cold-stenothermal species are restricted to cold springs (Diamesa dampfi, D. incallida, Tokunagaia rectangularis, T. tonollii), there are also species characteristic of hygropetric habitats (Syndiamesa edwardsi, S. nigra) or restricted to lacustrine habitats (Corynoneura lacustris, Paratanytarsus austriacus). It must be emphasised that different responses to environmental factors can be observed between species belonging to the same genus (e.g., Diamesa, Eukiefferiella, Orthocladius , Paratrichocladius), so species identification is really needed for a good ecological work. Water temperature, current velocity, substrate type are the most critical factors, sometime chironomid species appear to be rather opportunistic and their presence or absence cannot be clearly related to a well defined range of values of environmental variables: be it a lack of knowledge or a real datum will be the task of future studies. The waters of the Alps are still relatively unpolluted, but hydraulic stress due to river damming and canalization is a serious problem for macrofauna conservation, and as the glaciers retreat, the species confined to the glacial snouts are at risk of extinction, some of them possibly even before their existence be discovered. *The complete database with detailed taxonomical, ecological and biogeographical information can be obtained by the senior author to request (e-mail: bruno.rossaro@unimi.it). A table with species response to environmental variables is also available at the web site: http://users.unimi.it/~roma1999/rossaro.html, downloading file CHIRDB.)     

Historical divergence vs. contemporary gene flow: evolutionary history of the calcicole Ranunculus alpestris group (Ranunculaceae) in the European Alps and the Carpathians

Although many species have similar total distributional ranges, they might be restricted to very different habitats and might have different phylogeographical histories. In the European Alps, our excellent knowledge of the evolutionary history of silicate‐dwelling (silicicole) plants is contrasted by a virtual lack of data from limestone‐dwelling (calcicole) plants. These two categories exhibit fundamentally different distribution patterns within the Alps and are expected to differ strongly with respect to their glacial history. The calcicole Ranunculus alpestris group comprises three diploid species of alpine habitats. Ranunculus alpestris s. str. is distributed over the southern European mountain system, while R. bilobus and R. traunfellneri are southern Alpine narrow endemics. To explore their phylogenetic relationships and phylogeographical history, we investigated the correlation between information given by nuclear and chloroplast DNA data. Analyses of amplified fragment length polymorphism fingerprints and matK sequences gave incongruent results, indicative for reticulate evolution. Our data highlight historical episodes of range fragmentation and expansion, occasional long‐distance dispersal and on‐going gene flow as important processes shaping the genetic structure of the group. Genetic divergence, expressed as a rarity index (‘frequency‐down‐weighted marker values’) seems a better indicator of historical processes than patterns of genetic diversity, which rather mirror contemporary processes as connectivity of populations and population sizes. Three phylogeographical subgroups have been found within the R. alpestris group, neither following taxonomy nor geography. Genetic heterogeneity in the Southern Alps contrasts with Northern Alpine uniformity. The Carpathians have been stepwise‐colonised from the Eastern Alpine lineage, resulting in a marked diversity loss in the Southern Carpathians. The main divergence within the group, separating the ancestor of the two endemic species from R. alpestris s. str., predates the Quaternary. Therefore, range shifts produced by palaeoclimatic oscillations seem to have acted on the genetic structure of R. alpestris group on a more regional level, e.g. triggering an allopatric separation of R. traunfellneri from R. bilobus.     

New liverwort records for Vietnam

A short collecting expedition to Vietnam in 2016 yielded 700 specimens of 170 liverwort species of which 79 were new to the flora of Vietnam, including 43 species new to Indochina. Many of the newly recorded species have meta-Himalayan distributions (that predicts occurrence of these taxa in the areas of north-west Vietnam situated in the south-easternmost spurs of the Himalaya). Some species were recorded based on the study of living material, permitting the examination of oil body characteristics for Riccardia and Calypogeia. The known taxonomic liverwort diversity of Vietnam is currently 379 taxa, estimated to represent ca 80% of the actual taxonomic diversity in the country.     

Revisiting the comparative phylogeography of unglaciated eastern North America: 15 years of patterns and progress

In a landmark comparative phylogeographic study, “Comparative phylogeography of unglaciated eastern North America,” Soltis et al. (Molecular Ecology, 2006, 15, 4261) identified geographic discontinuities in genetic variation shared across taxa occupying unglaciated eastern North America and proposed several common biogeographical discontinuities related to past climate fluctuations and geographic barriers. Since 2006, researchers have published many phylogeographical studies and achieved many advances in genotyping and analytical techniques; however, it is unknown how this work has changed our understanding of the factors shaping the phylogeography of eastern North American taxa. We analyzed 184 phylogeographical studies of eastern North American taxa published between 2007 and 2019 to evaluate: (1) the taxonomic focus of studies and whether a previously detected taxonomic bias towards studies focused on vertebrates has changed over time, (2) the extent to which studies have adopted genotyping technologies that improve the resolution of genetic groups (i.e., NGS DNA sequencing) and analytical approaches that facilitate hypothesis‐testing (i.e., divergence time estimation and niche modeling), and (3) whether new studies support the hypothesized biogeographic discontinuities proposed by Soltis et al. (Molecular Ecology, 2006, 15, 4261) or instead support new, previously undetected discontinuities. We observed little change in taxonomic focus over time, with studies still biased toward vertebrates. Although many technological and analytical advances became available during the period, uptake was slow and they were employed in only a small proportion of studies. We found variable support for previously identified discontinuities and identified one new recurrent discontinuity. However, the limited resolution and taxonomic breadth of many studies hindered our ability to clarify the most important climatological or geographical factors affecting taxa in the region. Broadening the taxonomic focus to include more non‐vertebrate taxa, employing technologies that improve genetic resolution, and using analytical approaches that improve hypothesis testing are necessary to strengthen our inference of the forces shaping the phylogeography of eastern North America.     

Die systematische Stellung von Melica uniflora Retz. und Melica rectiflora Boiss. er Heldr. (Melica L. Subgen. Bulbimelica,subgen. nov.) (Vorarbeiten zu einer Revision der Gattung Melica L.–I)

This work presents an investigation of the author on the systematical position of Melica uniflora Retz. and Melica rectiflora Boiss. et Heldr. The author proves the affinity of these Melica-species to those of the pacific-northamerican territories. The usefulness of striking characteristic features or signs (e. g.: the cilia (fringes) and the awns of the glumelles) is examined in respect to their taxonomic value; and the corresponding literature is discussed. The author proves that certain characteristic signs, hardly or not yet being noticed till now, play a decisive role in respect to the explanation of the affinity between the species Melica L.; the probative force of these features will not become evident but by comparison of the taxa of all continents. Following the author, the storage internodes, the formation of antiligula in front of the leaf-base, and the dynamics in the ontogeny of the elements of the spikelets (glumes) are thought to be very important characteristics of organization. The author compares these features these with their formation within the range of sub-genus Melica. As a result of this research, the new sub-genus Bulbimelica is described and its systematical classification is given. The new subgenus is furthermore more exactly separated from the subgenus Melica. The classification is followed by chorological interpretation as well as by indications to the ecology of the taxa and the distribution of diagnostically important signs within the whole generic distribution-area.     

An evaluation of floristic diversity in Medvednica Nature Park (northwestern Croatia)

Abstract

Mount Medvednica (northwestern Croatia), mostly consisting of slates and marls, rises to the north, above the Croatian capital of Zagreb, from 300 to 1,035 m a.s.l. A floristic research was carried out in the area of Medvednica Nature Park, which consists mainly of the western part of the mountain. On the whole, 1,352 taxa of vascular plants were recorded from all sources (field observations, literature and herbaria). Out of these, 48 taxa are strictly protected, 228 are protected, 67 taxa are considered threatened according to the IUCN categories, and 9 taxa are endemic for the Croatian flora. The life-form analysis of the investigated flora shows the predominance of hemicryptophytes, followed by therophytes and geophytes, while the chorological analysis has evidenced the prevalence of Euro-Asiatic, South European and cosmopolite geographical groups. The biological/chorological cross-spectrum was laid out by considering the percent of every life-form for each geographical element. In order to evaluate the floristic richness of the studied area, the α-index was calculated and then compared with the α-indices of similar regions in Croatia and several European countries. A floristic diversity map of Medvednica Nature Park is presented here for the first time.     

Littoral Chironomid Communities of Alpine Lakes in Relation to Environmental Factors

The results of a study of littoral chironomid communities from 89 lakes in the Alps are presented. The lakes are located on the northern and southern sides of the Alps from the western Bernese to the eastern Julian Alps. Due to the different origins of the data set here considered, different sampling years and sampling methodologies were adopted. All of the lakes were sampled during the ice-free season, but 79/89 lakes were sampled mainly in autumn 2000, while for a few of them the sample dated back to 1996 or the early 90s. Samples were taken by kicking the different substrata or a stretch of lakeshore (10–30 m) for at least 2–5 min with a standard net and were then preserved in alcohol. Larvae and pupal exuviae were sampled by skimming the lake surface with the same net, to extend identification to species level. Notwithstanding the large altitudinal gradient, almost all of the lakes are situated above the timberline, and show a wide range of morphological (depth, watershed and lake area) and chemical characteristics. Chironomids were the most abundant insects represented in these lakes, with highest abundances at pH between 6.0 and 7.5. In particular, Orthocladiinae and Chironominae were the two subfamilies with the widest distribution. Altitude and temperature played an important role in determining their distribution, the higher altitudes were dominated by the former, whereas the latter were more numerous in lower lakes. The prevalence of Orthocladiinae and Tanytarsini at high altitudes was regarded as a general pattern of taxonomic composition in harsh climatic areas. A reverse condition occurred only in the Julian Alps, where Tanytarsini dominate, followed by Tanypodinae and rare Orthocladiinae. Although our results demonstrated that the composition of chironomid assemblages was also determined by pH, the pattern was unbalanced. Due to the fact that no cases of strong water acidification were present, taxa restricted to very low pH were poorly represented (only three taxa—Limnophyes, Endochironomus and Orthocladius (O.) spp.) compared with circumneutral (8) and alkaline (14) taxa, which occurred in slightly acid and non-acidified soft water lakes. As regard conductivity and altitude, we found that almost all the taxa present at higher pH were contemporary present at conductivity higher than 100 μeq l⁻¹ and altitude lower than 2100 m a.s.l. At species level, Pseudodiamesa branickii, Corynoneura arctica, Heterotrissocladius marcidus and Paratanytarsus austriacus resulted to be the most ubiquitous and abundant species in the Alps. When the west to east distribution of taxa was taken into account, Chironomini (particularly the genera Chironomus and Dicrotendipes) and Tanypodinae (Larsia and Paramerina) were more typical of the eastern lakes (JA). They may be better indicators of more alkaline waters. Assembling all the existing data and presenting a comprehensive panorama of lake-littoral chironomid taxa of the Alps was one of the aims of this paper. Further monitoring, but also harmonization of the sampling methodologies and taxonomical identification including inter-calibration exercises among laboratories are recommended, to provide reliable basis and more knowledge for future studies of comparative biogeography, and to preserve these environments where global climatic changes may cause abrupt shifts in the faunal assemblages with a loss of taxa typical of these mountainous areas.     

Peroxidases as taxonomic characters in Lophozia incisa (Schrad.) Dum. and Lophozia opacifolia (Culm.) Meyl.

Abstract

Peroxidases in 21 samples of Lophozia incisa from the Tatra Mountains and 14 samples of L. opacifolia from the Tatra Mountains and the Swiss Alps were electrophoretically assayed. Although both taxa proved to be polymorphic, consistent differences were found between them. This indicates that electrophoretic peroxidase phenotypes provide an additional taxonomic character supporting the morphological and ecological differences, a summary of which is provided.     

Statistical and ecological analysis for the evaluation of floristic diversity: The case of a volcanic complex in North-eastern Italy (Colli Euganei,Padova, Italy)

ABSTRACT

The Euganean Hills are a volcanic mountainous complex, which rises from the eastern Po Plain, and consists of about one hundred hills, rising from 80 m to 604 m above sea level. In the studied area, 1158 taxa of Tracheophytes have been collected. The chorological and life-form analyses of this flora have shown the predominance of the Mediterranean s.l. elements and of the hemicryptophytes, followed by the therophytes. The chorological aspect of this floristic complex was analysed. A cross-spectrum was calculated to see how life-forms are represented in the different chorotypes. A comparison with the biological and chorological spectra of the Veneto Region and of Italy as a whole was also carried out. Several species of remarkable floristic and phytogeographical interest have been found, as well as some included in the national and Regional lists of protected species.     

A floristic investigation of the islet groups Arki and Lipsi (East Aegean Area, Greece)

Arki and Lipsi are two islet groups situated in the NNW part of the prefecture of Dodecannisos (E Aegean area, Greece), which consist of 37 islets in total, of which three (Lipsos, Arki and Marathi) are permanently inhabited. From the area studied 557 taxa of Tracheophytes have been registered and the chorological and life-form analyses of the flora have shown the predominance of the Mediterranean elements and the therophytes, respectively, confirming the Mediterranean character of the flora. However, significant fluctuations have been observed regarding the representation of both, chorological and life-form types, from islet to islet. A comparison of the individual flora of the 37 islets studied, revealed very low floristic similarity even between neighbouring islets (β-diversity). Not one of the taxa registered was present on all 37 islets; yet, 199 taxa were present on only one islet. Eight of the taxa registered in the studied area fall under a protection status according to international lists. The floristic data were statistically evaluated with respect to species-area relationship and other geographical factors such as altitude, minimum distance from a larger inhabited island and sea depth.     

Effects of water quality and season on diatom community structure in the Damour River,Lebanon

The diatom flora in the lower Damour River, a small coastal river in Lebanon, was studied during 1981. The study area included the Damour estuary and a tributary, the el-Hamam River. Achnanthes minutissima was the most abundant diatom in the flora. Other dominant taxa included Nitzschia dissipata and Navicula cryptocephala var. veneta in the spring and Anomoeoneis vitrea in the fall. The diatom community structure was characterized by 1 or 2 dominant taxa, a few common and many rare taxa, but the taxa in these categories varied according to season and locality. The freshwater flora had a group of 20 taxa which were widely distributed in the study area throughout the study period. These taxa, in addition to a few taxa of more restricted seasonal occurrence, were the major contributers to the flora and are characteristic of this river system. Certain aspects of the flora were resistant to change. Others were more sensitive to environmental conditions. The estuarine flora reflected brackish conditions beginning in June and extending through October.     

Control of Histidine Biosynthesis in Streptomyces Coelicolor

Abstract

Some data on the benthic flora of Pantelleria Harbour (Channel of Sicily, Mediterranean).—The benthic flora of the harbour of Pantelleria includes: 10 Myxophyceae, 56 Rhodophyceae, 44 Diatomeae, 19 Phaeophyceae, 18 Chlorophyceae and 2 Angiospermae. The Rh/Ph value (2.9) is in agreement with the values found from the open-sea. A chorological examination shows a dominance of Atlantic-Mediterranean species (54.36%).     

Allopatric distribution,ecology and conservation status of the Pilosella alpicola group (Asteraceae)

The Pilosella alpicola group comprises four morphologically distinct and geographically vicariant alpine taxa. We performed a thorough herbarium revision and literature survey to infer their distributional pattern(s). Pilosella alpicola s.s. occurs in the Alps in two disjunct areas: the Swiss Valais Alps and the Italian Dolomites. Historical records come also from the Austrian Alps (Gurktaler Alps and Hohe Tauern) and from one site from the Alpes Maritimes (Col de Larche), but the localities have not been recently confirmed. Pilosella rhodopea, a Balkan subendemic taxon, is quite widespread in Bulgaria (Stara planina Mts, Rila Mts and Pirin Mts), but is more rare in Albania, Greece and Macedonia. Interestingly, this species has also been recorded at two isolated sites in the Romanian southern Carpathians (the C?p??înii and Cozia Mts). This occurrence underlines the floristic affinities of this part of the Carpathians to the Balkan flora. Only two localities of P. serbica, based on voucher specimens, have been recorded so far; Kopaonik Mts in Serbia and the Prokletije Mts in Montenegro. The records from other ranges are related to P. rhodopea. Pilosella ullepitschii, the detailed distribution of which has already been published, is a Carpathian endemic with its core area of distribution in the western Carpathians (Slovakia and Poland). Three isolated localities are also known in the eastern Carpathians (Nemira Mts) and one locality in the southern Carpathians (Bucegi Mts). The possible causes of disjunctions between and within species ranges are briefly discussed. Based on the distributional data, population sizes and ecology, we evaluate the conservation status of the P. alpicola taxa and propose their inclusion in national Red Lists.