293 research outputs found

    Spring weed communities of rice agrocoenoses in central Nepal

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    Rice field weed communities occurring in central Nepal are presented in this study. The research was focussed on the classification of segetal plant communities occurring in paddy fi elds, which had been poorly investigated from a geobotanical standpoint. In all, 108 phytosociological relevés were sampled, using the Braun-Blanquet method. The analyses classified the vegetation into 9 communities, including 7 associations and one subassociation. Four new plant associations and one new subassociation were proposed: Elatinetum triandro-ambiguae, Mazo pumili-Lindernietum ciliatae, Mazo pumili-Lindernietum ciliatae caesulietosum axillaris, Rotaletum rotundifoliae and Ammanietum pygmeae. Due to species composition and habitat preferences all phytocoenoses were included into the Oryzetea sativae class and the Ludwigion hyssopifolio-octovalvis alliance. As in other rice field phytocoenoses, the main discrimination factors for the plots are depth of water, soil trophy and species richness. The altitudinal distribution also has a significant influence and separates the Rotaletum rotundifoliae and Elatinetum triandro-ambiguae associations. The study shows that anthropogenic rice fields can harbour relatively rich rush and water vegetation. More than 80 species were noted in the vegetation plots. Several of them are considered to be extremely rare and have been recorded on the world Red List

    Diversity and distribution of rush communities from the Phragmito-Magno-Caricetea class in Pamir Alai Mountains (Middle Asia : Tajikistan)

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    The study presents results of geobotanical investigations conducted in rush vegetation from the Phragmito-MagnoCaricetea class in the central Pamir-Alai Mts (Tajikistan, Middle Asia). Studies were carried out mainly within the SyrDaria, Pyandzh, Zeravshan, Kafirnighan, Khanaka and Surkhandaria river valleys in the years 2008‒2012. The research was focused on the classification of rush plant communities developing within this poorly-investigated area. Habitat conditions were checked for all vegetation plots, including pH reaction, water depth, inclination and altitude. Altogether 231 phytosociological relevés using the Braun-Blanquet method were sampled. The analyses classified the vegetation into 28 plant communities, including 26 associations. Eight new plant associations were proposed: Scirpetum hippolytii, Mentho asiaticae-Nasturtietum microphyllae, Juncetum brachytepali, Sparganietum stoloniferi, Eleocharitetum argyrolepis, Eleocharitetum mitracarpae, Caricetum songoricae and Rorippo palustris-Alismatetum graminei. The main discrimination factor for the data set is the floristic structure of the associations. Rush vegetation from the PhragmitoMagno-Caricetea class is spread throughout all river valleys of the research areas in montane and subalpine as well as in alpine zones. The vegetation patches occur mainly along the shores of water bodies and in ditches. Only sporadically have rush communities been noted within rice fields, where communities of the class Oryzetea sativae prevail. The study shows that riverside habitats with rush vegetation can harbour a relatively rich flora. Almost 200 species were found in vegetation plots, including some which are rare and have not been recorded until now in this part of Middle Asia

    Dwarf shrub vegetation of rock ledges and clefts in the Pamir Alai Mountains (Middle Asia: Tajikistan)

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    The paper presents the results of phytosociological researches on rocky slope vegetation in Tajikistan with the aim to establish a comprehensive syntaxonomical classifi cation system. Field studies were conducted in 2010–2014 in Pamir Alai ranges and Pamirian plateau. Nearly 500 relevés documenting rock and scree vegetation were made according to the Braun-Blanquet method. Numerical analyses of selected 58 relevés representing dwarf shrub vegetation on rock ledges made it possible to distinguish: Ephedro glaucae- Spiraeion baldschuanicae and Ephedrion regeliano-fedtschenkoi alliances, as well as Spiraeetum baldschuanicae, Rhamnetum coriaceae, Pentaphylloidetum parvifoliae and Pentaphylloidetum dryadanthoidis associations, community of Ephedra glauca and community of Rhamnus minuta. The classification of vegetation of dwarf shrubs on rock walls occurring in the Pamir Alai Mts is proposed. Because of the species composition, physiognomy and microhabitat conditions, the plant communities were included into Artemisio santolinifoliae- Berberidetea sibiricae class Ermakov et al. 2006. The main factors determining the species composition of the classifi ed associations seem to be the elevation above sea level.The newly described syntaxa are largely defined by species restricted to very narrow ranges in Middle Asi

    Distribution patterns, floristic structure and habitat requirements of the alpine river plant community Stuckenietum amblyphyllae ass. nova (Potametea) in the Pamir Alai Mountains (Tajikistan)

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    This paper discusses the floristic structure, distribution and habitat requirements of a new aquatic syntaxon, Stuckenietum amblyphyllae ass. nova. Patches of the Stuckenietum amblyphyllae association occur in the Pamir Alai Mountains in Middle Asia (Tajikistan). The biotope of this community represent high mountain rivers and ponds at the bottom of glacial river valleys situ- ated at elevations between 1900 and 3800 m. Patches of the Stuckenietum amblyphyllae association are characterised by a clear predominance of the typical species, i.e. Stuckenia amblyphylla, which occupies an aerial extent of between near 40 up to 90% of the surface studied. Patches of the community are poor in species, comprising a maximum of five taxa. Among associated species mainly rush, aquatic, meadow and marsh taxa have been noted. The Stuckenietum amblyphyllae community prefers cold, open, alkaline waters with medium flow-rate, ranging in depth from 15 to 75 cm. It is also, but rarely, found in the mountain ponds. Together with the Stuckenia filiformis community it designates in the Pamir Alai Mountains the upper limit of aquatic vegetation

    Distribution, floristic structure and habitat requirements of the riparian forest community Populetum talassicae ass. nova in the Central Pamir-Alai Mts (Tajikistan, Middle Asia)

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    This paper discusses the floristic structure, distribution and habitat requirements of a new forest syntaxon, Populetum talassicae ass. nova. The potential range of the Populetum talassicae association comprises the central Pamir-Alai and Tian-Shan Mountains in Middle Asia. The biotope of this community comprises high mountain river valleys and shore zones of mountain lakes situ- ated at elevations between 2200 and 2750 m. Phytocoenoses of the Populetum talassicae association are characterized by a clear predominance in the tree layer of a characteristic species of the association ‒ Populus talassica. Shrubs are not so abundant; how- ever, the undergrowth layer of the community could reach up to 60% of the total cover, consisting mainly of Salix spp., Hipophaë rhamnoides, Lonicera stenantha, Juniperus semiglobosa and J. seravschanica. The herbaceous layer is quite rich and has about 20 species on average. Among associated species mainly meadow, rush and marsh taxa have been noted. Regarding the considerable cover of the meadow species, the association of Populetum talassicae has been classified as the Populetea laurifolio-suaveolentis syntaxon. A new plant alliance was proposed ‒ Populion talassicae all. nova with Pedicularis dolichorhiza and Astragalus tibetanus as diagnostic species. The described forest association is one of the rarest and most rapidly disappearing wood communities in Tajikistan, which means that special conservation attention is called for

    Classification of tall-forb vegetation in the Pamir-Alai and western Tian Shan Mountains (Tajikistan and Kyrgyzstan, Middle Asia)

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    Aims: To complete the syntaxonomic scheme for tall-forb vegetation of the montane and alpine belts in the Pamir-Alai and western Tian Shan Mountains in Tajikistan and Kyrgyzstan with some remarks on its environmental predictors. Study area: Middle Asia: Tajikistan and Kyrgyzstan. Methods: A total of 244 relevés were sampled in 2013–2019 using the seven-degree cover-abundance scale of the Braun-Blanquet approach. These were classified with a modified TWINSPAN algorithm with pseudospecies cut-levels 0%, 5% and 25%, and total inertia as a measure of cluster heterogeneity. Diagnostic species were identified using the phi coefficient as a fidelity measure. NMDS was used to explore the relationships between the distinguished groups. Results: Our classification revealed 19 clusters of tall-forb vegetation in Middle Asia. Among others we found forb communities typical for Tian Shan, western Pamir-Alai, forb-scree vegetation of Pamir-Alai, dry tall-forbs and typical forbs of the alpine belt. A total of eight new tall-forb associations and five communities were distinguished. The forb vegetation of Middle Asia has been assigned to the class Prangetea ulopterae Klein. The main factors differentiating the species composition of the researched vegetation are elevation, mean annual temperature, sum of annual precipitation and inclination of the slope. Conclusions: The paper presents the first insight into the comprehensive classification of the alpine forb vegetation in Middle Asia and fosters progress in explaining the relationship of boreo-temperate and Mediterranean-like (Irano-Turanian) vegetation in western Asian and central Asian subregions of the Irano-Turanian phytogeographical region. Taxonomic references: The nomenclature of the vascular plants follows generally Cherepanov (1995) and for Bromus spp. The Plant List (2020) Version 1.1. http://www.theplantlist.org/. Syntaxonomic references: The names of syntaxa are used in accordance with Ermakov (2012), Gadghiev et al. (2002) and Nowak et al. (2018). Abbreviation: NMDS = Non-metric Multidimensional Scaling

    Distribution, ecology and conservation status of Dionysia involucrata Zaprjag., an endangered endemic of Hissar Mts (Tajikistan, Middle Asia)

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    Dionysia involucrata Zaprjag. (Primulaceae) is known as critically endangered endemic species of Hissar Mountains in Tajikistan. It is reported from few localities mainly in Varzob River valley and its tributaries. The species inhabits steep or overhanging faces of granite rocks in narrow river gorges. During the research all known populations of D. involucrata were examined in respect of the habitat conditions and species composition of vegetation plots. We analyzed the population extent of the species in its range in Tajikistan and the main threats in order to assess its conservation status. The detrended correspondence analysis was performed on a matrix of 65 relevés and 49 species (vascular plants and mosses), to classify the phytocoenosis with domination of D. involucrata according to their floristic composition in relation to other petrophytic vegetation units. Using our field data regarding present extent of occurrence and area of occupancy we conclude that the threat category of D. involucrata should be reassessed from critically endangered to endangered. The species shows decline tendency in extent of occurrence, area of occupancy as well as in number of locations. The vegetation plots with domination of D. involucrata have relatively high level of separateness due to different species composition. We define the new association – Dionysietum involucratae – representing chasmophytic vegetation of submontane and montane zone in Middle Asia (ca. 1000–1600 m a.s.l.). The plots of Dionysietum involucratae were found mainly on granite rocks, on very steep or overhanging faces, on southwestern or southern exposition. The association is rather poor in species with inconsiderable contribution of mosses. Despite the diagnostic species, Campanula incanescens, Carex koshewnikowii and Scutellaria hissarica were the most abundant and frequent taxa within the researched patches of vegetation

    Leczenie operacyjne oponiaków tylnej ściany piramidy kości skroniowej

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    Background and purpose The aim of the study is to present our experience in the surgical treatment of posterior petrous meningiomas in regard to clinical presentation, surgical anatomy, complications and long-term functional postoperative results. Material and methods A series of 48 consecutive patients operated on for posterior petrous meningiomas at the authors’ institution between 2002 and 2011 is reported. The main symptom on first admission was hypoacusis, impairment of the fifth cranial nerve and cerebellar ataxia. The tumour was found to be attached to the premeatal dura in 46%, the inframeatal dura in 29% and the postmeatal dura in 25% of cases. Tumour resection was categorized as grade I in 16 patients, grade II in 29 patients, grade III in 1 patient and grade IV in 2 patients, according to the Simpson classification system. The petrosal approach and retrosigmoid approach were suitable for posterior petrous meningiomas. Results Postoperative facial nerve dysfunction appeared in 8 and further deteriorated in 2 patients. Hearing function deteriorated after surgery in 8 and improved in 2 cases. Perioperative death occurred in two patients. Tumour recurrence was observed in two patients, and both underwent a second operation and postoperative stereotactic radiotherapy. Conclusions Surgical treatment of posterior petrous meningiomas has become increasingly safe but these tumours still remain a surgical challenge because of the relatively high incidence of permanent complications associated with their removal. The site of displacement of the cranial nerves depending on the dural origin of the tumour has the most influence on the related difficulties in its removal.Wstęp i cel pracy Celem pracy jest przedstawienie własnych doświadczeń w leczeniu operacyjnym oponiaków tylnej ściany piramidy kości skroniowej z uwzględnieniem objawów klinicznych choroby, anatomii chirurgicznej, powikłań pooperacyjnych i odległej oceny stanu neurologicznego. Materiał i metody Materiał kliniczny obejmuje kolejnych 48 chorych leczonych operacyjnie w naszym ośrodku w latach 2002–2011 z rozpoznaniem oponiaka tylnej ściany piramidy kości skroniowej. W badanej grupie były 44 kobiety i 4 mężczyzn, a średnia wieku pacjentów wyniosła 55 lat. Najczęstszymi objawami stwierdzanymi przy przyjęciu pacjenta były niedosłuch, zaburzenia funkcji nerwu trójdzielnego i ataksja móżdżkowa. Przyczep guza zlokalizowany był do przodu, poniżej i do tyłu od otworu słuchowego wewnętrznego odpowiednio u 46%, 29% i 25% pacjentów. Guz usunięto całkowicie w 45 przypadkach (Simpson I i II), a subtotalnie u 3 pacjentów (Simpson III i IV). Guzy usuwano drogą dostępu podpotylicznego zasutkowego i dostępu przezskalistego. Wyniki Po operacji u 8 pacjentów wystąpiło porażenie nerwu twarzowego, a u 2 chorych nasilił się niedowład uprzednio istniejący. U 8 pacjentów zaobserwowano pogorszenie słuchu po operacji, a u 2 chorych nastąpiła poprawa w tym zakresie. Dwóch pacjentów po operacji zmarło. W 2 przypadkach stwierdzono w dalszej obserwacji wznowę guza. Obu pacjentów operowano ponownie i poddano stereotaktycznej radioterapii. Wnioski Oponiaki tylnej ściany piramidy kości skroniowej mogą być leczone operacyjnie z dobrym wynikiem, niemniej jednak istnieje ryzyko zgonu i wystąpienia istotnych deficytów z zakresu nerwów czaszkowych. Najistotniejsze znaczenie dla oceny ryzyka leczenia ma lokalizacja przyczepu oponowego na podstawie czaszki, decydująca o kierunku przemieszczenia nerwów czaszkowych
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