scholarly journals Syntaxonomical and ecological diversity of the class Polygono-Poetea annuae in Bulgaria

2022 ◽  
Vol 81 (1) ◽  
Author(s):  
Kiril Vassilev ◽  
Momchil Nazarov ◽  
Constantin Mardari ◽  
Borislav Grigorov ◽  
Stoyan Georgiev ◽  
...  

Class Polygono-Poetea annuae Rivas-Mart. 1975 includes therophyte-rich vegetation on trampled habitats. The study presents the first analysis of the syntaxonomy of this class and its ecology in Bulgaria. One hundred seventy-five relevés from this class were collected and stored in the Balkan Vegetation Database during 2017–2020. Numerical classification (hierarchical divisive) and ordination were performed by JUICE and CANOCO software packages. Diagnostic species were determined by calculating the Phi-coefficient. Four associations, Sclerochloo durae-Polygonetum arenastri, Polygonetum arenastri, Lolio-Polygonetum arenastri and Poëtum annuae, were recognized. Their floristic composition has been shaped mainly by climatic and soil conditions. Sclerochloo durae-Polygonetum arenastri association has been found at lower altitudes, occurring in fully lighted habitats with high radiation, whereas Poëtum annuae has been found at higher altitudes in wetter and cooler areas. On the other hand, stands of Polygonetum arenastri have been found on nutrient-rich soils, whereas communities of Lolio-Polygonetum arenastri were distributed in warmer and nutrient-poor areas. The Polygono-Poetea annuae class is still poorly studied in Bulgaria and much more information from all regions of the country needs to be collected and analyzed.

Hacquetia ◽  
2020 ◽  
Vol 19 (1) ◽  
pp. 81-97
Author(s):  
Kiril Vassilev ◽  
Momchil Nazarov ◽  
Nikolay Velev

AbstractMantle vegetation includes plant communities dominated mostly by shrubs and occurs in habitats where the typical tree layers meet difficulties to evolve. This study was conducted in three areas of Bulgaria – Western Balkan Range, Western Sredna Gora Mt. and the Fore-Balkan. Numerical classification and ordination were performed by PC-ORD and JUICE software packages. Diagnostic species were determined by calculating the Phi-coefficient. Two associations and one plant community of the Berberidion alliance were recognized – Corno-Ligustretum Horvat ex Trinajstić ---amp--- Z. Pavletić 1991, Pruno spinosae-Ligustretum vulgaris Tüxen 1952 and Elytrigia repens-Crataegus monogyna community. The latter considered as a successional stage of shrub encroachment into the grasslands. Its species composition is very close to that of the ass. Corno-Ligustretum. The species composition of ass. Pruno-Ligustretum represents a mixture of species characteristic for dry and mesic grasslands, fringe and forest vegetation. The Crataego-Prunetea class is still poorly studied in Bulgaria and much more data from all regions in the country have to be collected.


Biologia ◽  
2010 ◽  
Vol 65 (4) ◽  
Author(s):  
Ingrid Turisová ◽  
Tomáš Hlásny

AbstractThe paper proposes a methodology of phytogeographical regionalisation using grassland vegetation data. The research area is located in the West Carpathians, in volcanic field with adjacent post-tectonic basins and valleys in the Central Slovakia. The applied techniques were variogram modelling, ordinary kriging and lattice wombling. Phi coefficient was used to determine the diagnostic species of proposed phytochoria (fidelity test). The 1978 unevenly distributed grassland polygons that comprised 1071 taxa of vascular plants were the subject of the analyses. Ecological indicator values for temperature (EITs), weighted by species coverage in the Tansley scale in each grassland polygon, were used for the modelling. The gradients in the surface of the indicator value produced by ordinary kriging were analyzed. The steepest gradients indicate the most radical changes in floristic composition typical of border locations.The steepest gradient divides the study area into main cold and main warm regions. Less intensive gradients determined the position of 15 subdistricts. Subsequently, 7 out of 15 subdistricts were merged on the basis of similar natural conditions and floristic composition into 3 districts.Ten, mostly thermophilous, diagnostic species were determined for the main warm region. Fourteen, mostly psychrophilous, diagnostic species were determined for the main cold region. Subsequently, diagnostic species were determined for districts. High number of diagnostic species (57) characterize the Pol’ana Mts district. Eleven diagnostic species were determined for the Zvolenská kotlina basin district. The Javorie and Ostrôžy Mts district was very poorly diferentiated with 3 diagnostic species.Such evaluation suggests that proposed methodology allowed for the identification of phytochoria with specific floristic composition. The obtained results are discussed.


2021 ◽  
Vol 42 ◽  
pp. e68062
Author(s):  
Pauline Delbosc ◽  
Mathieu Le Dez ◽  
Jean-Bernard Bouzillé ◽  
Kevin Cianfaglione ◽  
Frédéric Bioret

Carici-Genistetea lobelii Klein 1972 corresponds to cyrno-sardinian oromediterranean cushion scrub and related grasslands. In France, this class is only present in Corsica and the syntaxonomic scheme is debated among phytosociologists. The aim of this paper is to highlight the main plant associations of Carici-Genistetea lobelii Klein 1972 and to define the diagnostic species for each phytosociological unit. We compiled 519 vegetation plots and we applied EuropeanVegetationChecklist expert system for the classes of European vegetation to retain only vegetation plots belonging to Carici-Genistetea lobelii. We obtained a dataset with 189 vegetation plots and we classified them with Modified TWINSPAN classification. Our analyses recognized 6 plant associations and 3 sub-associations already described in the literature; and to describe a new alliance corresponding to the supra-mediterranean vegetations (Genistion salzmannii), a new association (Brimeuro fastigiatae-Juniperetum nanae) and its sub-association (alnetosum suaveolentis). For each of them, we identified diagnostic, constant and dominant species and produced their distribution map. Formal definitions were then written for each phytosociological unit (from subassociation to class) and grouped in an expert system to automatically classify the vegetations of Carici-Genistetea lobelii.


Author(s):  
Innocent A. Ugbong ◽  
Ivan V. Budagov

This paper seeks to show that due to changing climates, there are salient marginal Sahelian conditions (conditions of aridity) emerging on the Northern fringes of Cross River State, a state that is geographical positioned in the southern rainforest belt of Nigeria. The paper adopts a simple descriptive approach and shows the distinct characteristics of this zone, in terms of floristic composition and edaphic and geomorphic structures under changing conditions. Some relationships are established between environmental variables like health, water supply and crop-yield on one hand, and climatic variation, floral life-forms and soil conditions on the other. The changing land use patterns relative to environmental changes are also examined. The paper concludes with a look at current and future adaption strategies to these climate-induced conditions.


1992 ◽  
Vol 10 (3) ◽  
pp. 139-145 ◽  
Author(s):  
Roger K. Kjelgren ◽  
James R. Clark

Abstract Microclimates characteristic of urban park, plaza, and canyon spaces were related to physiology and growth of even-aged sweetgum (Liquidambar styraciflua L.) street trees. Microclimates, tree growth, and physiological responses were characterized diurnally and seasonally. Park and plaza sites received unobstructed sunlight while the canyon was limited to four hours of direct solar radiation in midsummer. Potential seasonal insolation was 44% of the potential maximum at the canyon and over 90% at the park. Afternoon air temperatures and vapor pressure deficits were somewhat greater at the plaza than the other two sites, and potential pan evaporation was nearly 50% greater over the season. Tree growth at the plaza and canyon acclimated physiologically and developmentally to the prevailing environmental conditions. Thinner leaves and less trunk growth when compared with the park were indications of shade acclimation in the canyon trees. This did not, however, appear to affect crown size or shoot growth of canyon trees. In contrast, plaza trees were sparse and stunted, exhibiting diminished crown size and diameter increment when compared with tree at the other sites. Less favorable water relations suggested that chronically higher evaporative demand and limited soil resources restricted growth of the plaza trees. Park, plaza, and canyon designations of urban spaces can provide a useful framework for predicting microclimatic factors that can affect tree growth for an urban site. Long-term growth and development, however, with in any of these urban spaces will depend on interactions with existing soil conditions.


2016 ◽  
Vol 2016 (HiTEC) ◽  
pp. 000046-000050
Author(s):  
R. Bannatyne ◽  
D. Gifford ◽  
K. Klein ◽  
C. Merritt

Abstract VORAGO Technologies has developed a pair of ARM Cortex M0 MCUs designed from the ground up to be high temperature capable. One of these devices is specifically developed for high temperature applications, the other adds capabilities that make it suitable for use in high radiation environments as well. These devices are fabricated using a modified version of commercial bulk 130nm CMOS technology utilizing our HARDSIL® technology, which provides immunity to the increased effects of latchup and EOS encountered at higher application temperatures. In addition to the processor these devices include features more typical of low temperature SoCs including on-chip memory, timers, and communications peripherals. In addition to the ceramic package and die format typically utilized at high temperature, a new lower-cost plastic package is available that has been characterized at higher temperatures. These devices have been characterized at temperatures up to 200C and results showing the latchup behavior and device performance are provided. Some of the tradeoffs involved in creating such devices are discussed, as well as some of the similarities and tradeoffs in creating a radiation hardened devices vs. a high temperature device.


Soil Research ◽  
2012 ◽  
Vol 50 (8) ◽  
pp. 685 ◽  
Author(s):  
Arcângelo Loss ◽  
Marcos Gervasio Pereira ◽  
Adriano Perin ◽  
Fernando Silva Coutinho ◽  
Lúcia Helena Cunha dos Anjos

The combination of the no-till planting system (NTS) and pasture (e.g. brachiaria grass, Urochloa sp.) for livestock production constitutes a crop–livestock integration (CLI) system. CLI systems significantly increase the total organic carbon (TOC) content of soil and the particulate organic carbon (POC) of soil organic matter (SOM). The present study evaluated TOC and the granulometric fractions of SOM under different management systems in a Cerrado area in the state of Goiás. Two areas applying crop rotation were evaluated, one using CLI (corn/brachiaria grass/bean/cotton/soybean planted sequentially) and the other NTS (sunflower/pearl millet/soybean/corn planted sequentially). A third area covered with natural Cerrado vegetation (Cerradão) served as a reference to determine original soil conditions. Soil was randomly sampled at 0–5, 5–10, 10–20, and 20–40 cm. The TOC, POC, and mineral-associated organic carbon (MOC) were assessed, and POC and MOC stocks calculated. The CLI system resulted in greater TOC levels than NTS (0–5, 5–10, and 10–20 cm). Compared with the Cerradão, CLI areas exhibited higher stocks of TOC (at 5–10 and 10–20 cm) and POC (at 0–40 cm). Results obtained for TOC and POC fractions show that land management with CLI was more efficient in increasing SOM than NTS. Moreover, when compared with NTS, the CLI system provided better POC stratification.


2019 ◽  
Vol 129 (1) ◽  
pp. 99-113
Author(s):  
Oliver J S Tallowin ◽  
Shai Meiri ◽  
Stephen C Donnellan ◽  
Stephen J Richards ◽  
Christopher C Austin ◽  
...  

Abstract New Guinea has been considered both as a refuge for mesic rainforest-associated lineages that contracted in response to the late Cenozoic aridification of Australia and as a centre of biotic diversification and radiation since the mid-Miocene or earlier. Here, we estimate the diversity and a phylogeny for the Australo-Papuan forest dragons (Sauria: Agamidae; ~20 species) in order to examine the following: (1) whether New Guinea and/or proto-Papuan Islands may have been a biogeographical refuge or a source for diversity in Australia; (2) whether mesic rainforest environments are ancestral to the entire radiation, as may be predicted by the New Guinea refuge hypothesis; and (3) more broadly, how agamid ecological diversity varies across the contrasting environments of Australia and New Guinea. Patterns of lineage distribution and diversity suggest that extinction in Australia, and colonization and radiation on proto-Papuan islands, have both shaped the extant diversity and distribution of forest dragons since the mid-Miocene. The ancestral biome for all Australo-Papuan agamids is ambiguous. Both rainforest and arid-adapted radiations probably started in the early Miocene. However, despite deep-lineage diversity in New Guinea rainforest habitats, overall species and ecological diversity is low when compared with more arid areas, with terrestrial taxa being strikingly absent.


1956 ◽  
Vol 34 (1) ◽  
pp. 197-207 ◽  
Author(s):  
Kornelius Lems

This paper presents data and observations concerning Chamaedaphne calyculata (L.) Moench. (Ericaceae). The branching pattern, the longevity of different types of leaves, and features of flowering are shown to be correlated. The relationship between this complex of features and the habitat is studied, and a few speculations are advanced to explain the physiological basis for the behavior of Chamaedaphne. This study is essentially autecological, and it is hoped that it may constitute a link between the study of soil conditions and the response of plant hormones on the one hand, and phytosociological work in peat bogs on the other hand.


Author(s):  
Abdorasool Mayahy ◽  
Aghil Yousefi-Koma ◽  
Hesam Maleki ◽  
Donya Mohammadshahi ◽  
Sina Salek

Systems and mechanisms of motion and stability applied in underwater vehicles although various but almost all rely on a conventional structure and frame work. In this paper in pursue of development a new mechanism in term of motion and performance, mainly biomimeticly inspired from fish flapping and their movement principles particularly flatfish, a new Micro Underwater Vehicle (MUV) is designed and fabricated. In modelling phase using ADAMS we simulated the dynamic performance of the mechanism. On the other hand in order to take the flexibility of the fins into account, we used ANSYS as a meshing tool. Linking these two software packages the modelling stages were completed.


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