Search results for "LPI"
showing 10 items of 535 documents
Vegetation of feather grass steppes in the western Pamir Alai Mountains (Tajikistan, Middle Asia)
2016
Aims: To propose the first syntaxonomical scheme for the graminoid steppe vegetation of the montane and alpine zones in the Pamir-Alai Mts. in Tajikistan with some remarks on its environmental gradients. Location: Tajikistan. Methods: A total of 155 relevés were sampled in 2015 using the seven-degree cover-abundance scale of Braun-Blanquet and subsequently 148 of these relevés were selected and classified by the modified TWINSPAN method using the four step interval scale with cutoff levels of 0%, 5%, 10% and 25% and total inertia as a measure of cluster heterogeneity. Diagnostic species were identified using the phi coefficient as a fidelity measure. The detrended correspondance analysis wa…
Arbuscular mycorrhiza and fungal root endophytes of weeds in an altitudinal gradient in the Pamir Alai Mountains of Central Asia
2014
Arbuscular mycorrhiza and fungal root endophytes of three weeds, Galium tricornutum, Lycopsis orientalis and Scandix pecten-veneris, were studied in an altitudinal gradient of the Pamir Alai Mountains. Colonisation by arbuscular mycorrhizal fungi (AMF) was found in all species. Only in the case of G. tricornutum was there a rise in mycorrhizal parameters values found for the medium altitude range. Similar tendencies were observed in the case of the AMF colonisation potential assessment. This suggests that plant species' identity, dependency on symbiosis and interactions with soil properties determine root colonisation and the abundance of AMF in soils at the elevations in question. Four AMF…
Long-term modelling of weed control strategies: analysis of threshold-based options for weed species with contrasted competitive abilities
2002
A simple life-cycle-based demography model was adapted for two contrasting weed species (Alopecurus myosuroides and Poa annual. This model included a seed production function that accounted for population self-regulation through weed:weed interactions. The A. myosuroides version of the model was tested with field data. Long-term simulations of population demography were then performed to investigate the relationship between weed control strategies based on density thresholds and both the frequency of herbicide use and the long-term economic profitability. This study confirms that threshold-based weed management strategies are more cost-effective than spraying every year and may allow import…
Effect of vernalization on the development and growth of Alopecurus myosuroides
2002
Alopecurus myosuroides is an annual winter grass weed present in many winter and spring crops. The vernalization responses of three populations of A. myosuroides were assessed using natural exposure during winter in two field experiments and using cold exposure of imbibed seeds in a refrigerator in two greenhouse experiments. It was observed that a period of chilling during the pregermination phase had a marked effect on subsequent phenology. In the greenhouse, the major effect of vernalization was the reduction in the vegetative period because of an early reproductive induction of the apex. Plant morphology was affected by vernalization via a decrease in biomass resulting from a reduced ti…
Global functional variation in alpine vegetation
2021
International audience; Questions. What are the functional trade-offs of vascular plant species in global alpine ecosystems? How is functional variation related to vegetation zones, climatic groups and biogeographic realms? What is the relative contribution of macroclimate and evolutionary history in shaping the functional variation of alpine plant communities? Location. Global. Methods. We compiled a data set of alpine vegetation with 5,532 geo-referenced plots, 1,933 species and six plant functional traits. We used principal component analysis to quantify functional trade-offs among species and trait probability density to assess the functional dissimilarity of alpine vegetation in differ…
Study of the growth of herbicide-resistant black-grass populations
1991
International audience
Global patterns and drivers of alpine plant species richness
2021
B.J.-A. was funded by the Marie Curie Clarín-COFUND program of the Principality of Asturias-EU (ACB17-26) and the Spanish Research Agency (AEI/10.13039/501100011033).
Fen and spring vegetation in western Pamir-Alai Mountains in Tajikistan (Middle Asia)
2016
The paper presents the results of phytosociological research on spring and fen vegetation of the western Pamir-Alai Mountains in Tajikistan. In total, 211 relevés were sampled during field studies conducted in 2008–2013 and 2015 with application of the Braun-Blanquet method. Plant communities of spring heads and peat-accumulated fens inhabiting the high montane and alpine zones in the Zeravshan, Hissar, Hazratishoh, Darvaz, Turkestan and Peter the 1st Mountains are described. A hierarchical syntaxonomic synopsis of spring and fen plant communities in the western Pamir-Alai Mountains is provided. As a result of field investigations and numerical analyses, three fen associations: Caricetum ps…
Syntaxonomy and biogeography of the Irano‐Turanian mires and springs
2021
Aims: To develop the first comprehensive syntaxonomic classification for patchy montane mire and spring vegetation across the Irano-Turanian phytogeographical region in Iran, Tajikistan and Kyrgyzstan and to explore the effects of the main environmental and geographic gradients on their distribution. Location: Alborz Mountain range (Iran), Pamir-Alai Mountains (Tajikistan) and Tian Shan Mountains (Kyrgyzstan); total area of about 3,000,000 km2. Methods: A database of 1,015 vegetation relevés including a total of 675 vascular and bryophyte taxa was established, covering the large mountains ranges of the Irano-Turanian regions in Iran, Tajikistan and Kyrgyzstan, at altitude ranging from 1,300…
Responses of above- and below-ground fungal symbionts to cessation of mowing in subalpine grassland
2017
Abstract The cessation of mowing in subalpine grasslands promotes the dominance of Festuca paniculata leading to the reduction in plant diversity. Moreover, it affects positively the abundance of Epichloe sp. inhabiting F. paniculata leaves and negatively the soil density of arbuscular mycorrhizal fungi (AMF). We explored how the cessation of mowing influences root AMF communities in F. paniculata and the neighboring plants, and Epichloe sp alkaloids. Thirteen AMF operational taxonomical units were found. The neighboring plants affected positively the abundances of Aalpin and GLOM_7 whereas the interaction plant/management type influenced significantly Claroide_1 , GLOM_1 and GLOM_7 . The N…