Floristic Composition Of Communities Research Articles

CHANGES IN FLORA SPECIES COMPOSITION AND SOIL ENZYME ACTIVITY IN COMMUNITIES OF ACER NEGUNDO IN THE KEMEROVO REGION

The article presents the study results of the species composition of vascular plants and soil activity in communities dominated by Acer negundo . The studies were carried out on accounting sites located in the mountain-taiga and forest-steppe zones of Kuzbass. The selection of trial plots was made taking into account the horizontal differentiation of space into under-crown (registration plots) and external zones (control) of phytogenic fields. Floristic descriptions and analysis of the soil by the level of activity of enzymes (invertase, protease, phosphatase) were carried out using standard methods. The species diversity of vascular plants in the areas under study constituted 64 species. The dominant plant species in the ash-leaved maple communities were identified. Under the canopy of A. negundo , ruderal species - Cirsium setosum, Elytrigia repens, Lamium album, Urtica dioica, and Taraxacum officinale - dominate, while in the outer zones, the proportion of meadow species increases - Achillea millefolium, Dactylis glomerata, and Festuca pratensis . It has been established that the floristic composition of communities does not affect significantly the level of activity of soil enzymes. In the undercrown space of A. negundo , an increase in the activity of hydrolytic enzymes by an average of 11% was noted, compared with the outer zones.

Растительность газонов города Уфы (Республика Башкортостан)

Растительность газонов города Уфы (Республика Башкортостан)

Variations in the Botanical Diversity of Forbs–Bunchgrass Steppes of Eastern Mongolia over an 11-Year Period (2008–2018)

The dynamics of the botanical diversity of plain forbs–bunchgrass steppes is analyzed for the period of 2008–2018 based on materials from the biomonitoring of plant cover at the Tumentsogt experimental station (Eastern Mongolia) as part of the scientific program of an integrated Russian–Mongolian biological expedition. Eight permanent test plots of 100 m2 were laid along the transect on the plain between hills in the northeastern part of the experimental station. We analyzed the correlation between the main parameters of the plant communities (the species composition, richness, and saturation; the height and abundance of species; and the density of grass stands) with the meteorological conditions (the heat supply and the amount and distribution of precipitation during the growing period). A combined analysis of phytocenotic and climatic data was performed with nonparametric multidimensional scaling of indirect ordination. Ecotopic fluctuations caused by changes in the amount and regime of precipitation in different years, as well as by the dynamics of the temperature regime, were studied. The species saturation of communities was maximal in years with low ombrothermic indices and lowest in years with high indices. The floristic composition of communities of three–feather-grass steppes includes a flora-cenotic core composed of 23 permanent perennial steppe and forest–steppe species, which provides a relative stability of ecosystems under changing environmental conditions. The dynamics of steppe ecosystems of the East Mongolian steppes is phytocyclic.

The intrinsic effects of environment and space on the composition of woody plant species vary between Brazilian savannas growing on distinct types of substrate

The relationship between the floristic composition of communities and the underlying environmental and spatial determinants is still the subject of intense debate, mainly because only recently has geographical distance been cited as an important driver of plant communities. We analysed environmental (elevation, climate and soil properties [E]) and spatial (geographic distance [S]) effects on the floristic composition of savannas on different substrates, one on a steep relief with shallow and rocky soils, and the other on flat terrain with deep soils. We show that: (1) savannas on rocky soils soils contain more nutrients, are more acidic and have a finer texture than savannas on deep soils; (2) that the dissimilarity between the rocky soils and deep soils is associated mainly with variation in altitude and soil properties and (3) that the individual and combined contributions of the environment and space to the floristic composition of woody plants differs between savannas on deep and rocky soils. Spatially structured environmental variation [E] + [S] explained 29% of the floristic composition variation in savannas on rocky soils and 41% in savannas on deep soils. In the rocky soils, the pure fraction explained by the [E] was larger (10%) than that recorded for deep soils (4%), but the pure effect of space [S] explained 2 and 3% of the variation on rocky and deep soils, respectively. The environmental variables analysed here are therefore strongly structured in space on both rocky and deep soils, but the total and combined environmental and spatial effects are larger in savannas on deep soils than in those on rocky soils.

FLORISTIC COMPOSITION AND PRODUCTIVITY OF MOUNTAIN PASTURES OF DAGESTAN

Ponte Academic JournalOct 2017, Volume 73, Issue 10 FLORISTIC COMPOSITION AND PRODUCTIVITY OF MOUNTAIN PASTURES OF DAGESTANAuthor(s): Shamil Salikhov ,Gasan Gasanov, Shamil Salikhov, Nurjagan Ramazanova, Tatiana Asvarova, Kamil Hajiyev, Rashid Bashirov, Aishat Abdulaeva, Zaira Akhmedova, Kabirat Gimbatova, Zhamilat Shaikhalova, Viktoriya Semenova, Radjab Usmanov, Maxim Mallaliev, Aytemir Aytemirov, Magomed Musaev, Nurulislan MagomedovJ. Ponte - Oct 2017 - Volume 73 - Issue 10 doi: 10.21506/j.ponte.2017.10.15 Abstract:The investigated pastures at various expositions of the slopes of the mountain Dagestan, located at 1000 and 1700 m above sea level. Significant differences in the floristic composition of communities in the southern, northern, south-western, north-western exposures of mountain slopes were revealed. The difference in species composition and climatic conditions led to the difference in the productivity of pastures. Relatively high air temperature on the southern exposure of the slope, at an altitude of 1700 m above sea level, with sufficient precipitation contributed to the higher productivity of the phytocenosis in the north. At around 1000 m, the productivity of south-west slope was also higher than the north-west, in connection with the best supply of moisture due to the proximity of the site to the river. Download full text:Check if you have access through your login credentials or your institution Username Password

Растительность залежей центральной части музея-заповедника «Куликово поле» (Тульская область)

The museum-preserve «The Kulikovo Field» is situated in the northern part of the Central Russian Upland within the forest-steppe zone near its northern border. There are a lot of abandoned fields, most of them left fallow since 1990–2000 years; the exact age of the old fields is unknown. Using the Braun-Blanquet approach as well as the method of K. Kopecký and S. Hejný (Kopecký, Hejný, 1974; Kopecký, 1992), the classification of the old-field vegetation of the central part of the museum-preserve was carried out. One derivate community, 2 basal communities (one of them with two variants), 3 communities and one association with three variants have been identified. The derivate community Conyza canadensis­ [Artemisietea vulgaris/Stellarietea mediae] is dominated by annual and biennial ruderal species: Conyza canadensis, Lactuca serriola and Carduus acanthoides. The association Convolvulo arvensis–Elytrigietum repentis is heterogeneous both in its floristic and subdominant composition and it can be divided into 3 variants. The variant typica represents monodominant communities where Elytrigia repens prevails. The variant Lactuca serriola is characterized by high constancy of Conyza canadensis, Lactuca serriola and some other ruderal plants and it represents coenoses dominated by Elytrigia repens with subdominants such as Lactuca serriola, Senecio jacobaea and Pilosella spp., mainly P. bauhini. The variant Cichorium intybus is dominated by Elytrigia repens with a subdominant Cichorium intybus; some mesophilous meadow species are often present. Variants Melilotus officinalis and Sonchus arvensis of the basal communityElytrigia repens–Cichorium intybus [Artemisietea vulgaris] are dominated by Cichorium intybus, Poa angustifolia and Elytrigia repens, the first of them also by Melilotus officinalis, Artemisia absinthium, and the second by Carduus acanthoides and Calamagrostis epigeios. Unlike the foregoing syntaxa the basal community Elytrigia repens–Cichorium intybus [Artemisietea vulgaris] is characterized by relative high constancy of some species pertaining to the order Galietalia veri, namely Fragaria viridis, Galium verum, Potentilla argentea. These species and also Poa angustifolia are the first steppificated meadow plants that appear in the old field communities under investigation. The community Pilosella bauhini [Onopordion acanthii] is dominated by Pilosella spp., mainly by P. bauhini that sometimes replaced by some ruderal plants, e. g. Achillea nobilis or Cichorium intybus. The peculiarity of this community is the low constancy and abundance of Elytrigia repens. The species of the orders Galietalia veri and Arrhenatheretalia play much noticeable role in the other syntaxa mentioned below, so these syntaxa are between the natural and synanthropic vegetation. The community Leucanthemum vulgare–Galium mollugo [Onopordion acanthii/Molinio-Arrhenatheretea] is distinguished by high abundance and constancy of some mesophilous and xeromesophilous meadow plants (Leucanthemum vulgare, Galium mollugo, Phleum pratense etc.). The community Artemisia marschalliana [Onopordion acanthii/Galietalia veri] is dominated mostly by Leontodon hispidus and Pilosella spp.; its peculiarity is a relatively high constancy of species common in the local steppificated meadows. The basal community Poa angustifolia [Galietalia veri/Artemisietea vulgaris] represents monodominant communities where Poa angustifolia prevails. Annual, biennial and some perennial ruderal species are rare in this variant, unlike most of the syntaxa mentioned above. The common feature of the last three syntaxa is subdominance of Fragaria viridis. It is known that the floristic composition of communities is changed during an old-field succession: the percentage of annual and biennial species declines and that of species pertaining to the classes of natural vegetation increases (Bonet, Pausas, 2007; Yamalov et al., 2008; Pankratova, Gannibal, 2009). Using the life-form and phytosociological spectrum of the syntaxa analysis an attempt to evaluate succession status of the described communities was made (tab. 9, 10). Based upon the results of this analysis, it is possible to suggest that the derivate community Conyza canadensis [Artemisietea vulgaris/Stellarietea mediae] is the earliest stage one can find in the investigated old fields. The variants Lactuca serriola and typica of the association Convolvulo arvensis–Elytrigietum repentis and the community Pilosella bauhini [Onopordion acanthii] are the next in the series. It seems that Pilosella spp. (P. bauhini and probably some other species of this genus) outcompete the pioneer species of initial stages, like Elytrigia repens, in some cases. The basal community Poa angustifolia [Galietalia veri / Artemisietea vulgaris] seems to be the most advanced stage: the percentage of annuals and biennials is minimal, and that of species pertaining to the syntaxa of natural vegetation of the high ranks, especially to the order Galietalia veri, increases greatly. Species richness of the communities is minimal at the most early stage, which is the peculiarity of the old-field vegetation (Pankratova, Gannibal, 2009; Ovcharova, Yamalov, 2013). Similar phenomenon was also noticed at the succession stages where strong dominant (Elytrigia repens or Poa angustifolia) pre­vails, regardless of how much advanced these stages are, the fact mentioned earlier (Prach, 1985). Species richness attains maximum at those stages of succession where the communities are polydominant and contain both early- and late-successional species, that was also previously described (Meiners et al., 2007).

Vegetation dynamics in side-channels reconnected to the Rhine River: what are the main factors controlling communities trajectories after restoration?

The hydraulic management of large rivers led to a disconnection of side-channels. Restoration works were to reconnect these side-channels to the main course in order to recover hydrological and ecological functions. The aim of the study was to analyze the vegetation dynamics after restoration and to link it to the change in chemical and hydro-geomorphological characteristics. Changes in species richness, cover and composition of the macrophytes communities were studied in nine side-channels of the Rhine river (France) after reconnection which occurred between 1998 and 2006. Vegetation dynamics was surveyed between 2007 and 2011 and compared to the ones of three target side-channels (never disconnected). Three vegetation communities were identified: one characterized by rheophilic species, a second one by mesotrophic species, and a third one by eutrophic species. Distribution of communities depended mainly on the flow velocity and the sediment texture of the side-channels. The floristic composition of communities evolved rapidly and remained stable a few years after restoration. Changes in species richness and cover remained relatively low in all side-channels over the study period. Time after restoration did not affect the dynamics of colonization. Reconnection allowed the restored side-channels to exhibit vegetation dynamics similar to those of the target side-channels.

Fire severity, feedback effects and resilience to alternative community states in forest assemblages

Alternative stable state theory is often used to explain the occurrence of flammable vegetation adjacent to less flammable vegetation where fire regimes mediate the shift between states. In 2002 an extreme landscape scale fire burnt extensive areas of forests in eastern Australia, including rainforests that are rarely severely burnt. This unique event allowed us to test long-held assumptions that predict landscape scale change after major disturbance. We tested three assumptions for detecting alternative community states; (1) that the scale of the event was large enough to remove canopy dominants, (2) fire feedbacks, both positive and negative are present, and (3) shifts in the floristic composition of communities are detected. We also examined whether high severity fires resulted in a community shift from less flammable to more flammable vegetation (e.g. from rainforest to wet sclerophyll vegetation), by examining floristic composition of vegetation communities (rainforest, wet sclerophyll forest, and dry sclerophyll forest) when burnt at different fire severities (high and low). Conversely, we tested whether there was a state shift from flammable to less flammable vegetation communities in sclerophyll forests long unburnt. In addition, we determined if there was any evidence that antecedent fire regimes and fire severity influenced flammability feedbacks. Severe fire caused significant ongoing disruption to forest canopies and fire effects were still detectable some 7 years after fire. Whilst some pyrogenic environmental feedbacks were detected from historic fire regimes, we found no shifts in the floristic composition or pyrogenic traits of forests burned at high severity. Medium-term (30 year) fire exclusion did not result in the sclerophyll forest becoming more pyrophobic although some fire-cued species senesced in the absence of fire. Contrary to expectation, we found no evidence that the floristic composition of less flammable vegetation burnt at high severity became more similar to flammable vegetation burnt at low severity or that were unburnt. Conversely, with more than 30 years of fire exclusion there was no evidence that the sclerophyllous communities became more floristically similar to rainforest. We have shown that species assemblages in warm-temperate rainforest were resilient to a catastrophic fire event and propose that these forests are unlikely to represent alternative community states driven by fire alone.

Soil Bacterial and Fungal Community Structure Across a Range of Unimproved and Semi-Improved Upland Grasslands

Changes in soil microbial community structure due to improvement are often attributed to concurrent shifts in floristic community composition. The bacterial and fungal communities of unimproved and semi-improved (as determined by floristic classification) grassland soils were studied at five upland sites on similar geological substrata using both broad-scale (microbial activity and fungal biomass) and molecular [terminal restriction fragment length polymorphism (TRFLP), automated ribosomal intergenic spacer analysis (ARISA)] approaches. It was hypothesized that microbial community structure would be similar in soils from the same grassland type, and that grassland vegetation classifications could thus be used as predictors of microbial community structure. Microbial community measurements varied widely according to both site and grassland type, and trends in the effect of grassland improvement differed between sites. These results were consistent with those from similar studies, and indicated that floristic community composition was not a stable predictor of microbial community structure across sites. This may indicate a lack of correlation between grassland plant composition and soil microbial community structure, or that differences in soil chemistry between sites had larger impacts on soil microbial populations than plant-related effects.

Effects of fire intensity on plant species composition of sandstone communities in the Sydney region

Abstract Fire intensity measures the heat output of a fire, and variation in fire intensity has been shown to have many effects on the demography of plant species, although the consequent effects on the floristic composition of communities have rarely been quantified. The effects of variation in fire intensity on the floristic composition of dry sclerophyll vegetation with different fire histories near Sydney was estimated. In particular, differences in species abundance of woodland and shrubland communities subjected to four fire‐intensity classes: unburnt, low intensity (<500 kW m−1), medium intensity (500–2500 kW m−1) and high intensity (>2500 kW m−1) were examined. The samples had a standardized previous fire frequency and season, thus minimizing the effects of other aspects of the fire regime. There was a clear effect of fire intensity on the relative abundances of the vascular plant species, with increasing intensity of the fire producing vegetation that was increasingly different from the unburnt vegetation. This pattern was repeated in both the woodland and shrubland vegetation types, suggesting that it was not an artefact of the experimental conditions. However, the effects of fire intensity on floristic composition were no greater than were the differences between these two similar vegetation types, with variation in fire intensity accounting for only approximately 10% of the floristic variation. Nevertheless, the effects of fire intensity on the abundance of individual species were consistent across taxonomic groups, with the monocotyledon and Fabaceae species being more abundant at higher than lower intensities, the Proteaceae and Rutaceae more abundant at intermediate intensities, and the Epacridaceae more abundant at lower rather than higher intensities. The number of fire‐tolerant species increased with increasing fire intensity, and those fire‐tolerant species present were most abundant in the areas burnt with medium intensity. The number of fire‐sensitive species did not respond to fire intensity, and those species present were most abundant in the areas burnt with low intensity. This suggests that either fire‐sensitive species respond poorly to higher fire intensities or fire‐tolerant species respond poorly to lower fire intensities, perhaps because of differences in seed germination, seedling survival or competition among adults.

Early use of the succession concept by G.M. Lancisi in 1714

The description of sea shore vegetation near Rome published by G.M. Lancisi in 1714 includes a discussion on vegetation changes, floristic composition of communities and causes of the process. The concepts of succession and pioneer plant are clearly expressed (the language used in this publication is latin, and consequently the words ‘successio’ and ‘plantae primigeniae’ had been used for these terms). The plant communities can be identified and correspond to the present ones growing in the same site. This may be the very first mentioning of vegetation dynamics in botanical literature.