ANTHROPOGENIC TRANSFORMATION OF RANGELAND VEGETATION OF KOCHUBEY BIOSPHERE STATION OF NORTH-WESTERN PRE-CASPIAN

Author(s):  
M. A. Babaeva ◽  
S. V. Osipova

The influence of environmental and anthropogenic factors on the change in species diversity and transformation in plant communities has been studied. Studies have shown negative effect of external factors to preserve valuable fodder grass depends on different pasture use patterns on the territory of the Kochubey Biosphere Station. A marked decline in the phytocenosis productivity dynamics with an increased load of 9.53-10.95c / ha under insufficient humidification conditions was shown. The results of the studies are shown that the vegetation change features are primarily caused the occurrence of anthropogenic landscape with dominance of the most persistent xerophytes shrubs and change of native species of communities of unsuitable plant species for feed that form in the continental climate. Changes in the vegetation cover composition and the ratio of the forage grasses species are traced. The uneven distribution of fodder mass between plant species in different seasons of the year was revealed. Established significant changes in the vegetation cover in the experimental plots. Stand of grass is thinned, low projective cover – 20-30%. In places of accumulation of growing species, especially in cereals, the loss of unstable species is observed. The productivity of pasture phytocenosis due to ephemera, forbs, especially dominant xerophytic shrubs of the wet period ranges 14.4-14.18 c / ha, which is associated with increased moisture and normalized load compared to dry years (9.53-10.9c / ha).

Author(s):  
М. А. Babaeva ◽  
S. V. Osipova

The regularities of changes in the resistance of different groups of fodder plants to adverse conditions were studied. This is due to the physiological properties that allow them to overcome the harmful effects of the environment. As a result of research species - plant groups with great adaptive potential to the harsh continental semi-desert conditions were identified. Monitoring observation and experimental studies showed too thin vegetation cover as a mosaic, consisting of perennial xerophytic herbs and semishrubs, sod grasses, saltwort and wormwood, as well as ephemera and ephemeroids under the same environmental conditions, depending on various climatic and anthropogenic factors. This is due to the inability or instability of plant species to aggressive living environment. It results in horizontal heterogeneity of the grass stand, division into smaller structures, and mosaic in the vegetation cover of the Kochubey biosphere station. The relative resistance to moderate stress was identified in the following species from fodder plants Agropyron cristatum, A. desertorum, Festuca valesiaca, Cynodon dactylon, Avena fatua; as for strong increasing their abundance these are poorly eaten plant species Artemisia taurica, Atriplex tatarica, Falcaria vulgaris, Veronica arvensis, Arabidopsis thaliana and other. On the site with an increasing pressure in the herbage of phytocenoses the number of xerophytes of ruderal species increases and the spatial structure of the vegetation cover is simplified. In plant communities indigenous species are replaced by adventive plant species. The mosaic of the plant cover of phytocenoses arises due to the uneven distribution in the space of environmental formation, i.e. an edificatory: Salsola orientalis, S. dendroides, Avena fatua, Cynodon dactylon, Artemisia taurica, A. lercheanum, Xanthium spinosum, Carex pachystyli, under which the remaining components of the community adapt. Based on the phytocenotic indicators of pasture phytocenoses it can be concluded that the vegetation cover is in the stage of ecological stress and a decrease in the share of fodder crops and an increase in the number of herbs indicates this fact.


2014 ◽  
Vol 281 (1780) ◽  
pp. 20133330 ◽  
Author(s):  
Myla F. J. Aronson ◽  
Frank A. La Sorte ◽  
Charles H. Nilon ◽  
Madhusudan Katti ◽  
Mark A. Goddard ◽  
...  

Urbanization contributes to the loss of the world's biodiversity and the homogenization of its biota. However, comparative studies of urban biodiversity leading to robust generalities of the status and drivers of biodiversity in cities at the global scale are lacking. Here, we compiled the largest global dataset to date of two diverse taxa in cities: birds (54 cities) and plants (110 cities). We found that the majority of urban bird and plant species are native in the world's cities. Few plants and birds are cosmopolitan, the most common being Columba livia and Poa annua . The density of bird and plant species (the number of species per km 2 ) has declined substantially: only 8% of native bird and 25% of native plant species are currently present compared with estimates of non-urban density of species. The current density of species in cities and the loss in density of species was best explained by anthropogenic features (landcover, city age) rather than by non-anthropogenic factors (geography, climate, topography). As urbanization continues to expand, efforts directed towards the conservation of intact vegetation within urban landscapes could support higher concentrations of both bird and plant species. Despite declines in the density of species, cities still retain endemic native species, thus providing opportunities for regional and global biodiversity conservation, restoration and education.


2015 ◽  
Vol 112 (14) ◽  
pp. 4387-4392 ◽  
Author(s):  
Chris D. Thomas ◽  
G. Palmer

Plants are commonly listed as invasive species, presuming that they cause harm at both global and regional scales. Approximately 40% of all species listed as invasive within Britain are plants. However, invasive plants are rarely linked to the national or global extinction of native plant species. The possible explanation is that competitive exclusion takes place slowly and that invasive plants will eventually eliminate native species (the “time-to-exclusion hypothesis”). Using the extensive British Countryside Survey Data, we find that changes to plant occurrence and cover between 1990 and 2007 at 479 British sites do not differ between native and non-native plant species. More than 80% of the plant species that are widespread enough to be sampled are native species; hence, total cover changes have been dominated by native species (total cover increases by native species are more than nine times greater than those by non-native species). This implies that factors other than plant “invasions” are the key drivers of vegetation change. We also find that the diversity of native species is increasing in locations where the diversity of non-native species is increasing, suggesting that high diversities of native and non-native plant species are compatible with one another. We reject the time-to-exclusion hypothesis as the reason why extinctions have not been observed and suggest that non-native plant species are not a threat to floral diversity in Britain. Further research is needed in island-like environments, but we question whether it is appropriate that more than three-quarters of taxa listed globally as invasive species are plants.


2015 ◽  
Vol 67 (2) ◽  
pp. 591-609 ◽  
Author(s):  
Snezana Jaric ◽  
Branko Karadzic ◽  
Sava Vrbnicanin ◽  
Miroslava Mitrovic ◽  
Olga Kostic ◽  
...  

Segetal vegetation was studied in the cultivated areas of southern Srem with the aim of analyzing its taxonomy, phytocoenology, syntaxonomy and phytogeography, as well as determining to what extent ecological factors influenced the differentiation of segetal plant communities among row crops, small grain crops and in alfalfa fields. Segetal flora was comprised of 124 plant species, classified into 38 families, of which Asteraceae (28), Fabaceae (10) and Poaceae (10) contained the greatest number of species. Three associations were selected based on phytocoenological analysis: Polygonetum convolvulo-avicularis, Consolido-Polygonetum avicularis and Lolio-Plantaginetum majoris, as well as five lower syntaxa (subassociations and facies). Crop type, moisture, habitat acidity (pH), temperature and anthropogenic factors had the greatest impact on the ecological differentiation of the studied vegetation. The significant presence of non-native species (18) was another consequence of the anthropogenic effects and geographic position of southern Srem, and these, as coenobionts of segetal plant communities and undesirable species, had a significant impact on crop yield.


Author(s):  
Yohannes B. Tesfay ◽  
Juergen Kreyling

Abstract Invasion by exotic species is recognized as one of the major threats to biodiversity. The effects of invasion by Opuntia ficus-indica (Cactaceae) on the species diversity, richness and composition of invaded communities were studied at three sites in the highlands of Eritrea, East Africa. This paper investigates whether the presence of O. ficus-indica causes a negative effect on the native biodiversity in a region rarely studied so far. The vegetation in invaded and uninvaded plots with similar habitat conditions was sampled and differences in the species composition, diversity and richness were compared between the plots. The overall plant species composition differed significantly with invasion by O. ficus-indica. The invasion by O. ficus-indica also led to a significant homogenization of community compositions. The species richness and Shannon diversity index did not differ significantly between the invaded and uninvaded plots. Nevertheless, we still detected species with significantly lower occurrence in the invaded plots (Psiadia punctulata), but also species which preferred invaded plots (Plectranthus hadiensis). We conclude that O. ficus-indica exerts a negligible effect on the species diversity and richness but that it affects species composition and that there are species which suffer due to its presence. Due to the continuous pressure of the invasion by O. ficus-indica on the species composition and dry climates, further homogenization in the native species diversity is to be expected in the future for the highlands of Eritrea.


Author(s):  
M. I. Dzhalalova ◽  
A. B. Biarslanov ◽  
D. B. Asgerova

The state of plant communities in areas located in the Tersko-Sulak lowland was studied by assessing phytocenotic indicators: the structure of vegetation cover, projective cover, species diversity, species abundance and elevated production, as well as automated decoding methods. There are almost no virgin soils and natural phytocenoses here; all of them have been transformed into agrocenoses (irrigated arable lands and hayfields, rice-trees and pastures). The long-term impact on pasture ecosystems of natural and anthropogenic factors leads to significant changes in the indigenous communities of this region. Phytocenoses are formed mainly by dry-steppe types of cereals with the participation of feather grass, forbs and ephemera, a semi-desert haloxerophytic shrub - Taurida wormwood. At the base of the grass stand is common coastal wormwood and Taurida wormwood - species resistant to anthropogenic influences. Anthropogenic impacts have led to a decrease in the number of species of feed-rich grain crops and a decrease in the overall productivity of pastures. Plant communities in all areas are littered with ruderal species. The seasonal dynamics of the land cover of the sites was estimated by the methods of automatic decoding of satellite images of the Landsat8 OLI series satellite for 2015, dated by the periods: spring - May 20, summer - July 23, autumn - October 20. Satellite imagery data obtained by Landsat satellite with a resolution in the multispectral image of 30 m per pixel, and in the panchromatic image - 10 m per pixel, which correspond to the requirements for satellite imagery to assess the dynamics of soil and vegetation cover. Lower resolution data, for example, NDVI MODIS, does not provide a reliable reflection of the state of soil and vegetation cover under arid conditions. In this regard, remote sensing data obtained from the Internet resource https://earthexplorer.usgs.gov/ was used.


2021 ◽  
Vol 232 (7) ◽  
Author(s):  
N. Matanzas ◽  
E. Afif ◽  
T. E. Díaz ◽  
J. R. Gallego

AbstractPhytomanagement techniques using native species allow the recovery of contaminated soils at low cost and circumvent the ecological risks associated with the use of non-native species. In this context, a paradigmatic brownfield megasite highly contaminated by As and Pb was sampled in order to analyze soil–plant interactions and identify plant species with phytoremediation potential. A survey was first carried out in a 20-ha area to obtain an inventory of species growing spontaneously throughout the site. We then performed another survey in the most polluted sub-area (1 ha) within the site. Pseudototal concentrations of contaminants in the soil, aerial parts of the plants, and roots were measured by ICP-MS. A detailed habitat classification was done, and a specific index of coverage was applied by means of a 1-year quadrat study in various sampling stations. Results converged in the selection of six herbaceous species (Dysphania botrys, Lotus corniculatus, Lotus hispidus, Plantago lanceolata, Trifolium repens, Medicago lupulina). All of these plants are fast-growing, thereby making them suitable for use in phytostabilization strategies. Furthermore, they are all easy to grow and propagate and are generally self-sustaining. All six plants showed accumulation factors below 1, thus revealing them as pseudomethallophytes and excluders. However, L. hispidus and M. lupulina showed translocation capacity and are considered worthy of further study.


2013 ◽  
Vol 779-780 ◽  
pp. 1213-1219
Author(s):  
Shu Qin Chen ◽  
Lei Zhang ◽  
Zhao Sheng Chu ◽  
She Rong Hu

At present there are few studies on the AVS and SEM in sediments of Chaohu Lake. Most of the previous studies on heavy metals based on the one time, the short-time or a local-scale survey. In this paper, [AVS] and [SEM] in Chaohu Lake surface sediments were studied for different seasons in 2007, 2008 and 2009. The results showed that: (a) The three-year average of [AV and [ΣSE in surface sediments of Chaohu Lake is 4.2μmolg-1and 2.31μmolg-1, respectively. The maximum of [AV appears on spot 5 (14.845μmolg-1) in summer while the minimum appears on spot 9 (0.13μmolg-1) in winter. (b) In spot 5 which near the estuary of Yuxi River, three-year average of [SE was the maximum (5.81μmolg-1), and the minimum of [ΣSE (0.07μmolg-1) appears on spot 8 which locates in the middle of Chaohu Lake. In spot 13 the [ΣSEM]-[AVS]=3.2>2 and [ΣSEM]/[AVS]=4.45>2.34 indicate that heavy metal contaminants from Hefei city have threatened the biosafety of Chaohu Lake. (c) The spatial autocorrelation of SEMCdis weak, which indicates that spatial distribution of SEMCdis determined by anthropogenic factors rather than sediments' own attribute. Chaohu Lake has been heavily polluted by Cd from no-point source and electronic electroplating industry.


2017 ◽  
Vol 9 (4) ◽  
pp. 86 ◽  
Author(s):  
Cristina A. Gómez-Moya ◽  
Talita P. S. Lima ◽  
Elisângela G. F. Morais ◽  
Manoel G. C. Gondim Jr. ◽  
Gilberto J. De Moraes

The expansion of red palm mite (RPM), Raoiella indica (Acari: Tenuipalpidae) in Brazil could impact negatively the native plant species, especially of the family Arecaceae. To determine which species could be at risk, we investigated the development and reproductive potential of R. indica on 19 plant species including 13 native species to the Brazilian Amazon (12 Arecaceae and one Heliconiaceae), and six exotic species, four Arecaceae, a Musaceae and a Zingiberaceae. Values of the instantaneous rate of increase (ri) were initially estimated at 7, 14, 21 and 28 days after infestation of each species. Higher values of ri (> 0.05) were determined on the Arecaceae Adonidia merrillii, Astrocaryum jauari, Cocos nucifera, Bactris simplicifrons, Mauritia flexuosa, Phoenix dactylifera and Socratea exorrhiza, and on the Heliconiaceae Heliconia psittacorum Sassy; these were classified as “potential primary hosts”. Lower, but still positive values of ri (0-0.05) were determined on the Arecaceae Bactris maraja, Oenocarpus bacaba, Oenocarpus bataua and on the Musaceae Musa × paradisiaca (Prata variety); these were classified as “potential secondary hosts”. Negative values of ri were determined for the remaining plants, i.e., the Arecaceae Astrocaryum aculeatum, Attalea maripa, Bactris gasipaes, Elaeis guineensis, Euterpe oleracea, Euterpe precatoria, and the Zingiberaceae Alpinia rosea; these were considered “non-hosts”. Species with ri < 0.05 were considered not to be threatened by the RPM. Biological parameters of RPM were evaluated on the plant species with positive ri (except B. maraja) and two native species with negative ri (E. oleracea and E. precatoria). Mean developmental time ranged from 14.7 days on C. nucifera to 21.4 days on Musa × paradisiaca, showing a significant influence of the plant substrate. Immature viability, oviposition rate, net reproductive rate (R0) and intrinsic rate of increase (rm) were affected by the plant species.


2015 ◽  
Vol 22 (2) ◽  
pp. 32-41 ◽  
Author(s):  
Csaba Vadász ◽  
Miklós Lóránt

Abstract In this study, we identified the key mortality causes of eggs, juveniles and adults of the Great Bustard (Otis tarda) and quantified the relative importance of those, based on systematic data collection that have been carried out during the period between 2005 and 2014 at the Upper-Kiskunság region in Central Hungary. Rate of mortality regarding juveniles and adults was 39.71% caused by anthropogenic factors. Within the anthropogenic factors leading to mortality, collision was represented by 81.48% of fatalities, whereas mowing/hay making represented by 18.52%. Hay making/mowing was the factor leading to unsuccessful breeding attempt with the strongest negative effect on the breeding success of the investigated population of the Great Bustard, as it was represented by 50.96% of all known mortality cases. Chemical treatment had the factor with the second strongest effect, as it was represented by 12.33% of all known mortality cases. The rate of unsuccessful breeding (hatching) caused by particular activities (hay making/mowing, tillage, harvesting) varied between 68.42% and 75.00%. It was the disturbance by passers-by which led to the highest portion of unsuccessful breeding with 83.33% unsuccessful nests.


Sign in / Sign up

Export Citation Format

Share Document