Degree Of Vegetation Cover Research Articles

Study of vegetation spectral anomaly behaviour in a porphyry copper mine area based on hyperspectral indices

ABSTRACTHyperspectral remote sensing is economical and fast, and it can reveal detailed spectral information of plants. Hence, hyperspectral data are used in this study to analyse the spectral anomaly behaviours of vegetation in porphyry copper mine areas. This analytical method is used to compare the leaf spectra and relative differences among the vegetation indices; then, the correlation coefficients were computed between the soil copper content and vegetation index of Quercus spinosa leaves at both the leaf scale and the canopy scale in the Chundu mine area with different geological backgrounds. Lastly, this study adopts hyperspectral data for the level slicing of vegetation anomalies in the Chundu mine area. The results showed that leaf spectra in the orebody and background area differed greatly, especially in the infrared band (750 nm – 1300 nm); moreover, some indices like the normalized water index (NWI) and normalized difference water index (NDWI) of Quercus spinosa and Lamellosa leaves are sensitive to changes in the geological background. Compared with the canopy, the leaf hyperspectral indices of Quercus spinosa in Chundu can better reflect soil cuprum (Cu) anomaly. In addition, the NWI and NDWI of Quercus spinosa are significantly correlated with the soil Cu content at both the canopy scale and the leaf scale. Consequently, the results of the vegetation anomaly level slicing can adequately reflect the plant anomalies from ore bodies and nearby areas, thereby providing a new ore-finding method for areas with a high degree of vegetation coverage.

Experimental study on the influence of vegetation on the slope flow concentration time

Due to the steep slope of mountainous watersheds and large changes in vegetation coverage degree, flood response processes after rainstorms are complicated. The flow concentration time of the slope is a key parameter for the simulation of flood processes. The most widely used flow concentration time formula currently in the distributed hydrological model is T = L0.6n0.6i−0.4S−0.3, which is derived from the kinematic wave theory (Melesse and Graham in J Am Water Resour As 40(4):863–879, 2004; Lee in Hydrol Sci 53(2):323–337, 2008). The flow confluence time T is characterized by the constant exponent of the slope length L, roughness n, effective rainfall intensity i and slope S, and the influence of vegetation on the flow concentration time is implied by the roughness. In this study, a series of heavy rainfall slope surface confluence tests under different slopes and vegetation coverage were carried out, a vegetation coverage factor, C, which was introduced, a statistical analysis method was used, and the vegetation coverage index was fitted. The results showed that the types of vegetation have a certain influence on the flow concentration time of slope, and the flow confluence time under turf vegetation was larger than the flow confluence time under shrubs vegetation; especially in the slope of the larger slope, the relative impact is more significant; at the same time, the influence of vegetation coverage on the flow concentration time of slope was more significant; no matter the condition of turf or shrub, the slope confluence time increased obviously with the increase in vegetation coverage. The index of vegetation coverage factor C varied with the slope and rain intensity. In general, the index of vegetation coverage factor C increased with the decrease in slope and decreased with the increase in rain intensity. In regard to the turf vegetation coverage index, when the slope is 45° and 30°, the decreasing trend of the vegetation coverage index a0 is obvious with increasing rainfall intensity. When the slope is 15°, the vegetation coverage index a0 also decreases with increasing rainfall intensity. When the slope is 5°, the vegetation coverage index a0 basically has no change. In regard to the shrubs vegetation coverage index, when the slope is 45° and 30°, the decreasing trend of the vegetation coverage index a0 is obvious with increasing rainfall intensity. When the slope is 15°, the vegetation coverage index a0 also decreases with increasing rainfall intensity. When the slope is 5°, the vegetation coverage index a0 basically has no change.

Primena malih bespilotnih sistema u logistici i planiranju

The application of modern technologies makes it easy to collect, process, present, and apply data for logistics in hard to reach areas. Proper delivery of equipment, personnel, and materials directly affects the quality of work. The need for precise and real information about the condition of the terrain and the conditions of the environment has always existed since this knowledge enables proper planning, forecasting and task performing in the field. Improvement in the digital industry enables fast and easy transfer of unchanged digital data from the field to the information processing centers, which consequently improves decision making and planning processes. New workflows made proper logistics even more important because it increased the precision of field work and better anticipation of previously unforeseen circumstances. Work on hard to reach areas, with large slopes, non-existent and/or non-persistent infrastructure, and different degree of vegetation coverage requires precise planning and organization of works, in order to minimize the number of unforeseen situations and make the most expeditious workflows. This paper presents the practical application of small unmanned aerial systems for collecting a large amount of data in a short time, the processing of the data, and the production of relevant information for decision making. There are two most important aspects of this paper. First one is fast, easy, safe and precise collection of large amounts of data which is an alternative to the traditional methods. The second is computer data processing, which enables a fast and automatic transformation of raw data into relevant information in digital formats that are suitable for further processing and easily accessible to decision makers. This work shows that it is possible to record quickly and in detail a large area, and obtain real, current, accurate and high-fidelity information about each point of terrain, with high precision and reliability

Evaluation of the ecological protective effect of the “large basin” comprehensive management system in the Tarim River basin, China

It is very important to construct a reasonable and efficient basin management system to meet the ecological water demand in arid areas with natural vegetation, and to maintain the integrity and stability of fragile ecosystems. However, how to assess the effect of basin management on ecological protection in arid areas as well as how to achieve the optimal control and efficient use of ecological water are major issues for many researchers and river basin managers. To address these two questions, we investigated the comprehensive management system for the Tarim River basin in China as a typical case study. The results showed that the natural vegetation coverage degree, the ecological water supply, temperature vegetation dryness index (TVDI), and the tree-ring chronology of Populus euphratica increased, whereas the disturbance of water resources by human activities decreased. Therefore, the effects of ecological protection were obvious after comprehensive “large basin” management. Based on an innovative application of tree-ring chronology to estimate the water leakage from the river, we determined the minimum runoff level (43.1 × 108 m3) when the natural vegetation needs to overflow. To further improve the effect of comprehensive management, the optimal regulation mode (i.e. maintaining the groundwater depth at 2–6 m, and the frequency and duration of overflowing at 2–3 times per year for a duration of 15–20 days during July to September) for the ecological sluices was formulated from the perspective of the efficient utilization of ecological water. These results provide a scientific reference for constructing reasonable management systems for similar river basins in arid areas.

Technogenic Ecological Sequences in Tailing Pond from Căpușu Mare, Built between 1975-1981

In Romania, all actions related to mining management are found in “Strategy of the mining industry for 2012-2035”. Today, numerous tailing ponds have remained outside rehabilitation operations, and they are becoming more natural, as is the case of the tailing pond in Capusu Mare. The vegetation study was conducted in 2015, at the tailing pond III in Căpușu Mare that was operational between 1975-1981. The following phytopopulation and phytocenotic indices were calculated: presence, frequency, class of presence, abundance-dominance and average abundance-dominance (ADm) of species. Floral studies show the presence of 40 plant species. The wood species with the highest mean dominant abundance are Hippophäe rhamnoides (14.78%) and Salix alba (10.55%), and of herbaceous species stands Phragmites communis with 7.49%. After 34 years from the heap closure, the degree of vegetation coverage is 77%. Wood species occupy about 32% of the heap surface.

Coverage-dependent amplifiers of vegetation change on global water cycle dynamics

The terrestrial water cycle describes the circulation of water worldwide from one store to another via repeated evapotranspiration (E) from land and precipitation (P) back to the surface. The cycle presents significant spatial variability, which is strongly affected by natural climate and anthropogenic influences. As one of the major anthropogenic influences, vegetation change unavoidably alters surface property and subsequent the terrestrial water cycle, while its contribution is yet difficult to isolate from the mixed influences. Here, we use satellite and in-situ datasets to identify the terrestrial water cycle dynamics in spatial detail and to evaluate the impact of vegetation change. Methodologically, the water cycle is identified by the indicator of difference between evapotranspiration and precipitation (E-P). Then the scalar form of the indicator’s trend (ΔE+ΔP) is used for evaluating the dynamics of water cycle, with the positive value means acceleration and negative means deceleration. Then, the contributions of climate and vegetation change are isolated by the trajectory-based method. Our results indicate that 4 accelerating and 4 decelerating water cycles can be identified, affecting 42.11% of global land. The major water cycle type is characterized by non-changing precipitation and increasing evapotranspiration (PNO-EIN), which covers 20.88% of globally land. Vegetation change amplifies both accelerating and decelerating water cycles. It tends to intensify the trend of the decelerating water cycles, while climate change weakens the trend. In the accelerating water cycles, both vegetation and climate change present positive effect to intensify the trend. The effect of plant cover change varies with the coverage. In particular, vegetation change intensifies the water cycle in moderately vegetated regions (0.1<NDVI<0.6), but weakens the cycle in sparsely or highly vegetated regions (NDVI<0.1 or 0.6<NDVI<0.8). In extremely vegetated regions (NDVI>0.85), the water cycle is accelerated because of the significant increase of precipitation. We conclude that vegetation change acts as an amplifier for both accelerating and decelerating terrestrial water cycles, depending on the degree of vegetation coverage.

Delineation of Hydrological Response Unit Based on Remote Sensing Data

Using GIS, take Guanshan basin of Yongdinghe River as an example, based on the remote sensing data of watershed underlying surface, we delineate Guanshan basin into 9 hydrological response units (HRU) through reclassification and spatial overlaying analysis of watershed terrain, land use, soil and vegetation coverage degree, analyze the hydrological characteristics of each hydrological response unit, and the spatial discretization of distributed basin modeling gets realized.

Percepción de seguridad, uso y mantenimiento de los parques municipales en Costa Rica, según el sexo de los usuarios

Los parques y otras zonas verdes mejoran la salud física y mental de los habitantes de las ciudades, pero en Costa Rica se sabe muy poco sobre la percepción que tienen de ellos sus usuarios. Aquí analiza­mos la influencia del sexo en la percepción de la seguridad, el uso y el mantenimiento en una muestra grande y representativa de Costa Rica (27 parques municipales escogidos aleatoriamente). Aplicamos oral­mente y en persona una encuesta validada a 30 visitantes por parque. Hallamos que independientemente de la iluminación y la vegetación, las mujeres se sienten inseguras a toda hora; creen que hay muchos delitos; aunque en muy pocos casos han sido víctimas, y que califican más bajo el mantenimiento y la vigilancia que los hombres. La compa­ración con otros estudios indica que nuestros resultados son similares a los obtenidos en el resto de América Latina y más allá.

Dynamic Monitoring of the Strong Sandstorm Migration in Northern and Northwestern China via Satellite Data

ABSTRACTSand and dust storms (hereafter, sandstorms) not only damage the ecological environment in northern and northwestern China but also influence the economic and social development of the affected regions and constitute a threat to human health. This study focuses on monitoring sandstorms and analyzing the sandstorm migration process in northern and northwestern China. These sandstorms are characterized by their high frequency occurrences, strong dust intensity, long durations and highly destructive effects. The dry climate conditions and low degree of vegetation coverage in this region increase the difficulty of sandstorm monitoring. This paper proposes a remote sensing monitoring method for sandstorms in northern and northwestern China based on Moderate Resolution Imaging Spectroradiometer (MODIS) data and the radiation characteristics of the research region and of the sandstorms. A strong sandstorm that occurred on April 23–25, 2014, is analyzed to illustrate the proposed monitoring method. Information on the sandstorm is validated and analyzed through visual interpretation and comparison with Meteorological Information Comprehensive Analysis and Process System (MICAPS) ground measurements. The spatial distribution of the sandstorm is highly consistent with the true-color MODIS data. The comparison of the results of the remote sensing monitoring of the sandstorm with the MICAPS measurements yields a high coincidence rate of 96.3%. Additionally, the migration process of the sandstorm can be clearly recognized in 6 MODIS images captured during the 3-day sandstorm. Based on the above results, we conclude that the proposed method can be used for dynamic remote sensing monitoring of sandstorms in northern and northwestern China.

Comparison of soil physico-chemical properties under different land-use and cover types in northeastern China's Horqin Sandy Land

The Horqin Sandy Land of northeastern China was originally a grassland with plenty of water and lush vegetation dominated by palatable grass species along with sparsely scattered woody species. However, it has experienced severe desertification in recent decades due to its fragile ecology together with inappropriate human activities. Currently, the landscape of the Horqin Sandy Land is dominated by irrigated croplands and sand dunes with different degrees of vegetation cover, as the region has become the most important part of the semiarid agro-pastoral ecotone of northern China. In this study, we compared soil physical and chemical properties under different land-use and cover types (irrigated cropland, rainfed cropland, sandy grassland, fixed dunes, and mobile dunes) . We found that soil particle size distribution; organic C, total N, and total mineral element, microelement, and available microelement and nutrient contents; pH; CEC; and bulk density differed significantly among the land-use and cover types. In general, soil quality was highest in the cropland, intermediate in the sandy grassland, and lowest in the dunes. The most important soil quality attribute, soil organic carbon (SOC) storage, decreased in the following order: irrigated cropland (5, 699 g/m 2 ) ＞ sandy grassland (3, 390 g/m 2 ) ＞ rainfed cropland (2, 411 g/m 2 ) ＞ fixed dunes (821 g/m 2 ) ＞ mobile dunes (463 g/m 2 ) . SOC was significantly positively correlated with a large proportion of the other soil physico-chemical parameters. Our results suggest that the key issue in restoration of the degraded soils will be to increase SOC storage, which would also create a high potential for sequestering soil C in desertified areas of the Horqin Sandy Land.

Sediment and Phosphorus Loads from a Stream Draining Agricultural and Forest Lands in Northwest Spain

ABSTRACTTransport of suspended sediment (SS) and phosphorus (P) via surface runoff from soils to surface waters is a major problem of water quality degradation in many European rivers and in other parts of the world. This problem is especially serious during wet periods, which can produce twice the P loads of dry periods. In this study, the SS load and particulate phosphorus (PP) exported from a small catchment located in NW Spain (in which cultivated soils had different degrees of vegetation cover) were analyzed during two rainy periods of February 2006 and February 2007. The SS and PP loads were calculated from the data of discharge, and SS and PP concentrations were measured in water samples collected at the catchment outlet. SS and PP loads were higher in 2006 than in 2007, while there was higher rainfall and stream flow in 2007. Differences in the degree of vegetation cover in the cultivated fields with good connectivity with the stream, which was the main source area of sediment in this catchment, explain the differences in SS and PP loads between the two periods. Soil losses caused during both rainy periods were low (0.02 Mg ha−1); however, they may be detrimental to quality of the stream water due to the P linked to soil particles. PP concentrations were above the critical values of P for eutrophication during the study periods, highlighting the need to take conservation measures to reduce soil erosion and sediment delivery to watercourse.

Infiltration in layered loessial deposits: Revised numerical simulations and recharge assessment

Summary The objective of this study is to assess recharge rates and their timing under layered loessial deposits at the edge of arid zones. Particularly, this study is focused on the case of the coastal plain of Israel and Gaza. First, results of a large-scale field infiltration test were used to calibrate the van Genuchten parameters of hydraulic properties of the loessial sediments using HYDRUS (2D/3D). Second, optimized soil hydraulic parameters were used by HYDRUS-1D to simulate the water balance of the sandy-loess sediments during a 25-year period (1990–2015) for three environmental conditions: bare soil, and soil with both sparse and dense natural vegetation. The best inverse parameter optimization run fitted the infiltration test data with the RMSE of 0.27 d (with respect to a moisture front arrival) and R 2 of 96%. The calibrated model indicates that hydraulic conductivities of the two soil horizons, namely sandy loam and sandy clay loam, are 81 cm/d and 17.5 cm/d, respectively. These values are significantly lower than those previously reported, based on numerical simulations, for the same site. HYDRUS-1D simulation of natural recharge under bare soil resulted in recharge estimates (to the aquifer) in the range of 21–93 mm/yr, with an average recharge of 63 mm/yr. Annual precipitation in the same period varied between 100 and 300 mm/yr, with an average of 185 mm/yr. For semi-stabilized dunes, with 26% of the soil surface covered by local shrub ( Artemisia monosperma ), the mean annual recharge was 28 mm. For the stabilized landscape, with as much as 50% vegetation coverage, it was only 2–3 mm/yr. In other words, loessial sediments can either be a source of significant recharge, or of no recharge at all, depending on the degree of vegetative cover. Additionally, the time lag between specific rainy seasons and corresponding recharge events at a depth of 22 m, increased from 2.5 to 5 years, and to about 20 years, respectively, with an increasing vegetative cover. For this reason, and also likely due to a great depth of loessial sediments, no correlation was found between annual recharge and annual precipitations of the same year or subsequent years. Similarly, no differences were found between summer and winter recharge fluxes. Instead, numerical simulations indicated continuous year-round recharge of the aquifer. We conclude that the layered subsurface acts as a short-term (annual) and long-term (multi-annual) buffer to smooth sudden precipitation/infiltration events. Vegetation conditions can help in predicting long-term recharge rates (as percentage of annual precipitation), which in turn need to be considered when assigning recharge characteristics in regional assessments and models.

Contemporary suspended sediment dynamics within two partly glacierized mountain drainage basins in western Norway (Erdalen and Bødalen, inner Nordfjord)

This paper focuses on environmental controls, spatiotemporal variability and rates of contemporary fluvial suspended sediment transport in the neighboring, partly glacierized and steep Erdalen (79.5km2) and Bødalen (60.1km2) drainage basins in the fjord landscape of the inner Nordfjord in western Norway. Field work, including extended samplings and measurements, was conducted since 2004 in Erdalen and since 2008 in Bødalen. The distinct intra- and inter-annual temporal variability of suspended sediment transport found is mostly controlled by meteorological events, with most suspended sediment transport occurring during pluvial events in autumn (September–November), followed by mostly thermally determined glacier melt in summer (July–August), and by mostly thermally determined snowmelt in spring (April–June). Extreme rainfall events (>70mmd−1) in autumn can trigger significant debris-flow activity that can cause significant transfers of suspended sediments from ice-free surface areas with sedimentary covers into main stream channels and is particularly important for fluvial suspended sediment transport. In years with occurring relevant debris-flow activity the total annual drainage-basin wide suspended sediment yields are strongly determined by these single extreme events. The proportion of glacier coverage, followed by steepness of slopes, and degree of vegetation cover in ice-free surface areas with sedimentary covers are the main controls for the detected spatial variability of suspended sediment yields. The contemporary sediment supply from glacierized surface areas and the Jostedalsbreen ice cap through different defined outlet glaciers shows a high spatial variability. The fact that the mean annual suspended sediment yield of Bødalen is with 31.3tkm−2yr−1 almost twice as high as the mean annual suspended sediment yield of Erdalen (16.4tkm−2yr−1) is to a large extent explained by the higher proportion of glacier coverage in Bødalen (38% of the drainage basin surface area) as compared to Erdalen (18% of the drainage basin surface area) and by a significantly higher sediment yield from the glacierized area of the Bødalen drainage basin compared to the glacierized surface area in Erdalen. When looking at the total annual mass of suspended sediments being fluvially exported from both entire drainage basin systems, the total amount of suspended sediments coming from the ice-free drainage basin surface areas altogether dominates over the total amount of suspended sediments coming from the glacierized surface area of both drainage basins. Drainage-basin wide annual suspended sediment yields are rather low when compared with yields of other partly glacierized drainage basin systems in Norway and in other cold climate environments worldwide, which is mainly due to the high resistance of the predominant gneisses towards glacial erosion and weathering, the altogether only small amounts of sediments being available within the entire drainage basin systems, the stable and nearly closed vegetation cover in the ice-free surface areas with sedimentary covers, and the efficiency of proglacial lakes in trapping sediments supplied by defined outlet glaciers. Both contemporary and long-term suspended sediment yields are altogether supply-limited. Contemporary suspended sediment transport accounts for nearly two-thirds of the total fluvial transport and, accordingly, plays an important role within the sedimentary budgets of the entire Erdalen and Bødalen drainage basins.

Habitat and Time Are More Important Predictors of Weed Seed Predation than Space on a Diversified Vegetable Farm in Maine, USA

Postdispersal weed seed predation is a significant source of weed mortality in agroecosystems. The magnitude of seed predation, however, is variable. Understanding the relative importance of factors driving variability in seed predation rates will increase the potential utility of seed predation to farmers. We conducted landscape-scale field experiments to quantify and compare the effects of space, time of sampling, and habitat on weed seed predation. Seed predation assays, with and without vertebrate exclosures, measured seed predation rates at spatially explicit sample sites across 8.5 ha of crop and noncrop habitats on a diversified organic vegetable farm in Maine. Total and invertebrate seed predation averaged 8% and 3% d−1, respectively. Vertebrate seed predators detected by motion-sensing cameras included small mammals and birds. A ground beetle,Harpalus rufipes, was highly dominant in pitfall traps, comprising 66% of invertebrate seed predators captured within crop fields. Seed predation was randomly distributed in space. However, time of sampling and habitat were highly significant predictors of seed predation. Variance partitioning indicated that habitat factors explained more variation than did time of sampling. Total seed predation was greater in crop and riparian forest habitats than in mowed grass, meadow, or softwood forest. Generally, invertebrate seed predation was greatest at sites with an intermediate degree of vegetative cover, whereas habitat type was the chief biotic determinant of vertebrate seed predation rates. These results suggest cover cropping and wetland conservation as practices that may bolster seed predation rates.

Effects of river bed regulation on habitats and communities: A case study for ostracods in the Oder River, Poland

The effects of damming, groyne building, and channelizing on habitats and ostracod assemblages in the Oder River, one of the six largest European river systems, were analyzed. Regulation works had been conducted on the river from the 18th to the beginning of the 20th century. Main objectives of the study were to detect the effect of river bed regulation on attributes of habitats and ostracod communities. The values of nitrogen were the highest in the dammed stretch and the lowest in the channelized one. As for conductivity, TDS (total dissolved solids) and salinity were the highest in the groyned stretch. Hardness had the highest values in the channelized and groyned stretches. The lowest visibility was noted in the dammed stretched. The stretch influenced by damming was dominated by habitats with a considerable proportion of detritus in sediments. In the stretch influenced by groynes, the proportions of habitats with mineral and organic substrates were similar and the proportion of habitats covered with vegetation was the highest. Habitats with rocky, sandy bottoms dominated in the channelized stretch and nearly half of the habitats were covered with vegetation. The highest ostracod density characterized the groyned stretch (658 ind · m−2), was moderate in the case of the dammed stretch (290 ind · m−2) and the lowest in the channelized one (107 ind · m−2). Bradleystrandesia reticulata, Candona neglecta, and Limnocythere inopinata dominated in the groyned and channelized stretches. Cypridopsis vidua, Darwinula stevensoni, and Pseudocandona compressa dominated in the dammed stretch. The type of river bed regulation significantly differentiated both habitats and ostracod assemblages. Differences among ostracod assemblages were related to particular species, but also regarding density and evenness. The degree of vegetation coverage and detritus content in the sediments were strong predictors for ostracod community composition.

Phytotoponyms, Geographical Features and Vegetation Coverage in Western Hubei, China

The purpose of this paper is to present and exploit fundamental information, such as semantic meanings and geographical features, of phytotoponyms (a type of toponym that includes plant names) in Western Hubei (China). Long-term vegetation degradation is also estimated. Toponym data for this study were obtained from the place names database of Hubei Province at the Civil Affairs Department of Hubei. In total, 1259 instances of phytotoponyms were recognised; 898 (71.3%) were woody plant toponyms, and 361 (28.7%) were herbaceous plant toponyms. Subsequently, we randomly selected a similar number (1250) of non-phytotoponyms to compare with the phytotoponyms. All toponyms were localised and geo-referenced. The results showed that the most common plant names recognisable in place names are common plants that have a close connection with daily life and positive morals in Chinese culture and literature. The occurrence of plant names can reflect the characteristic plants of a city. The vegetation coverage rate where phytotoponyms are located is higher than that in non-phytotoponym areas. Altitude has a stronger correlation with the number of phytotoponyms than slope and vegetation coverage degree. The identification of long-term vegetation degradation based on phytotoponyms is presented for reference only, and other methods and materials are needed to validate these results.

Considerations Regarding the Relation Between Meadow and Animal in Baisoara Commune

The mountains formed of the oldest times an environment inhabited by the humans. (All over the European mountains, mountain people have ensured that feed in the first place by agriculture focused on the animal husbandry especially ruminants. Increasing cattle, sheep and goats has been widespread concern in Europe with accents and northern temperate climate zones. Pastures have a very important role in mountain agriculture and are characterized mainly by small structures and low input systems. After 1990 the management of grassland systems in Romania has undergone of many important changes. This situation is mainly caused by the decreasing number of animals and by the diminished interest of people responsible on its management. In this tendency we can include the natural landscape of Apuseni Mountains, on which we focused all our attention and which, in fact represents the object of our study. The aim of this study was to evaluate the quality of mountain grassland reported of grazing capacity (grassland belongs to Baisoara commune, Apuseni Mountains) under the influence of the management applied, the level of anthropogenic and tradition influence. For these purposes, studies aimed to determine the floristic structure, the evolution of livestock and demographic tendency have been conducted. Vegetation study was made using Braun- BlanquA©t method. With the results obtained, vegetation coverage degree and grazing capacity were determinate and the direction in evolution of vegetation cover was established. For these we used data regarding the number of animals, as well as data about agricultural surfaces and demographic evolution. These were taken from the Agricultural Registers of BAƒisoara commune (data related to the number of animal and agricultural surfaces) and from The National Institute of Statistics (data about demographic evolution). The obtained results showed a close relationship between grassland status and the number of animals, which led us to the conclusion that the level of intensification of the crop system determines the direction of evolution.

Curvilinear effects of invasive plants on plant diversity: plant community invaded by Sphagneticola trilobata.

The effects of invasive plants on the species diversity of plant communities are controversial, showing either a positive or negative linear relationship. Based on community data collected from forty 5 m×5 m plots invaded by Sphagneticola trilobata in eight cities across Hainan Island, China, we found S. trilobata decreased plant community diversity once its cover was beyond 10%. We demonstrated that the effects of invasive/native plants on the plant diversity of communities invaded by S. trilobata were curvilinear. These effects, which showed peaks under different degrees of vegetation cover, appeared not only for S. trilobata and all invasive plants, but also for all native plants. Invasive plants primarily had negative effects on plant diversity when they became abundant at a much lower cover level (less than 35%), compared with the native plants (over 60%). Thus, it is necessary to distinguish a range for assessing the effects of plants, especially invasive plants. Our results also confirmed that the invasion intensity of invasive alien plants increased with the intensity of local economic development. We highlight and further discuss the critical importance of curvilinear effects of biological invasion to provide ideas regarding the conservation of local biodiversity and the management of invasive plants.

Bionomic differences in odonates and their influence on the efficiency of indicator species of environmental quality

The influence of environmental changes on organisms depends on their bionomic characteristics, such as mobility, body size, and resource use. Thermoregulatory and dispersal abilities may directly affect the use of odonates as bioindicators since organisms with low dispersal ability can track fine-scale environmental variations and are usually resource specialists. We investigated the utility of dragonflies (Anisoptera) and damselflies (Zygoptera) as bioindicators testing possible relationships to their bionomic characteristics. We assessed the variation in species richness, composition, and indicator values in Cerrado areas by quantitative sampling of adult odonates in streams surrounded by different vegetation types, ordered by the degree of vegetation cover. Species composition was efficient in discriminating impacts affecting riparian vegetation, with low richness of rare and specialist species in impacted areas. Damselflies had more narrow requirements, associated to different shading, depth, and environmental integrity levels. No relation between body-size and species indicator value was observed. Despite this, the main use of those species as indicators, especially the Zygoptera, may be related to environmental disturbance created by changes on vegetation cover suggesting their potential use in the analysis of the environmental quality of riparian areas.

Successive development of soil ecosystems at abandoned coal-ash landfills

The main goal of the present study was to determine the effect of the native vegetation on the successive development of the soil ecosystem at abandoned coal-ash landfills of the Angren coal-fired power plant in Uzbekistan. Two different landfills (one not in use for 3 years, termed newer, and the other not in use for 10 years, termed older) with different degrees of vegetation cover were chosen to assess the time and vegetation effects on soil biota and habitat development. The soil biotic structure, including soil microorganisms and soil free-living nematode communities, was investigated both at open plots and under different native plants at the coal-ash landfill area. The observed soil microorganisms were found to be the most important component of the observed ecosystems. Total abundance, biomass, species, trophic and sexual diversity of soil free-living nematodes, along with fungi and organic-matter content, were found to be correlated with trace metals. The nematode trophic and species abundance and diversity increased from the newer toward the older coal-ash landfills. The sex ratio of the nematode communities was found to be dependent on the environmental conditions of the study area, with the males being the most sensitive nematode group. All applied ecological indices confirmed that open landfill plots distant from plants are the most unfavorable areas for soil biota. In that respect, the native plants Alhagi maurorum Desv. and Tamarix sp. were found to be important environmental components for the natural remediation of a soil ecosystem in the coal-ash landfill area.