A model of vegetation pattern at the Verkhneussuriysky Biogeocenotic Station

A model of relationships between forest communities and basic parameters of environmental conditions, which is suitable for making prognostic maps of forest types, has been developed and tested on the territory of Verkhneussuriysky Biogeocenotic Station of the Institute of Biology and Soil Science. A comparative analysis of the spatial distribution of forest communities has been performed according to this model and to the large-scale map of recent forest vegetation on the territory of the station.     

Seasonality of Cs in roe deer from Austria and Germany

Empirical data on the ¹³⁷Cs activity concentration in meat of roe deer (Capreolus capreolus) roaming in 3 spruce forest areas and one peat bog area are presented and compared. They cover time series of nearly 20 years after a spike contamination in 1986 originating from Chernobyl. A model is presented which considers three soil compartments to describe the change of the availability of ¹³⁷Cs with time.     

The effect of greenhouse vegetation coverage and area on the performance of an earth-to-air heat exchanger for heating and cooling modes

The underground temperature at a depth of about 3–4 m is almost constant all the year round. In summer, the underground temperature is lower than the ambient temperature, but in winter it is vice versa. This potentiality is considered for greenhouse cooling and heating by using an earth-to-air heat exchanger (EAHE). This paper considers the effects of two parameters as independent variables including the area of greenhouse and the percentage of vegetation coverage inside the greenhouse on the performance of an EAHE system during both cooling and heating modes. The inside temperature, the thermal energy exchange and the coefficient of performance (COP) of the system were considered as dependent variables. The results showed that both greenhouse area and the percentage of vegetation coverage inside the greenhouse had significant effects on the performance of the EAHE system during both cooling and heating modes. However, the COP of the EAHE system was higher in the cooling mode (4.32) than during the heating mode (1.01). The percentage of vegetation coverage negatively affected the performance of the EAHE system in the cooling mode. However, the performance of the EAHE system improved with the increase in the percentage of vegetation coverage during the heating mode.     

Ecological aspects of larval drift in coregonids with long migration routes

Downstream migration (larval drift) of coregonids in the lower reaches of the Severnaya Sos??va River (the largest spawning tributary of the Lower Ob) has been analyzed from ecological aspects such as the long-term, seasonal, and daily dynamics and the spatial distribution, growth, and feeding of larvae in the current. Considerable changes in the abundance of coregonid generations have been revealed. It is shown that downstream larval migration over a long route has a number of features distinguishing it from that at spawning grounds. In particular, mass migration takes place after the ice drift, and its intensity is independent of changes in flow discharge. The drifting larvae display species-specific distribution in the current, and their density is the lowest in the surface water layer. In the course of migration, their linear body growth is accompanied by considerable depletion of endogenous food reserves and transition to active feeding.     

Hydrologic and land use impacts on vegetation growth and NPP at the watershed scale in a semi-arid environment

Significant, adverse climatic change and drastically increased demographic pressure have strongly affected, in recent years, the hydrology and environment in the semi-arid Sahel region of West Africa. Marked rain deficits have coincided with increased water runoff, meaning less water availability for the vegetation. Conversely, changes in vegetation cover have had strong repercussions on the hydrologic cycle. To study these phenomena, the coupling of two explicit, process-based models, of catchment hydrology and of mixed vegetation cover, respectively, has been undertaken and applied to a 2 km² site in Niger. Some of the first significant results are presented herein. Some are consistent with intuitive judgments that can be made in the absence of a coupled model, others are much less so and show that representation through model coupling of hydrosphere/biosphere interactions is essential to produce more reliable analyses and projections. In particular, it is found that the relation of biomass productivity to rainfall under this dry, water-limited climate is not as straightforward as one would expect, more specifically, that its main control may not be the total season rainfall.     

Investigations on indoor radon in Austria, Part 1: Seasonality of indoor radon concentration

In general, indoor radon concentration is subject to seasonal variability. The reasons are to be found (1) in meteorological influence on the transport properties of soil, e.g. through temperature, frozen soil layers and soil water saturation; and (2) in living habits, e.g. the tendency to open windows in summer and keep them closed in winter, which in general leads to higher accumulation of geogenic Rn in closed rooms in winter. If one wants to standardize indoor Rn measurements originally performed at different times of the year, e.g. in order to make them comparable, some correction transform as a function of measurement time which accounts for these effects must be estimated. In this paper, the seasonality of indoor Rn concentration measured in Austria is investigated as a function of other factors that influence indoor Rn. Indoor radon concentration is clearly shown to have seasonal variability, with higher Rn levels in winter. However, it is complicated to quantify the effect because, as a consequence of the history of an Rn survey, the measurement season maybe correlated to geological regions, which may introduce a bias in the estimate of the seasonality amplitude.     

Fallout strontium and caesium transfer from vegetation to cow milk at two lowland and two Alpine pastures

Vegetation-to-milk transfer coefficients for 137Cs, 90Sr and stable strontium were determined for cows grazing on two intensively managed lowland pastures and two Alpine pastures in Austria. The 90Sr transfer coefficient at the four pastures ranged from 0.0005 to 0.0012 dl-1 and correlated with the stable strontium transfer coefficient (0.0006-0.0013 dl-1) with the lower values found on the intensively managed pastures. The 137Cs transfer coefficient ranged from 0.0009-0.0045 dl-1.     

Environmental effects of new herbicides for vegetation control in forestry

Environmental fate of and toxicity data for ammonium ethyl carbamoylphosphonate [fosamine ammonium], N-(phosphonomethyl)glycine [glyphosate], and 3-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H, 3H)-dione [hexazinone] which appear promising for vegetation control in forestry are reviewed. None of the three herbicides is very persistent in soil, with half-lives reported of about 7–10 days for fosamine ammonium, 8–19 weeks for glyphosate, and 1–6 months for hexazinone, depending on soil type and climatic conditions. Degradation in soil is primarily via microbial routes. Whereas hexazinone is a very mobile herbicide (with mobility dependent on soil type), fosamine ammonium and glyphosate are strongly adsorbed and not readily leached in many soil types. Based on bioassay results, the three herbicides exhibit “very low” to “low” toxicity. Fosamine ammonium is not mutagenic and was not teratogenic when fed to pregnant rats at 10,000 ppm. Data on hexazinone indicate no carcinogenic effect in rats, negative in bacterial and mammalian point mutation assays, and not embryotoxic or teratogenic at up to 5000 ppm in diet of rats. The three herbicides have minimum-to-nil effect on soil microorganisms and exhibit little or no potential for bioaccumulation. Limitations of the available data are discussed and suggestions are made for future studies.     

Lead content in roadside vegetation as indicators of atmospheric pollution

Leaves of six plant species from 31 different locations in Ibadan, Nigeria, were analysed for their lead content. The lead concentrations found ranged between 12 and 32 μg/g, 50 m or more away from the roadside, between 47 and 115 μg/g in the residential low traffic density areas, 5 m from the roadside, and between 165 and 312 μg/g in the commercial high traffic density roadsides, 5 m away from the roadside.     

Soil as a factor of vegetation regeneration in natural pastures

Data are presented that show the significance of the humus state of chernozem soils, their amphiphilic (hydrophobic-hydrophilic) components, and related physical properties (density, structural condition, and water permeability) for regeneration of natural vegetation and restoration of its species com-position in pasture ecosystems.     

Biodiversity of forest vegetation under industrial pollution

Parameters of species and typological diversity of forest vegetation have been evaluated on macroslopes descending to Lake Imandra in the vicinity of the Severonickel Mining and Smelting Complex (SMSC) (Murmansk oblast). It has been shown that these parameters change upon an increase in the pollution level, with the pattern of changes in northern taiga forests differing from that in krummholz stands. The species richness and typological diversity of forest communities increase in the middle zone of the pollution gradient, compared to those in the krummholz belt occupying the upper parts of the slopes. Species saturation in all types of communities on landscape transects consistently decreases along the pollution gradient. In general, changes in parameters of diversity provide evidence for strong digression of plant communities in the vicinity of the SMSC.     

Plutonium in sheep faeces as an indicator of deposition on vegetation

In order to study the deposition on vegetation of plutonium arising from the testing of nuclear weapons and discharges from nuclear facilities, sheep faeces were collected from the South-west and North of England. The plutonium content of faeces has been shown to be a reproducible and sensitive indicator of deposition on herbage and, with this technique, plutonium discharged from the Sellafield Works of British Nuclear Fuels LImited can be detected 60 km from the site. On moorland pastures the concentration of ^239+240Pu in faeces, expressed as activity per gram of ash, is roughly equal numerically to the deposit of plutonium on 1 m² of vegetation.Some of the plutonium ingested by a grazing sheep is absorbed and the highest concentrations are found in liver. The liver of a sheep grazing on pasture where the ^239+240Pu concentration in faeces was about 2 pCi (74 mBq) g⁻¹ of ash, was found to contain <1% of the Generalised Derived Limit for mutton and offal, and the meat <0·001%.     

Zonal patterns in the formation of synanthropic vegetation in the city of Kursk

Analysis of zonal patterns in the formation of synanthropic vegetation has shown that the intensity of manifestation of its zonal differentiation increases with the advancement of the successional stage of synanthropic communities. The rate of successional processes in these communities depends on the initial (potential) type of vegetation in the territory of the city.     

Main regularities in synanthropization of different vegetation types in the Republic of Bashkortostan

The contribution of synanthropization to the anthropogenic evolution of vegetation has been analyzed by assessing its level in approximately 260 associations and communities of 31 vegetation classes in the Republic of Bashkortostan. The results show that this level is high in communities of synanthropic classes Secalietea, Chenopodietea, Artemisietea vulgaris, and Robinietea. Synanthropization of communities under the effect of human activities is also characteristic of many classes of natural vegetation, especially those of meadows, floodplain forests, and ravine-gully systems. Some communities are protected from synanthropization due to the existence of abiotic or biotic barriers to the expansion of synanthropic species (communities of high-mountain areas and zonal forests, many aquatic communities, and mountain meadows and steppes).     

Sequential impacts of Polynesian and European settlement on vegetation and environmental processes recorded in sediments at Whangapoua Estuary, Great Barrier Island, New Zealand

Whangapoua Estuary, Great Barrier Island, New Zealand, is central to a proposed Marine Reserve, and is currently managed for conservation by the Department of Conservation. This paper describes the sequential impacts of Maori and European people on the process of estuarine vegetation succession in time and space, and the rate of estuarine sedimentation. Multiple cores from one estuary gave confidence in assessing the temporal sequence of vegetation change, but bioturbation and other disturbance factors made it difficult to interpret ¹⁴C dates from the estuarine environment. The modern vegetation zonation pattern on the estuary is an active succession, which has been generated by rapid estuary in-filling, probably initiated as a consequence of erosion following Maori burning of the adjacent forest. European forest clearance for agriculture resulted in a further increase in estuarine sedimentation, and may have re-activated earlier sediments trapped in adjacent swamps. The combined effects of two phases of human exploitation have resulted in large-scale loss of nutrients and top-soil from catchments throughout Great Barrier Island. Conservation management of the estuary should take account of the anthropogenic impacts that have driven the plant succession and created the current vegetation zonation pattern. This pattern is neither static nor ‘natural’, but rather an on-going response to the changing human activities in the surrounding catchment.     

14C content in vegetation in the vicinities of Brazilian nuclear power reactors

(14)C specific activities were measured in grass samples collected around Brazilian nuclear power reactors. The specific activity values varied between 227 and 299 Bq/kg C. Except for two samples which showed (14)C specific activities 22% above background values, half of the samples showed background specific activities, and the other half had a (14)C excess of 1-18%. The highest specific activities were found close to the nuclear power plants and along the main wind directions (NE and NNE). The activity values were found to decrease with increasing distance from the reactors. The unexpectedly high (14)C excess values found in two samples were related to the local topography, which favors (14)C accumulation and limits the dispersion of the plume. The results indicate a clear (14)C anthropogenic signal within 5 km around the nuclear power plants which is most prominent along northeastwards, the prevailing wind direction.     

Exposure of biota in the cooling pond of Ignalina NPP: hydrophytes

The radiological assessment of non-human biota is now accepted by a number of international bodies. In this connection the scientific basis to assess and evaluate biota internal and external radiation exposure is required. This paper presents the comparison of freshwater biota (hydrophyte species) exposure due to discharged anthropogenic radionuclides with that due to natural background radiation. The radionuclides from Ignalina Nuclear Power Plant (Lithuania) are discharged into cooling pond - Druksiai Lake. Submerged hydrophytes were selected as biota exposure indicators because they represent the largest biomass in this lake and have comparatively high radionuclide activity concentrations. The detailed methodology evaluation of the submerged hydrophyte dose rate is presented. The ionizing radiation exposure dose rates to submerged hydrophyte roots and above sediment parts due to the major radionuclides ((54)Mn, (60)Co, (137)Cs, (90)Sr) discharged into the INPP cooling pond - Druksiai Lake were 0.044 microGyh(-1) and 0.004 microGyh(-1), respectively. The internal exposure dose rate due to natural background alpha-emitters ((210)Po,(238)U, (226)Ra) was estimated to be 1.24 microGyh(-1), as compared with that of anthropogenic alpha-emitter (240)Pu - 0.04 microGyh(-1), whereas the external exposure was 0.069 microGyh(-1). The presented data deeper the knowledge about the concentration of radionuclides and submerged hydrophytes' exposure dose rates in European freshwater ecosystems.