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941.
The influence of the Kosogorsky Metallurgical Plant (KMP; Tula region, Russia) on the abundance and biodiversity of carabid beetles and soil macrofauna and on the trophic activity of soil biota was studied. Metal concentrations in the impact plot were many times higher than those in the control plot located on the same transect. As the transect approached KMP, both the abundance of soil invertebrates (geobionts) and trophic activity of the soil biota remained unchanged, whereas the abundance and diversity of carabids (herpetobionts) decreased drastically. It is suggested that the impact of the KMP on herpetobionts is accounted for by modification of the structure of ecosystems and that herpetobiontic and geobiontic groups of the macrofauna respond differently to this impact because of differences in the ecological mechanisms of population response.  相似文献   
942.
General trends in simplification of the structure and composition of forest communities in the zone of impact from the metallurgical industry are revealed. The load of toxicants is estimated from the concentrations of heavy metals in the snow and soil. The method is proposed for assessing biological damage on the basis of the main characteristics of phytocenosis, such as its species diversity and the cenotic significance of its structural components. The resultant integrated index of phytocenosis preservation (IIP p) characterizes the degree of biological damage, and its value depends on the load of toxicants and resistance of plant communities characteristic of different natural zones.  相似文献   
943.
Paleoethnobotanical materials and buried soils from the site of the ancient settlement of Idnakar and neighboring archaeological monuments were analyzed to reconstruct the agroecosystems of the 9th through the 13th centuries AD near the present-day city of Glazov. The results provided data on the main features of the agroecosystem structure and composition, climate, and agriculture in the Middle Ages.  相似文献   
944.
In the southern-taiga low grass–green moss fir forest completely defoliated by the Siberian moth, the rate of soil respiration in the third year after the pest population outbreak was 1.5 times higher than in an undisturbed tree stand. This was explained by a significant increase in the abundance and activity of soil microorganisms in the pest-defoliated forest, which occurred due to the qualitative changes in the litter composition and the increased temperature and moisture in the upper soil layers. The rate of carbon emission from the soil in the defoliated forest was 41.7 kg/ha per day, compared to 28.3 kg/ha per day in the undisturbed fir forest.  相似文献   
945.
The reproductive capacity of Taraxacum officinale s.l. (two morphological forms: T. off. f. dahlstedtii Lindb. fil. and T. off. f. pectinatiforme Lindb. fil.) under conditions of chemical environmental pollution was studied in years differing in weather conditions. The number of generative shoots in plants increased along the toxic load gradient, which led to an increase in the total number of seeds and the weight of filled seeds. The relative energy value of seeds was determined from the amount of plastic substances in them. The number of seeds was shown to increase at a considerably higher rate than the energy expenditures for the formation of each seed. A general principle was revealed that determines the energy expenditures for the formation of a normal seed in both T. officinale forms under different weather conditions and under the chemical pollution of the environment.  相似文献   
946.
Ninety-three beavers were tagged in 1998–2000 on the Azas River (Tyva Republic), and 28 returns were obtained within one to two years. The results of the study indicated that, unfavorable environment notwithstanding, most beavers did not move outside their settlements. Animals under two years of age were especially active. Females were more resident, whereas males migrated over longer distances. The section of the Azas River with numerous rapids was not an insuperable obstacle for the animals; genetic exchange between the upper and lower subpopulations was found to occur through this section.  相似文献   
947.
948.
949.
Total and particulate metal concentrations, measured during intensive synoptic studies of the Genesee River, NY, correlated with suspended-sediment concentration and river discharge. Dissolved metal concentrations, on the other hand, showed little systematic variation over the length of the river. Metal and sediment fluxes for two elevated-discharged periods peaked at a midbasin sampling site. For most metals at most sampling sties particulate materials comprised over one-half of the total material. Comparison of particulate material metal concentrations, normalized to the measured suspended-sediment concentrations had with basinwide average values shows that sites having low suspended-sediment concentrations had high particulate material metal contents relative to the basin averages, while sites with high suspended-sediment concentration had low metal contents. These results are consistent with a metal transport mechanism in the Genesee River involving (1) a nearly constant dissolved component, (2) a fine acid-soluble component, and (3) a coarse component that is effectively a neutral diluent in the sediment. Chemical factors, such as sediment organic content, also appear to affect metal transport in the Genesee River.  相似文献   
950.
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