Impact of point polluters on terrestrial ecosystems: Methodology of research,experimental design,and typical errors

The current state of the ecology of the impact regions is outlined. It is argued that the complex of ecosystems situated around a point polluter (an impact region) is an appropriate model for solving several fundamental and applied ecological problems related to the exploration of strong external impacts on biota. Typical methodological errors resulting from insufficient attention to specific features of passive experiments are analysed, and ways to avoid them are proposed. The principles of spatial arrangements of study sites within the impact region and of the selection of experimental and evaluation units are discussed.     

Sources of variation in concentrations of nickel and copper in mountain birch foliage near a nickel-copper smelter at Monchegorsk, north-western Russia: results of long-term monitoring

Concentrations of nickel and copper, two principal metal pollutants of the 'Severonikel' smelter at Monchegorsk, NW Russia, were measured in unwashed leaves of mountain birch, Betula pubescens subsp. czerepanovii, collected in eight study sites along the pollution gradient during 1991-2003. In spite of significant decline in metal emissions, concentrations of foliar metals in most of the study sites did not decrease, indicating that soil contamination remains extremely high. Multiyear mean values peaked at 6.6 km S of the smelter, where they were 20-25 times higher than in the most distant study site. Concentrations of both metals demonstrated pronounced annual variation, which was explained by the meteorological conditions of early summer: higher precipitation in May increased foliar concentrations of both metals, whereas higher precipitation in June resulted in lower foliar concentrations of nickel. These data suggest that ecotoxicological situation in metal-contaminated areas can be modified by the expected climate change. In heavily polluted sites individual birch trees generally retained their ranks in terms of metal contamination during 1995-2003, demonstrating that the use of the same set of trees can significantly increase the accuracy of the monitoring data.     

Heavy metals in birch leaves around a nickel-copper smelter at Monchegorsk, northwestern Russia

Concentrations of metals in birch leaves were measured around the Severonikel smelter at Monchegorsk, Kola Peninsula, northwestern Russia, between 1991 and 1994. Concentrations of Ni, Cu and Fe near the smelter were 6-12 times higher than the recent regional background concentrations, while concentrations of Mn and Zn were 5-10 and 1.5-2 times lower, respectively. The regional background concentrations of Ni and Cu have increased 3-5 times during the last 20 years. Foliage concentrations of micronutrients (Zn and Mn) showed less annual variation than Ni and Cu. Contamination changed more sharply along the northeastern gradient than along the southern one. Subalpine birch forests were significantly less affected by Ni and Cu than lowland forests, but the lower concentration of Mn indicated a greater impact of SO(2) in mountainous regions. Although birch accumulated relatively less pollutants than conifers, birch resistance to pollution makes it a possible indicator in environmental studies since it survives even within the wastelands where conifers have vanished.     

Retrospective analysis of the age at death in two heavily polluted and two unpolluted Russian towns

Mean age at death during 1981-1999 was recorded in four small industrial towns located in the Kola Peninsula, north-western Russia. Two of these towns (Nikel and Monchegorsk) are heavily contaminated by sulphur dioxide and toxic metals (primarily Ni, Cu, Cd) emitted by large nickel-copper smelters; two other towns (Apatity and Polyarnye Zori) are nearly unpolluted. The results did not support the hypothesis that human life span is significantly shorter in the contaminated communities; moreover, mean age at death was lowest in Polyarnye Zori, the town not polluted by either sulfur dioxide or heavy metals but located close to the nuclear power plant. It seems that the impact of hazards other than pollution (both social and environmental), which are common for the populations of the investigated towns, shorten the life span so much that the contribution of pollutants to the decline in life expectancy cannot be detected. However, the relative importance of the life-shortening diseases associated with pollution may increase with the (expected) improvement of the quality of life.     

Pollution resistance of mountain birch, Betula pubescens subsp. czerepanovii, near the copper-nickel smelter: natural selection or phenotypic acclimation?

Mountain birch, Betula pubescens subsp. czerepanovii (Orlova) Hamet-Ahti, is one of the very few woody plants surviving in the heavily polluted industrial barrens of the Kola Peninsula, north-western Russia. The present study was designed to find out whether long-lasting pollution impact caused selection of resistant birch genotypes, and to investigate possible trade-offs between pollution resistance and performance by exploring growth of birch seedlings in the different environments. In the reciprocal planting experiments, progenies of birches from polluted sites performed slightly better in the polluted environment (in terms of survival, leaf number, and leaf size) than progenies of birches from clean sites; and vice versa, in the clean environment progenies of birches from polluted sites performed slightly worse than progenies of birches from clean sites. However, this pattern was detected only in some of statistical tests, while the majority of comparisons showed no genotype or genotype by environment effects. Although some of the results indicate that long-lasting pollution impact may have increased pollution resistance of the affected populations by elimination of sensitive genotypes (survival selection), this conclusion should be considered tentative. The resistance did not reach the level sufficient to assure re-colonisation of polluted habitats: progenies of all trees completely died on the contaminated soils by the end of the first growth season. Therefore persistence of mountain birch populations near the strong polluters may be transient, being explained not only by higher resistance of the survivors, but also by phenotypic acclimatisation of mature trees to gradual increase in pollution.     

Patterns in content of phenolic compounds in leaves of mountain birches along a strong pollution gradient

The contents of individual low-molecular weight phenolic compounds (LMWPs) in mountain birch, Betula pubescens ssp. czerepanovii, leaves collected during 1996-1998 in six plots 7-65 km south of the nickel-copper smelter at Monchegorsk, Kola Peninsula, NW Russia, were reported. A high-performance liquid chromatography-electrospray ionisation-mass spectrometry (HPLC-ESI-MS) was used for the rapid identification of low-molecular weight phenolics. Quantification was performed by the analytical high-performance liquid chromatography with UV-detection. Contents of (+)-catechin and some gallic acid derivatives decreased significantly, and contents of flavonol glycosides slightly increased with the distance from the smelter. Hydroxycinnamic acid derivatives remained unaffected. These changes in birch leaf phenolics are probably related to the effect of environmental contamination on the biosynthetic reactions both in the shikimate and phenylpropanoid pathways.     

A second life for old data: global patterns in pollution ecology revealed from published observational studies

A synthesis of research on the responses of terrestrial biota (1095 effect sizes) to industrial pollution (206 point emission sources) was conducted to reveal regional and global patterns from small-scale observational studies. A meta-analysis, in combination with other statistical methods, showed that the effects of pollution depend on characteristics of the specific polluter (type, amount of emission, duration of impact on biota), the affected organism (trophic group, life history), the level at which the response was measured (organism, population, community), and the environment (biome, climate). In spite of high heterogeneity in responses, we have detected several general patterns. We suggest that the development of evolutionary adaptations to pollution is a common phenomenon and that the harmful effects of pollution on terrestrial ecosystems are likely to increase as the climate warms. We argue that community- and ecosystem-level responses to pollution should be explored directly, rather than deduced from organism-level studies.     

Slow growth of Empetrum nigrum in industrial barrens: combined effect of pollution and age of extant plants

We studied the impact of industrial pollution on population demography (age structure), growth and reproduction of crowberry, Empetrum nigrum L. Crowberry growing in severely polluted sites near non-ferrous smelters (at Harjavalta, Monchegorsk and Nikel) was on average twice as old as in unpolluted habitats, as indicated by the number of annual rings at root collar. Shoot length decreased both with plant ageing and due to pollution impact, while neither the proportion of generative plants nor berry production was affected by pollution or plant age. Our results suggest that death of the extant individuals of E. nigrum near the non-ferrous smelters is to a large extent explained by age-related damage of the main stem accelerated by pollution. Since vegetative propagation, seed germination and seedling establishment are hampered by soil toxicity, E. nigrum populations near the smelters continue to decline with ageing in spite of the gradual decline of emissions.     

Responses of terrestrial arthropods to air pollution: a meta-analysis

Background, aim, and scope  

Arthropods, with over a million species described, are ubiquitous throughout different environments. Knowledge of their responses to human impact is crucial for understanding and predicting changes in ecosystem structure and functions. Our aim was to investigate the general patterns and to identify sources of variation in changes of the diversity, abundance and fitness of terrestrial arthropods (including Arachnida, Collembola and Insecta) in habitats affected by point polluters.