Mikhail V. Kozlov

Root versus canopy uptake of heavy metals by birch in an industrially polluted area: contrasting behaviour of nickel and copper.

We investigated root versus canopy uptake of nickel and copper by mountain birch, Betula pubescens subsp. czerepanovi, close to a nickel-copper smelter on the Kola Peninsula, northwest Russia. To distinguish between aerial contamination of leaf surfaces by dust particles and root-derived contamination of leaves by soluble metals, we transplanted seedlings from a control site to clean and metal-contaminated soils and exposed these seedlings both in clean and polluted sites. Patterns of leaf surface contamination and root uptake were similar for nickel and copper; however, nickel but not copper was effectively translocated from roots to shoots and leaves. The majority (80-95%) of nickel and copper found in birch foliage in the heavily contaminated site was due to deposition of dust particles on leaf surfaces; 32-40% of foliar nickel and 9-19% of foliar copper were in water soluble forms. Washing of fresh leaves removed only a minor part of surface contaminants; boiling of unwashed leaves in distilled water for 15 min removed >90% of soluble nickel and copper.

Stress Responses of Salix borealis to Pollution and Defoliation

Morphological characters of Salix borealis were monitored during 1994-96 at 10 sites along a transect crossing the heavily polluted surroundings of Severonikel smelter in NW Russia, and analysed with respect to pollution load and density of the principal herbivore, the leaf beetle Melasoma lapponica. Leaf size and shoot growth increased and leaf pubescence decreased with an increase in pollution, whereas variation in other characteristics was not related to pollution load. Leaf fluctuating asymmetry (FA) and leaf pubescence increased with an increase in herbivory, whereas variation in other characters was not related to foliar damage. A field experiment demonstrated that leaf FA and pubescence were high in the year after defoliation. The data on leaf FA, a non-specific stress indicator, suggest that for the extant individuals of S. borealis, defoliation resulted in detectable stress, whereas long-lasting severe pollution by sulphur dioxide and heavy metals caused no measurable stress response and may even stimulate growth of leaves and shoots. Leaf FA of woody plants may serve as an early indicator of the biotic stress caused by herbivory, which expands the use of FA as a tool in helping to compare the relative strengths of different stressing agents.

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.

Delayed induced resistance and increase in leaf fluctuating asymmetry as responses of Salix borealis to insect herbivory

Abstract An outbreak of leaf beetle Melasoma lapponica in two localities around the Severonikel smelter in Kola Peninsula, north-west Russia, resulted in severe defoliation of Salix borealis, observed for the first time in August 1993 and then again in 1994 and 1995. Before the first severe defoliation, in July 1993, performance of M. lapponica larvae in plots with a high beetle density was either better or the same as in low-density plots. However, in 1994 and 1995, the years following severe willow defoliation in high-density plots,  M. lapponica performance (in terms of survival, developmental time and beetle weight) decreased with increasing beetle density. Retarded larval growth in high-density plots was related to a decreased consumption rate, whereas the efficiency of the conversion of ingested food was similar in high- and low-density plots. These results indicate that defoliation triggered delayed induced resistance in S. borealis. Leaf fluctuating asymmetry (FA, a non-specific stress indicator) of this willow species in 1992 was similar in low- and high-density plots, but it increased in high-density plots in 1994, at the same time that detrimental effects on beetle performance were recorded at these sites. Plot-specific indices of beetle performance and FA were negatively correlated both in 1994 and 1995, suggesting that plants stressed by defoliation the previous-year were less favourable for leaf beetles.

Sources of variation in plant responses to belowground insect herbivory: a meta-analysis.

Growing interest in belowground herbivory and the remarkable diversity of the accumulated information on this topic inspired us to quantitatively explore the variation in the outcomes of individual studies. We conducted a meta-analysis of 85 experimental studies reporting the effects of root-feeding insect herbivores (36 species) on plants (75 species). On average, belowground herbivory led to a 36.3% loss of root biomass, which was accompanied by a reduction in aboveground growth (−16.3%), photosynthesis (−11.7%) and reproduction (−15.5%). The effects of root herbivory on aboveground plant characteristics were significant in agricultural and biological control studies, but not in studies of natural systems. Experiments conducted in controlled environments yielded larger effects on plants than field experiments, and infestation experiments resulted in more severe effects than removal studies employing natural levels of herbivory. Simulated root herbivory led to greater aboveground growth reductions than similar root loss imposed by insect feeding. External root chewers caused stronger detrimental effects than sap feeders or root borers; specialist herbivores imposed milder adverse effects on plants than generalists. Woody plants suffered from root herbivory more than herbaceous plants, although root loss was similar in these two groups. Evergreen woody plants responded to root herbivory more strongly than deciduous woody plants, and grasses suffered from root herbivory more than herbs. Environmental factors such as drought, poor nutrient supply, among-plant competition, and aboveground herbivory increased the adverse effects of root damage on plants in an additive manner. In general, plant tolerance to root herbivores is lower than tolerance to defoliating aboveground herbivores.

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

Background, aim, and scopeArthropods, 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.Main featuresWe found 134 suitable studies which were published between 1965 and 2007. These data came from impact zones of 74 polluters in 20 countries with the largest representation from Russia (28 polluters), Poland (12 polluters) and the USA (six polluters). The database allowed calculation of 448 effect sizes (i.e. relative differences between measurements taken from polluted and control sites) on the effects of various point polluters like non-ferrous industries, aluminium plants, cement, magnezite, fertilising and chemical plants, power plants, iron- and steel-producing factories. We used meta-analysis to search for general effects and to compare between polluter types and arthropod groups, and linear regression to describe the latitudinal gradient and to quantify relationships between pollution and arthropod responses.ResultsThe overall effect of pollution on arthropod diversity did not differ from zero. However, species richness of soil arthropods (both living on the soil surface and within the soil) tended to decrease, and species richness of herbivores to increase, near point polluters. Abundance of terrestrial arthropods near point polluters decreased in general. This decrease resulted from strong adverse effects on soil arthropods, especially on decomposers and predators. Densities of herbivores increased, but a number of research biases that we discovered in published data may have led to overestimation of the latter effect. The dome-shaped density pattern along pollution gradients was discovered only in 5% of data sets. Among herbivores, only free-living defoliators and sap-feeders demonstrated higher densities in polluted sites; the effects of pollution on other guilds were not significant. Near the polluters, conifers suffered higher increase in damage from herbivores than deciduous woody plants and herbs. Overall effect of pollution on arthropod performance was negative; in particular, individuals from polluted sites were generally smaller than individuals from control sites. This negative effect weakened with increase in duration of the pollution impact, hinting evolution of pollution resistance in populations inhabiting polluted sites. Stepwise regression analysis demonstrated that pollution-induced changes in both the density and performance of arthropods depended on climate of the locality. Negative effects on soil fauna increased with increase in annual precipitation; positive effects on herbivore population density increased with increases in both mean July temperature and annual precipitation.DiscussionWe detected effects of research methodology on the outcome of published studies. Many of them suffer from research bias—the tendency to collect data on organisms or under conditions in which one has an expectation of detecting significant effects. Pseudoreplicated studies (one polluted site contrasted to one control site) frequently reported larger effects than replicated studies (several polluted sites contrasted with several control sites). These methodological flaws especially influenced herbivory studies; we conclude that increase in herbivory in both heavily and moderately polluted habitats is not as frequent as it was earlier suggested. In contrast, the decrease in abundance of predators is likely to be a widespread phenomenon. Thus, our analysis supports the hypothesis that pollution may favour herbivore populations by creating an enemy-free space. Consistent declines in abundance of soil arthropods in impact zones of different polluters suggest that this group can potentially be used in bioindication of pollution-induced changes in terrestrial ecosystems.ConclusionsMain effects of pollution on arthropod communities (decreased abundance of decomposers and predators and increased herbivory) may have negative consequences for structure and services of entire ecosystems. Responses of arthropods to pollution depend on both temperature and precipitation in such a way that ecosystem-wide adverse effects are likely to increase under predicted climate change.Recommendations and perspectivesOur analysis confirmed that local severe impacts of industrial enterprises on biota are well-suited to reveal the direction and magnitude of the biotic effects of aerial pollution, as well as to explore the sources of variation in responses of organisms and communities. Although we analysed the effects of point polluters, our conclusions can be applied to predict consequences of pollution impacts on regional and even global scales. We argue that possible interactions between pollution and climate should be accounted for in the analyses of global change impacts on biota.

Decline in Length of the Summer Season on the Kola Peninsula, Russia

By analysing records made in the northern taiga forests of the Lapland Reserve (Kola Peninsula, Russia) during 1930–1998, we unexpectedly discovered a decline in the length of the snow-free and ice-free periods by 15–20 days due to both delayed spring and advanced autumn/winter. Respective seasonal temperatures best explained the dates of all phenological phases: 1 °C shift in temperature was approximately equal to 2–5 day shift in phenology. However the phenological shiftsduring the observation period are much larger than could be expected from the slight (0.56 °C) drop in temperatures during August–September, suggesting that the biotic effects of a very slight cooling have been enhanced by one or more unknown factors. Although emissions of sulphur dioxide from the nickel-copper smelter at Monchegorsk may have contributed to the observed trend (via changes in regional radiative budget), we found no evidence of direct pollution impact on dates of birch autumnal coloration or birch leaf fall, which exhibited the largest (22 days) shift between 1930 and 1998. The detected phenological trends agree with an increase in winter (snow) precipitation in the study area by 44%; however, effects of precipitation on any of the investigated phenological phases were far from significant. Our results highlight the importance of phenological records for the assessment of past regional environmental changes, and demonstrates that the prediction of even the simplest biotic responses to the Global Changes requires a profound understanding of the interactive impact of abiotic factors on the ecosystem.

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.

Density and performance of Epirrita autumnata (Lepidoptera : Geometridae) along three air pollution gradients in northern Europe

1. Larval density, size of pheromone-trapped adult males, and survival and parasitism rates in the laboratory of field-collected larvae of Epirrita autumnata were investigated along three pollution gradients: the surroundings of smelters at Monchegorsk and Nikel in north-western Russia and a factory complex at Harjavalta, south-western Finland. 2. Along the gradients, the emissions are qualitatively similar, consisting mainly of Cu, Ni and SO 2 , but the amounts emitted vary. Cu and Ni concentrations in birch (Betula pubescens) leaves, a common diet of E. autumnata larvae, were monitored and used as general indices of pollution. 3. High Cu and/or Ni concentrations in birch foliage, and/or associated changes in other pollutants, were associated with detrimental effects on E. autumnata performance. They occurred when concentrations of foliage Cu and/or Ni exceeded 20-30 μg g -l . 4. In the Harjavalta and Monchegorsk gradients, crossing the above threshold values in heavy metal concentrations in the foliage, larval density and survival increased significantly with distance from the smelters. No pollution-related trends with distance were found either for male size or for larval parameters in that section of the Nikel gradient where foliage heavy metals were below this threshold value. 5. Parasitism rates were not associated with pollution, indicating that parasitoids were not differently sensitive to pollutants than their herbivorous host. 6. No indication was found of a positive effect of moderate pollution on E. autumnata and heavy pollution had detrimental effects. The results do not suggest that the species might become a severe pest in polluted areas outside its natural outbreak range.

Identification of a novel moth sex pheromone inEriocrania cicatricella (Zett.) (Lepidoptera: Eriocraniidae) and its phylogenetic implications

Extracts from different body parts of adult femaleEriocrania cicatricella (Zett.) were tested for electrophysiological activity on conspecific male antennae. Extracts from the Vth abdominal segment, containing a pair of exocrine glands, elicited the largest electroantennographic response when compared to extracts of other body parts. Female extracts were analyzed by gas chromatography with simultaneous flame ionization and electroantennographic detection (EAD). The EAD active peaks were identified as (Z)-4-hepten-2-one, (2R)-heptane-2-ol, and (2R)-(Z)-4-hepten-2-ol by coinjection on a gas chromatography and by comparison of mass spectra with those of synthetic standards. In field tests, a blend of these three pheromone components was highly attractive to conspecific males, and a subtractive assay confirmed that the unsaturated alcohol is the major pheromone component, whereas no definite behavioral activity could be assigned to the ketone or the saturated alcohol. A bait containing the two alcohols withS-configuration was attractive to maleE. sparrmannella (Bosc), whereas no males ofE. cicatricella were found in these traps. The sex pheromone compounds inE. cicatricella are chemically similar to pheromones reported in Trichoptera and they are produced in homologous glands.