Relatives reproduce in synchrony: kinship and individual condition shape intraspecific variation in masting phenotype.

Masting (synchronous and interannually variable seed production) is frequently called a reproductive strategy; yet it is unclear whether the reproductive behaviour of individuals has a heritable component. To address this, we used 22 years of annual fruit production data from 110 Sorbus aucuparia L. trees to examine the contributions of genetic factors to the reproductive phenotype of individuals, while controlling for environmental variation. Trees sharing close genetic relationships and experiencing similar habitat conditions exhibited similar levels of reproductive synchrony. Trees of comparable sizes displayed similar levels of year-to-year variation in fruiting, with relatedness contributing to this variation. External factors, such as shading, influenced the time intervals between years with abundant fruit production. The effects of genetic relatedness on the synchrony of reproduction among trees and on interannual variation provide long-awaited evidence that the masting phenotype is heritable, and can respond to natural selection.

Long-term moss monitoring of atmospheric deposition near a large steelworks reveals the growing importance of local non-industrial sources of pollution.

Although air quality in Europe is continually improving, there are regions, especially in central and eastern European countries, where this trend has been unnoticeable and even reversed in recent years. To understand the possible reasons for the persistence of these pollution "hotspots", we investigated the case of the Kraków region (S Poland) known for its heavy pollution caused by a large steelworks. In 1975, at the apogee of industrial emissions, atmospheric deposition of trace metals was evaluated in this area using moss Pleurozium schreberi as a biomonitor. The survey was repeated in 1992, 1998 and 2014. The collected data showed that air quality improved significantly over 40 years: the amount of Cd, Pb, Fe, Cu and Zn accumulated by mosses decreased by a factor of 10, 9, 3.5, 2 and 2, respectively. The downward trend continued for most metals throughout the study period, although the biggest changes occurred at the very beginning (1975-1992). This improvement was mostly due to drops in industrial production and the introduction of environmentally friendly technologies. At the end of the study (1998-2014), clear increases in the concentrations of some trace metals in moss were observed (overall or at some locations). Spatiotemporal variability of moss elemental composition suggests that this is the result of the recent emergence of new (non-industrial) sources of metal pollution, associated with the urban sprawl and intensification of agriculture. Since this process is unlikely to stop in the near future, air quality will deteriorate rather than improve.

Albanian violets of the section Melanium, their morphological variability, genetic similarity and their adaptations to serpentine or chalk soils.

Violets of the section Melanium from Albanian serpentine and chalk soils were examined for their taxonomic affiliations, their ability to accumulate heavy metals and their colonization by arbuscular mycorrhizal fungi (AMF). The sequence analysis of the ITS1-5.8S rDNA-ITS2 region showed that all the sampled six Albanian violets grouped between Viola lutea and Viola arvensis, but not with Viola tricolor. The fine resolution of the ITS sequences was not sufficient for a further delimitation of the Albanian violets within the V. lutea-V. arvensis clade. Therefore, the Albanian violets were classified by a set of morphological characters. Viola albanica, Viola dukadjinica and Viola raunsiensis from serpentine soils as well as Viola aetolica from a chalk meadow were unambiguously identified, whereas the samples of Viola macedonica showed high morphological variability. All the violets, in both roots and shoots contained less than or similar levels of heavy metals as their harboring soils, indicating that they were heavy metal excluders. All the violets were strongly colonized by AMF with the remarkable exception of V. albanica. This violet lived as a scree creeper in shallow serpentine soil where the concentration of heavy metals was high but those of P, K and N were scarce.

Soil fertility and plant diversity enhance microbial performance in metal-polluted soils.

This study examined the effects of soil physicochemical properties (including heavy metal pollution) and vegetation parameters on soil basal respiration, microbial biomass, and the activity and functional richness of culturable soil bacteria and fungi. In a zinc and lead mining area (S Poland), 49 sites were selected to represent all common plant communities and comprise the area's diverse soil types. Numerous variables describing habitat properties were reduced by PCA to 7 independent factors, mainly representing subsoil type (metal-rich mining waste vs. sand), soil fertility (exchangeable Ca, Mg and K, total C and N, organic C), plant species richness, phosphorus content, water-soluble heavy metals (Zn, Cd and Pb), clay content and plant functional diversity (based on graminoids, legumes and non-leguminous forbs). Multiple regression analysis including these factors explained much of the variation in most microbial parameters; in the case of microbial respiration and biomass, it was 86% and 71%, respectively. The activity of soil microbes was positively affected mainly by soil fertility and, apparently, by the presence of mining waste in the subsoil. The mining waste contained vast amounts of trace metals (total Zn, Cd and Pb), but it promoted microbial performance due to its inherently high content of macronutrients (total Ca, Mg, K and C). Plant species richness had a relatively strong positive effect on all microbial parameters, except for the fungal component. In contrast, plant functional diversity was practically negligible in its effect on microbes. Other explanatory variables had only a minor positive effect (clay content) or no significant influence (phosphorus content) on microbial communities. The main conclusion from this study is that high nutrient availability and plant species richness positively affected the soil microbes and that this apparently counteracted the toxic effects of metal contamination.

Direct and indirect effects of metal contamination on soil biota in a Zn-Pb post-mining and smelting area (S Poland).

Effects of metal contamination on soil biota activity were investigated at 43 sites in 5 different habitats (defined by substratum and vegetation type) in a post-mining area. Sites were characterised in terms of soil pH and texture, nutrient status, total and exchangeable metal concentrations, as well as plant species richness and cover, abundances of enchytraeids, nematodes and tardigrades, and microbial respiration and biomass. The concentrations of total trace metals were highest in soils developed on mining waste (metal-rich dolomite), but these habitats were more attractive than sandy sites for plants and soil biota because of their higher content of organic matter, clay and nutrients. Soil mesofauna and microbes were strongly dependent on natural habitat properties. Pollution (exchangeable Zn and Cd) negatively affected only enchytraeid density; due to a positive relationship between enchytraeids and microbes it indirectly reduced microbial activity.

Pine forest and grassland differently influence the response of soil microbial communities to metal contamination.

Metal pollution can affect soil microbial communities, and vegetation potentially influences this relationship. It can, for example, modify the toxicity of metal to soil microbes by controlling its input to the ground or by altering soil physicochemical properties. This study examined metal effects on soil respiration, potentially active microbial biomass (SIR) and catabolic abilities of culturable heterotrophic bacterial communities (Biolog GN) in pine forest and grassland ecosystems developed on soils contaminated with Zn, Pb and Cd. In samples from non-forested areas we found that metal pollution reduced the microbial biomass and functional diversity of bacteria, while increasing the metabolic quotient. In samples from pine forests we found no relationship between metal pollution and microbial parameters. Metals induced changes in soil respiration neither in forest nor in grassland sites. Generally, microbial performance was determined predominantly by soil physicochemical properties (nutrient content, acidity, contamination level). Vegetation type seemed a minor but important factor influencing microbial communities. More work is needed to determine why even relatively high metal concentrations do not significantly affect microbial communities in forest soils.

Spatio-temporal variation of element accumulation by Moehringia trinervia in a polluted forest ecosystem (South Poland).

The aim of this study was to identify factors affecting accumulation of elements by Moehringia trinervia (L.) Clairv. in a forest ecosystem impacted by long-term inflow of air pollution. The concentrations of N, S, Ca, K, Mg, Cd, Cu, Fe, Pb and Zn were determined in plants collected in 1999. In addition, Cd, Cu, Pb and Zn content was compared with measurements from 1984. Soil properties and bulk precipitation chemistry were used as explaining variables. The amount of heavy metals accumulated by M. trinervia depended on the magnitude of industrial emissions, but only Cu and Pb concentrations were clearly related to the distance from the pollution sources. The spatial distribution of Fe content was shaped by habitat conditions, whereas the distributions of Cd and Zn content were unexplained. Among the macronutrients, only Mg uptake was affected by environmental properties: it was lower under high concentrations of soil Cd and Zn.