Urbanization decreases species richness, and increases abundance in dry climates whereas decreases in wet climates: A global meta-analysis.

Soil invertebrates have an essential role in decomposition, nutrient turnover and soil structure formation, all of which are strongly threatened by urbanization. Sealing, compaction by trampling and pollution destroy and degrade city soils and potentially damage soil-living invertebrates. The existing literature on how urbanization affects soil invertebrates is inconsistent, presenting both negative and positive effects. Therefore, here we aimed to synthesize the effects of urbanization on soil invertebrates considering their taxonomic (Acari, Annelida, Carabidae, Collembola, Gastropoda, Isopoda, Myriapoda, Nematoda) and functional (soil living vs. soil-related; mobility) identities, as well as to examine how the overall effect is modulated by climatic conditions (total annual precipitation, annual mean ambient temperature), urban heat island effect (based on ambient temperature differences between urban and rural areas) and city population. In a systematic review using hierarchical and categorical meta-analyses, we extracted 158 effect sizes from 75 studies on abundance and 125 effect sizes from 84 studies on species richness. Invertebrate abundance showed an increase (r = 0.085), whereas species richness significantly decreased with increasing urbanization (r = -0.168). The reason behind this could be that a few generalist species can adapt well to the urban environment and achieve strongly elevated densities. The species richness of annelids (r = -0.301), springtails (r = -0.579), and snails (r = -0.233) decreased with advancing urbanization, most probably because these animals are sensitive to soil compaction and pollution, both of which are common consequences of urbanization. The temperature did not modify the effects of urbanization, but precipitation modified the effects on abundance (r = -0.457). Abundance increased with advancing urbanization in drier climates, probably because irrigation increased soil moisture, whereas it decreased in wet climates, as urban areas were drier than their surroundings. Making future cities more climate-neutral could better sustain soil biodiversity.

Contrasting mtDNA and microsatellite data of great reed warbler Acrocephalus arundinaceus breeding populations on a small geographic scale.

The great reed warbler has two genetically distinguishable haplogroups: "Clade A" occurs in higher proportions in Western Europe and Kazakhstan, and colonised Europe and Asia from a refugium in South-West Europe; and "Clade B", which is more common in Eastern Europe, and colonised parts of Europe from a refugium in the Middle East. Our aims were (i) to analyse the rate of differentiation in Hungarian breeding populations in order to see whether European-scale pattern is visible or not on as a small scale as the territory of Hungary and (ii) to compare the results obtained with mtDNA sequencing and microsatellite markers. To analyse the genetic differentiation, the mtDNA control region II was sequenced in 68 adult breeding birds, and 51 were fingerprinted at 11 microsatellite loci, while both analyses were performed on 36 birds (a total of 83 birds). The microsatellite data gave a better resolution and represented the fine-scale pattern of the suspected recolonisation. The lack of genetic differentiation among the breeding populations based on mitochondrial data seems to support this finding, because the admixture of the clades in this particular geographic region obliterates differentiation. Accordingly, the Fst values from different branches are significantly based on microsatellite data only. The mtDNA methods only give reliable results when a geographic and ecological factor plays a role in the population subdivision, but in the case of an intermixing population larger-scale studies are needed.

Pollution impacts on water bugs (Nepomorpha, Gerromorpha): state of the art and their biomonitoring potential.

As water pollution poses an increasing risk worldwide, it is timely to assess the achievements of the aquatic macroinvertebrate ecotoxicology to provide a sound basis for the discipline's future and support the development of biomonitoring. Aquatic and semi-aquatic bugs (Hemiptera: Nepomorpha, Gerromorpha) are ubiquitous in almost all water types, sometimes in high densities, and play a significant role in organic material turnover and energy flow. Nevertheless, they are ignored in the water pollution biomonitoring schemes. Here, based on 300 papers, we review and evaluate the effects of chemical pesticides, microorganism-derived pesticides, insecticides of plant origin, heavy metals, eutrophication, salinisation and light pollution which are summarised for the first time. Our review encompasses the results of 100 laboratory and 39 semi-field/field experiments with 47 pesticides and 70 active ingredients. Pyrethroids were found to be more toxic than organochlorine, organophosphate and neonicotinoid insecticides to water bugs, like other macroinvertebrate groups. Additionally, in 10 out of 17 cases, the recommended field concentration of the pesticide was higher than the LC50 values, indicating potential hazards to water bugs. The recommended field concentrations of pesticides used in mosquito larvae control were found non-toxic to water bugs. As very few replicated studies are available, other findings on the effects of pesticides cannot be generalised. The microorganism-derived pesticide Bti appears to be safe when used at the recommended field concentration. Data indicates that plant-derived pesticides are safe with a high degree of certainty. We have identified three research areas where water bugs could be better involved in water biomonitoring. First, some Halobates spp. are excellent, and Gerris spp. are promising sentinels for Cd contamination. Second, Micronecta and, to a certain extent, Corixidae species composition is connected to and the indicator of eutrophication. Third, the species composition of the Corixidae is related to salinisation, and a preliminary method to quantify the relationship is already available. Our review highlights the potential of water bugs in water pollution monitoring.

The inter-individual variance can provide additional information for the ecotoxicologists beside the mean.

The hypothesis that the inter-individual parameter variability is an unexploited area of ecotoxicology was proposed several decades ago. Although some illustrative examples were presented to support this hypothesis in the last decades, it has never been tested on an extensive, coherent database. In this study, variance changes of 105 dose-response curves were analysed. All data originated from the same experiment, where the effects of the insecticide Trebon EC were investigated in a dose-response manner on 15 traits of the collembolan Folsomia candida in four subsequent generations and two types of insecticide treatments. A consistent relationship between inter-individual variance and insecticide application was found in 2 (first clutch size and growth-reproduction trade-off) out of the 15 of the parameters. Contrary to the mean, the variance of the first clutch size showed consistent differences compared to the control. Furthermore, the variance of the growth-reproduction trade-off was consistently different from the control except in one case (F3 generation of the transgenerational treatment). Higher first clutch size variances were found in F1 and a lower one in the F2 and F3 generations than in that of the control. This overall pattern of the variance changes of the first clutch size and the trade-off seems to be a quick response to the insecticide application. In the short term, we have found that variance increased with insecticide treatment (P and F1 generation), because phenotypic variance generally increases due to environmental stress. Disruptive selection could be another mechanism between the more detoxification less reproduction strategy and the more reproduction less detoxification strategy. However, in the later generations (F2-F3) the variance decreases compared to the control, which could be because on short term selection stronger on the viability parameters and in long-term selection on reproduction becomes stronger. According to our results, analysis of the variance changes of some parameters may give information about the effects of the pesticide even when the mean does not predict any impact. Testing variance changes are important in ecotoxicology because variance change can signalise toxicant impact even when the mean does not change in certain cases.

Transgenerational and multigenerational stress gene responses to the insecticide etofenprox in Folsomia candida (Collembola).

Insecticide exposure may cause both transgenerational and multigenerational effects on populations, but the molecular mechanisms of these changes remain largely unclear. Many studies have focused on either transgenerational or multigenerational mechanisms but did neglect the comparative aspects. This study assessed whether the pyrethroid insecticide etofenprox (formulation Trebon® 30 EC) shows transgenerational and/or multigenerational effects on the survival and reproduction of Folsomia candida (Collembola). The activation of stress-related genes was studied to detect whether etofenprox modifies the expression of reproduction-associated genes in trans- and multigenerational treatments. A laboratory study was carried out for three generations with five insecticide concentrations in LUFA 2.2 soil. In the transgenerational treatment, only the parent generation (P) was exposed, but the subsequent generations were not. In the multigenerational treatment, all three generations were exposed to the insecticide in the same manner. Multigenerational exposure resulted in reduced reproduction effects over generations, suggesting that F. candida is capable of acclimating to enhanced concentration levels of etofenprox during prolonged exposure over multiple generations. In the transgenerational treatment, the heat shock protein 70 was up-regulated and cytochrome oxidase 6N4v1 expression down-regulated in a dose-dependent manner in the F2 generation. This finding raises the possibility of the epigenetic inheritance of insecticide impacts on parents. Furthermore, CYP6N4v1 expression was oppositely regulated in the trans- and multigenerational treatments. Our results draw attention to the differences in molecular level responses of F. candida to trans- and multigenerational etofenprox exposure.

Revised and annotated checklist of aquatic and semi-aquatic Heteroptera of Hungary with comments on biodiversity patterns.

A basic knowledge of regional faunas is necessary to follow the changes in macroinvertebrate communities caused by environmental influences and climatic trends in the future. We collected all the available data on water bugs in Hungary using an inventory method, a UTM grid based database was built, and Jackknife richness estimates and species accumulation curves were calculated. Fauna compositions were compared among Central-European states. As a result, an updated and annotated checklist for Hungary is provided, containing 58 species in 21 genera and 12 families. A total 66.8% of the total UTM 10 × 10 km squares in Hungary possess faunistic data for water bugs. The species number in grid cells numbered from 0 to 42, and their diversity patterns showed heterogeneity. The estimated species number of 58 is equal to the actual number of species known from the country. The asymptotic shape of the accumulative species curve predicts that additional sampling efforts will not increase the number of species currently known from Hungary. These results suggest that the number of species in the country was estimated correctly and that the species accumulation curve levels off at an asymptotic value. Thus a considerable increase in species richness is not expected in the future. Even with the species composition changing the chance of species turn-over does exist. Overall, 36.7% of the European water bug species were found in Hungary. The differences in faunal composition between Hungary and its surrounding countries were caused by the rare or unique species, whereas 33 species are common in the faunas of the eight countries. Species richness does show a correlation with latitude, and similar species compositions were observed in the countries along the same latitude. The species list and the UTM-based database are now up-to-date for Hungary, and it will provide a basis for future studies of distributional and biodiversity patterns, biogeography, relative abundance and frequency of occurrences important in community ecology, or the determination of conservation status.

New method for automatic body length measurement of the collembolan, Folsomia candida Willem 1902 (Insecta: Collembola).

The collembolan, Folsomia candida, is widely used in soil ecotoxicology. In recent years, growth rate of collembolans has become as frequently used endpoint as reproduction rate in ecotoxicological studies. However, measuring collembolan body sizes to estimate growth rate is a complicated and time-consuming task. Here we present a new image analysis method, which facilitates and accelerates the body length measurement of the collembolan Folsomia candida. The new software package, called CollScope, consists of three elements: 1) an imaging device; 2) photographing software; 3) an ImageJ macro for image processing, measurement and data analysis. We give a complete description of the operation of the software, the image analyzing process and describe its accuracy and reliability. The software with a detailed usage manual is attached as Supplementary Material. We report a case study to demonstrate that the automated measurement of collembolan body sizes is highly correlated with the traditional manual measurements (estimated measuring accuracy 0.05 mm). Furthermore, we performed a dose-response ecotoxicity test using cadmium-sulfate by using CollScope as well as classical methods for size measurement. Size data measured by CollScope or manually did not differ significantly. Furthermore the new software package decreased time consumption of the measurements to 42% when tested on 35 animals. Consequently, methodological investigations performed in this study should be regarded as a recommendation for any other routine dose-response study where body growth is an endpoint.

Effects of Consumption of Bt-maize (MON 810) on the Collembolan Folsomia candida, Over Multiple Generations: A Laboratory Study.

The effect of long-term feeding on Bt-maize by collembolans in the laboratory is virtually unestablished. That is why the aim of the present study was to test whether the reproduction, fecal pellet production or food preference of the collembolan F. candida is affected when fed on Bt-maize for several consecutive generations. The collembolans were fed with Bt-maize for 0, 6, 16 and 22 months and the number of eggs and fecal pellets were determined. The experiment was repeated seven months later with the same populations. Food preference tests were additionally performed. Significant differences were found in food consumption, egg production and food preference between populations in some cases, but no time-response effect was observed. In conclusion, several generations feeding of F. candida on Cry1Ab toxin containing Bt-maize seems not to be harmful to this collembolan species.

Toxicity of selenate and selenite to the potworm Enchytraeus albidus (Annelida: Enchytraeidae): a laboratory test.

Little information is available about the toxicity of inorganic selenium forms in soil animals. Therefore, the effects of selenate and selenite on the mortality and reproduction of Enchytraeus albidus were examined in standard laboratory tests with chronic exposure. Total and available amount of selenate and selenite were tested in a calcareous loamy chernozem soil. The LC(50) of selenate was 5.69 (2.7-8.12) mg kg(-1) dry wt. for total Se and 4.74 (2.14-6.98) mg kg(-1) dry wt. for available Se. Selenite LC(50) was as high as 22.5 (19.6-25.7) mg kg(-1) dry wt. for total Se and 8.10 (6.8-9.6) mg kg(-1) dry wt. for available Se. The EC(50) of selenate was 0.41 (0.35-0.48) mg kg(-1) dry wt. for total Se and 0.28 (0.24-0.34) mg kg(-1) dry wt. for available Se. Selenite EC(50) was as high as 7.3 (6.2-8.5) mg kg(-1) dry wt. for total Se and 2.46 (2.05-2.91) mg kg(-1) dry wt. for available Se. The response in reproduction was more sensitive to Se toxicity than the response in mortality. Selenate proved to be more toxic than selenite. Available data show that E. albidus may function as a biological indicator for some inorganic selenium forms in the soil.

Water pollution by Cu and Pb can adversely affect mallard embryonic development.

The effects of heavy metal pollutants on aquatic birds have been widely studied in ecotoxicological investigations; however, the predominant focus has been on the postnatal period of life. Limited information on the adverse effects of metals to bird eggs is available. The possible toxic effects of lead and copper were studied in mallard eggs. After the accidental severe heavy metal pollution of the Tisa river (Hungary) in March 2000, these metals were detected in the highest concentration in both the water and the sediment, reaching far beyond acceptable concentrations. Pb treatment (2.9 mg/L) significantly increased the rate of mortality after a single immersion of the eggs into polluted water for 30 min. The rate of dead embryos significantly increased after the combined exposure to Cu and Pb (0.86 and 2.9 mg/L, respectively) both in the single- (once for 30 min) and in the multiple- (10s daily during first trimester of incubation) immersion groups. It was concluded that elevated metal concentrations similar to those found in the Tisa river after the tailing dam failure may cause toxic effects (mortality and teratogenicity) upon exposure of mallard eggs.

Effects of microelements on soil nematode assemblages seven years after contaminating an agricultural field.

Long-term effects of Cd, Cr, Cu, Se and Zn were studied 7 years after artificially contaminating plots of an agricultural field on a calcareous chernozem soil. Effects of three to four different contamination levels (originally 10, 30, 90 and 270 mg kg(-1)) were studied. Nematode density was significantly reduced by 90 and 270 mg kg(-1) Se as well as by 270 mg kg(-1) Cr, while 90 and 270 mg kg(-1) Se also reduced nematode generic richness. Maturity Index values (calculated for c-p 2-5 nematodes) consistently decreased with increasing Cr and Se concentration and to a lesser extent in Zn plots as well. Structure Index showed decreasing trends in increasing Cr, Se and (to a lesser extent) in Zn treatments, while in Cd it shows a moderate increase. Distribution of c-p groups was negatively affected by the increasing Cr and Se concentration, while in Zn plots, this decrease was not significant. Response of feeding groups to pollutions was similar to other parameters: Cr and Se caused significant changes toward the loss of variability. The proportion of the most sensitive omnivorous and predatory nematodes decreased clearly as a consequence of Cr and Se treatments. Zn pollution also resulted in a slight decrease in this group, while Cd caused an increase. Nematode diversity profiles showed a significant decrease in the plots of increased Cr and Se concentrations, while increased concentrations of Cu and Zn resulted in ambiguous effects. Besides providing evidence on the harmful effects of Cr and Se on a soil nematode assemblage, our results suggest that simultaneous analysis of Maturity Index, Structure Index and diversity profiles provide a promising tool in nematological indication of soil pollution.

Long-term effects of heavy metals and microelements on nematode assemblage.

Effects of Cd, Cr, Se and Zn at a maximum rate of 270 mg kg(-1) were studied on a nematode assemblage after 6-10 years of application. Winter wheat, sunflower, sorrel, barley and rape were grown on the experimental field. Cd had a moderate effect on nematodes in spite of the fact that this element significantly decreased plant biomass. Cr was harmful to plants only in the first year of the study. However, Cr decreased Aporcelaimellus density and maturity index, increased Pratylenchus density and bacterial-fungal ratio, changed the c-p structure and feeding type composition. Se proved to be very toxic at a concentration of 11 mg kg(-1) (NH(4)-acetate+EDTA soluble form). Some advantageous effects of Zn were found in the first year. These disappeared later on. Remarkable between-year fluctuations of the nematode assemblage composition were observed.