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31.
In recent years, several species of alien scale insects have arrived and spread rapidly through European and Mediterranean countries. One hundred and twenty‐nine species of alien scale insects have so far been recorded in Europe. This paper presents a list of alien scale insect species for Croatia, comprising 56 species from 8 different families. Four of them are new records for Croatia: Aonidiella taxus Leonardi, 1906, Ichnaspis longirostris (Signoret, 1882), Phoenicococcus marlatii (Cockerell, 1899) and Spilococcus mammillariae (Bouche, 1844). The majority of species recorded belong to the following families: Diaspididae (28 species), Coccidae (12 species), Pseudococcidae (10 species), Eriococcidae (two species). The scale insect families Dactylopidae, Margarodidae, Ortheziidae and Pheniococcidae comprised only one recorded alien species each. During the time frame covered in the review (from the beginning of the 20th century until 2015), the majority of alien scale insect species (23) were registered in the period from 2000 to 2015. Data on the origin of introduced alien scale insects shows that the majority of the species originate from Asia (22 species), followed by North America (6 species), Africa, Australia and Central America (5 species each) and South America (4 species), with 9 species being of unknown origin.  相似文献   
32.
Dendrobaena mrazeki is an endemic earthworm species inhabiting dry habitats such as pine and thermophilous oak forests in Central Europe. Metabolically, D. mrazeki showed some features typical for endogeic species and some of epigeic ones. In comparison with the related Dendrobaena octaedra, D. mrazeki was a larger earthworm with fresh body mass of adult and subadult individuals of W = 0.59 ± 0.05 g. Its body mass-specific oxygen consumption (M/W = 48 ± 5 μl O2 g?1 h?1, at 15 °C) was the lowest of all earthworms studied (Aporrectodea caliginosa, Aporrectodea rosea, D. octaedra, Lumbricus castaneus, Lumbricus rubellus and Octolasion lacteum), being strongly dependent on W (b from the equation M/W = aWb about ?0.8). D. mrazeki had low relative water content (77.4% of fresh body mass) and small relative amount of dry weight of the intestinal content (20.1% of dry body mass), which is similar to the epigeic D. octaedra. The respiration rate of D. mrazeki remained the lowest even after recalculating M/W to respiration rate per dry mass or per dry mass without the intestine content to correct for the differences among species in body water content and gut content.  相似文献   
33.
The impact of storm water runoff on a small urban stream   总被引:2,自引:0,他引:2  
Background, aim, and scope  In urban areas, storm water runoff often transports various pollutants, some of which settle and form sediments. In order to have the comprehensive view of the ecological state of storm water runoff recipients, both water and sediments of the stream must be assessed. In the Baltic Sea Area, the Water Framework Directive & HELCOM Recommendations aim to prevent or minimise pollution caused by harmful substances arising from storm water runoff, in order to promote the ecological restoration of the Baltic Sea—one of the most vulnerable seas. The aim of the study was to investigate the toxicity of bottom sediments of a small storm water runoff recipient focusing on the potential impact of successive discharges of urban storm water. Some storm water runoff quality parameters and the toxicity of bottom sediments of recipients was studied in this research. Materials and methods  During 9 years, at four discharge points, minimum four grab samples per year at each discharge point were taken for chemical characterisation. General parameters (pH, SS, BOD7, CODCr and TPH) in liquid phase samples were analysed according to standard methods. Annual limit values were taken from the Lithuanian EPA requirements for the management of storm water runoff with a focus on prevention and control of contamination. Eleven composite samples of stream bottom sediments, each consisting of ten sub-samples, were collected in 2006. Toxicity screening from sediments was performed using the plant Lepidium sativum according to modified I. Magone’s methodology (Magone I, Bioindication of phytotoxicity of transport emission. In: Kachalova O-L, Zinatne (eds) Bioindication of toxicity of transport emissions in the impact of highway emissions on natural environment. Riga, pp 108–116, 1989). The level of toxic impact of Lepidium sativum (compared to control) was assessed according to the modified method of Wang (Rev Environ Contam Toxicol 126:88–127, 1992). Results  The mean pH of urban storm water runoff does not vary much from neutral, but range values are quite different, from 4.0 up to 8.7. The highest concentration of SS reached 800 mg L−1, TPH—2.4 mg L−1, BOD7—300 mg O2 L−1 and CODCr—1,400 mg L−1. The SS was above the limit in 64% of total amount of grab samples, TPH—37%, BOD7—41% and CODCr—55%. The toxicity analysis of the bottom sediments showed varying toxicity of bottom sediments along the stream. From nine analysed samples of bottom sediments, 30% had weak toxicity, 30% medium and 30% strong toxicity on the test organism plant L. sativum. There was one single sample with no toxic effects, so that the results showed that urban storm water has an unacceptable environmental impact on recipients. It was also indicated that storm water runoff discharge alone is not the potential source of toxicity of bottom sediments. The litter demonstrated a weak toxicity of bottom sediments as well. Discussion  Most local authorities do not consider storm water runoff discharges to be a matter of great concern because they believe that surface runoff arising from rainfall is still relatively clean. The study showed that the current method of monitoring storm water runoff quality by chemical analyses is not the best tool for environmental impact assessment and must be combined with toxicity tests of bottom sediments of recipients. Recommendations and perspectives  To avoid the environmental impact of storm water runoff more attention should be paid to the development and implementation of storm water runoff pollution prevention measures. The study implies that future research concerning the relationships between storm water runoff deposit characteristics and biological activities must be developed to evaluate the contamination potential of stream sediment deposits for local aquatic ecosystems. Further studies should be developed to characterise the activities of the microbial community of storm water runoff sediments, and to monitor bioremediation in situ.  相似文献   
34.
Fruit pigmentation in ripening cv. Gala, Schniga’ apples was monitored under the influence of fertigation weekly during 21 July–31 August 2009, i.e. 34 days before and 7 days after the optimal harvest date in Slovenia. The soil was a heavy loam clay with high humus content (2.8 %) and high acidity (low pH 4.9). The spectral indices NDVI (Normalized Difference Vegetation Index) and NAI (Normalized Anthocyanin Index) were obtained by a PA 1101 on attached fruit on the transition between the ground and blush colour of the fruit surface. NAI increased slowly from 0.25 to 0.6 two weeks prior to optimum maturity. NDVI values fell from 0.9 to 0.2 before and during ripening, with significant changes starting ca. 3 weeks before and during the week after the optimum harvest date. Fertigation delayed fruit ripening viz harvest date by ca. 4 days. Fertigation delayed changes in the intensity of the fruit’s epidermal pigments, expressed as NDVI for 1 week and NAI for 4 weeks, respectively, but had no significant effect on fruit colour or NDVI and NAI values at the optimal harvest date. At this time, those fruits from the fertigated trees were firmer with a lower starch index compared with the un-fertigated control. Statistically, highly significant correlations were found (p?≤?0.01) (r?=?0.35 to r?=?0.91, R2?=?0.11–0.83) between all the studied spectral and standard parameters i.e. fruit fresh firmness, soluble solids content and starch index.  相似文献   
35.
We conducted a study to determine why the pH of wood ant nest materials is typically higher than that of the surrounding forest soil. An experiment with litter bags demonstrated that the pH of litter increased significantly (after only 7 months) in ant nests. Because the food that foraging ants bring into the nest contains easily decomposed carbohydrates and basic cations (largely in the form of honeydew and prey) that can cause increases in pH, we then estimated the amount of this influ of basic cations and easily decomposed carbohydrates. Based on these estimates, we conducted a second experiment to determine whether addition of field-determined quantities of an easily decomposed carbohydrate (glucose) or a basic cation (Ca2+) would increase the pH of the litter in artificial ant nests in the forest. Both glucose and Ca2+ additions significantly increased the pH of the litter but the increase was greater with Ca2+. The rate of pH increase in the artificial nests was similar to the rate of increase in natural nests. According to our study, ants collect substantial amounts of mineral-enriched materials in this ecosystem, which collectively increase the pH of nest material.  相似文献   
36.
 The response of the microbial community to changes in aeration status, from oxic to anoxic and from anoxic to oxic, was determined in arable soil incubated in a continuous flow incubation apparatus. Soil incubated in permanently oxic (air) and/or anoxic (O2-free N2) conditions was used as the control. Before experiments soil was preincubated for 6 days, then aeration status was changed and glucose added. Glucose concentration, extractable C, CO2 production, microbial biomass, pH and redox potential were determined 0, 4, 8, 12, 16, 24, 36 and 48 h after change of aeration status. If oxic conditions were changed to anoxic, the amount of glucose consumed was reduced by about 60%, and CO2 production was 10 times lower at the end of incubation compared to the control (permanently oxic conditions). Microbial biomass increased by 114% in glucose-amended soil but did not change in unamended soil. C immobilization prevailed over C mineralization. Redox potential decreased from +627 mV to –306 mV. If anoxic conditions were changed to oxic, consumption of glucose and CO2 evolution significantly increased, compared to permanently anoxic conditions. Microbial biomass did not change in glucose-amended soil, but decreased by 78% in unamended soil. C mineralization was accelerated. Redox potential increased from +238 to +541 mV. The rate of glucose consumption was low in anoxic conditions if soil was incubated in pure N2 but increased significantly when incubation was carried out in a CO2/N2 mixture. Received: 6 January 1999  相似文献   
37.
The aim of this study was to elucidate the introduction history of P. mugo in the unique landscape of the Lithuanian seaside spit of Kursiu Nerija by assessing its genetic structure and the genetic diversity. The individuals were sampled in 12 populations within an area of 3 km × 50 km along the Lithuanian part of Kursiu Nerija. P. mugo was introduced over 200 years ago to prevent sand erosion by establishing a forest cover. Chloroplast DNA polymorphism of 220 individuals of P. mugo together with 18 P. sylvestris and 11 putative P. sylvestris × P. mugo hybrids was assessed by the aid of five microsatellite markers. The standard intra-population diversity indexes were calculated. The intra-specific variation between distinct morphotypes as well as the population differentiation within the most spread P. mugo ssp. rotundata morphotype was assessed based on the haplotype frequencies by hierarchical AMOVA, GST/RST test, UPGMA clustering and PCA methods. The genetic diversity of P. mugo in Kursiu Nerija was high (He = 0.95; 83 different haplotypes). All except one of the P. mugo populations sampled contained a notable share of private haplotypes. AMOVA revealed high intra-specific diversity but low differentiation between the P. mugo populations. Most of the haplotypic variance was within populations. The UPGMA clustering produced groups more corresponding to the sub-species morphotypes than the geography of the populations. There was no geographical pattern of reduction in genetic diversity towards the younger plantations. A strong candidate for a species-specific DNA marker was found. After several events of introduction, the genetic diversity of P. mugo in Kursiu Nerija is very high and is structured based on the sub-species morphotypes rather than geography. The high frequency of shared and notable frequency of private haplotypes in most of the populations indicate that the major part of the P. mugo material originates from a number of geographically and genetically related sources, which more likely are introductions from abroad that the local collections. The high frequency of private haplotypes in the northernmost populations leaves a possibility for minor introductions from other genetically distinct sources. The absence of private haplotypes in one of the sampled populations indicates the use of local seed collections. The large number of shared haplotypes provides a strong evidence for a geneflow among the P. mugo taxa.  相似文献   
38.
39.
We performed a comparative study of strongly acidified mountain streams covering 10 sites in the Czech Republic in the season 1999/2000. The aim of the study was to determine how acidification influenced macroinvertebrate community structure within a relatively narrow pH range. We focused on strongly acidified, non-humic running waters with low ionic content (pH < 4.6, total organic carbon < 10 mg l?1, specific conductivity < 100 μS cm?1) and minimum human influence in the catchment. The actual pH values ranged from 3.98 to 4.65, and concentrations of reactive aluminium ranged from 0.2 to 2.0 mg l?1. Characteristic macroinvertebrates were the stoneflies Leuctra nigra, Nemurella pictetii, and Protonemura spp.; the chironomids Corynoneura spp.; and the caddisfly Plectrocnemia conspersa – the former two stoneflies formed together 46% of total organisms. The sites were divided into three groups with use of divisive classification. Individual groups reflected similarity in water chemistry, catchment characteristics, and geographical proximity. The largest biotic difference detected by PCA was in the abundance of stoneflies, mainly Diura bicaudata and Leuctra major. The strongest correlation with this gradient was shown by pH (and associated heavy metals), followed by the distance from source. The results show that even in such narrow pH range, the number of taxa is determined by the low pH value and related high concentrations of aluminium and heavy metals.  相似文献   
40.
Tree-specific management practice related to individual tree physiological condition is necessary for higher quality and quantity in apple fruit production. Detection of apple flowering abundance based on analysis of HSL (hue, saturation, luminance) images was used to estimate the number of flower clusters (FC) of individual trees in a high density apple orchard. The image acquisition was performed with a still camera and an industrial color camera during the day and night. The FC estimation algorithm included HSL thresholding with parameter optimization. Three hypothetical, tree-specific management practices (sprayings) were assumed, using >25, >50 and >100 FC thresholds to carry out the practice. When an industrial camera was used for image acquisition during the daytime and hypothetical spraying was done by on/off criterion >100 FC per tree, 10 % incorrect executions were identified. Comparable FC counting performance was achieved by using a still camera or an industrial camera.  相似文献   
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