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In the year 2012 a small autochthonic population of Leucorrhinia albifrons (BURMEISTER, 1839) was discovered in the area of the former underground mine of sulphur „Je- ziórko” (south-eastern Poland, 50°33’34”N, 21°48’00”E, UTM EB50). It inhabited one of the arti;cial water bodies created in the frames of reclamation of this area, situated in the depression, gathering +owing or dis- charging waters from the surrounding areas (Phot. 1). In May and June a few individuals of L. albifrons was observed, with juvenile specimens of both sexes in it. A site of L. albifrons was characterized by abundant swamp vegetation (Phragmites australis mainly) and moderately abundant +oating and submerged vegetation (Potamogeton natans, Ceratophyllum demersum, Utricularia vulgaris). Water was transparent, moderately alkaline (pH: 7.71), quite strongly mineralized (electrolytic conductivity: 2325 μS·cm-1, dissolved solids:1163 mg·dm-1, sa- linity: 1.2 PSU). Compact range of L. albifrons in Poland is limited to lakelands in the north of the coun- try. Farther towards the south there is a zone of the insular occurrence, on single sites or their groups. This zone reaches south-eastern Poland through which the range boundary is running – from Slovakia only one single sites is known, historical and doubtful one. The site in „Jeziórko” is situated near the southern range boundary of L. albifrons which is marked nowadays by three sites in the Przemyśl Foothills. Its discovery is a val- uable supplement to the knowledge about the distribution of the species on the edge of its range. This shows that this species can occur at more sites and in more regions than pre- viously thought. The new site con;rms also the previous data that the occurrence of the species in the marginal zone of the range is in large part connected with secondary habitats which can locally contribute to the increase in species distribution in comparison to his- torical period.
In the year 2011 Leucorrhinia pectoralis was recorded in the former borehole sulphur mine „Jeziórko” (E of Tarnobrzeg, south– eastern Poland). The species was observed in two drainage canals of mining subsidence (sites 1 and 3) as well as along the road running through the area of flood lands in mining subsidence (site 2). At sites 2 and 3 the species was very numerous (on May 28, more than 100 specimens per 100 m of observation transect), at site 3 numerous territorial males were observed. For the L. pectoralis the examined areas are typical secondary habitats to which this species is being adapted and in the suitable stages of succession it often forms large populations in Poland. New data is essential for the knowledge about the distribution of this species in Poland (Bernard et al. 2009). It fills the gap on the map of distribution situated between central Poland and the Lublin Region. It is also the first one from the central part of the Sandomierz Basin, the area with very little data in general so far. This situation results mainly from the lack of respectively targeted studies on odonatofauna of this macroregion.
Humans and animals come into contact with various compounds in their natural environment. Most of the encountered substances are neutral, yet some may carry adverse health effects. The ingested food may be a source of harmful substances, including benzoquinones which, as shown by research results cited in this paper, demonstrate toxic, carcinogenic and enterotoxic activity. This group of compounds is inclusive of 2-methyl-1,4-benzoquinone (MBQ) and 2-ethyl-1,4-benzoquinone (EBQ), defensive secretions of the confused flour beetle (Tribolium confusum J. du V) and the red flour beetle (Tribolium castaneum Herbst). Benzoquinones have a carcinogenic effect, they are inhibitors of growth of various microorganisms, they produce a self-defense mechanism in threat situations and affect population aggregation. As noted by the referenced authors, the properties of benzoquinones have not been fully researched to this date.
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