Results of two-year studies on the aphids number in different uncultivated habitats (field boundaries, roadsides, field shrubs and forest margins) are presented. The analysis of data permitted to distinguish two basic types of change in the aphids number in a vegetation season.
The objective of this study was to investigate magnesium concentrations and load, and to determine their seasonal changes in runoff water from catchments classified as nitrate vulnerable zones. The results indicate that the average concentrations of 12.2 mg Mg⋅dm-3, with fluctuations within the range of 3.3 to 26.2 mg⋅dm-3, and average annual load of 14.3 kg Mg⋅ha-1⋅year-1, with fluctuations within the range of 4.8 to 41.6 kg Mg⋅ha-1⋅year-1, in runoff water from agricultural areas are determined by weather conditions (season), type of drainage system (ditches, drains) and fertilization intensity. In comparison with land drained by a network of drainage ditches, intensive farming in drained areas increases magnesium loss 2.5-fold from 10 kg per hectare of semi-intensively farmed area to 25 kg Mg⋅ha-1 in an intensively farmed area. The highest magnesium loss was reported in the non-growing season, and around 46% of total magnesium load was leached out in the winter. The magnesium loss was minimized during harsh winters and summer draughts (to around 1.2 kg Mg⋅ha-1⋅year-1) due to a seasonal absence of runoffs.
The paper presents seasonal changes in the concentrations of ammonia, nitrate and phosphate ions in podzolic soils under the Vaccinio uliginosi–Betuletum pubescentis and Empetro nigri-Pinetum plant communities. It results from the conducted investigations that the distribution and accumulation of mineral forms of nitrogen and phosphorus are considerably affected by atmospheric conditions such as temperature, humidity and precipitation. Analysed soils were characterised by a strongly acid reaction, which decreases with the depth of the soil profiles. A statistically significant correlation was found between the content of biogenic substances in soil and litterfall. The highest concentration of biogenic substances was observed in spring and summer months. Among analysed ions the ammonia form predominated, which mean content remained within the range from 0.12 to 6.69 mg/100 g d.m. Concentration of nitrates ranged from 0.05 to 0.13 mg/100 g d.m., while that of phosphates – from 0.04 to 3.09 mg/100 g d.m. The predominance of the ammonia and phosphate forms over the nitrate form in the organic horizons may result from their retention by the sorption complex. Nitrate ions exhibit greater mobility and are leached deeper into the analysed soil profiles.
The objective of the study has been to determine magnesium concentrations and their seasonal changes in waters of re-naturised reservoirs situated in a rural area, 25 years after their re-creation. The study included 3 small, non-flow-through reservoirs, situated close to the village of Setal, in the commune of Dywity. Water samples for analysis were collected once a month in 2005 and 2006. They were examined in respect of the magnesium level and such physicochemical parameters as temperature, pH, oxygenation, dissolved oxygen, electrolyte conduction and water depth. The results prove that the environment of the surface waters in this area is poor in magnesium (5.2 mg⋅dm-3 - 6.6 mg⋅dm-3 on average), which is characteristic for postglacial regions. The re-created water reservoirs can be listed in water quality class I in terms of their magnesium content. The waters of these small re-created lakes were characterised by huge seasonal changes of magnesium concentrations. However, the fluctuations of Mg+2 concentrations were often larger within particular sites than between the examined reservoirs. The highest average seasonal magnesium concentration of 6.6 mg.dm-3, varying from 3.9 mg⋅dm-3 to 10.0 mg⋅dm-3, was determined in the waters of a reservoir whose whole catchment had for many years been used for agriculture. The lowest magnesium concentrations in the waters of the reservoirs occurred in springtime, with a slight increase in early summer and an equally slight decline afterwards. No significant increase in magnesium amounts was found until autumn, before they reached their peaks in wintertime. Such a course of fluctuations was caused by the maximum magnesium biosorption in spring and releasing internal reserves (green matter and bottom deposits) of the reservoirs in autumn and winter. Decrease and increase in the Mg+2 ion concentration in the waters of the reservoirs occurred in two ‘pulses’: in the springtime and wintertime, respectively.
Post-mortem examination of 22 red deer (in January, May, August and October 1990-1991) yielded ca 18,000 parasites representing 15 species. For one species, Spiculopteragia dagestanica, red deer appeared to be new host. Prevalence and intensity of infection in relation to the season of the year was considered. All red deer examined harboured nematodes of the subfamily Ostertagiinae in the abomasum, the mean intensity amounted to 830 parasites per host, the highest intensity (1610) was observed in May, the lowest (262) in January. The level of infection was compared with parasitological data from other hunting grounds in Poland. High density of red deer stock in the area examined (100/1000 ha) seems to have little bearing on the level of infection of red deer with helminth parasites.
Survival in an annual cycle of Escherichia coli, Streptococcus faecalis, Salmonella typhimurium and Salmonella typhi dublin were examined in non-sterilized lake water, water sterilized by heating in an autoclave (121°C/10 min.), incubated without light at 4 and 20°C, respectively. All examined bacterial strains generally survived for shorter periods in non-sterilized lake water than in sterilized lake water, and shorter at 20°C than at 4°C. Survival curves of these bacteria in non-sterilized lake water were similar to a logarythmic curve, whereas in sterilized lake water they resembled a sigmoidal curve regardless of incubation temperature. The time necessary for 90% reduction of these bacteria ranged from 1 to 32 days. It was generally shorter in non-sterilized lake water and longer for sterilized water; and it was shorter for Streptococcus faecalis and longer for Escherichia coli, Salmonella typhimurium and Salmonella typhi dublin. All four examined bacteria were more quickly reduced in summer, and slower in spring, autumn and winter.
Zooseston of the Vistula River section almost 340 km long was investigated in the years 1997/98. In 99 samples collected 90 species of rotifers, 16 cladocerans, 9 copepods and other animals belonging to: Harpacticoidea, Oligochaeta, Nematoda, Chironomidae, Odonata, Simulidae, Tardigrada and Coelenterata were found. Multiple regression analysis showed that the number of rotifers is significantly correlated with basic chemical indicators of water trophic state - phosphate, nitrate and nitrite as well as with the number of copepods which are usually predators. The numbers of copepods depends on the availability of possible prey, i.e. rotifers and cladocerans. Multiple regression confirmed known dependence of cladocerans from trophic conditions. Clustering of similarity matrices showed complex structure of sestonic assemblages on rhitral-potamal gradient additionally modified by hydrotechnical constructions. These constructions broke old river continuum. Ordination of sites gave complex pattern not only representing a simple gradient rithral - potamal but also all transient stages caused by hydrotechnical construction (large dam reservoir) or by inflows of polluted waters from the tributaries. Ecological meaning of principal component ordination (PC) for river zooseston assemblages is not simple and might be susceptible of various interpretations.
There was previously no information on nesting, seasonal body mass or the hibernation behaviour of the hedgehog in Ireland. Between 2008 and 2009, hedgehogs were caught, weighed weekly and monitored by radio tracking at a rural Irish site. Day nests were recorded in the active period and hibernacula thereafter. Arable land has been reported to be poorly utilised by hedgehogs in the UK and Denmark. In Ireland, day nests and hibernacula were constructed in the hedgerows of arable land indicating that these areas will be exploited if hedgerow is maintained and highlights the importance of maintaining hedgerows in arable areas. Individual females returned to the same day nest significantly more than males. Over the 2 years, individuals were found to occupy a mean of 1.8 (±0.9; SD) hibernacula (maximum of 3) and they rotated between nests up to four times (mean of 2.5 ± 1.6). When hedgehogs occupied multiple hibernacula, those occupied in mid winter (December and January) were occupied for significantly longer than those occupied at the start (October and November) and end (February and March) of hibernation. Studies in the UK and Denmark have reported on hedgehog hibernation. However, the winter climate in southern Ireland is milder than other areas of Europe and thus it was expected that hibernation characteristics would also differ, i.e. shorter hibernation periods, earlier emergence, lower body mass loss and the ability to survive hibernation at a lower body mass. This proved to be the case with a mean hibernation period (±SE) of 148.9 (±0.5) days, a mean body mass loss of 17.0 (±0.53) %, emergence in March and the ability of late juveniles to survive at a pre-hibernation body mass of 475 g.