Changes in body mass and body reserves of Little Auks (Alle alle) were studied throughout the breeding season. Body mass loss after chick hatching was analyzed with respect to two hypotheses: (1) mass loss reflects the stress of reproduction, (2) mass loss is adaptive by reducing power consumption during flight. Body mass of both males and females increased during incubation, dropped abruptly after hatching, and remained stable until the end of the chick-rearing period. These changes were largely due to change in mass of fat reserves. Body mass, fat, and protein reserves, when corrected for body size, did not differ between sexes at the end of incubation. Female size-corrected body mass at that time was correlated with peak body mass of chicks. The estimated energy savings for flight due to the decline in adult body mass after chick hatching were small compared with the total energy expenditure of adults feedings chicks, which did not support hypothesis (2). The contribution to chick feeding was not equal; the ratio of females to males caught with food for chicks was 1.8. Size-corrected body mass during chick-rearing was lower in females, proportional to their higher chick feeding effort compared with males. Females, in contrast to males, lost protein reserves during chick-rearing. Digestive tract mass of adults increased by half throughout the breeding period. These findings supported elements of hypothesis (1). Despite high energy expenditure rates, both sexes had about 10 g of fat reserves at the end of chick feeding. Body mass of both sexes was constant during the greater part of the chick-feeding period. It was suggested therefore that mass loss is regulated with respect to lower fat reserves required during chick-rearing.
Scheuchzeria palustris is a species regarded as an arctic-boreal relic and critically en-dangered. The study was conducted on one of the recent stands in the Łódź region, in the Czarny Ług Reserve, located near Wolbórz. The primary aim of the study was to know the amount of this species and the associated species. Quantitative, morphological and floristic features were ana-lysed. In the study area occurred about 150 specimens per 1 m2. Among the associated species were found species representing classes: Scheuchzerio-Caricetea Nigrae and Oxycocco-Sphagnetea. Eriopho-prum angustifolium was dominant among the first class species (60% coverage), while Andromeda polifolia and Oxycoccus palustris from the second class. From here it can be assumed that the succession will be in the direction of Scheuchzerio-Caricetea Nigrae. However, high water levels may inhibit this process. Specific biotic and abiotic conditions allow for the survival of this spe-cies. This is visible, among other things, in the mosaic structure of the studied stand.
In a study on the click beetles (Coleoptera: Elateridae) of selected plant communities of the Lasy Janowskie Reserve, 21 species of these beetles were recorded – 10 each in riparian forests and a sub-Atlantic mesic coniferous forest, 11 in a continental mixed coniferous forest, and 6 in wet grassland communities. The numbers of species in the communities was similar to numbers recorded in other, comparable areas of Poland, with the exception of the wet grasslands. Forest species that can also occur outside of forests – Athous subfuscus and Dalopius marginatus – were dominant. The biodiversity of the click beetle fauna in the communities was at an average level. An ecological and zoogeographical analysis was carried out as well.
The paper presents the impact of the reformed EU ETS (Emission Trading Scheme – ETS in the European Union) on the currently operating market for trading in CO2 emission allowances. The new Directive introduced a number of changes aimed at tightening the climate policy, which the Polish energy sector based mainly on hard coal may mean an increase in the costs of electricity production, and thus an increase in the cost of the entire economy. The main goal of the changes is to achieve one of the objectives the European Union has set for itself, i.e. the reduction of CO2 emissions by 40% until the year 2030. These assumptions are the result of joint arrangements of the EU countries under the Paris Agreement on climate change adopted in 2015. The Directive introduces a new market stability reserve mechanism (MSR) which, according to its assumptions, is designed to ensure a demand and supply balance of the ETS. Bearing the balance in mind, it means the reduction of excess allowances, which, although their number is decreasing, it is decreasing to slowly according to EU legislators, still oscillating around 2 billion EUA. The paper also draws attention to the rigorous assumptions adopted in the new Directive, aimed at increasing the price of CO2, that is the costs in electricity production. Due to manually-controlled prices, are we doomed to high CO2 prices and therefore the prices of electricity? What are its estimated maximum levels? Will the new assumptions encourage the Member States to switch to lowcarbon technologies? Can they weaken the economies of countries that are currently based mainly on coal energy sources, and strengthen countries where green energy is developed?
Genetic diversity is often considered a major determinant of long term population persistence and its potential to adapt to variable environmental conditions. The ability of populations to maintain their genetic diversity across generations seems to be a major prerequisite for their sustainability, which is particularly important for keystone forest tree species. However, little is known about genetic consequences of demographic alterations occurring during natural processes of ecological succession involving changes in the species composition. Using microsatellites, we investigated genetic diversity of adult and offspring generations in beech (Fagus sylvatica L.) and oak (Quercus robur L.) populations coexisting in a naturally established old-growth forest stand, showing some symptoms of ongoing ecological succession from oak- to beech- dominated forest. In general, adult generations of both species exhibited high levels of genetic diversity (0.657 for beech; 0.821 for oak), which, however, depended on the sets of selected genetic markers. Nevertheless, several symptoms such as differences in genetic diversity indices between generations, significant levels of inbreeding (up to 0.029) and low estimates of effective population size (48-80) confirmed the declining status of the oak population. On the other hand, the uniform distribution of genetic diversity indices across generations, low levels of inbreeding (0.004), low genetic differentiation among adults and offspring and, most importantly, large estimates of effective population size (119-716), all supported beech as a successive and successful tree species in the studied forest stand.
Pedunculate and sessile oaks (Quercus robur L.; Q. petraea [Matt] Liebl.) often coexist in mixed forest stands. However, species-specific investigations and forest management actions in such populations require reliable methods of identification of the species status of individuals. We investigated genetic diversity and species differentiation of adult and naturally established seedling cohorts in a mixed forest stand composed of Q. robur and Q. petraea, located in the Jamy Nature Reserve in north-central Poland. Using nineteen nuclear microsatellite loci and a model-based clustering approach as a tool for species delineation, we efficiently identified 105 and 60 adults, as well as 191 and 456 seedlings of pedunculate and sessile oaks, respectively. While the adult trees of both species were randomly distributed throughout the sample plot, the seedlings demonstrated significant spatial clustering, which was particularly evident for Q. petraea. The two oak species exhibited similar levels of genetic diversity in adult and offspring cohorts. Inbreeding was found to be low and significant only at the stage of seedlings. The estimates of effective population size were higher for Q. robur than Q. petraea, despite the overall greater reproductive success of the later one. There was a significant level of differentiation between the studied oak species, as measured by Fst coefficient (0.084 – adults; 0.099 – seedlings). The results on genetic diversity and species differentiation obtained in the studied indigenous near-natural stand of Q. robur and Q. petraea could be considered as a reference for other population genetic studies of oaks.