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Small mammals that are specialists in homeothermic thermoregulation reduce their self-maintenance costs of normothermy to survive the winter. By contrast, heterothermic ones that are considered generalists in thermoregulation can lower energy expenditure by entering torpor. It is well known that different species vary the use of their strategies to cope with harsh winters in temperate zones; however, little is still known about the intraspecific variation within populations and the associated external and internal factors. We hypothesized that yellow-necked mice Apodemus flavicollis decrease their resting metabolic rate (RMR) from autumn to winter, and then increase it during spring. However, since the alternative for seasonal reduction of RMR could be the development of heterothermy, we also considered the use of this strategy. We measured body mass (mb), RMR, and body temperature (Tb) of mice during 2 consecutive years. In the 1st year, mice decreased whole animal RMR in winter, but did not do so in the 2nd year. All mice entered torpor during the 2nd winter, whereas only a few did so during the first one. Mice showed a continuous increase of mb, which was steepest during the 2nd year. The relationship between RMR and mb varied among seasons and years most likely due to different mouse development stages. The mb gain at the individual level was correlated positively with RMR and heterothermy. This indicates that high metabolism in winter supports the growth of smaller animals, which use torpor as a compensatory mechanism. Isotope composition of mice hair suggests that in the 1st year they fed mainly on seeds, while in the 2nd, they likely consumed significant amounts of less digestible herbs. The study suggests that the use of specialist or generalist thermoregulatory strategies can differ with environmental variation and associated differences in developmental processes.

We measured the content of nitrogen and phosphorus, as well as nitrogen stable isotopes in plant biomass and marmot faeces in a distance gradient up to 20 meters from marmot burrows in an extremely arid glacier valley in Eastern Pamir, Tajikistan. The goal of this study was to test well-known mechanisms of ecosystem engineering by burrowing animals in previously unstudied conditions. We captured aerial images of the area inhabited by marmots to study the spatial distribution of vegetation. There was no relationship between the presence of burrows and vegetation cover. Burrow mounds were not colonised by plants, as opposed to other ecosystems, where mounds are often microhabitats that enhance plant diversity. A significant increase in N and P in aboveground green plant biomass in the proximity of burrows was found in one out of six studied species. Stable N isotopes did not give further insight into N routing, contrary to our expectations. We assume that plant growth is strongly limited by water availability, which prevents them from utilizing the local increase in nutrients, certainly provided by marmot activity. The results are contrary to numerous studies which showed that the role of burrowing animals as ecosystem engineers increases with increasing abiotic stress, including aridity. This shows a lack of this type of study in the end of the gradient of abiotic factors.

Invasive alien predators pose a threat to native fauna and the studies of their feeding habits are crucial to understanding their impact on prey populations. Diet of the American mink Neovison vison, an invasive species in Europe, is relatively well studied based on scat analysis, however, the use of other methods of diet analysis enables a better overview of this issue. We analyzed the isotopic composition of carbon and nitrogen in the livers, which reflects the diet from about 30–40 days (scat analysis provides information on the diet over 1–2 days only) of the American mink from four national parks in Poland and in the muscles of three types of mink prey (root voles, common frogs, and roach) in order to estimate their contribution to the mink diet. Mink in Biebrza and Narew National Parks fed mainly on frogs and fish, in Drawa National Park on voles and fish, and in Warta Mouth National Park almost exclusively on fish—as shown by Bayesian mixing models calculated for three selected groups of prey. There was no isotopic evidence for differences between the diets of male and female mink. In all groups of prey, we found surprisingly high differences between individuals of the same species from different study sites in the isotopic composition of both δ13C (up to 3‰) and δ15N (up to 6‰). Based on a detailed literature review, we predict that the main reasons for these variations are differences in abiotic environment, food availability, and trophic position. We also indicate a lack of data on trophic discrimination in fish and amphibians, which makes it hard to assess the influence of differences in trophic position on isotopic variations. We suggest caution to authors who plan to study geographical variations in diet of animals using stable isotope analysis without acknowledging that taxonomically and ecologically similar prey can differ in isotopic composition between studied areas.

Colonial breeding in birds provides protection from predators and may be particularly important when birds have to cope with an invasive predator. The probability of nest predation in a colony can vary depending on several factors, such as the nest’s location in the colony and the level of aggregation of nests. We studied the nesting success of colonial great crested grebes and monitored the occurrence of the non-native invasive American mink in the colony. From among 92 grebe nests, 54.3% were successful. The daily survival rate (DSR) of grebe nests was positively affected by the increasing distance between the nest and lake shoreline, and negatively affected by the increasing distance between the nest and the five nearest grebe nests. The probability of mink occurrence in the colony increased with consecutive days of the breeding season and decreased with increasing distance from the lake shoreline. The DSR of grebe nests decreased with the increasing probability of mink occurrence along the shoreline distance gradient and the day of the breeding season. The results of the study confirm the impact of the American mink on waterbirds during the breeding season but also indicate that large breeding colonies are partially safe from mink predation, and that nest accessibility and the dilution effect influence the probability of nest survival. Our data suggest that the limited access to safe breeding sites on large lakes that can supply adult grebes and their chicks with food may affect bird productivity and population numbers at the landscape level. Electronic supplementary material The online version of this article (10.1007/s00442-018-4270-8) contains supplementary material, which is available to authorized users.

The purpose of the article was the analysis of the change in the equipment of Ukraine's agriculture in selected means of mechanization of plant growing in the period of 2000-2015. The analysis is limited of tractors, combine harvesters, machines for harvesting potatoes and sugar beet. By preparing the article, data of the State Statistics Service of Ukraine was used, as well as available publications. The changes that have occurred in the agriculture of Ukraine caused significant on depletion of the technical base of agricultural enterprises. At the same time, the area of agricultural land for one tractor and the sown area for one machine increased significantly. One of the important problems facing the Ukrainian agriculture is considerable technical, moral and economical wear and tear of the machinery and tractor fleet in households and enterprises. Synopsis. Celem opracowania jest analiza zmian stanu wyposazenia ukrainskiego rolnictwa w wybrane środki mechanizacji do produkcji roślinnej w latach 2000-2015. Analizy ograniczono do ciągnikow rolniczych, kombajnow zbozowych, maszyn do zbioru ziemniakow i burakow cukrowych. W przygotowaniu opracowania wykorzystano materialy statystyczne Panstwowej Sluzby Statystyki Ukrainy (UKRSTAT) oraz dostepną literature przedmiotu. Przemiany jakie nastąpily w rolnictwie Ukrainy spowodowaly znaczne uszczuplenie bazy technicznej przedsiebiorstw rolnych. Jednocześnie znacznie wzrosla powierzchnia UR przypadająca na ciągniki rolnicze oraz powierzchnia upraw w przeliczeniu na jedną maszyne do zbioru. Istotnym problemem z ktorym boryka sie ukrainskie rolnictwo jest znaczne zuzycie techniczne, moralne i ekonomiczne parku ciągnikowo- maszynowego w gospodarstwach i przedsiebiorstwach rolnych.

Habitat selection often involves choices made at different spatial scales, but the underlying mechanisms are still poorly understood, and studies that investigate the relative importance of individual scales are rare. We investigated the effect of three spatial scales (landscape, territory, nest-site) on the occurrence pattern of little crake Zapornia parva and water rail Rallus aquaticus at 74 ponds in the Masurian Lakeland, Poland. Habitat structure, food abundance and water chemical parameters were measured at nests and random points within landscape plots (from 300-m to 50-m radius), territory (14-m) and nest-site plots (3-m). Regression analyses suggested that the most relevant scale was territory level, followed by landscape, and finally by nest-site for both species. Variation partitioning confirmed this pattern for water rail, but also highlighted the importance of nest-site (the level explaining the highest share of unique variation) for little crake. The most important variables determining the occurrence of both species were water body fragmentation (landscape), vegetation density (territory) and water depth (at territory level for little crake, and at nest-site level for water rail). Finally, for both species multi-scale models including factors from different levels were more parsimonious than single-scale ones, i.e. habitat selection was likely a multi-scale process. The importance of particular spatial scales seemed more related to life-history traits than to the extent of the scales considered. In the case of our study species, the territory level was highly important likely because both rallids have to obtain all the resources they need (nest site, food and mates) in relatively small areas, the multi-purpose territories they defend.

W opracowaniu dokonano analizy stanu i perspektyw produkcji roślin oleistych w Polsce i na Ukrainie. W Polsce podstawową roślina oleistą jest rzepak, natomiast na Ukrainie dominuje słonecznik. Znaczny udział w strukturze upraw oleistych na Ukrainie oprócz słonecznika zajmują rzepak oraz soja. Zarówno w Polsce, jak i na Ukrainie odnotowano wzrost produkcji roślin oleistych. W Polsce stan ten wynika ze wzrostu popytu na surowce do produkcji biopaliw, natomiast na Ukrainie wzrost ten jest związany ze zwiększonym zapotrzebowaniem na nasiona roślin oleistych na rynkach światowych. Sektor biopaliwowy na Ukrainie znajduje się w początkowej fazie rozwoju i nie ma on istotnego wpływu na produkcję roślin oleistych w tym kraju. Dostrzegalny jest natomiast wpływ sektora biopaliw w krajach Unii Europejskiej na produkcję roślin oleistych i olejów roślinnych na Ukrainie. Sektor biopaliwowy w Polsce będzie odgrywał istotne znaczenie dla rozwoju produkcji rzepaku. W przypadku Ukrainy w związku z przyjętym ustawodawstwem o rozwoju OZE, w tym sektora biopaliw może w dalszej przyszłości nastąpić wzrost wewnętrznego zapotrzebowania na nasiona z roślin oleistych.

We tested the influence of nest concealment (vegetation type, density and height), water depth and nest distance from the bank on predation rates upon simulated nests of the water rail (Rallus aquaticus) and the little crake (Porzana parva). Broods of both rallids were simulated by real and wax-filled quail (Coturnix coturnix) eggs coloured typically for each species. Three grades of nest concealment were used: uncovered nests located on wooden floating boards, nests hidden in littoral vegetation and nests hidden under a plastic mesh covered with plants, which made them invisible from the air. Concealment proved to have a stronger impact on the fate of artificial nests than water depth; 95% of the nests on boards were depredated after one week of exposure. Nests attached to a peg at water level and hidden in vegetation had survival rates of 18 and 22%, after three weeks of exposure in two experiment repetitions. In 2012, we found significant differences between survival rates of nests located in ...

Capsule Nest survival of Water Rail and Little Crake nesting at small, midfield ponds was determined by vegetation density and proximity to the shore, respectively.Aims To determine which habitat variables affect nest predation for two rallid species inhabiting small ponds.Methods Habitat variables describing nest location (water depth, distance to the shore and distance to open water) and nest concealment (density and height of vegetation) were measured for natural and artificial nests. All nests were monitored to determine their fate and to identify nest predators. We used generalized linear models to assess nest survival rates and to evaluate the influence of particular variables.Results Little Crake nest success was negatively correlated with distance to shore (the land-water edge). The survival of Water Rail nests and artificial nests was positively correlated with vegetation density. During three breeding seasons, predation rates on Little Crake nests varied from 22% to 58%, and on Water Rail nests ...