Semi-dry grasslands in the White Carpathian (Bílé Karpaty) Mountains on the Czech-Slovak border are famous for their extremely high species richness. In places they contain more than 130 species of vascular plants per 100m2 and for some plot sizes they hold world records in the number of vascular plant species, but the reasons for this are poorly understood. Here we ask whether the high number of species in these grasslands can be explained by local ecological factors. We compared the White Carpathian grasslands with similar grasslands in adjacent areas in the west (southern Moravia) and the east (Inner Western Carpathians), which are on average notably poorer in species than those in the White Carpathians. In both of these areas, we sampled grasslands that were among the species richest in the regional context and had a similar physiognomy, species composition and ecology as those in the White Carpathians. We found 75 sites with >70 and >25 species of vascular plants per 100 m2 and 1 m2, respectively, in which we recorded species composition and local environmental conditions, including precipitation, soil depth, soil pH and nutrient concentrations, above-ground biomass production and nutrients in plant biomass. Although the White Carpathian grasslands were considerably richer in species than the richest grasslands in the adjacent regions, there were no differences in the values of the factors studied that could provide an unequivocal explanation of their high species richness. However, the values of the factors studied were within the ranges reported in the literature as conducive to high species richness in temperate grasslands. We conclude that the high species richness recorded in the White Carpathian grasslands cannot be explained by a single factor. It results from a unique combination of regional factors (long history of these grasslands, large size of individual grassland areas and their existence in a landscape mosaic with forests, scrub and small wetlands), local abiotic factors (soil pH, soil nutrient status, moisture regime and resulting grassland productivity that are suitable for many species from the regional species pool) and management (low fertilizer input and mowing once a year in late spring or summer).
Former studies demonstrated that the river loach species Lefua sp. and Lefua echigonia (Nemacheilidae) have thin white linear markings from the pectoral fin base to the ventral fin base on both right and left sides of the abdomen that can be used to identify individuals in laboratory and in the field. In the present study we demonstrate the existence of such markings and the uniqueness of their shape in reared individuals of a further six species of Nemacheilidae, but found them absent in three species of Balitoridae. Furthermore, the long-term stability of the shape of the markings was examined in reared individuals of the nemacheilid Barbatula toni over two years. The white line markings offer a non-invasive tool for the individual recognition of nemacheilid species, some of which are threatened with extinction.
Many insects masquerade as parts of plants, such as bark or leaves, or mimic poisonous organisms in order to defend themselves against predators. However, recent studies indicate that plants may mimic insects and other arthropods to deter herbivores. Here, I report visually similar white structures of plants and arthropods in Japan and suggest they are part of a mimicry complex. Young shoots covered with white trichomes or waxy substances may mimic wax-producing insects, such as woolly aphids, coccids and caterpillars, potentially resulting in reduced herbivory. Since wax-producing insects would reduce plant quality and quantity, be distasteful and attract natural enemies, herbivorous insects and mammals may avoid such white shoots. Furthermore, fungus-infected insects, gregarious braconid cocoons, spider egg sacs and froth made by froghopper nymphs or blasticotomid sawfly larvae are also conspicuously white and impose risks for herbivorous insects. Thus, these white structures may be mimicry models for white shoots and are likely to be part of a defensive mimicry complex. Although this study focuses on defence against herbivores, there are simultaneous physiological roles for white colouration that will not be discussed in depth here., Kazuo Yamazaki., and Obsahuje bibliografii
White-tailed deer were introduced into the Czech Republic about one hundred years ago. Population numbers have remained stable at low density despite almost no harvesting. This differs from other introductions of this species in Europe. We presumed that one of the possible factors preventing expansion of the white-tailed deer population is lack of high-quality food components in an area overpopulated by sympatric roe, fallow and red deer. We analyzed the WTD winter diet and diets of the other deer species to get information on their feeding strategy during a critical period of a year. We focused primarily on conifer needle consumption, a generally accepted indicator of starvation and on bramble leaves as an indicator of high-quality items. We tested the following hypotheses: (1) If the environment has a limited food supply, the poorest competitors of the four deer species will have the highest proportion of conifer needles in the diet ; (2) the deer will overlap in trophic niches and will share limited nutritious resource (bramble). White-tailed, roe, fallow, and red deer diets were investigated by microscopic analysis of plant remains in their faeces. The volume of bramble decreased in the diet of all four deer species from November to March. The content of conifer needles in the diet of white-tailed and roe deer was negatively correlated with bramble and in spring made up 90 % of their diet volume. On the other hand conifer needles in the diet of red and fallow deer occurred only in January with snow cover. Fallow and red deer started the compensation of winter starvation at least one monthearlier than both roe and white-tailed deer. a high content of conifers in white-tailed deer diet in the second half of the winter fully support the presumption about low nutritional food supply and its diet. It can lead to a markedly impaired condition for white-tailed and roe deer and negatively affect their condition. The dietary overlap of four sympatric deer species was extensive in winter. All species share a limited good quality food supply (bramble) when food is scarce, suggesting that interspecific competition may occur.
This article analyses recent developments in Croatian housing finance to update the established account of housing finance and peripheral financialisation in Eastern Europe that is based on the boom-bust cycle of the 2000s and early-to-mid 2010s. During the bust stage of that cycle, changes in regulation and in the behaviour of debtors and creditors resulted in deleveraging and a shift away from the risky and exploitative lending practices characteristic of peripheral housing finance. However, new increases in household debt and housing prices since 2016–17, coupled with the COVID-19 pandemic, seem to have reversed these trends. While a boom-bust cycle of similar scope and modality to the first one is unlikely to be repeated, peripheral forms of housing finance have persisted to some degree.
The citation frequency of papers on invasion ecology published between 1981 and 2003 and that had accumulated at least 30 citations on the Web of Science on 9 August 2006 was analysed. The dataset comprised 329 papers and 27,240 citations. For each paper, the total number of citations was recorded and the annual citation rate (number of citations per year) was calculated. Papers were classified into broad research fields: plant invasions, animal invasions, biological control, and general papers (reviews and syntheses). Eight papers were cited more than 300 times, five of them dealt with general topics, and the mean value of the total number of citations across the whole data set is 82.8±73.1. The mean annual citation rate is 11.5±11.3 citations per year; six studies received on average at least 50 citations each year. About a half (50.8%) of papers in the data set deal with plant invasions. General papers are significantly more cited than papers from the other categories. The annual citation rate increased with time over the analysed period (1981–2003), by 1.0 citations per year. To compare the trends in invasion ecology with those in other fields of ecology, comparable data were compiled for population ecology and dynamics, and global change. The annual citation rate for invasion ecology as a whole increased faster than that for population ecology and dynamics, but not exponentially as is the case with studies on global change. The best-cited papers on invasion ecology were distributed among most of the top ecology journals. Those published in Oikos, Journal of Ecology, Ecological Applications and BioScience are cited 3.8–5.8 times more than the average for these journals (based on the impact factor). Papers on biodiversity, community ecology, impact, invasibility, dispersal, population ecology, competition, resources, genetical issues, biological control and species invasiveness received the highest total number of citations. However, measured by the annual citation rate, the hottest current topics in invasion ecology are the effect of global change on invasions, the role of natural enemies, character of the invasion process, evolutionary aspects, invasibility of communities and ecosystem processes. Some topics are disproportionally more cited than studied and vice versa. Studies on plant and animal invasions differ in focus: the topics of invasibility, biodiversity, resources, species invasiveness and population genetics are more emphasized in botanical studies, dispersal, competition, impact and pathways in papers dealing with animal invasions. Studies of grasslands and marine environment are most frequently cited in botanical and zoological studies, respectively. Most of the highly cited papers deal with multiple species; only 14 plant species and four animal species are the primary focus of one or more of the highly-cited papers. Twenty-two authors (4.5% of the total involved in the papers analysed), each with seven or more contributions cited at least 30 times, together contributed 49.4% of the most-cited papers, and attracted 55.6% of the total number of citations.