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Lithuania is on the edge of the main distribution range of the root vole (Microtus oeconomus). It was found that the trappability of M. oeconomus did not depend on the trapping effort, the number of recorded species and individuals or the species diversity. All 13 localities with proportions of M. oeconomus constituting over 30% of the small mammal community are situated in the south and west of Lithuania. Analysis of data collected over 50 years confirms that the species has become more abundant, more widespread and its distribution range has spread north and east from the south and west of the country. The main habitats for M. oeconomus in Lithuania are reedbeds, meadows, shrubby areas and shores of water bodies. Abandoned former agricultural areas create suitable habitats for the species, thus promoting its increased abundance and wider distribution.
Winter habitat use, niche breadth and overlap between the native and invasive species of medium sized predators, the red fox, pine marten and raccoon dog in particular, were studied in three landscapes with different habitat structure in Lithuania. Meadows were preferred by foxes but avoided by raccoon dogs and pine martens. Pine martens intensively used various forest habitats, whilst raccoon dogs tended to prefer swamps. The habitat niche breadth (Hurlbert's standardized niche breadth) varied with respect to both the species and the study site. The habitat niche overlap was larger between raccoon dog and pine marten than that between raccoon dog and red fox. Our results suggest a low impact of the invasive raccoon dog on red fox and pine marten in studied landscapes.
For the evaluation of sexual dimorphism 739 red fox skulls (including 433 males and 306 females) from the Czech Republic were examined. The individuals younger than six months were excluded from the study of sexual dimorphism and the rest was divided into three age classes (individuals at the age of 6.5–12 months, 12.5–24 months and 24.5 months and older). Skull size differences between males and females were significant in all age classes. Males exceeded females in all dimensions with the exception of postorbital breadth, which was wider in females. Other skull shape differences between males and females were not confirmed. Age class including individuals 12.5–24 months old was the only, in which significant skull shape differences were found. We suppose that competition between males could play the major role in sexual dimorphism formation.
The incisor morphology of rodents varies a good deal among different genera and each structure may have a special evolutionary significance. Some basic and lateral profile measurements of upper and lower incisors which may reflect morphological adaptations of the Gansu zokor (Myospalax cansus, a typical subterranean rodent in northern Asia) and the brown rat (Rattus norvegicus, a typical aboveground rodent that has close body size to the Gansu zokor) were analyzed. GIS (Geographic Information System) software and nonlinear regression were used to analyze incisor lateral profile, allowing the incisors to be viewed as circular arcs with a high degree of accuracy. The results show that: i) zokors have more robust (i.e. larger anteroposterior diameter and transverse diameter values), heavier and longer upper as well as lower incisors than rats; ii) zokors show a significantly higher level of sexual dimorphism (male dominant) than rats on the incisor morphology (including basic and lateral profile measurements) and iii) the upper incisor is heavier than lower incisor in rats, as opposed to zokors, in which the lower incisor is heavier than the upper incisor, indicating that more resources must have been allocated to lower incisors of zokors.
Tibetan macaques (Macaca thibetana) are a threatened primate species endemic to China. The current taxonomy of the species is based on external morphological and anatomical variations. To further understand the intraspecific variation and relationships among populations, we analyzed 44 mitochondrial DNA control region sequences (475 bp fragment) from individuals across the species range. Results revealed 11 major haplotypes with a high nucleotide diversity (0.792), but nucleotide diversity within haplotype lineages was only 0.042. Neighbor-joining phylogenetic analyses indicated support for four distinct haplotype clades corresponding to regional groups consistent with the recognized subspecies M .t. thibetana, M. t. guizhonensis, M. t. huangshanensis and M. t. pullus. As a result of regional geographic variation and genetic differences, we recommend the four subspecies should be considered different management units for conservation efforts.
The Asiatic ibex is a threatened endemic species that is distributed in the mountains of central and northern Asia. Using the method of group scan sampling, the behaviour of the Asiatic ibex was studied in the autumn of 2005. The effects of group size and sex on vigilance were tested. The results indicated that both group size and sex affected vigilance levels. Male ibex were significantly more vigilant than females at both the group scan level (percentage of individuals scanned during a session) and group scan frequency (percentage of intervals with at least one individual scanning). The group scan level was negatively correlated with group size, and group scan frequency was positively correlated with the group size in male, female, and overall groups. These results showed that group size and sex affected vigilance in Asiatic ibex.
Winter weather limits populations of resident bird species. Although many small-scale or speciesspecific studies illustrated this fact, our knowledge of interspecific differences in population responses to winter temperatures is incomplete due to lack of community-level studies. For this purpose, we have used long-term monitoring data on breeding bird populations of 37 common bird species wintering in the Czech Republic. We predicted that species will differ in their relationship between winter temperature and abundance with respect to their body mass and dietary niche. Smaller species having relatively higher energy expenditure should show closer relationship between breeding abundance and winter temperature than larger species. Concerning dietary niche, abundance of species feeding on animals should be more affected by temperature than abundance of species feeding on plants or omnivorous species. Our results confirmed the second prediction: populations of species preying on animals followed winter temperatures more closely than populations of species feeding on both animals and plants. Food-mediated mortality is probably more important than direct effects of low temperatures. In general, relationships between abundance and temperature were relatively weak in most species and we suggest that possible changes in winter temperatures may not seriously affect populations of common breeding birds in the Czech Republic.
Gekkotan lizards are widely distributed in tropical regions and extend into more northern regions in Asia and Europe. Unfortunately, gekkotans lack significant fossil record and many aspects of their evolutionary biology are still poorly understood. Our study provides the first information about occurrence of this group in the Czech Republic. The fossil material comes from the Lower Miocene sediments (MN 3) of the locality Merkur-North. All the gekkonid bones can be assigned to the family Sphaerodactylidae and represent a single taxon, Euleptes gallica. This taxon was previously known only from the French locality Montaigu (zone MN 2), and thus our study extends its stratigraphic and geographic range.
The skin histology from the Danubian spined loach Cobitis elongatoides disputes the notion that the spawning marks (lighter spots on the body sides of the females) are the result of physical damage to the epidermis by a male during spawning. Physiological changes that induce a specific local decrease in lateral pigmentation in some individuals appear to be a more likely source.
Amongst the non-native Ponto-Caspian gobies that have invaded the Middle Danube is the monkey goby Neogobius fluviatilis (Pallas, 1814). Despite a strong specialization towards sandy substratum, revealed in a previous study, monkey goby is considered an invasive species and therefore should demonstrate great plasticity in its biological traits. The main aim of the present study was to evaluate the age and growth of a non-native population of monkey goby from the River Ipeľ in Slovakia. Six age groups (0 - V) were observed in the sample from the River Ipeľ (n = 165), with males demonstrating faster growth than females, which was reflected both in the smoothing cubic B-spline model and in the annual increment. The cubic B-spline model indicated a reverse Lee's phenomenon, especially in males, which is likely to have arisen from the size selective mortality. Growth of invading monkey goby from the River Ipeľ was slower than that reported for the species' native range. Together with other growth patterns, this may suggest (among other possible explanations) a greater allocation of resources to reproduction than to somatic growth, which is a life-history pattern typical for newly established populations of successful invaders.
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