The impact of the striped field mouse's range expansion on communities of native small mammals.

Understanding species expansion as an element of the dispersal process is crucial to gaining a better comprehension of the functioning of the populations and the communities. Populations of the same species that are native in one area could be considered nonindigenous, naturalised or invasive somewhere else. The striped field mouse has been expanding its range in south-western Slovakia since 2010, although the origin of the spread has still not been clarified. In light of the striped field mouse's life history, the recent range expansion is considered to be the expansion of a native species. This study analyses the impact of the striped field mouse's expansion on the native population and small mammal communities and confronts the documented stages of striped field mouse expansion with the stages of invasion biology. Our research replicates the design and compares results from past research of small mammals prior to this expansion at the same three study areas with the same 20 study sites and control sites. Several years after expansion, the striped field mouse has a 100% frequency of occurrence in all study sites and has become the dominant species in two of the study areas. The native community is significantly affected by the striped field mouse's increasing dominance, specifically: (i) we found a re-ordering of the species rank, mainly in areas with higher dominance, and (ii) an initial positive impact on diversity and evenness during low dominance of the striped field mouse turned markedly negative after crossing the 25% dominance threshold. Results suggested that the variation in the striped field mouse's dominance is affected by the northern direction of its spread. Our findings show that establishment in a new area, spread and impact on the native community are stages possibly shared by both invasive and native species during their range expansion.

The Prediction of Distribution of the Invasive Fallopia Taxa in Slovakia.

Invasive species are now considered the second biggest threat for biodiversity and have adverse environmental, economic and social impacts. Understanding its spatial distribution and dynamics is crucial for the development of tools for large-scale mapping, monitoring and management. The aim of this study was to predict the distribution of invasive Fallopia taxa in Slovakia and to identify the most important predictors of spreading of these species. We designed models of species distribution for invasive species of Fallopia­Fallopia japonica­Japanese knotweed, Fallopia sachalinensis­Sakhalin knotweed and their hybrid Fallopia × bohemica­Czech knotweed. We designed 12 models­generalized linear model (GLM), generalized additive model (GAM), classification and regression trees (CART), boosted regression trees (BRT), multivariate adaptive regression spline (MARS), random forests (RF), support vector machine (SVM), artificial neural networks (ANN), maximum entropy (Maxent), penalized maximum likelihood GLM (GLMNET), domain, and radial basis function network (RBF). The accuracy of the models was evaluated using occurrence data for the presence and absence of species. The final simplified logistic regression model showed the three most important prediction variables lead by distances from roads and rails, then type of soil and distances from water bodies. The probability of invasive Fallopia species occurrence was evaluated using Pearson's chi-squared test (χ21). It significantly decreases with increasing distance from transport lines (χ21 = 118.85, p < 0.001) and depends on soil type (χ21 = 49.56, p < 0.001) and the distance from the water, where increasing the distance decrease the probability (χ21 = 8.95, p = 0.003).

Biometric Analysis of Cranial and Somatic Features in the Pannonian Root Vole.

The Pannonian root vole Alexandromys oeconomus ssp. mehelyi represents a rare glacial relict, whose occurrence is nowadays bound to several areas in Europe. Four somatic and 25 craniological features were analysed, based on 355 measured specimens. Sex is a significant factor affecting the average value of all four somatic features, where all of them achieve higher values in males than in females. While body length and tail length were also affected by seasons, body weight and the length of the hind foot were stable features present across the seasons. In cranial features, the largest variability in the adult population is characterised by neurocranium breadth (LaN), total length of the cranial base (LB), and skull (LCr); whereas the smallest variability of the cranial dimensions is reflected in the values of the greatest palatal breadth (PS) and postorbital breadth (Io). Calculating the weight from cranial remains may be used to estimate the size of the prey and to determine vole biomass consumed by predators, such as raptors, highlighting the utility of studying feeding ecology.

Diversity, distribution and changes in communities of fleas on small mammals along the elevational gradient from the Pannonian Plain to the Carpathian Mountains.

The causal chain of parasite-host-environment interactions, the so-called 'dual parasite environment', makes studying parasites more complicated than other wild organisms. A sample of 65 282 fleas taken from 336 different locations were analysed for changes in the distribution, diversity and compensation of flea communities found on small mammals along an elevational diversity gradient ranging from the Pannonian Plain to the base of the Carpathian summits. The fleas were divided into four groups, which were derived from changes in abundance and occurrence determined from cluster analysis. They are (1) flea species whose range seems unrelated to any change in elevation; (2) species that avoid high altitudes; (3) a group that can be subdivided into two types: (i) host-specific fleas and (ii) mountains species and (4) species opting for high altitudes on the gradient or preferring lower to middle elevations below 1000 m. Our study showed a unimodal pattern of flea diversity along the elevational gradient. It indicated that seasonality significantly conditions changes in biodiversity and patterns of spatial change along the elevational gradient, with specific flea species influenced by their host, while the impact of environmental conditions is more pronounced in opportunistic flea species.

Measuring and comparing the water activity and salt content in Parenica cheeses made by traditional and industrial technology.

BACKGROUND: Slovenská Parenica is one of the most traditional and ever-popular sheep´s milk cheese specialities. This cheese has been registered as a geographical indication (PGI) in the EU. Parenica cheese is produced also from cow´s milk, but without the trade name "Slovenská/Slovak". OBJECTIVE: The aim of our research was was statistical reporting and results visualization of water activity analysis and salt content in cow´s milk Parenica cheeses from 8 small and medium-sized Slovak dairy producers. MATERIAL AND METHOD: A total of 320 samples of smoked and non-smoked Parenica cheeses made from cow´s milk using traditional and industrial technology were examined during the 10-month period. Each cheese was analysed immediately after sampling (A) and subsequently after 7 days of storing at 4°C (B). The salt content was measured on the Chloride analyser M 926 and the water activity on the Fast-Lab meter. Due to the hierarchical design of the experiment, the linear mixed models via the R statistical environment to compare the differences in the water activity and salt content were used. RESULTS: Statistical reporting and visualization of water activity measurements showed significant differences between samples A and B ( p = 0.0129) and between kinds of Parenica cheese ( p = 0.0196). The value of water activity ranged from 0.908 to 0.975 (A) with the increasing trend after storing in both kinds of Parenica cheese. The impact of dairy producer type was not significant. The higher content of NaCl was found in fresh Parenica cheese from small farms (nonsmoked: 2.51 ±1.12 g/100 g, smoked: 1.97 ±0.89 g/100 g). The average salt content in cheeses from industrial dairies was 1.65 ±0.34 g/100 g (non-smoked) and 1.96 ±0.43 g/100 g (smoked). Results showed lower variability of salt content in cheeses from industrial dairies. CONCLUSIONS: It can be concluded that especially the small producers can have probably problem in noncompliance with the technological processes, non-implementation of standardized procedures and underestimation of hygiene regulations.