Perch and its parasites as heavy metal biomonitors in a freshwater environment: the case study of the Ružín water reservoir, Slovakia

Heavy metal concentrations were determined in 43 perches (Perca fluviatilis) and in two of its most common parasites, the acanthocephalan Acanthocephalus lucii and the cestode Proteocephalus percae, collected in the period 2009-2010 from Ružín, a seriously polluted water reservoir in Slovakia. Samples of muscle, liver, kidney, brain, male and female reproductive organs and adipose tissue of fish and both parasites were analyzed for As, Cd, Cr, Cu, Hg, Mn, Ni, Pb and Zn, by ICP-MS. Mean concentrations of individual heavy metals in all fish samples decreased in the order zinc > copper > manganese > mercury > arsenic > chromium > cadmium > nickel > lead. Zinc was found to be the dominant element and its antagonistic interaction with copper was confirmed. The kidney was a key target organ receiving the highest mean concentrations of all analyzed metals, but some metals showed specific affinity for particular tissues. In terms of human health, concentration of Hg in fish muscle, which exceeded more than two-times its maximum level admitted in foodstuffs in European countries, is of great importance and should be taken into account. Bioaccumulation factors s (C[parasite]/C[fish tissue]) calculated for all elements indicated much higher detection skills of A. lucii and P. percae parasites than fish organs and hence, present results allow proposing both parasite models as useful tools to monitor aquatic environmental quality. Acanthocephalans, however, seem to be superior for heavy metal monitoring, also demonstrated under experimental conditions. Present results also indicate the decreasing heavy metal burden of the reservoir and its gradual recovery in the course of time.publishe

Distribution of Oribatida (Acari) along a depth gradient in forested scree slopes

Mesovoid shallow substratum (MSS) of scree slopes constitutes a transition habitat between the soil and the network of voids in the vadose zone of a bedrock massif. In the present study, the vertical distribution of oribatid communities along a depth of 95 cm was studied at five forested MSS sites in the Western Carpathians, Slovakia. The sites differed in type of bedrock, topography and gradient of the microclimate and nutrients content. In all, 909 specimens were captured in subterranean traps exposed for one year. Most Oribatida represented edaphic forms, and their presence in the depth profile of the screes was accidental. Pantelozetes cavatica (Kunst, 1962) was the only species closely linked to deep subterranean environments found in the deeper part of the single limestone site studied. Species richness and the activity of oribatids along the scree profile at the sites clearly reflected the content of organic carbon in the soil substratum. The communities had very low numbers of individuals and low species richness at three sites with soil pH < 7 and organic carbon content in the upper soil layer ≤ 10%. However, they differed markedly in internal temperature dynamics. The other two sites, with a slightly alkaline soil pH and a higher carbon content, showed distinctly higher activity and a relatively uniform pattern of oribatid distribution across the depth profile. The soil pH and organic carbon content in the topsoil layer were substantial factors that determined the Oribatida diversity and vertical distribution in the forested screes

A unique small-scale microclimatic gradient in a temperate karst harbours exceptionally high diversity of soil Collembola

The collapse doline of the Silická ľadnica Ice Cave, 351 m2 in area, is a unique phenomenon, a steep microclimate gradient in a low-altitude temperate karst in the Western Carpathian Mts, Slovakia, with a remarkable temperature decrease from the edge of karst plateau towards the doline bottom, which harbours perennial ice deposits. Collembola communities were studied in detail at seven sites along the 117.5 m long gradient slope during 2005–2007. An exceptionally high species richness of soil Collembola was observed, 129 species, which is about 91% of the total species richness generated by Chao1/ACE estimator. Species richness positively correlated with soil temperature at the sites. Among the occupants of the karst doline, 10 were Carpathian or Western-Carpathian endemics, and 21 were cold-adapted (psychrophilic) species with montane or boreo-montane disjunctive distribution. A high number and high abundance of endemic species occurred in the middle zone of the gradient slope. The study further showed that cold and wet karst scree slopes in the transition zone between surface habitats and caves may represent borderline habitats for obligate subterranean species. Communities at cold sites had much steeper rank-dominance curves compared to upper mesophilous and thermophilous sites, thereby documenting the harsh character of this environment. Our results suggest that small-scale microclimatic gradients in a low altitude karst in a temperate zone may serve as a reservoir (source) of exceptional soil fauna diversity, providing important climatic microrefugia for endemic and relict taxa. Karst landforms in the temperate zone with strong climatic inversions may harbour high biodiversity and thus should be central in biodiversity conservation programs

Figure 1 in Terrestrial isopods and myriapods in a forested scree slope: subterranean biodiversity, depth gradient and annual dynamics

Figure 1. Distribution of Isopoda, Diplopoda and Chilopoda along the depth gradient of the scree slope expressed as the total number of individuals trapped in two sampling periods (November 2008–November 2009; November 2009–July 2010).Published as part of Rendoš, Michal, Mock, Andrej & Miklisová, Dana, 2016, Terrestrial isopods and myriapods in a forested scree slope: subterranean biodiversity, depth gradient and annual dynamics, pp. 2129-2142 in Journal of Natural History 50 on page 2134, DOI: 10.1080/00222933.2016.1193642, http://zenodo.org/record/399292

Terrestrial isopods and myriapods in a forested scree slope: subterranean biodiversity, depth gradient and annual dynamics

Rendoš, Michal, Mock, Andrej, Miklisová, Dana (2016): Terrestrial isopods and myriapods in a forested scree slope: subterranean biodiversity, depth gradient and annual dynamics. Journal of Natural History 50: 2129-2142, DOI: 10.1080/00222933.2016.1193642, URL: http://dx.doi.org/10.1080/00222933.2016.119364

A comparison of collecting methods in relation to the diversity of Collembola in scree habitats

We compared the species composition, relative abundances and life form structure of subterranean Collembola (Hexapoda) captured by two different methods along a depth gradient of five forested scree sites in the Western Carpathians, Slovakia: (1) high-gradient extraction of soil samples, and (2) collection using subterranean traps. Our results showed that the soil samples were more efficient in covering species richness at the majority of the sites. The body size of the captured animals depended remarkably on the sampling method. Extraction was more effective in collecting smaller, less active hemi- and euedaphic forms of Collembola, while collection by subterranean traps favoured both motile ground-dwelling as well as relatively large, active euedaphobionts. Additionally, different trends in the vertical stratification of Collembola life forms and their relative abundances were detected by the two methods. Atmobionts and epigeonts, forming the greater part of the communities in traps compared to soil samples, were distributed along the entire scree profiles, but their relative abundance and species numbers had a strongly decreasing trend with depth. Moreover, motile, large hemi- and euedaphic forms had high relative abundances in traps in the middle and deeper scree levels at three sites. In contrast, in soil samples the hemi- and euedaphobionts with small body size were abundant on the surface of the MSS sites. Thus, soil sampling applied before installation of subterranean traps may serve as an appropriate complementary technique to obtain a more complete pattern of Collembola diversity in forested scree habitats

Rodents as Sentinels for <i>Toxoplasma gondii</i> in Rural Ecosystems in Slovakia—Seroprevalence Study

Toxoplasma gondii is a ubiquitous intracellular parasite with felids as definitive hosts and a broad range of intermediate hosts. Rodents are considered suitable sentinels for prevalence studies of many infections, including toxoplasmosis. This study aimed to estimate the seroprevalence of T. gondii in rodents from different localities of Slovakia and investigate the correlation between the seropositivity and the species, age, sex, and sexual activity of animals. Altogether, 1009 wild rodents belonging to 9 species were trapped in 2015 and 2019, and antibodies to T. gondii were detected in 6.7% of the animals. Seropositivity was detected in seven species, ranging from 0.0% in Micromys minutus and Apodemus sylvaticus to 7.7% in A. flavicollis. The females reached significantly higher seropositivity (9.7%) than the males (3.8%), and the adults were positive significantly more often (9.2%) than the subadults (4.9%). The seropositivity differed also among localities, with significantly higher positivity detected in suburban and touristic areas (12.2%) than in localities with a lower level of human activities (5.5%). This study showed that the occurrence of T. gondii varies significantly in rodent species and habitats with various environmental conditions and different levels of anthropic use. Several biological and ecological factors, e.g., soil contamination, soil conditions, the susceptibility of rodent species etc., may influence this variability