Extreme Environment Effects on Cognitive Functions: A Longitudinal Study in High Altitude in Antarctica.

This paper focuses on the impact of long-term Antarctic conditions on cognitive processes. Behavioral responses and event-related potentials were recorded during an auditory distraction task and an attention network paradigm. Participants were members of the over-wintering crew at Concordia Antarctic Research Station. Due to the reduced partial pressure of oxygen this environment caused moderate hypoxia. Beyond the hypoxia, the fluctuation of sunshine duration, isolation and confinement were the main stress factors of this environment. We compared 6 measurement periods completed during the campaign. Behavioral responses and N1/MMN (mismatch negativity), N1, N2, P3, RON (reorientation negativity) event-related potential components have been analyzed. Reaction time decreased in both tasks in response to repeated testing during the course of mission. The alerting effect increased, the inhibition effect decreased and the orienting effect did not change in the ANT task. Contrary to our expectations the N2, P3, RON components related to the attentional functions did not show any significant changes. Changes attributable to early stages of information processing were observed in the ANT task (N1 component) but not in the distraction task (N1/MMN). The reaction time decrements and the N1 amplitude reduction in ANT task could be attributed to sustained effect of practice. We conclude that the Antarctic conditions had no negative impacts on cognitive activity despite the presence of numerous stressors

Steppe rodents at the edge of their range: A case study of Spalax microphthalmus in the north of Ukraine

Based on results obtained during 2000–2018 by field research, polls of colleagues, and OSINT analysis, features of distribution of the greater mole rat Spalax microphthalmus in the eastern forest steppe of Ukraine were considered. The studied part of the species’ range is unique and represents the northern range edge of the entire Spalacidae family and of European steppe faunal assemblages in general. In total, data on 146 record localities were amassed, including 13 localities in the fragmented and 133 in the continuous part of the range. The offshoots of the Central Russian Upland in the valley of the Psel river (east of Sumy Oblast) are the sites with the highest density of settlements, while the species’ type biotopes are steppe balka slopes. The abundance of the greater mole rat decreased from the east to the west, and its colonies are the most fragmented along the Dnipro River. The species occurs in steppe and meadow habitats of an area of at least 20–50 ha. Analysis of the current and former distribution of the greater mole rat revealed that the species range contracts from the west; earlier it was a common species in different regions of the Middle Dnipro Area (including Kyiv city), but the current range edge runs along the line connecting Buryn – Nedryhailiv – Lokhvytsia – Myrhorod – Hadiach – Zinkiv – Zaliznychne. Isolated settlements exist in adjacent territories, particularly in Ichnia Raion of Chernihiv Oblast, and Lubny, Khorol, and Kobeliaky Raions of Poltava Oblast. The study showed that the species’ range contracted by two times to 35,000 km2 for the last 100 years, which includes only 430,000 ha of suitable habitats (15% of the range), allowing the existence here of 86,000–215,000 individuals. In fact, the species remained only in habitats that have been minimally affected by arable farming and other forms of active agricultural use. Besides, the species shows a clear confinement to habitats located near human settlements such as untilled lands, pastures with moderate grazing, waste and neglected lands, which constitute a separate group of transformed and semi-natural habitats. Formally, this allows the greater mole rat to be considered as a synanthropic species, because its inhabited biotopes, beside the zone of offshoots of the Central Russian Upland, have remained only near villages and along roads. The species also has an important biocoenotic role due to its burrowing activity and as prey of predatory birds (e.g., of the long-legged buzzard and Eurasian eagle owl) and mammals. The feeding period of the offspring of these predators generally coincides with the aboveground activity of mole rats, which lasts during May–July with a peak in June. Aboveground activity is mainly related to the resettlement of mole rats to new sites and dispersal of the young, due to which they became victims of predators

Living on the edge: distribution patterns of steppe mammals in Transcar­pathia (Ukraine)

We analysed the composition of the steppe assemblage in the mammal fauna of Transcarpathia (Ukraine), which is represented by three rodent species such as the European ground squirrel Spermophilus citellus, the common hamster Cricetus cricetus, and the steppe mouse Mus spicilegus. These species have not been considered in the composition of the local fauna or they were mentioned only in general checklists, or even with obvious mistakes in descriptions of both key characters and record localities. Here we present detailed descriptions of distribution of each steppe species based on actual record localities as well as ecological and biogeographic features. In total, we have generalized data on 13 record localities of Spermophilus citellus, 7 of Cricetus cricetus, and 8 of Mus spicilegus. We also revealed and described general trends in the distribution of these species: all of them occur in the lowland part of Transcarpathia between the valleys of the Tisza and Latorica rivers and adjacent areas. Generally, steppe species in Transcarpathia are related to anthropogenically transformed biotopes: the European ground squirrel mainly occurs along banks of dammed rivers in zones of floods, while the common hamster and the steppe mouse are both related to agricultural lands. The absence of natural populations in indigenous biotopes and, in fact, the absence of typical key steppe habitats suggest that steppe species appeared in Trans­carpathia as the result of expansion from their main geographic range as suitable habitats gradually appeared at the range periphery. The closest centre of distribution of each species is located beyond the studied region, namely in the Great Hungarian Plain, and the records described here are marginal: they are instable and attributed to the zones of range pulsation, which depends on climatic factors and current landscape features of the lowland part of Transcarpathia. The state and dynamics of range-edge populations of steppe species in Transcarpathia might be largely affected by the hydrological regi­me, wintering conditions, human activity, etc., as well as by “edge effects” that usually take place in fragmented populations. The influence of such processes probably could explain the low abundance and rarity of steppe species in the region, and, in the same time, makes topical the issue of their conservation. At present, conservation issues especially concern two species, namely the European ground squirrel and the common hamster, which are keystone species in steppe and forest steppe ecosystems