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Ionizing radiation is a mutagen with known negative impacts on individual fitness. However, much less is known about how these individual fitness effects translate into population‐level variation in natural environments that have experienced varying levels of radiation exposure. In this study, we sampled genotypes of the freshwater crustacean, Daphnia pulex, from the eight inhabited lakes across the Chernobyl Exclusion Zone (CEZ). Each lake has experienced very different levels of chronic radiation exposure since a nuclear power reactor exploded there over thirty years ago. The sampled Daphnia genotypes represent genetic snapshots of current populations and allowed us to examine fitness‐related traits under controlled laboratory conditions at UK background dose rates. We found that whilst there was variation in survival and schedules of reproduction among populations, there was no compelling evidence that this was driven by variation in exposure to radiation. Previous studies have shown that controlled exposure to radiation at dose rates included in the range measured in the current study reduce survival, or fecundity, or both. One limitation of this study is the lack of available sites at high dose rates, and future work could test life history variation in various organisms at other high radiation areas. Our results are nevertheless consistent with the idea that other ecological factors, for example competition, predation or parasitism, are likely to play a much bigger role in driving variation among populations than exposure to the high radiation dose rates found in the CEZ. These findings clearly demonstrate that it is important to examine the potential negative effects of radiation across wild populations that are subject to many and varied selection pressures as a result of complex ecological interactions.

The effects of exposure to different levels of ionising radiation were assessed on the genetic, epigenetic and microbiome characteristics of the “hologenome” of earthworms collected at sites within the Chernobyl exclusion zone (CEZ). The earthworms Aporrectodea caliginosa (Savigny, 1826) and Octolasion lacteum (Örley, 1881) were the two species that were most frequently found at visited sites, however, only O. lacteum was present at sufficient number across different exposure levels to enable comparative hologenome analysis. The identification of morphotype O. lacteum as a probable single clade was established using a combination of mitochondrial (cytochrome oxidase I) and nuclear genome (Amplified Fragment Length Polymorphism (AFLP) using MspI loci). No clear site associated differences in population genetic structure was found between populations using the AFLP marker loci. Further, no relationship between ionising radiation exposure levels and the percentage of methylated loci or pattern of distribution of DNA methylation marks was found. Microbiome structure was clearly site dependent, with gut microbiome community structure and diversity being systematically associated with calculated site-specific earthworm dose rates. There was, however, also co-correlation between earthworm dose rates and other soil properties, notably soil pH; a property known to affect soil bacterial community structure. Such co-correlation means that it is not possible to attribute microbiome changes unequivocally to radionuclide exposure. A better understanding of the relationship between radionuclide exposure soil properties and their interactions on bacterial microbiome community response is, therefore, needed to establish whether these the observed microbiome changes are attributed directly to radiation exposure, other soil properties or to an interaction between multiple variables at sites within the CEZ.

Bats are a protected species and as such may be an object of protection in radiological assessments of the environment. However, there have previously been only few radioecological studies of species of bats. In this paper, results for >140 measurements of (90)Sr and (137)Cs in 10 species of bats collected within the Chernobyl zone are presented. There was some indication of a decreasing transfer of (90)Sr with increasing deposition, although this was inconsistent across species and explained little of the observed variability. There was no difference between male and female bats in the transfer (expressed as the ratio of whole-body activity concentrations to those in soil) of either radionuclide. There was considerable variability in transfer across all species groups. At two sites where there were sufficient data, Eptesicus serotinus was found to have higher transfer than other species.

A study in 2012–2016 using camera traps confirmed the presence of brown bear in the Chornobyl exclusion zone (Ukraine). The presence of ca. 2–3 individuals was established in an area of up to 80 km² near the village of Tovstyi Lis. Bears were observed on 17 occasions in all seasons except winter. Confirmed sightings were also recorded near the villages of Paryshiv and Ladyzhychi, though number of the animals in this area is unknown. Both locations include vast broadleaved woodlands with moist soil and abundant food reserves. The evidence collected (photographs, video, footprints, markings on trees, oral reports of a female bear with cubs) suggest the development of a resident breeding group and the revival of the species in Kyiv Polissia after centuries of its absence. This is facilitated by the size of the exclusion zone (2,600 km²), abundant resources and the absence of humans. A similar revival of bear has been reported in the neighbouring Poliskyi Radioecological Reserve in Belarus. Together both territories (4,750 km²) promise to be a new large reservation for brown bear in Eastern Europe. Дослідження з фотопастками у 2012–2016 рр. довели наявність бурого ведмедя у Чорнобильській зоні відчуження (Україна). Близько 2–3 особин мешкає на ділянці до 80 км² біля с. Товстий ліс. Ведмедів реєстрували 17 разів у всі сезони, крім зими. Підтверджені спостереження також надійшли з району с. Паришів та Ладижичі, хоча кількість звірів там невідома. Обидві ділянки включають великі широколистяні ліси з добрим зволоженням ґрунтів і багатою кормовою базою. Зібрані свідчення (фотографії, відео, сліди, подряпини на деревах, усні повідомлення про ведмедицю з ведмежатами) вказують на розвиток місцевою групи, що розмножується, і відновлення виду у Київському Поліссі після століть відсутності. Цьому сприяє розмір зони відчуження (2600 км²), рясність ресурсів та відсутність людей. За літературними даними, подібне відновлення ведмедя відбувається у сусідньому Поліському радіоекологічному заповіднику Білорусії. Обидві території разом (4750 км²) обіцяють стати новим великим резерватом ведмедя у Східній Європі.