Since the accident at the Chornobyl Nuclear Power Plant in 1986, there have been few studies published on medium and large mammals inhabiting the area from which the human population was removed (now referred to as the Chornobyl Exclusion Zone, CEZ). The dataset presented in this paper describes a motion-activated camera trap study (n=21 cameras) conducted from September 2016 to September 2017 in the Red Forest located within the Chornobyl Exclusion Zone. The Red Forest, which is likely the most anthropogenically contaminated radioactive terrestrial ecosystem on earth, suffered a severe wildfire in July 2016. The motion-activated trap cameras were therefore in place as the Red Forest recovered from the wildfire. A total of 45 859 images were captured, and of these 19 391 contained identifiable species or organism types (e.g. insects). A total of 14 mammal species were positively identified together with 23 species of birds (though birds were not a focus of the study). Weighted absorbed radiation dose rates were estimated for mammals across the different camera trap locations; the number of species observed did not vary with estimated dose rate. We also observed no relationship between estimated weighted absorbed radiation dose rates and the number of triggering events for the four main species observed during the study (brown hare, Eurasian elk, red deer, roe deer). The data presented will be of value to those studying wildlife within the CEZ from the perspectives of the potential effects of radiation on wildlife and also rewilding in this large, abandoned area. They may also have value in any future studies investigating the impacts of the recent Russian military action in the CEZ. The data and supporting documentation are freely available from the Environmental Information Data Centre (EIDC) under the terms and conditions of a Creative Commons Attribution (CC BY) license: 10.5285/bf82cec2-5f8a-407c-bf74-f8689ca35e83 (Barnett et al., 2022a).
MAP: Figure 1 Map showing the location of the study cameras overlaid on a 137Cs deposition surface (decay corrected to 2017). The large circle is the 5 km radius area over which absorbed weighted dose rates were calculated. Figure produced by and published with the permission of the Chornobyl Center.
Following the 1986 Chornobyl Nuclear Power Plant accident, coniferous trees up to 4 km to the west of the reactor were killed by radiation over an area of approximately 4–6 km
In July 2016 there was a severe fire within the Red Forest with approximately 80 % of the forest being burnt (Beresford et al., 2021). In September 2016 as one of a number of studies (e.g. Antwis et al., 2021; Beresford et al., 2021) considering the effects of and recovery from the fire, we set up a network of 21 motion-activated camera traps across the Red Forest, which were left in place to record primarily medium and large mammals for a period of approximately 1 year. This paper describes and discusses this study; all the photographs are freely available from 10.5285/bf82cec2-5f8a-407c-bf74-f8689ca35e83 (Barnett et al., 2022a).
Twenty-one Little Acorn 6210MC motion-activated digital trap cameras, fitted with 8 GB memory card to record images, were installed across the Red Forest in early September 2016; the cameras were operated for approximately a year until September 2017. The cameras were deployed using an approximate grid pattern with three rows of seven cameras (see Fig. 1). No bait was used to attract animals.
When deploying each camera for the first time, approximately 20 poles (1 m high with markings at every 20 cm) were positioned in front of the camera in three parallel rows 1 m apart; each row began 3 m in front of the camera and ended 8 m away from the camera. The camera was then activated to capture an image of the poles in situ, and the poles were then removed (an image of the pole positions at sites where these were recorded has been included within the dataset associated with this study (Barnett et al., 2022a); some of these images contain images of co-authors with their permission). The images of the poles can be used to estimate animal height and distance from the camera should this be desired. Tree branches, tall grasses and bushes that were likely to obscure the camera or cause false activation by their movement were cleared from an area of about 40–60 m
Each camera was mounted at a height of approximately 0.7 m (typically attached to trees) to principally record images of medium and large mammals, although images of small mammals, birds and occasional insects were also captured. The cameras were positioned such that they mostly faced north to shelter them from false activation caused by direct sunlight. When triggered by movement, all the cameras were preset to take a three-image burst; the interval between these three images was
Information related to each camera and each deployment period has been provided in file "REDFIRE_Trap_Camera_Details_And_Image_Summary", which is included within the dataset associated with this study (Barnett et al., 2022a). The information provided includes the following: location (site number); numerical camera identifier; setup number (
At sites 163, 168 and 169, the trap cameras were stolen during setup 1; therefore, no images from these cameras were recovered for that setup. The cameras were replaced at the start of setup 2 with new cameras located at nearby sites 362, 364 and 365, respectively. During setup 2, cameras from sites 157, 164, 170, 175 and 362 were stolen and not replaced, and the memory cards from cameras 158 and 171 were changed part way through; during setup 3, camera 158 did not operate. In total, images were recovered from 18 cameras for setup 1, from 16 cameras for setup 2 and from 15 cameras for setup 3. The camera located at site 172 was set to record video in error during setup 1 at a service visit in late October (photographs were recorded September to October as for the other cameras); the videos (20 s each) are included in the image catalogue and have been analysed in the same way as the photographs (see Sect. 2.3).
The site descriptive parameters, recorded by the same person for every site in early September 2016, include the following: numerical site identifier and location (latitude and longitude, WGS84); ambient dose rate measured at a height of 1 m above soil surface; an evaluation of the fire damage as visible in September 2016 ("none", "low", "medium" or "high") together with an estimate of the percentage of the area within 100 m of the site affected by the fire; an estimation of the density of grassy vegetation and undergrowth over a 20 m radius of the camera location; notes on habitat within a 100 m radius of the camera location; the dominant (
The image catalogue contains a description of information related to each image. The majority of the images obtained have been included within the dataset associated with this study (Barnett et al., 2022a). However, to protect privacy, any images containing people have not been included, although observations of people (other than members of the research team setting up and servicing the cameras) have been recorded in the catalogue. For cataloguing the images, a triggering event was assumed to begin when the camera motion sensor was triggered by an animal. A new triggering event was not assumed until at least 90 s had elapsed since an animal was last observed. However, there may be longer time periods between triggering events where images are obviously part of the same sequence (e.g. an animal lays down for a period of time).
Within the dataset associated with this study (Barnett et al., 2022a), all the images (including those which did not capture any animal) are located within three sub-folders called REDFIRE_Setup_1, REDFIRE_Setup_2 and REDFIRE_Setup_3, and within each of these folders are multiple sub-folders (with the format "Setup1_Site155_2317"), which correspond to the "Image_Location_Folder_Name" column within the image catalogue described below. Within each of these sub-folders are further sub-folders entitled the common species names of animals observed. The individual images of each animal are located within these folders and are supplied as *.jpg files and have the format IMAG0016. As noted in Sect. 2.2, at site 172 the camera was set, at a service visit in October, to record videos in error; the text "Video" has been used within the notes column of the image catalogue to identify where video rather than photographs was recorded (camera 172 setup 1 only); the videos have been provided within the dataset.
In the file "REDFIRE_Trap_Camera_Image_Catalogue", which is included within the dataset associated with this study (Barnett et al., 2022a), each image record (row) within the catalogue gives details of the following: setup number (
Data were entered into the image catalogue by UKCEH staff (who were not aware of the comparative contamination levels at the different camera sites), these data were then compared to a second set of data entered into a second catalogue by staff at the Chornobyl Center; any disparities were investigated and amended manually where necessary. Once this check was completed a final check was conducted by further UKCEH staff to ensure the information within the catalogue matched the images included within the dataset.
Indicative total weighted absorbed dose rates (i.e. internal plus external exposures) have been estimated for example mammals in the study area using the ERICA Tool (v2.0; Brown et al., 2016). As inputs to the dose estimation, the
A total of 45 857 images were captured (not including photographs recorded during camera setup and servicing); of these, 19 391 contained identifiable species or organism types (e.g. insects), 565 recorded people, 349 were of poor quality such that the species could not be determined and 25 552 images recorded no animals (i.e. predominantly false triggers due to vegetation movement, light or potentially a triggering by an animal that was not captured). A total of 14 mammal species were positively identified together with 23 species of birds (Table 1).
Table 1 Species captured on the motion-activated digital trap cameras.
Common species name Latin species name Mammals Brown hare Eurasian elk Eurasian lynx European badger Domesticated dog (feral) Grey wolf Marten sp. Martes (genus) Mouse sp. Muridae (family) Przewalski's horse Raccoon dog Red deer Red fox Red squirrel Roe deer Wild boar Unidentifiable Not applicable Birds Black grouse Common blackbird Common buzzard Common quail Common snipe Common wood pigeon Corncrake Eurasian bittern Eurasian hoopoe Eurasian jay Eurasian sparrowhawk Eurasian woodcock European nightjar European robin Fieldfare Finch sp. Fringillidae (family) Great egret Great grey shrike Great spotted woodpecker Great tit Hazel grouse Marsh tit Mistle thrush Red-backed shrike Shrike sp. Song thrush Thrush sp. Unidentifiable bird Not applicable Other species Unidentifiable insect Insecta (class) Butterfly or moth Lepidoptera (order) Dragonfly Odonata (order) Spider Araneae (order)
Table 2 Summary of medium and large mammal observations by setup.
Species Setup 1 Setup 1 Setup 1 Setup 2 Setup 2 Setup 2 Setup 3 Setup 3 Setup 3 Number of cameras species observed on Mean number triggering events per 75 d Mean/ maximum number of animals recorded per triggering event Number of cameras species observed on Mean number triggering events per 75 d Mean/ maximum number of animals recorded per triggering event Number of cameras species observed on Mean number triggering events per 75 d Mean/ maximum number of animals recorded per triggering event Brown hare 16 6.1 1.0/2 16 27.0 1.1/3 13 15.9 1.0/1 Eurasian elk 18 5.4 1.2/3 16 6.3 1.3/3 15 12.8 1.3/3 Eurasian lynx 6 0.6 1.2/2 2 1.5 1.0/1 1 2.0 1.0/1 European badger 3 0.5 1.0/1 4 2.7 1.0/1 2 1.5 1.0/1 Domesticated dog (feral) 4 1.0 2.1/4 6 1.5 6.0/4 3 2.0 1.7/5 Grey wolf 13 0.9 1.6/6 5 0.9 1.2/2 5 1.8 1.1/2 Przewalski's horse 6 1.5 1.2/5 5 1.5 1.2/3 n/a n/a n/a Raccoon dog 2 0.8 1.0/1 8 2.3 1.0/2 8 3.4 1.0/2 Red deer 15 2.7 1.5/8 13 5.4 1.4/4 10 6.6 1.4/6 Red fox 9 2.1 1.1/2 9 3.9 1.0/1 7 3.1 1.0/1 Roe deer 15 1.4 1.3/4 16 8.1 1.1/1 13 7.1 1.2/3 Wild boar 5 0.8 2.0/6 6 1.4 2.5/7 n/a n/a n/a
Deployment periods were the following: setup 1: September 2016 to March 2017; setup 2: March–June 2017; setup 3: June–September 2017. The total number of cameras operating in setups 1, 2 and 3 were 18, 16 and 15, respectively. n/a: not applicable, species not observed.
Table 3 Estimated weighted absorbed dose rates to mammals comparing those estimated for a large mammal (a deer) and a relatively small mammal spending some time underground (red fox). Estimates are presented for an area of 5 km radius centred on the Red Forest and also for an area of 0.5 km radius centred on each camera site.
Site Large mammal Large mammal Large mammal Red fox Red fox Red fox total dose rate total dose rate total dose rate total dose rate total dose rate total dose rate () () () () () () Mean SD Median Mean SD Median 5 km radius area 47 123 17 40 100 16 155 94 188 44 81 150 40 156 197 366 99 168 281 89 157 90 166 45 78 131 41 158 132 270 61 113 216 55 159 413 675 227 348 512 205 160 171 363 77 145 282 70 161 293 543 146 247 412 132 162 448 725 247 377 550 223 164 95 222 40 80 171 37 165 386 620 215 324 469 193 166 262 463 136 221 349 123 167 183 299 100 154 226 90 170 182 322 97 150 233 86 171 131 211 72 109 158 65 172 105 177 57 86 129 50 173 164 282 87 134 204 78 174 55 132 23 46 98 21 175 40 98 29 33 71 15 364 277 452 152 230 336 137 365 130 270 60 109 199 55
A summary of the images within the catalogue (e.g. number of images with mammals, birds, or insects; number of images with nothing; number of images with people in) and the total number of triggering events recorded (by setup, by site, by camera) has been provided in the file "REDFIRE_Trap_Camera_Details_And_Image_Summary" within the dataset associated with this study (Barnett et al., 2022a). The dataset also provides a summary for mammals (filename: "REDFIRE_Trap_Camera_Summary_Mammals"), by species, by camera and by setup of the number of triggering events and the mean, minimum and maximum of the number of individuals recorded per triggering event. For ease of comparing across setups, triggering events are presented as events per 75 camera trap days; 75 d was the shortest deployment period (setup 3). A similar summary for birds (which were not the target of this study) can also be found in Barnett et al. (2022a) (filename: "REDFIRE_Trap_Camera_Summary_Birds_And_Other").
Graph: Figure 2 Number of species observed by estimated weighted absorbed dose rate (note the estimated weighted absorbed dose rates presented are those estimated for the geometry approximating to a red fox).
Graph: Figure 3 Relationship between number of triggering events and estimated absorbed weighted dose rates (using that calculated for the red fox geometry as an example); data presented are from setup 3.
The mammalian species observed in the Red Forest (Table 1) included most of those observed in our other camera trapping studies across the CEZ (Wood and Beresford, 2016). Exceptions were that we did not observe brown bear (Ursus arctos), European bison (Bison bonasus) or Eurasian beaver (Castor fiber). The lack of these species in the Red Forest is to be expected:
- The Red Forest did not contain suitable habitat for beaver during the study period.
- Photographic evidence of European bison in the Ukrainian CEZ was first recorded in 2015 at a site close to the Belarusian border (the species having been introduced into the Belarusian CEZ in 1996) (Gashchak et al., 2017); only one individual bull was recorded by camera traps 2015–2016 in the Ukrainian CEZ.
- The numbers of brown bear in the Ukrainian CEZ are low with no recorded sightings in the vicinity of the Red Forest at the time of this study (Gashchak et al., 2016).
A number of images recorded small groups of feral (domesticated) dogs which we have not observed elsewhere in the CEZ. It is likely that these are animals fed by workers at the nearby nuclear power plant complex. Images of so-called "stalkers" (illegal tourists) were also captured; these are not included in the dataset though they are identified in the image catalogue.
For mammals, Table 2 presents a summary by species and setup. For a number of species (brown hare, roe deer, red deer), the number of triggering events was higher in setups 2 and 3; for Eurasian elk, triggering events were highest during setup 3 (Table 2). Whilst wild boar and Przewalski's horse were observed during setups 1 and 2, none were recorded during setup 3. Observations of Eurasian lynx, European badger and Raccoon dog were lowest during setup 1. Young (newborn) Eurasian elk started to be observed in April/May 2017, with young red deer and roe deer being observed from June. Przewalski's horse were only observed in areas that had been burnt, potentially attracted by the new growth of grassy vegetation.
Table 3 presents a summary of estimated total (internal plus external) weighted absorbed radiation dose rates for the example large mammal and red fox for each camera location, assuming a home range of 0.5 km radius and also over a radius of 5 km centred on the middle of our study area as estimated using the ERICA Tool. All mean, and most median, estimated dose rates are above the lower end of the International Commission on Radiological Protections (ICRP) Derived Consideration Reference Level (DCRL) for mammals of 1 mGy d
Our results do not support the low mammal abundance at Red Forest sites reported from the 2009 snow track study of Møller and Mousseau (2013). Furthermore, we observed no reduction in the abundance of mammals with increasing total weighted dose rate (which ranged over circa 1 order of magnitude). The number of species observed at camera locations was relatively consistent with estimated median weighted absorbed radiation dose rate (Fig. 2). We also observed no relationship between estimated median weighted absorbed radiation dose and the number of triggering events for the main species observed (brown hare, Eurasian elk, red deer, roe deer) (see examples from setup 3 in Fig. 3).
The data described here (10.5285/bf82cec2-5f8a-407c-bf74-f8689ca35e83; Barnett et al., 2022a) are freely available from the Environmental Information Data Centre (https://eidc.ac.uk/, last access: 16 January 2023) under a Creative Commons Attribution (CC BY) licence.
The data presented will be of value to those studying wildlife within the CEZ from the perspectives of the potential effects of radiation on wildlife and also rewilding in this large, abandoned area. Together with other trap camera datasets being published (e.g. Barnett et al., 2022b; Gashchak et al., 2022), the data will help in establishing a picture of wildlife across the CEZ. The data may also have value in any future studies investigating the impacts of recent Russian military action in the CEZ.
The authors are grateful to the following people for their assistance during the project: Eugene Guliaichenko (Chornobyl Center) for assistance during fieldwork and Claire Wells (UKCEH) for assistance with data entry. We also thank Jacky Chaplow (UKCEH) for proofreading the article.
By Nicholas A. Beresford; Sergii Gashchak; Michael D. Wood and Catherine L. Barnett
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