{"id":38771,"date":"2026-06-19T16:37:34","date_gmt":"2026-06-19T14:37:34","guid":{"rendered":"https:\/\/uni-freiburg.de\/en\/?p=38771"},"modified":"2026-06-22T13:37:51","modified_gmt":"2026-06-22T11:37:51","slug":"wildlife-in-chornobyl-is-changing-its-behaviour-during-russian-invasion","status":"publish","type":"post","link":"https:\/\/uni-freiburg.de\/en\/wildlife-in-chornobyl-is-changing-its-behaviour-during-russian-invasion\/","title":{"rendered":"Wildlife in Chornobyl is changing its behaviour during Russian invasion"},"content":{"rendered":"\n
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Freiburg, 19\/06\/2026<\/em><\/p>\n\n\n\n

An international research team has for the first time investigated how an unfolding armed conflict affected wildlife. During the Russian occupation of the Chornobyl Exclusion Zone in 2022, the scientists used camera traps to document that red deer, roe deer, foxes, and wild boar adjusted their activity patterns in response to the hostilities. The findings have been published in the journal Science.<\/strong><\/strong><\/strong><\/strong><\/strong><\/p>\n<\/div>\n\n\n\n

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Przewalski\u2019s horses near the former Chernobyl nuclear power station in 2020. Photo: Kateryna Korepanova<\/em><\/p>\n<\/div>\n\n\n\n

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An international research team has for the first time investigated how an unfolding armed conflict influenced the behaviour of wild animals. Using camera traps, the scientists documented how the Russian occupation of the Chornobyl Exclusion Zone during the 2022 war in Ukraine affected the activity of the animals living in the area. Data analysis shows that red deer, roe deer, foxes, and wild boar adjusted their day and night activity to the hostilities during this period. The team led by Dr Svitlana Kudrenko<\/strong>, who earned her PhD at the University of Freiburg, and Prof. Dr Marco Heurich<\/strong> of the University of Freiburg has published its findings in the prestigious journal Science.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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\u201cOur findings show that the diurnal activity patterns of mammals, particularly their nocturnal activity, changed during intensifying armed conflict. This points to a broader transformation of the Chornobyl Exclusion Zone \u2014 away from an ecosystem that, in the absence of human disturbance, had recovered from the reactor disaster, toward a militarised landscape in which wildlife habitat use and behaviour changed,\u201d says Marco Heurich.<\/p>\n<\/div>\n\n\n\n

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\n\t\t\t\t \u201cOur findings show that the diurnal activity patterns of mammals, particularly their nocturnal activity, changed during intensifying armed conflict. This points to a broader transformation of the Chornobyl Exclusion Zone \u2014 away from an ecosystem that, in the absence of human disturbance, had recovered from the reactor disaster, toward a militarised landscape in which wildlife habitat use and behaviour changed,\u201d says Marco Heurich.\u201d\t\t\t<\/p>\n\t\t\t\t\t\t\t\t\t

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\n\t\t\t\tProf. Dr Marco Heurich\t\t\t<\/h3>\n\t\t\t\t\t\t

\n\t\t\t\tProfessor of Wildlife Ecology and Conservation Biology at the University of Freiburg\t\t\t<\/h4>\n\t\t\t\t\t\t\t\t<\/div>\n\t<\/div>\n<\/div>\n\n\n\n
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An unintended scientific experiment amidst the Russian invasion<\/strong><\/h2>\n\n\n\n

The Chornobyl Exclusion Zone covers an area of 2,600 km\u00b2. Following the 1986 nuclear disaster and radioactive contamination, most of the area was designated a biosphere reserve. \u201cThe minimal human presence in the zone enhanced an increase in wildlife populations and led to recolonisation of the area by species that had become locally extinct before the catastrophe \u2014 such as brown bears and lynx \u2014 or those that were found only in small numbers, such as moose, red deer, wild boar, and grey wolf,\u201d explains Kudrenko. In addition, the endangered Przewalski\u2019s horse and the European bison were reintroduced in the 1990s.<\/p>\n<\/div>\n\n\n\n

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The Chernobyl Exclusion Zone covers an area of 2,600 square kilometres. The aerial photograph shows the cooling pond of the former nuclear power plant, among other things. Following the nuclear disaster of 1986 and the resulting radioactive contamination, much of the area was designated a biosphere and nature reserve. Photo: Kateryna Korepanova<\/em><\/p>\n<\/div>\n\n\n\n

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This map shows the study area within the Ukrainian part of the Chernobyl Exclusion Zone. Light brown dots indicate the locations of the 25 camera traps that were active in 2021, and black dots show the locations of the 31 traps that were active in both 2021 and during the occupation in 2022. Dashed lines indicate major roads through the area. Image: Svitlana Kudrenko<\/em><\/p>\n<\/div>\n<\/div>\n\n\t<\/div>\n\n\n\n

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Russian forces occupied the Chornobyl Exclusion Zone for 36 days, from February 24 to April 1, 2022. Since 2021, scientists had been monitoring a lynx population there using camera traps. After the end of the occupation, the team realised that the tragedy of war offered a chance to ask a new research question: How exactly did wild animals react to the immediate presence of armed conflict? \u201cAlongside our original research project, we were also able to investigate what had previously only been studied in military training areas,\u201d says Heurich. Following the withdrawal of the Russian forces, researchers were able to recover data from 31 camera traps, with the aid of Ukrainian armed forces who cleared mines and secured the area.<\/p>\n\n\n\n

Analysis reveals link between the intensity of conflict and species-specific behaviour<\/strong><\/h2>\n\n\n\n

The camera traps, which were triggered by infrared sensors, steadily recorded images from January 19 to May 6, 2022 \u2014 that is, immediately before, during, and after the occupation. As the basis for their analysis, the researchers compared this data with images from the 31 camera traps and an additional 25 camera traps from the year prior to the invasion between January 19 and March 21, 2021.<\/p>\n\n\n\n

In a further analysis, the team assessed the daily intensity of the armed conflict in 2022 and related it to the animals\u2019 daily activity patterns. \u201cTo do this, we derived an index of conflict intensity based on interviews, including with employees of the nuclear plant. In this index, we rated events such as military convoys, live firing, airstrikes, artillery shelling on a scale from zero to ten. We also took into account other factors, such as precipitation, proximity to roads or areas with a permanent human presence, and thermal anomalies such as bombardments or forest fires,\u201d explains Kudrenko.<\/p>\n\n\n\n

As conflict intensifies, animal activity during the day increases<\/strong><\/h2>\n\n\n\n

Using the data, researchers studied the behaviour of eleven animal species. \u201cWe initially assumed that, in response to disturbances caused by the armed conflict, animals would become more nocturnal, wary, and would avoid places with a constant human presence. Such behaviour has already been documented, and we had assumed that it would intensify during the armed conflict.\u201d<\/p>\n<\/div>\n\n\n\n

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In 2020 and 2021, Kudrenko and Heurich used camera traps in the Chernobyl Exclusion Zone to study the impact of human activity on the landscape and biodiversity. These images of a roe deer and a fox were captured by camera traps in 2020. Photos: Frankfurt Zoological Society & Chornobyl Radiation and Ecological Biosphere Reserve\/Wild Polissia Program (camera trap).<\/em><\/p>\n\n\t<\/div>\n\n\n\n

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While this was true for some of the species studied, the researchers also observed species-specific behaviours that deviated from previous assumptions: red deer and red foxes reduced their nocturnal activity during the occupation compared to the same period the previous year. \u201cThe decline in night-time detections suggests that these species have shifted their activity to daytime hours in response to increased conflict intensity,\u201d says Kudrenko. \u201cOverall detections of roe deer declined while overall detections of red deer increased amid rising conflict intensity. We also observed that brown hare and red deer responded to thermal anomalies, mainly conflict-related forest fires, by becoming more active at night.\u201d<\/p>\n\n\n\n

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Further information<\/strong><\/strong><\/strong><\/h3>\n\n\n\n
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