The rewilding of Chernobyl: A long term monitoring of passive rewilding after land abandonment using remote sensing

Abstract

In 1986, the nuclear disaster in Chernobyl caused large-scale land abandonment which
resulted in one of the largest unintended experiments of passive rewilding, yet no study
has combined remote sensing land cover classification using a pre-disturbance baseline
with vegetation productivity analysis across the full Chernobyl-Palieski Reserve under an
explicit rewilding framework.
This thesis quantifies land cover change and vegetation productivity dynamics between the
Chernobyl-Palieski Reserve and its surrounding buffer zone between 1986 and 2018. To
achieve this, a locally trained Random Forest classification of Landsat imagery is performed
and the Enhanced Vegetation Index 2 is used as a proxy for vegetation productivity.
Inside the reserve, 89.2% of pixels that were not classified as vegetation in 1986 had
transitioned to vegetated cover by 2018 through spontaneous ecological succession, while only
49.8% did so in the surrounding area, with agriculture to shrubland as the dominant transition.
Vegetation productivity increased across both zones, with the reserve displaying slightly higher
values, consistent with human exclusion as the primary driver. Cross-product comparison with
a global land cover product reveals that global products may be insensitive to the transitional
shrubland stage through which passive rewilding occurs.
Findings from this thesis contribute a large-scale remote sensing case to the emerging evidence
base for passive rewilding and highlight limitations of global monitoring products to capture
transitional vegetation classes central to ecological succession.

Popular Abstract

When Nature Takes Back: Three Decades of Rewilding at Chernobyl

On 26 April 1986, one of the most dramatic human-made catastrophes, the meltdown of a Chernobyl nuclear reactor in Ukraine, caused the evacuation of over 300 000 people in the vicinity of the power plant. Right after, an area of over 5000 square kilometers across Ukraine and Belarus was created and human activities were restricted. In this process, farmers abandoned their fields, villages became empty and forests were left unmanaged. Three decades after, what was once a disaster zone has transformed into one of the largest natural recovery experiments in recent history.
The process of nature bouncing back after decreased human pressure is known as passive rewilding. Unlike traditional conservation, which aims at the preservation of an ecosystem through active management, passive rewilding let nature find its own path to form the landscape. This strategy is increasingly seen as a cost-effective and promising approach to restore biodiversity and tackle climate change, and especially in Europe where agricultural land is being abandoned every year. Chernobyl represents one of the largest and long-running examples of this process on the planet, yet no study has used satellite imagery to explore these changes under an explicit rewilding framework.
Watching from space
In this thesis, satellite images from 1986 and 2018 were used to map how the landscape has evolved over 32 years. By training a computer algorithm to recognise different types of land cover, it was possible to track which areas in the exclusion zone had transformed and which had stayed the same. Vegetation health was also analysed using a vegetation index, a way of estimating how productive and green an area is based on how plants reflect light. Outside of the reserve, a buffer zone was established, where human activities continued at a reduced level, and was used as a comparison area to estimate the effect of human exclusion from broader regional trends.
What the results show
Striking results have been observed in this study. Within the reserve, nearly 90 % of what was either urban areas or farmland in 1986 had been colonised by vegetation by 2018, compared to roughly 50% in the surrounding buffer zone. The agricultural fields mainly evolved into young woodland and small shrubs, an expected vegetation state known as succession in ecology science. Plants have also become significantly more productive inside the reserve than outside suggesting a higher photosynthetic activity. The difference observed between the two zones is important because it suggests that the withdrawal of human activity more than any variation in climate or soil is the primary driver for landscape change at Chernobyl. Regarding radiation, while it can be harmful at the organism level, it does not appear to have prevented this large-scale ecological recovery. The study also compared the local classification against a globally trained satellite land cover product. Findings suggest that the transitional shrubland stage, which is key in vegetation recovery, may be undetected by such global datasets, raising questions about the current capacity of global monitoring frameworks to capture the full extent of ecological succession on abandoned land.
Why it matters
In Europe, over 100 million hectares of land have been described with rewilding potential, and ongoing agricultural abandonment is creating opportunities for nature to recover spontaneously. This study on Chernobyl adds to a growing body of evidence that passive rewilding on former agricultural land can drive substantial landscape transformation without active management. However, in the Chernobyl context, the densification of woody vegetation also increases wildfire risk and the potential spread of radionuclides, suggesting that passive rewilding alone may not be sufficient. The recovering populations of large herbivores within the reserve may offer a natural and self-sustaining mechanism to maintain a more open and heterogeneous landscape. The question for Chernobyl is no longer whether rewilding is occurring, but what kind of rewilding is most ecologically desirable and radiologically safe.

• author: Wiederkehr, Maxime Henri René
• supervisor: Hakim Abdi
• organization: Dept of Physical Geography and Ecosystem Science
• course: NGEM01 20261
• year: 2026
• type: H2 - Master's Degree (Two Years)
• subject: Biology and Life Sciences; Earth and Environmental Sciences
• keywords: Physical Geography and Ecosystem analysis, Passive rewilding, land cover change, remote sensing, ecological succession, Chernobyl Exclusion Zone, Random Forest classification, vegetation productivity
• publication/series: Student thesis series INES
• report number: 792
• language: English
• id: 9245160
• date added to LUP: 2026-07-29 11:31:07
• date last changed: 2026-07-29 11:31:07