Gone forever? How Polesia lost and regained its rare species

Gone forever? How Polesia lost and regained its rare species 

According to scientific estimates, around 1 million species of flora and fauna on Earth are currently threatened with extinction. We are witnessing a major biodiversity crisis that is, however, not the first one in the history of our planet. What makes it different is that this time, it is almost entirely due to human activity. Will rare species disappear forever, or do they still have a chance to move away from the danger line? It is hard to say for sure. But some local cases from Polesia give cause for cautious optimism.  

A terrible disaster as a chance for wildlife 

The accident at the Chornobyl nuclear power plant in 1986 is sometimes described as the worst man-made disaster in history. Its impact on people’s health and well-being, the economy and the environment is still enormous. A large area around the epicentre of the disaster, once densely populated and used for agriculture, was abandoned by people because of the contamination. Wildlife immediately seized the opportunity and began to reclaim the now uninhabited territory.  

One of the rare species to benefit from this situation is the Greater Spotted Eagle (Clanga clanga) – a globally endangered bird that was locally extinct in what is now known as the Chornobyl Exclusion Zone. These birds depend on intact wetlands for foraging and breeding and suffer from habitat degradation and human disturbance. After the unguided rewilding of the exclusion zone had begun and former croplands had given way to mires and forests, the Greater Spotted Eagles started recolonizing this territory which is now the only place on Earth where the population of this rare eagle is growing.  

A young Greater Spotted Eagle. © Adham Ashton-Butt

The Chornobyl Exclusion Zone is home to one more globally endangered species – the Przewalski’s horse (Equus przewalskii). Its population declined in the 1940-1950s and was considered extinct in the wild in the 1960s – only captive individuals in zoos of various countries were saved. However, as a result of successful captive breeding efforts, the number of Przewalski’s horses has increased and some were released into the wild. In 1998, 31 animals were introduced to the exclusion zone in Polesia. Within 20 years, the local population had grown to 150 animals. Indicators of genetic diversity show that this population of the Przewalski’s horse has good prospects for further growth.  

Przewalski's horses in Chornobyl Exclusion Zone. A camera trap picture.

Extinct or lying low? 

In the last century, the European mink (Mustela lutreola) was widespread in Polesia and in Europe as a whole, but now the species is as rare as hen’s teeth. This is because a few thousand American minks (Neogale vison) were brought to Europe in the 1930s for the fur trade. They were originally intended to be bred on farms. Later, however, some of the ‘aliens’ got into the wild. The native species could not compete with the more aggressive and strong invasive animals. The European mink was driven out of most of its historic range and became a critically endangered species. It has not been seen in Polesia for more than 20 years, and some experts believe it is extinct in the area.  

In 2021, field biologists from our project set out to rediscover the European mink in Polesia. They installed 25 camera traps along rivers and drainage canals in remote areas of the Almany Mires Nature Reserve. Unfortunately, no picture of the European mink was captured. However, this does not necessarily mean that the species has disappeared from the region: the next story shows what surprises are possible when it comes to biodiversity.  

An expedition searching for the European mink in Polesia. Summer, 2021.

Polesia is home to at least 12 species of bats, including a real rarity – the Greater Noctule (Nyctalus lasiopterus), the largest bat in Europe. This species is rare, its range is fragmented and the smallest among the European bats. The Greater Noctule was thought to be locally extinct in Polesia. Once a male bat was shot in 1930: this was the last sighting of the species in the region until 2015. However, after 85 years, two lactating female Greater Noctules were entrapped during a bat census in Belarusian Polesia. This proved that the rare bats were breeding in the region! In 2017, new observations of the Greater Noctule were made, and later, they were also identified in the course of acoustic monitoring as part of our project.  

A close-up photo of the Greater Noctule. Photo credit: Irina Kashpei.

The Greater Noctule is an indicator species for the natural state of the old-growth forests. Its decline in Europe is caused by lack of suitable habitat – old-growth forests with a large number of hollow trees in a small area to ensure the successful functioning of a bat colony. In more than half of the cases, the Greater Noctule prefers to live in dead trees. This demonstrates the crucial importance of deadwood preservation for biodiversity conservation.  

The cases described show that there is often a chance to reverse worrying trends and bring rare species back from the brink of extinction. And let’s use the memory of species that we will never see again in the wild as an incentive to do our best to ensure that their number grows as slowly as possible. 

The project “Polesia – Wilderness Without Borders” is part of the Endangered Landscapes & Seascapes Programme and is funded by Arcadia. The project is coordinated by Frankfurt Zoological Society (FZS).

Anthropogenic factors limit suitable habitat for wolves in Polesia

Anthropogenic factors limit suitable habitat for wolves in Polesia: new study

The conservation of the Grey wolf (Canis lupus) in Europe has been quite successful, with numbers increasing and the grey carnivore reappearing in many places where it was once completely extirpated. Meanwhile, the Polesian population of wolves is poorly understood, despite its high conservation importance. A new study supported by our project is one of the first attempts to fill this gap and analyse the habitat suitability of wolves in Polesia, taking into account both environmental and, more importantly, anthropogenic factors.

According to official estimates, wolves occur throughout Polesia and their numbers are the highest among the large carnivores of the region. However, the species is only regularly recorded in some protected areas, and overall, the wolves’ densities, distribution and movements in this large region have not yet been systematically studied. Meanwhile, this information is very important for understanding the status of the wolf in Europe as a whole: the Polesian population of the species is of high conservation importance as a link between the wolf population in Russia and those in Poland and the Baltic countries.

The Grey wolf has never disappeared from Polesia. Up to the middle of the 20th century, it used to be widely spread in both Belarus and Ukraine. After the Second World War, however, wolves were regarded as a vermin species threatening the economy and human safety. This entailed systematic overhunting, which, alongside with habitat fragmentation and degradation caused by anthropogenic impact, led to the decline of the wolf population. Still hunted year-round in most of Polesia (in both Ukraine and Belarus), wolves have not disappeared, however, but often find refuge in dense forests and impassable mires.

A photo of wolves from a camera trap intalled in the Chornobyl Exclusion Zone - the area where wolves are virtually not disturbed by people.

The authors of the study aimed to assess the influence of anthropogenic factors on habitat suitability for wolves and to quantify the extent of their suitable habitat in Polesia. They compiled the wolf presence data collected between 2014 and 2021 from several sources: telemetry data, remote camera-trapping studies, scat samples confirmed by genetic analysis, and geo-referenced wolf records (i.e. photos, remote camera records, and other confirmed observations). To predict suitable habitat, they selected a set of key variables characterizing the landscape, including three related to land cover in the study area (land cover type, tree cover, and Normalized Difference Vegetation Index (NDVI)). Among the variables that reflect the anthropogenic impact, artificial light at night (ALAN), the proportion of cropland, and road density were selected as the most relevant. The wolf presence data were matched to the characteristics of the landscape and then analysed in a 1 km resolution grid.

Data analysis showed that cells with wolf presence differed significantly from those without the species. The animals prefer areas with low ALAN values. The researchers point out that this variable is a better indicator of human presence than census data or the population density index. The proportion of cropland and the density of roads were also lower in the cells with wolves. At the same time, tree cover percentage and NDVI values positively correlated with recorded wolf presence. Additionally, wolf observations were more frequent in cells with forests and wetlands as the dominant habitat type. This could be explained by the abundance of prey and low human disturbance. Alongside similar European studies, the new research confirmed that wolves avoid areas with permanent human presence.

A map of Polesia with protected natural areas outlined with green.

Overall, the proposed model showed that 26% of the territory of Polesia (approximately 42,000 km2) is suitable habitat for the Grey wolf, of which more than 14,300 km2 is highly suitable. The rest of the landscape has low or very low suitability values. At the same time, even suitable habitats are only partially occupied by wolves.

The study showed that core protected areas for wolf conservation in the Polesia region are the Białowieża Forest, the Chornobyl Exclusion Zone with the neighbouring Drevlyanskyi Strict Nature Reserve and the central part of Polesia (Almany Mires Nature Reserve, the Pripyatskyi National Park, the Mid-Pripyat Nature Reserve and the Rivnenskyi Strict Nature Reserve). These protected areas have between 37% and 77% suitable habitat within their boundaries. High-quality unprotected areas suitable for wolves have also been identified. Some of these are isolated but still accessible for wolves.

The authors of the study explain that some high-quality areas are not well connected with other sites. Therefore it is very important to prevent their further fragmentation. The study made it possible to identify the areas that could be taken under protection in order to ensure better connectivity between core protected areas that are crucial for wolf conservation. Thus, this research lays the foundation for the further expansion of the protected area networks as well as for effective, long-term wolf monitoring and management programmes in both Belarus and Ukraine. This variety of measures has the potential to strengthen grey wolf conservation in the region.

The project “Polesia – Wilderness Without Borders” is part of the Endangered Landscapes & Seascapes Programme and is funded by Arcadia. The project is coordinated by Frankfurt Zoological Society (FZS).

Between Polesia and Zambia: a Polesian eagle chooses a very unusual wintering site in Africa

Between Polesia and Zambia: a Polesian eagle chooses a very unusual wintering site in Africa

Greater ​S​potted ​E​agles from Polesia are about to start their autumn migration southwards. Their wintering sites are scattered across Europe, Asia and Africa: these birds spend the cold season in​ the​ Balkan Peninsula, Israel, South Sudan, Zambia, and even South Africa. Thanks to GPS-tracking, we not only have a chance to discover migration patterns that are important for​ the conservation of this rare species, ​but also ​learn​ many​ ​​curious details ​that make even experienced scientists surprised. One of these was recently discovered and described by ornithologist Valery Dombrovski.

Liada is a female eagle nesting in the Mid-Pripyat Nature Reserve in Polesia. She spends every winter in Zambia, in a tiny area of only 3 square kilometers. This is too small even for a Greater Spotted Eagle, but Liada is a hybrid between ​G​reater and Lesser Spotted ​E​agles. Typically, wintering​ ​​L​esser ​S​potted ​E​agles have several feeding sites located at a significant distance from each other. ​Because of this, ​vast wintering areas of tens of thousands of square kilometers are formed.

Polesian Greater Spotted Eagle Liada in Zambia. Photo credit: Brett Lewis

Wintering grounds of ​G​reater Spotted ​E​agles are much smaller;​​ however, they usually also reach dozens of square kilometers. It means that Liada is an exception to the general rule. Every day, she flies only a couple of kilometers from one part of the forest to another. How can she survive in such non-typical conditions? I had to dig ​deep​​ ​​into ​the internet to figure it out. Fortunately, this part of Zambia is well known to scientists and naturalists. The area belongs to the Kasanka National Park​,​ famous for its biodiversity. It is home to various species of bushbucks, blue monkeys, and about 400 bird species. And then I found out that one of the most famous natural “shows” occurs in Kasanka annually, and it attracts numerous tourists from around the world.

From​ the​ middle​ of​ October to late December, over 10 million​ ​of Eidolon​ ​​F​ruit ​B​ats (Eidolon helvum) congregate in Kasanka. All of them arrive​ in ​the wetland forest with ​a ​total area of about 2 ha​,​ thus forming the highest density of mammals in the world. Eidolon ​F​ruit ​B​ats are​ quite b​​ig​​​ ​​– their weight can reach 350 g. The enormous number of resting bats causes tree branches to bend and even break.

Millions of bats fill the sky, Kasanka NP. Photo credit: Will Burrard-Lucas www.willbl.com

No wonder that the congregation of bats attracts numerous predators. The forest turns into a feeding ground for birds of prey. In addition, there are crocodiles, snakes and l​​eguans waiting for some unfortunate bat to come​ tumbling down​​.​

And what about our Liada? Is she part of this natural spectacle? Yes, she is! She arrives in Zambia in late October, simultaneously with the bats, and then visits the bat forest almost every day. Obviously, Liada like many local predators, feeds on this mysterious natural phenomenon – ​the ​mass congregation of Eidolon ​F​ruit ​B​ats in the same place.

The yellow line on the map indicates Liada's wintering ground of 3 square kilometers in total. The red line marks the boundaries of the "bat forest" where millions of fruit bats congregate. The blue marks show Liada's location during the wintering period - from October to February.

Isn’t this impressive? Liada nests in Polesia, looks and behaves just like dozens of other​ ​​G​reater ​S​potted​ ​​E​agles, but at the same time she is the link that connects us to an outstanding natural phenomenon in a different part of the globe. What secrets ​do ​other ‘ordinary’ ​G​reater ​S​potted ​E​agles​ ​​hold​? We can only guess and hope for new, unexpected discoveries.

The top image features Greater Spotted Eagle Liada in flight. The photo is taken by Brett Lewis in Kasanka National Park, Zambia.

The project “Polesia – Wilderness Without Borders” is part of the Endangered Landscapes & Seascapes Programme and is funded by Arcadia. The project is coordinated by Frankfurt Zoological Society (FZS).

A bird's story told by a camera trap and a GPS-tracker

​​​​The adventures and dramas of birds: a story told by a camera trap and a GPS-tracker

Hi-tech equipment is helping our researchers gather valuable information about the endangered ​​​Greater ​​​Spotted ​​​Eagles. With the help of camera traps, we learn a lot about their behavior, diet and breeding, while GPS-trackers are revealing numerous patterns of the eagles’ migration. Ornithologist Valery Dombrovski has been researching Greater Spotted Eagles for decades. He knows how to systematize facts, numbers, graphs and trajectories… However, as a really sharp-sighted scientist, he can see whole stories behind this information. And here is one of those stories.

Male Greater Spotted Eagle Dzimon was captured and tagged with a GPS-tracker on the 9th of July 2020, in the eastern part of the Almany Mires in Polesia, not far from his nest. He wasn’t much different from other birds of the species: he hunted properly and raised a strong chick by autumn.

Dzimon and his chick in the nest.

​​But ​​​​​something strange began to happen with Dzimon following spring, after he had returned to Polesia from his wintering site near the border of Sudan, Ethiopia and South Sudan. Having arrived ​at​ his nest, Dzimon his female in ​the​​​ company of another male. The couple had already renewed the old nest with fresh branches and lined it with green leaves to make​ the​​​ eggs​’​ incubation more comfortable.

The new male in the nest. Dzimon hasn't arrived yet.

The female’s behavior was not at all strange. She never knows if her old partner will return, and therefore she accepts courtship from any male who likes her. Usually, the new male leaves the nest in case the female’s old partner returns. At first it seemed like that was happening. Dzimon and the female visited the nest together, and the alien disappeared. But this only lasted for a couple of weeks.

The last weeks of Dzimon's family life.

On the 27th of April, Dzimon flew to the edge of his hunting territory and stayed at the same place for three days in a row. Unfortunately, the camera trap at the nest was not working at that time, and we don’t know what happened ​​​i​n the nest right before he left. But the eagle was confused, it was noticeable in his behavior. It seemed that he didn’t know what to do next. So, three days later, he took to the air and left those places. He never returned to his female and the future chick.

Dzimon started wandering. At the beginning, he headed to the north to hunt in an agricultural area near the town of Turau/Turaw, which was rich in field mice. Well refreshed, the bird headed east in a week’s time, reaching the town of Pietrykaw 70 kilometers away. Then he flew back crossing the river Ubarc and the Almany Mires and found himself on the bank of the Jaselda river not far from the town of Pinsk. On the 16th of May, Dzimon surprisingly headed to the town of Pinsk and stayed there, in the urbanized area, for more than a month! It looks like he was hunting right in private gardens on the outskirts of the town. In late June, the eagle changed his location again and flew to the Belarusian-Ukrainian border, where he stayed until the beginning of the autumn migration.

The srack of Dzimon's wandering in summer 2021.

And what about the nest and the female? The new male that appeared in spring was still there. He spent the summer feeding the female and their chick that grew up and left the nest successfully in August. But why did Dzimon leave his nest? We can only guess. Maybe he lost the competition with a stronger and younger male, or maybe he guessed somehow that he would have to feed someone’s else chick… The bird’s thoughts will remain a secret.

During the spring migration of 2022, Dzimon arrived​ ​​in​ Polesia very late – on the 19th of April. It was one of the latest known dates for the return of a Greater Spotted Eagle. He rushed directly to his old nest. Perhaps he was still hoping for a happy family life? Apparently, no​ ​​o​ne was waiting for him at home. Having spent about 20 minutes there, he flew on into the depth of the Almany Mires. Over the next month, Dzimon tried to settle down there. But he didn’t succeed, since the area was already shared by other nesting birds. Gradually, they drove him out further south, to Ukraine, where the density of the species is not so high. He spent most of the season close to the village Stare Selo in Ukraine. On the 25th of July, Dzimon flew kilometers to the south-east, to​ the​ Zhytomyr region, where he died three days later. No​ o​ne knows what happened to him. The Ukrainian experts only found a tracker and the remains of Teflon straps that used to fix the device on the bird’s back. This was the end of Dzimon’s journey, during which he never found a new home.

The project “Polesia – Wilderness Without Borders” is part of the Endangered Landscapes & Seascapes Programme and is funded by Arcadia. The project is coordinated by Frankfurt Zoological Society (FZS).

Through a camera trap: the secret life of rare eagles at arm’s reach

Through a camera trap: the secret life of rare eagles at arm’s reach

Sitting for hours in the bushes and marshes, peering through a telescope or a binocular - a decade or two ago, this was the only way to make scanty observations of nesting Greater Spotted Eagles. These birds are elusive and difficult to observe, especially during the breeding season when they are extremely sensitive to human disturbance. Nowadays, however, camera traps set up next to a nest can give us a valuable glimpse into the family life of these rare eagles and reveal many important and curious facts about them. We invite you to find out how we observed a nesting pair of Greater Spotted Eagles through the lens of a camera trap.

In 2021, the female Greater Spotted Eagle of unusual light colour returned to her nest on the 2nd of April. This individual is very remarkable: Greater Spotted Eagles with pale morph are very rare in the European part of their range, and this very bird became the first Greater Spotted Eagle with such a phenotype observed in the Belarusian Polesia. Will her chicks inherit the pale morph? We can’t predict that.

The male Greater Spotted Eagle – with rings on his legs and a GPS transmitter on his back – appeared two days later, on the 4th of April.

Greater Spotted Eagles often build their nest on a branch fork high above the ground, so that their home is hidden behind dense foliage. Typically, the same nest is used by the same pair of birds for several years in a row. Having returned home, the birds immediately started working hard improving the old nest. They carried new branches to their nest for more than 2 weeks. Compare its appearance before and after the renovation!

In late April, the female Greater Spotted Eagle spends a lot of time in the nest: she is about to lay eggs. A Greater Spotted Eagle usually lays from 1 to 3 eggs, with a break in time. And here it is! We observe the first egg on the 30th of April. On the 4th of May we see two eggs in the nest already.

Now, the incubation of the eggs begins. It lasts from 40 to 44 days on average. Previously, researchers supposed that only the female stays in the nest throughout the entire incubation period. But the camera traps pictures show that the birds take turns incubating the eggs. The female spends more time in the nest. However, the male often gives her time to hunt and stretch her wings. It is quite cold in early May, only 5-10 °C. The female spreads her feathers to keep herself and the eggs warm.

The male eagle feeds the female while she incubates the eggs. Information on the composition of the Greater Spotted Eagle’s diet is very important for the study and conservation of this species. And camera traps give us a chance to observe what the birds eat! This time, it’s a vole. Small rodents are common prey of the Greater Spotted Eagles.

At the beginning of June, our Greater Spotted Eagles look forward to the most exciting event of the nesting season: their chicks are about to hatch. The female’s powerful paws with sharp claws allow her to tear apart her prey easily. But look how delicately she holds the egg!

Finally, the long-awaited moment comes: the first chick hatches on the 8th of June after 5 weeks of incubation! The parents celebrate with big catch: this time, it’s a hare. While the female is busy with the prey, we can see the first hatched chick clearly – it is one day old!

On the 12th of June, we see the second chick free of its shell. But will it survive? Greater Spotted Eagles have a strong tendency to cainism: a second-hatched chick often dies within the first two weeks, and its death is directly or indirectly caused by the elder.

At about two weeks old, the chicks of the Greater Spotted Eagles are quite active, stretching their wings and crawling. The adult birds have to keep an eye on them all the time so that they don’t fall out of the nest.

Meanwhile, the male has to spend a lot of time hunting to provide food for himself, the female and their chicks. The camera trap captured rodents and a mallard chick among their prey. The female feeds the chicks in turns tearing the prey into small pieces. The older chick is bigger, stronger and more assertive. But the adults pay equal attention to the second-hatched one, too. Obviously, it has a good chance to survive!

The older chick is nearly 3 weeks old, with the first feathers visible among the down covering its body. Remarkably, the parents started leaving the chicks alone in the nest for short periods! The fast-growing chicks need a lot of food, so the adults have to spend a lot of time hunting. This time the male caught a weasel.

As the camera trap photos prove, the diet of the Greater Spotted Eagle is quite varied. In the photo below, the female seems to reproachfully look at the chicks as they turned away from the fish. But the next day we see a chick trying to eat a vole on its own while the adults are away!

When raising chicks, adult Greater Spotted Eagles permanently renew their nest with fresh branches of oak, alder and birch. In this way, the birds cover the remains of prey and droppings, keeping the nest clean.

It’s early July, and the first-hatched chick is one month old. The second one is just a few days younger, but the difference is still noticeable – they are growing so fast! Both chicks continue receiving equal care and nutrition, and it’s very likely that both will survive.

By mid-July, the Greater Spotted Eagles chicks have grown quite big and strong and no longer need the constant presence of their parents. Ornithologists choose this time to replace the batteries and SD cards of the camera trap on the nest and ring the chicks. Look, one of them has a new ring on its leg! The chicks often flap their wings in training for their first flight. But the female still cares for them tirelessly. The camera trap caught her shielding the chicks from the sun with her wings.

Most often, Greater Spotted Eagles hunt small mammals. However, the most part of the biomass consumed by these predators consists of birds. Sometimes, even large birds: the bones identified on these camera traps images belonged to a heron!

At the beginning of the nesting season, we guessed whether the new chicks of the pale female would be of the rare pale or typical dark colour. In the second half of the summer we can clearly see that they have inherited the morph of their father and have grown up to the typical dark colour  of the Greater Spotted Eagle. However, there are known cases when chicks of two different phenotypes have been observed in the same brood!

By mid-August, the breeding story is over: the fledglings left the nest! They were last seen by our ornithologists in early September, when the young birds are usually quite independent. This is a remarkable story: both chicks survived and grew up! We hope that they are still well and that one day the rings will tell us more about them thanks.

Follow us on our Twitter account. There you will find more information about the wildlife of Polesia and more pictures from our camera trap surveys!

The project “Polesia – Wilderness Without Borders” is part of the Endangered Landscapes & Seascapes Programme and is funded by Arcadia. The project is coordinated by Frankfurt Zoological Society (FZS).

The sound of the wilderness

The sound of the wilderness 

A pilot project in Polesia captures part of the biodiversity using audio recordings. This is a promising new tool for biodiversity monitoring 

Those carrying out biodiversity surveys in Polesia must not be squeamish. It is a wilderness area of superlatives: half the size of Germany, the predominantly peatland landscape stretches from Poland through Ukraine and Belarus into Russia. Rivers in their natural state, overflowing their banks in spring, meander through a mosaic of alluvial forests, bogs, oxbow lakes, floodplain meadows and mires. 

Such large contiguous habitats have largely given way to agriculture in other parts of Europe. And these wet and boggy habitats are difficult to traverse. While our colleagues wade slowly across the mires to count rare birds of prey such as the Greater Spotted Eagle or set up camera traps to study wolves and lynx, swarms of mosquitoes and other insects are their faithful companions. 

One of the main goals of our work in Polesia is to identify areas that are worth protecting. A better understanding of where there are gaps in protection and where priority areas lie will help us to support and justify requests to expand existing protected areas and designate new ones. Biodiversity and the presence of strictly protected species are among the key criteria. 

However, population surveys are usually time-consuming. Additionally, nocturnal animals, such as insects or bats, which are difficult to find, are often overlooked, even though they usually have a high conservation status. Studying smaller animals such as bats, rodents and insects using conventional methods takes a lot of time, effort, patience and financial resources. Therefore, in Polesia we have turned to a new promising instrument for biodiversity research: acoustic monitoring. Bats and other species can now be identified using sound recordings. 

An acoustic sensor recordig sounds of nature in Pripyat-Stokhid National Park, Polesia, Ukraine. Photo credit: Daniel Rosengren.

 Two years of passive acoustic monitoring 

In the largest systematic survey of species diversity in Ukrainian and Belarusian Polesia to date, we carried out what is known as passive acoustic monitoring for two years. We recorded bats, birds, small mammals, bush crickets and some large mammals over an area of about 50,000 square kilometres, comparable in size to Slovakia. In this area, the recording devices were set up at 500 sites for four nights at a time. Thousands of hours of animal sounds have been recorded – day and night, in dense forests and extensive bogs and in every direction within a hundred metres of the recorder. 

An Aquatic Warbler in Pripyat-Stokhid National Park, Polesia, Ukraine. Photo credit: Daniel Rosengren

Shazam for animal sounds 

The current result is around three million recordings with around 500,000 animal sounds. It would take years to filter out these animal sounds from other environmental noise and identify them individually. Therefore, our project partners at the British Trust for Ornithology have developed an automatic sound classifier. Similar to the mobile phone app Shazam, which can identify pieces of music based on a melody fragment, the new sound classifier is able to match recordings of animal sounds to certain species. The algorithm analyses the spectrogram, i.e. the visual sound image of the recording. It then  searches for typical patterns according to known parameters and provides information about the type of sound recorded. 

In this way, we can now automatically classify over 50 species of bats, birds, bush crickets and small mammals. To be on the safe side, these are then manually checked and the algorithm is improved where necessary. This allows us to record many species simultaneously, from the Great Grey Owl (Strix nebulosa) and the Pygmy Shrew (Sorex minutus) to bush crickets such as the Great Green Bush Cricket (Tettigonia viridissima). 

This method of recording and monitoring the species is non-invasive as the animals are not disturbed compared to traditional methods. Bats, birds and insects do not have to be caught with nets and then examined and identified manually. In addition, acoustic monitoring is cost-effective as it allows the recording of different groups of animals simultaneously, and large amounts of data can be collected in a relatively short period compared to conventional recording methods. 

The main objectives of the acoustic monitoring are to systematically map biodiversity throughout Polesia, identify habitats of particular importantance to different species, identify priority conservation areas and assess the impact of human activities such as drainage, fires and road construction on the biodiversity. The species lists also serve as a basis for formal applications to extend protected areas. 

Elleni Vendras, Project Coordinator of “Polesia - Wilderness without Borders” 

The top image features a night landscape of the Skrypitsa river floodplain in Polesia. Photo credit: Viktar Malyshchyc.

The project “Polesia – Wilderness Without Borders” is part of the Endangered Landscapes & Seascapes Programme and is funded by ArcadiaThe project is coordinated by Frankfurt Zoological Society (FZS).

Polesia, satellite view: innovative technologies for studying the landscape

Polesia, satellite view: innovative technologies for studying the landscape

Conducting comprehensive research of a vast and varied landscape like Polesia is always a challenge. Fortunately,  scientists nowadays have alternative methods that can reduce labour and time taken for field studies and make the experts’ work more efficient. For instance, the application of satellite data has made it possible to build the first landcover map for the whole of Polesia, facilitating mapping and analysis of large-scale fires that occurred in the region over the past 19 years. What are the pitfalls of working with satellite data? What should be considered when building similar maps for other regions? Let’s give the floor to one of the authors of these two studies – Dr. Adham Ashton-Butt, Senior Research Ecologist at the British Trust for Ornithology. 

— Open-source satellite data can be extremely useful in obtaining environmental data over large areas and frequent measures over time. This is data that would often be too expensive or time-consuming to collect on the ground. There are limitations, however, as it is not always easy to see how data from satellites (spectral data) relates to “real” measurements on the ground e.g. moisture levels, growth of plants, soil carbon, or land cover. These relationships need to be estimated, which if not done well can result in large amounts of error.

— Your recent study analyzing the patterns of landscape fires in Polesia combines both conventional field surveys and innovative approaches that require special knowledge and skills to systematize and analyse large amounts of data. What specialists did you have to involve in your team to achieve the desired result? 

— We had specialists who analyse fire relationships from satellite data, classify and utilise satellite data,  and conduct statistical analysis and modeling of large data sets. Collaboration of people with special knowledge in different disciplines is very important for producing good and well-rounded research. 

— Is it an easy task to “translate” the conclusions of data scientists into the language of environmental science? 

— It was quite easy. In fact, environmental science and data science are very intertwined, so we understood each other very well.

— This study is the first one of its kind for the Polesia region. Did you face any difficulties along the way due to the specifics of the landscape itself or data related to it? What solutions helped you to overcome such difficulties? 

— One of the biggest challenges was getting an accurate land cover map for Polesia. Existing regional maps only covered small areas, often not digitised and sometimes costly to access. Large free land cover maps (European or global maps, processed through machine learning) were inaccurate, or didn’t include important land cover types in Polesia like bogs and mires. We overcame this by building our own land cover map, by using ground-truthed data from our colleagues and then our own machine learning algorithms to process satellite data.

— Did you use a large amount of the necessary data from the ground for this research? How would you estimate the accuracy of the final results and are you satisfied with it?

— As for the amount of ground-truthed data, we used over 2000 polygons of manually verified training data. The accuracy of the land cover map was about 80%. We tested this by holding back a percentage of the training data and then checking this with the classified map. It’s always nice to increase accuracy, but overall we were satisfied with this.

An area in Almany Mires damaged by fire. Photo credit: Ivan Murauyou.

— How can the methodology of this study be applied to other regions or landscapes? In this case, what basic principles will remain the same, and what aspects of the study will have to be changed and adapted?

The fire database is global so this data can be extracted anywhere. The big limitations are the land cover maps that cover a region, these are often readily available in Europe or North America, but less so in other continents and regions. 

— Are there any general recommendations for collecting preliminary data from the ground and creating a land cover map? What parameters and characteristics of a landscape, in addition to the space distribution of different land cover types, should be taken into account in order to most accurately identify the patterns of landscape fires?

Training data evenly distributed across the region of interest is needed, as there can be spatial patterns of landcover types. For example, areas close together are more likely to be similar due to climate, geology, etc. Climate features (temperature, wind, precipitation) and topography are just some natural factors that are very important in identifying fire patterns. Human factors, such as settlements, land use intensity and land management (grazing intensity, farming practices, wetland drainage) should be certainly taken into account. 

— Looking back, is there anything in your work that you wish you had done differently?

It would have been great to have the outcome of building the land cover map of the project area as a priority at the start of the ELP project. This way we would have had more training data earlier in the process.

— What do you see as the prospects for the further application of this research? 

There are still many questions to answer. Do restored wetlands actually burn less? How long does it take them to get wet enough? How does this interact with the effects of climate change? It would be great to test our hypotheses on real restoration events.

The top image features an area in Almany Mires damaged by fire in 2018. Aerial photo by Ivan Murauyou. 

The project “Polesia – Wilderness Without Borders” is part of the Endangered Landscapes & Seascapes Programme and is funded by ArcadiaThe project is coordinated by Frankfurt Zoological Society (FZS).

Meeting on the ground: disturbed mires of Ukrainian Polesia are waiting for restoration

Meeting on the ground: disturbed mires of Ukrainian Polesia are waiting for restoration  


Experts from the “Polesia – Wilderness Without Borders” project and our partner organization the Michael Succow Foundation visited Ukraine. The visit was dedicated to the prospective restoration of disturbed and degraded mires in the Ukrainian part of Polesia. Its program included meetings with stakeholders, trips to protected natural areas and a round-table session  

The delegation’s members discussed the cooperation prospects with executives and employees of Cheremskyi, Rivnenskyi and Poliskyi nature reserves as well as the Chornobyl Radiation and Ecological Biosphere Reserve. In all these protected areas there are drained mires with good prospects for successful restoration – its feasibility was assessed by experts of the Michael Succow Foundation.    

Field visit of experts to the mires of Ukrainian Polesia. Photo by Olga Denyshchyk.

An important task was to listen to opinions of different groups of stakeholders. The position of specialists of the nature reserves is clear: they know the benefits of the mires’ restoration better than others and therefore highly appreciate the international assistance in organizing this work and demonstrate their willingness to cooperate. Their support is extremely valuable, just like the one of the State Agency of Water Resources of Ukraine.  

At the same time, the opinions of the local communities are not always unambiguous. On the one hand, a stricter protection regime and rewetting of drained areas may mean certain limitations for economic activities of the local residents. On the other hand, lack of pure water caused by drainage is the argument that makes many people change their minds in favor of the mires’ restoration. 

Olga Denyshchyk, scientific project coordinator at the Succow Foundation 

"All the stakeholders in Ukraine are constructive, interactive and ready to cooperate more than ever before. This is truly inspiring. Peatland restoration is getting a strategic meaning, not only as freshwater reservoir, but also as a defense line. A lot of communities in Polesia are looking for investors and ready to consider any ecologically-sustainable offer. If you have something in mind, please do reach us out!"

Members of the foreign delegation accompanied by Ukrainian experts visited Cheremskyi, Rivnenskyi and Poliskyi nature reserves to learn more about them on the ground. Each of the reserves has its peculiarities, and the areas to be restored have different degrees of disturbance, spatial organization and features of drainage systems.  

Mykhailo Franchuk, deputy director of the Rivnenskyi Nature Reserve: 

“Mires make up 50% of the territory of the Rivnenskyi NR, and 20% are covered with fen forests. Over the past 100 years, they have been subjected to significant anthropogenic impact. I mean land reclamation, peat mining and illegal amber mining. As the climate changes intensified in recent years, the disturbed marshes with unstable hydrological regimes have become very vulnerable - the water disappears from wetland areas quicker than before. As a result, droughts, the transformation of typical marsh biotopes, and the biodiversity loss have intensified.  

It is important for the Rivnenskyi NR to conserve the mires because it was created to protect the typical natural complexes of Polesia and is the largest marsh reserve in Ukraine. Currently, the reserve protects 13 communities of the Green Book of Ukraine. 53 species of plants, 106 species of animals occurring here are listed in the Red Book of Ukraine, 38 animals belong to the IUCN Red List.  

The mires need saving! And restoration of the hydrological regimes planned within the framework of the project "Polesia - Wilderness Without Borders" is timely and necessary. I hope that our joint work will help to retain water in the mires and mitigate its loss”. 

Mires of Ukrainian Polesia. Photo by Olga Denyshchyk.

It has been decided that prior to the construction works, experts will conduct a one-year-long hydrological monitoring as well as peat layer analysis. It will allow assessing the present water levels in the project territories and then evaluating the efficiency of the restoration. The proposed monitoring methodology and further modeling based on the data obtained was elaborated and successfully tested by Polish experts.   

Measuring water level in Syra Pogonia swamp massif, Polesia, Ukraine. Photo by Olga Denyshchyk.

During a round-table session that took part at the National University of Water and Environmental Engineering in Rivne, experts discussed the value, present state, threats and prospects of the Polesian wetlands. Among other topics, they touched upon the historical importance of mires as natural barriers during military conflicts which is unfortunately up on the agenda today. We hope that this aspect will lose its urgency very soon. However, mires in Polesia, being a source of drinking water for millions of people, an effective carbon storage and a hotspot of biodiversity, are worth being restored and preserved for generations to come.

The project “Polesia – Wilderness Without Borders” is part of the Endangered Landscapes & Seascapes Programme and is funded by ArcadiaThe project is coordinated by Frankfurt Zoological Society (FZS).

Burnt areas and fires on Turov Meadows. © Maksim Belotsky

Natural hydrological regimes are key for Polesia's resilience to devastating landscape fires

New study: natural hydrological regimes are key for Polesia's resilience to devastating landscape fires

Landscape fires disproportionally affect areas of conservation priority but only under low moisture conditions - this is the conclusion of the new peer-reviewed study where scientists mapped and analyzed large fires that occurred over a 19-year period in Polesia, a region containing some of Europe’s last pristine peatlands and lowland forests in Eastern Europe.

Fires are of great concern to policymakers in the region due to the economic and health costs, and a lot of resources are used to suppress fires during hot and dry years. There are potentially natural solutions to fires, however, that could also benefit birds, biodiversity and climate issues. These ‘nature-based’ solutions include restoring drained wetlands. In this study, freely-available satellite data were used to explore the prevalence of large fires and the factors causing them. This allowed researchers to explore whether restoring the landscape’s wetlands could reduce the increasing risk of large, damaging fires as the climate changes.

This study identified five fires reaching more than 100 km2, a threshold often used to classify ‘megafires’. Frequent spring and summer fires predominantly started in agricultural areas, where farmers burn the land to clear it, both before planting and following the harvest. However, these fires often spread into neighbouring peatlands and floodplain meadows, endangering threatened wildlife, such as the Greater Spotted Eagle and Aquatic Warbler, and damaging a globally important carbon sink.

The largest fires burned in native deciduous forests, threatening protected old-growth oak and beech forests, which are more vulnerable and less likely to recover than more fire-adapted trees. Overall, more than one fifth of protected land burned. This is compared with 8% of unprotected land. One fire reached 97 km2 and burned significant areas of the Chernobyl Exclusion Zone, where radioactive contamination from the Chernobyl 1986 disaster is highest, and where the impacts of large fires on human health may be particularly severe.

Burnt areas and fires on Turov Meadows. © Maksim Belotsky
Burnt areas and fires on Turov Meadows. © Maksim Belotsky

The results of the study suggest that landscape restoration in Polesia’s wetlands would help to limit the spread and intensity of unnaturally large, damaging fires, while reinstating natural, periodic low-intensity fires, providing ecosystem benefits and supporting long-term carbon storage.

Throughout Europe, including in Polesia, years of drainage for agriculture and commercial forestry has created overgrown, drier landscapes that are more susceptible to fires. This study showed that open peatlands, meadows, and deciduous forests were far more likely to burn when moisture conditions in the soil and litter were low. In contrast, peatlands were very unlikely to burn under high moisture conditions. Preserving and restoring large, intact, well-hydrated peatlands would help to create natural barriers to large, severe fires, while reinstating periodic low-intensity fires. Doing so would provide ecosystem and conservation benefits, support long-term carbon storage and help tackle climate change, and protect human lives.

The article was originally published on www.bto.org.

The project “Polesia – Wilderness Without Borders” is part of the Endangered Landscapes & Seascapes Programme and is funded by Arcadia. The project is coordinated by Frankfurt Zoological Society (FZS).

War beneath their wings: Greater Spotted Eagles are flying back to Polesia

War beneath their wings: Greater Spotted Eagles are flying back to Polesia

The spring migration of Greater Spotted Eagles has begun. Twenty percent of the European population of these birds breed in Polesia. Thanks to satellite tagging, we are able to keep a close eye on their movement. Now, researchers have special concerns about the migration of these endangered eagles: the birds’ path crosses Ukraine where the military conflict continues. While the war rages on the ground, the eagles fly their route undeterred.  

Greater Spotted Eagles are returning to their nests in Polesia from the Balkan Peninsula, Israel, South Sudan, Zambia, and even South Africa. Every year, they fly thousands of kilometers to reach their breeding and wintering sites. Their journey is full of the expected difficulties and threats. However, they face another trial: the war is now right on their migration route. Polesia’s Greater Spotted Eagles faced this for the first time last spring. Ornithologist Valery Dombrovski, who has been researching Greater Spotted Eagles for decades and keeps a close eye on the GPS-tagged birds, shared some of his observations with us…   

“Spring migration in 2022 was quite typical in terms of dates and average duration. But our close attention was riveted to Greater Spotted Eagles nesting in the Chornobyl Exclusion Zone – they had to cross the Kyiv region where active hostilities were going on. One of them, a male by the name of Borovets, was the first to start on his way. He followed his traditional route through Odessa and Cherkasy regions. Borovets approached Kyiv on the 29th of March, at the very moment when the Russian troops withdrew under attack by the Ukrainian forces. Borovets stopped on the left bank of the Dnieper River to wait out bad weather: the sky was cloudy, and cold rain had started. The eagle spent the following day at the same place. Sounds of explosions were heard from far away – Kyiv was still being shelled. Could the bird tell these sounds from spring thunder? It is not really possible. On the 31st of March, when the sun shone again, Borovets rushed further north.   

The location in the Dnieper floodplain where Borovets stayed on 29-30 March 2022. Photo credit: Sergiy L, Google Earth

He flew above the eastern outskirts of Kyiv and then along the Kyiv Water Reservoir. With his sharp vision, it is likely he could observe long columns of military vehicles retreating from Kyiv, probably an uninteresting sight for the bird. Foul weather forced Borovets to stop again, now further up the reservoir, and about 20 kilometers from the Belarusian border. This time, he stayed in one place longer – from the 31st of March until the 3rd of April. It was quiet: explosions were no longer audible. The Russian troops had retreated from the Kyiv Region and the Chornobyl Exclusion Zone. Borovets fed happily on birds and mammals hiding in riverside reeds, and  visited the farmlands around the neighboring villages.  

The site where Borovets stayed from the 31st of March to the 3rd of April 2022. Photo credit: Dmitry Dmitdino, Google Earth

On the 4th of April, a fair wind blew from the south and drew the clouds away. Just 4 hours later, the eagle reached his nest in the Polesie State Radioecological Reserve. Fortunately, the helicopters that were flying back and forth above the reserve every day during the past month had already followed the rest of Russian military units. Thankfully, Borovets could occupy himself with his “family” concerns. During the remainder of the 2022 season, he successfully bred a chick. 

A young Greater Spotted Eagle. © Adham Ashton-Butt

A female eagle, named Elleni, arrived in Ukraine much later. On the 4th of April, she stopped shortly in the Odessa Region. By the end of the next day, thanks to favorable weather, Elleni reached the western outskirts of Kyiv. There, she stayed overnight alongside the Irpin river. The fighting had stopped there several days earlier.  The bird showed no unusual behavior. On the morning of April 6, she flew further north. Her flight path crossed now infamous places: Irpin, Gostomel, and Bucha where terrible massacres took place. Luckily, birds cannot understand such horrors. The next day, Elleni reached her nest, nearby to the nest of Borovets. Elleni’s breeding season ended with its own sadness, as her chick died in the middle of summer from an unknown cause. 

In spring 2022, other Greater Spotted Eagles from Polesia flew across the Western part of Ukraine where there were no active battles. All the birds reached their nests successfully. The fastest one was Blond, on the 17th of March, he was already in his nest in Almany Mires. Most birds arrived later, in the first week of April. Vialuta was the last to return, arriving home on the 20th of April.  By the way, this is the latest date of the end of spring migration for five years of observations.” 

The war in Ukraine gave ornithologists not only food for thought, but also material for scientific research. We expect a research paper to be published analyzing the war’s impact upon the migration patterns of the Greater Spotted Eagles. In the meanwhile, though we can’t stop the war immediately, we hope for a safe migration back home for the birds – wild Polesia is waiting for them.  

Top image fatures a Greater Spotted Eagle in flight. Photo credit: Daniel Rosengren. 

The project “Polesia – Wilderness Without Borders” is part of the Endangered Landscapes & Seascapes Programme and is funded by Arcadia. The project is coordinated by Frankfurt Zoological Society (FZS).