They Released Water Buffalo on a Dead Island — What Happened 5 Years Later Shocked the World

Added: 2026-05-28

[00:00:04][music] >> With just seven water buffaloes, engineers are trying to save the entire Danube Delta from a massive ecological disaster.

[00:00:12]As the second largest [music] wetland in Europe, this place was once considered the natural lungs of the continent. But after more than a [music] century of building dams, digging canals, and draining wetlands to create massive [music] farmland, the ecosystem here slowly began to collapse. As the natural [music] water flow was cut off, reeds spread out of control, covering more than 220,000 hectares of wetlands, and turning many areas into stagnant oxygen-poor [music] water.

[00:00:40]Fish began to disappear, migratory birds [music] left, and the scariest part is that from above, the Danube Delta still looks green and alive, as if nothing [music] ever happened. But that endless green is quietly suffocating all life underneath it.

[00:00:56]So, what is really [music] happening here?

[00:01:08]Located near the border of Romania and Ukraine, Omer Island was once one of the most fertile parts of the Danube Delta, a wetland ecosystem covering more than 4,000 square kilometers, and the second largest in Europe. For thousands of years, this place functioned like a giant natural circulation system, where water from the Danube River continuously flowed through the marshes, bringing sediment, oxygen, and nutrients that sustain the entire region. But everything began to change during the Soviet era, when large numbers of dikes and canals were built to stop water from reaching the island. Wetlands were gradually drained and [music] converted into large-scale farmland. At first, this was considered an engineering success >> [music] >> because it expanded agricultural land and increased food production. But from that moment on, the region also began [music] losing the one thing that mattered most, the natural flow of water.

[00:02:01]As water stopped circulating like before, >> [music] >> reeds began spreading out of control.

[00:02:06]Over time, they covered up to 80 to 100% of the area. Reed fields 2 to 4 m tall grew densely across the island, making the entire landscape from above look like a giant green ocean. On the surface, the region still appeared very much alive, but underneath that thick vegetation, life was slowly collapsing.

[00:02:26]As the reeds became too dense, sunlight could barely reach the water [music] surface, causing dissolved oxygen levels to drop below 2 mg per liter, low enough to suffocate many fish species.

[00:02:39]Natural spawning grounds gradually disappeared, causing fish populations to decline by 30 to 60% while many water birds also began leaving the area.

[00:02:49]Even aquatic insects, the foundation of the entire wetland food chain, slowly disappeared as well.

[00:02:56]There were no wildfires or toxic chemicals visible to the human eye, yet this entire wetland ecosystem was still collapsing in a way that was almost invisible.

[00:03:10]After decades of research, ecologists finally realized that reeds were not the cause of Omer Island's collapse, but only the result of a much larger problem.

[00:03:19]In the past, [music] every flood season, water from the Danube flowed through the marshes, bringing sediment, oxygen, and nutrients that constantly refreshed the wetlands.

[00:03:29]These natural water level changes created [music] ideal conditions for fish spawning, aquatic plants to grow, and the ecosystem to survive for thousands of years.

[00:03:39]But after the dike and canal systems were built, the natural flow of the Danube was almost completely cut off.

[00:03:45]Flood frequency dropped by more than 50 to 70%, while water levels on Omer Island fluctuated by only around 10 cm throughout the year, compared to nearly 1 m in nearby natural wetlands.

[00:03:58]For ecologists, this difference was critical. A wetland cut off from its parent river is like a body losing its blood circulation system.

[00:04:06]Once water stopped flowing and oxygen was no longer replenished, the entire natural environment slowly began collapsing from within. [music] That was why engineers decided to bring water back to the island.

[00:04:17]The first turning point came in 2009 when part of a dike on Omar Island was removed for the first time to reconnect the area with the Danube.

[00:04:25]After decades, water finally began flowing back into the old [music] marshes, bringing moisture, mud, and natural currents that had disappeared for years.

[00:04:34]The project expanded further during 2021 to 2022 when another 200 to 300 m of dikes were removed.

[00:04:42]Thousands of hectares of land began flooding again during seasonal water rises, while surface water areas also increased significantly compared to before.

[00:04:52]More importantly, life itself also began returning. Dissolved oxygen levels rose to around 4 to 6 mg per liter, >> [music] >> and fish started appearing again in newly formed channels between reed fields that had remained almost motionless for decades.

[00:05:06]>> [music] >> When water finally started returning to Omar Island, scientists quickly realized that simply removing the dikes was not enough.

[00:05:16]After decades of being left untouched, the reeds had become far too dense, leaving many areas almost completely blocked even as water from the Danube slowly began flowing back in.

[00:05:27]That was when Rewilding Europe and Rewilding Ukraine came up with a rather unusual idea, bringing water buffalo back to the island.

[00:05:36]At first, it sounded like a very primitive solution, but in reality, water buffalo are almost perfectly designed for wetlands.

[00:05:44]Unlike cattle, which prefer dry grasslands, buffalo can move through deep mud and live comfortably among dense reed fields. For ecologists, the buffalo were not just grazing animals.

[00:05:55]Every step they took could create small open spaces that held water, while their movement also helped water flow back into areas that had been blocked by reeds for years. In other words, the buffalo were doing a job that even million-dollar machines would struggle to perform effectively in such soft marshland conditions.

[00:06:13]Interestingly, water buffalo were not actually foreign to Europe. About 100 years ago, they still existed in several parts of the Danube Delta before gradually disappearing during the large-scale drainage of wetlands across the region.

[00:06:27]Engineers even joked that if you release seven buffalo onto an island in China, then came back a month later, even the buffalo dung would probably be gone. But on Omer Island, those same seven buffalo were expected to help revive thousands of hectares of wetlands.

[00:06:45]After the decision to bring water buffalo back to the Danube Delta was approved, scientists began searching for [music] suitable animals in the Transcarpathia region of western Ukraine. One of the few places where buffalo still [music] live naturally in wetlands and muddy environments. But getting them to Omer Island required a journey of more than 1,000 km across Ukraine.

[00:07:05]Before the trip began, the buffalo were carefully examined and vaccinated [music] to make sure they could adapt to the new environment without bringing diseases into the recovering wetland.

[00:07:15]After days of traveling by road, the herd finally arrived at the town of Vilkovo on the edge of the Danube Delta.

[00:07:22]From there, they were loaded onto barges and transported deeper into the marshlands, into an area almost completely isolated from the outside world.

[00:07:32]Then, in May 2019, the first seven buffalo finally stepped onto Omer Island. The herd included five males, two females, and even one pregnant buffalo.

[00:07:43]What made the project especially unusual was that once the animals were released onto the island, almost all human intervention stopped. There were no fences, no barns, and no additional food supplies.

[00:07:55]In the middle of a wetland that had been neglected for decades, the buffalo were left completely free as if a very old part of the Danube had finally returned.

[00:08:07]The buffalo herd soon began creating changes that even scientists did not expect. In a surprisingly short time, the structure of the entire island started changing in ways that could clearly be seen from above.

[00:08:20]Each buffalo can eat around 25 to 40 kg of reeds and wetland plants every day.

[00:08:25]As a herd, that adds up to roughly 150 to 250 tons of vegetation every year.

[00:08:31]But the most important impact was not the amount of plants they consumed. It was the way they constantly moved through reed fields that had remained dense and untouched for decades.

[00:08:41]An adult buffalo can weigh nearly half a ton. The weight of their bodies alone was enough to crush old layers of hardened reeds, creating narrow pathways through wetlands that had once been almost completely blocked.

[00:08:53]Those openings allowed water to slowly flow back deeper into the island again.

[00:08:57]To ecologists, the herd was behaving almost like a giant team of biological bulldozers moving continuously across the landscape.

[00:09:05]But unlike heavy machinery, the buffalo were not destroying the environment.

[00:09:10]They were gradually rebuilding it in the same natural way this ecosystem had functioned [music] for thousands of years.

[00:09:17]As the dense reed layers began breaking apart, sunlight could finally reach the water surface in areas that had remained covered for decades.

[00:09:26]Soft mud zones and shallow pools [music] also started reappearing, creating ideal conditions for insects, small fish, and aquatic life to return.

[00:09:35]But perhaps the most impressive effect [music] came from something unexpected.

[00:09:40]Buffalo dung.

[00:09:41]Every year the herd can produce around 100 to 150 tons of natural fertilizer filled with nutrients and seeds.

[00:09:49]As the buffalo moved across the island, they unintentionally spread more than 200 [music] different plant species.

[00:09:56]While the mud holes created by their movement began trapping water and slowly turning into small biological islands in the middle of [music] the vast reed fields.

[00:10:08]Over time the changes created by the buffalo began spreading across the entire island.

[00:10:14]Reed fields that once covered almost all of Omer Island slowly started shrinking with density dropping to around 50 to 70% in many areas.

[00:10:23]As the thick vegetation began breaking apart, shallow pools, muddy zones, and natural pathways slowly reappeared after disappearing for decades.

[00:10:33]Alongside the buffalo, ecologists also reintroduced Konik horses, an ancient wild horse breed from Europe that once lived in wetland environments.

[00:10:43]While the buffalo continuously crushed old reed layers and created muddy flooded areas, >> [music] >> the Konik horses grazed on young grasses in drier zones helping create different types of habitats across the same landscape. These early changes quickly triggered movement throughout the entire ecosystem. As sunlight finally began reaching the water surface again and oxygen levels stabilized at around 4 to 6 mg per liter, aquatic insect populations increased by roughly 30 to 70%.

[00:11:12]This was a critical turning point because insects are a major food source for small fish.

[00:11:17]And within just a few years, fish populations in some areas had increased by around 1.5 to two times.

[00:11:25]Fish species such as perch, young pike, and carp began reappearing in the shallow channels forming between the reeds.

[00:11:33]And as food became more abundant underwater, many water birds that had left the island years earlier also started returning with populations increasing by around 20 to 50% in some areas.

[00:11:45]White storks, grey herons, and even the Dalmatian pelican, one of Europe's rarest large bird species, could once again be seen flying above the wetlands after nearly disappearing for years. Omer Island no longer looked like a motionless mass of dense reeds.

[00:12:02]Natural water labyrinths had begun forming again across the marshes, >> [music] >> and the first buffalo calves were even born on land that had once been considered almost lifeless.

[00:12:15]As flocks of water birds slowly began returning to the skies above [music] the Danube Delta, and life gradually reappeared on Omer Island, many people believed the ecosystem had finally been saved. But for conservation organizations, the hardest stage may only [music] be beginning.

[00:12:32]Since 2022, the war in Ukraine has made research and environmental monitoring around the Danube border region >> [music] >> far more difficult.

[00:12:40]Many wildlife tracking, water testing, and ecosystem restoration programs [music] have been reduced or interrupted, even though recovering ecosystems like Omer Island depend heavily on long-term monitoring to [music] prevent everything from quickly falling back into imbalance again.

[00:12:56]At the same time, climate change is creating a new threat for the entire wetland region.

[00:13:01]Climate models show that temperatures around the Danube could rise by another 1.5 to 2°C in the coming decades, increasing the risk of prolonged droughts and unstable water levels.

[00:13:13]If water flow from the Danube continues to decline, many of the newly restored marshlands could dry out again, allowing reeds to spread out of control once more.

[00:13:23]However, what worries conservationists the most is that humans may repeat the very same mistake that caused the collapse in the first place. WWF Romania has warned that around 2,500 hectares [clears throat] of wetlands in the Danube region >> [music] >> are still at risk of being drained again for agriculture. To many people, these are simply areas that could be used more efficiently for economic purposes. But to ecologists, they are one of the most important natural systems still remaining in Europe.

[00:13:52]After decades of restoration, [music] Omer Island has finally started coming back to life.

[00:13:57]But the greatest irony is that humans, the same species that once pushed this place toward collapse, could also become the reason the entire ecosystem disappears once again.

[00:14:11]After everything, the most remarkable part of Omer Island's story may be that nobody truly rebuilt this ecosystem with concrete, machines, or massive engineering structures.

[00:14:22]Instead, humans simply tried to return the things that once belonged here.

[00:14:26]Water, animals, and the natural flow of the Danube. And from that point on, nature almost found its own way back to life.

[00:14:34]Just a few years ago, Omer Island was still a stagnant marsh almost completely covered by reeds. But once water began flowing again and herds of buffalo and wild horses returned to the island, the entire ecosystem slowly [music] began moving with them.

[00:14:49]Fish returned to shallow waters, water birds reappeared above the wetlands, and new muddy channels started forming through reed fields that had remained motionless for decades.

[00:14:59]All of this shows that nature is not always [music] as fragile as humans often believe.

[00:15:03]When the missing pieces are returned to the right place and ecosystems [music] are given enough time to rebalance themselves, life can slowly find its way back in the most natural way possible.

[00:15:15]Once isolated from the Danube, swallowed by reeds, and pushed close to losing almost all life, Omer Island is now slowly coming back to life.

[00:15:25]Water has started flowing through the wetlands again, animals are returning, and an ecosystem that remained [music] silent for decades is finally beginning to move once more.

[00:15:35]Natural water labyrinths are reappearing across the marshes, water birds are returning to the skies above the Danube, and fish and aquatic insects are slowly coming back to shallow waters that once seemed almost lifeless.

[00:15:47]And perhaps the most incredible part is that all of this change began with nothing more than water, a few buffalo, and a few wild horses. The story of Omer Island shows that nature does not always need humans to rebuild it. Sometimes it simply needs the chance to return to its natural balance again.