The health of the Po Delta Park depends on the care of those who live there

What are the irreversible effects of climate change that you and your team are tackling? 

“Today, in order to maintain oxygen levels in the water and prevent anoxic conditions – linked to the mass die-off of algae, which are already over-nourished by nitrates from sewage, or to a lack of water circulation due to stratification caused by high temperatures – a change in approach is needed. In a normal climate, cool nights would naturally circulate the water: the colder water, being heavier, would sink, allowing the water at the bottom to be oxygenated as well. With the current climate, which sees daytime highs of around 40° and a reduction in the daily temperature range, this no longer happens. Not to mention the gradual decline in rainfall, leading to a more prolonged summer drought. We have already witnessed large-scale fish and even bird die-offs on several occasions, precisely because a constant water level is artificially maintained under the assumption that a wetland must always be full of water, whereas a natural marsh, fed by the natural fluctuations of the river’s floodwaters, would dry up of its own accord.”

Why is a stagnant, oxygen-depleted pool much more dangerous than a temporary lack of water?

“If an area were to dry out, the seabed would naturally become oxygenated on contact with the air and then oxidise under the sun’s rays; when the water returned, the seabed would regenerate, providing significantly better conditions. Furthermore, this would prevent waterbirds from ingesting toxins, as botulinum, which develops under anoxic conditions, turns into a lethal poison. And the more animals die from the toxins, the more will inevitably die, because they feed on the remains of those that are decomposing in a chain reaction: the fly larva that feeds on the carcass of an animal killed by botulism becomes saturated with the toxin, but does not die as it is immune, thereby triggering a chain reaction that kills birds and fish.”

The only real problem remains how to handle the fish...

“Wherever possible, it is saved by transferring it to the deepest reservoirs, where water flow can be maintained even after the valley floors have been drained. Where this is not possible, recovery operations are carried out, involving significant financial investment. It is a difficult situation to explain to the public and even to the administrators themselves.”

One need only think of the recurring complaints made each summer by certain recreational fishing associations against local authorities.

“The vast Mezzano Valley, which links Ferrara to southern Romagna, was crossed during the summer when it belonged to the House of Este precisely because it was completely dry. The Este family travelled through it to reach their estates in the southern part of their territory. This was already happening six hundred years ago. In fact, the process of artificialisation began on a small scale under the Romans, became widespread under the Este family, and was decisive under the Papal States, which made extensive use of the natural gradient system in land reclamation projects between the 17th and 19th centuries, when the terrain’s elevation still allowed water to flow away naturally. “The aim was to create a dense network of canals that would channel water towards the main watercourses and thence to the sea by utilising gravity, without the need for pumping stations.”