One of the ecosystems that we speak less, at least in proportion to how threatened by human activities, is that of the prairie: the expanses of herbs are disappearing all over the world due to the consumption of soil, but also of simple abandonment. Over time, in fact, a “managed” prairie returns to be a forest, which is good news for the planet but a bad for biodiversity Specific of those habitats.
Do you want another bad news? A study that comes from Japan, published on Journal of Applied Ecologyshows that pollinators, an essential element for the health of the prairies, need decades before returning to force – in other words, we cannot hope that these ecosystems will recover in a short time if we want to protect them.
Why protect the prairie? The question of the disappearance of the prairies may seem absurd: if you leave them they come (relatively) soon replaced by a forest, which should be good. On the other hand, however, Many meadows have now existed long enough to have developed their own “identity” and a wealth of biodiversity.
In other words, even if many meadows are not the natural condition in which the landscape would exist, they are now quite old and rich to be worthy of protection. And the Japanese team has decided to study a prairie “piece” that has been managed and maintained for 300 years now: the ski slopes of the Nagano prefecture, which in the 19th century were used as pastures.
Old is better. The historical confrontation with the conditions of the meadows 300 years ago and today He allowed the team to discover first of all which insects pollinate as plants, and what is the link between the age of the prairie and the identity of the pollinators. When the prairie is still young, in fact, it is frequented above all by flies and other ditters, which are generalist pollinators: they visit different species of flowers in search of pollen, and often They therefore end up pollting the “wrong” species – A waste, from the point of view of plants.
When a prairie is at least 75 years old, however, other types of pollinators begin to appear in quantity: bees and butterflies, which focus on a single species and are therefore more effective in pollination. The arrival of bees and butterflies makes “the prairie explodes”, who is the older the more is rich. The study therefore suggests that The creation of new meadows to be managed is less effective than the conservation of existing meadowswhich should therefore become our priority.
