Wetlands are areas where land is permanently or seasonally saturated with water: marshes, swamps, bogs, and floodplains. These areas act as vital ecosystems that support biodiversity, regulate water flows, and improve water quality. And though not all of them are equally threatened, the riparian forests of South Tyrol’s valley floor have almost disappeared.

“Wetlands are extremely important for biodiversity. Across almost all taxonomic groups we study, we find highly specialized species that occur only in these habitats.” Biologist and Biodiversity South Tyrol Coordinator Andreas Hilpold details, “This includes insects such as grasshoppers and butterflies, as well as birds, many of which rely on wetlands for feeding, drinking, and hunting. Although birds are more mobile and not restricted to a single habitat, a significant portion of regional biodiversity is closely linked to wetlands and cannot persist without them.”

For centuries, a vast area between Merano/Meran and Salorno/Salurn was covered by riparian forests. The river Etsch/Adige (and some of its smaller streams) flowed freely, and wetlands dominated the valley floor. From a human perspective, however, these landscapes also brought problems. Malaria was widespread, especially in Bolzano and the Unterland.  The first major efforts to drain the swamps began in the 18th century under Empress Maria Theresa. Later, in the early 20th century, the remaining riparian forests were increasingly cleared to make space for apple orchards. Urbanization and industrialization further accelerated this process, leading to the steady disappearance of wetlands and riparian forests from the valley bottom.

A historical map of Bolzano and surrounding areas dating to 1716, the bottom left of the map shows the undrained “Unterland”

Credit: Gabriel Bodenehr | All rights reserved

And, when wetlands vanish, so do the specialized species that depend on them, including some of nature’s most unusual plants.

Plants like Drosera, Pinguicula and Utricularia may seem like curious oddities, but they play an important role in wetland ecosystems. Often referred to as carnivorous, it would be more correct to call the insectivorous, or, for the super nerdy, and in the case of Utricularia and Aldrovanda: zooplanktonous…if that is even a word.  

 Living in nutrient-poor soils, these insectivorous plants have evolved to supplement their diet by capturing… insects (and plankton), helping regulate populations as well as ensuring survival in terms of reproduction. This is why these specialists have such beautiful flowers. Their strategy is to place the flowers far away from the traps (the leaves). By growing flowers at the end of long stems, they attract insects for pollination while keeping them safely away from the “hungry” leaves. A brilliant evolutionary solution. Both features contribute to the delicate balance of wetland life. And the presence of these plants is often a sign of a healthy, functioning ecosystem.

“People are often surprised that these insectivorous plants exist in Italy, many think such exotic species live only in tropical forests. When visitors see these plants in the wild, they are astonished not only that they grow here, but also by how small they are.” Explains Roberto Dellavedova who often leads school children on botanical excursions. “Plants such as Drosera are highly specialized and can only survive in very specific environments. They grow on Sphagnum moss, which creates an acidic habitat with little competition from other plants. Drosera also needs a lot of light; when bogs change naturally and taller plants reduce light availability, these species disappear. In dense populations, Drosera plants can even work together, allowing them to capture relatively large insects, such as dragonflies.”

Perhaps the best known of these insectivorous species is Drosera, also called the sundews which capture prey using sticky glandular hairs on their leaves that trap insects, which are then digested by enzymes.

Credit: Eurac Research | Roberto Dellavedova

Pinguicula, commonly known as butterworts use two types of glandular hairs: one traps insects, while the second type secretes enzymes for digestion. Pinguicula species live in a variety of habitats. They are not mainly found in bogs, but rather near springs, along water seepages, and sometimes on wet cliffs or rocky surfaces where water is present. In the past, people used Pinguicula leaves for medicinal purposes.

Pinguicola uses its “buttery” leaves to lure and trap unsuspecting gnats.

Credit: Eurac Research | Roberto Dellavedova

Pinguicula vulgaris is believed to have antiseptic and vulnerary properties: Alpine shepherds used its leaves to treat wounds. In local Piedmotese dialects, the plant even had a specific traditional name linked to this use. Erba dal mal di tài means herb to treat cuts.

A tiny but fierce hunter. Often mistaken for a common succulent at first

Credit: Eurac Research | Roberto Dellavedova

Utricularia, or bladderworts, take a more dramatic approach: their tiny underwater bladders create a vacuum that sucks in prey in milliseconds. These different strategies have the same goal: survival in a challenging environment. Dellavedova explains “Utricularia is another remarkable insectivorous plant that lives in clean, unpolluted ponds and shallow water. It floats freely at the water’s surface and has no roots. Utricularia can colonize new ponds with the help of birds such as ducks, which carry plant fragments on their legs or feet. Even after drying out, these fragments can survive and regrow once they reach a new body of water.”

Bladderworts (Utricularia) are among the fastest hunters in nature. Their tiny traps snap shut in less than a millisecond, that’s faster than you can blink. They suck in prey like a microscopic vacuum cleaner.

Credit: Eurac Research | Roberto Dellavedova

Credit: Johann Georg Sturm | All rights reserved

Drosera - sundew plants have leaves covered with tiny hair-like stalks tipped with clear, sticky droplets. These droplets sparkle like morning dew, even though they are actually used to trap insects. Early observers thought the plant always looked dewy, even in dry conditions, which is why it was called sundew. The name Drosera comes from the Greek δροσερός = droserós, meaning… dew.

Another hungry sundew, this time its dinner is an ant.

Credit: Eurac Research | Roberto Dellavedova

Credit: Carl Axel Magnus Lindman | All rights reserved

One of the casualties of the vanishing wetlands is Aldrovanda vesiculosa. Known as the waterwheel plant, this rare, free-floating aquatic plant captures small prey using snap-trap leaves similar to those of the Venus fly-trap. Darwin himself was fascinated by insectivorous plants.  In his volume on the subject, first published in 1875, he enthuses “This plant, commonly called Venus’ flytrap, is one of the most wonderful in the world.”  

Once present in Italy’s nutrient-poor wetlands and slow-moving waters, Aldrovanda vesiculosa is now extinct in the country due to habitat loss, water pollution, and the drainage of wetlands.

Across the region, the habitats where these species occur are very small and fragmented. As a result, populations are limited in size and often widely separated. From a genetic perspective, this is important because each population may develop unique characteristics, making their conservation especially valuable.

The Biodiversity Monitoring South Tyrol project surveys wetland habitats across the region as part of a wider biodiversity monitoring effort. Wetlands are examined in two main categories – lake shores and peat bogs – each characterized by specialized vegetation shaped by constant water saturation. The program monitors 10 lake shore sites and 10 peat bog sites, for a total of 20 wetland areas, capturing the diversity and ecological dynamics of these habitats. The monitoring has recorded eight insectivorous plant species: three types of Drosera in bogland sites, three Pinguicula and two Utricularia.

“Some insectivorous plant species are extremely rare and require close monitoring to ensure their survival. One example is Drosera intermedia, which is known from only a handful of sites in the province – possibly fewer than five. Most populations of Drosera and Utricularia occur in protected areas, which play a crucial role in safeguarding their fragile habitats from drainage, pollution, and land-use change. While a positive population trend is unlikely, monitoring suggests that populations are currently stable in the best-protected sites.” Concludes Andreas Hilpold

Protecting wetlands means protecting these remarkable plants, even if most of us never see them up close. Their disappearance would signal not just the loss of botanical wonders but the unraveling of entire ecosystems that quietly support biodiversity, water quality, and climate resilience.

Some insectivorous plant species are extremely rare and require close monitoring to ensure their survival. One example is Drosera intermedia, which is known from only a handful of sites in the province – possibly fewer than five.