A set of dried flowers gathered from the slopes of Bologna half a millennium ago is revealing insights into the impact of climate change and human displacement on the terrain of northern Italy.

Between 1551 and 1586, the Renaissance naturalist Ulisse Aldrovandi selected a collection of 5,000 intricately cut and preserved plants, making it one of the most extensive collections of its era.

Aldrovandi’s initial goal was to recognize various types of plants and determine their potential for medicinal use. After almost 500 years, his preserved plant specimens are now aiding botanists in documenting the significant transformations that have occurred in the surrounding environments, as stated in a recent study released by the Royal Society.

In the era of Aldrovandi, the hills of Bologna were home to numerous species, many of which are now endangered or no longer exist, including motherwort, a plant once used for medicinal purposes that is now believed to be extinct in the region. While the overall number of species has risen since the 1500s, there has been a decline in the diversity of flora, with several rare species experiencing a decrease in population. The study also found that the Italian population grew by 560% during this time period.

Aldrovandi’s collection of plant specimens consists of 15 books, with each book containing a maximum of 580 specimens attached to sheets. Along with the plants, the books also contain information on the frequency, abundance, ecology, local names, and traditional uses in medicine. Experts consider this to be the oldest herbarium with such thorough documentation. The researchers state that the significance of this herbarium is immeasurable from both a historical and scientific viewpoint.

The paper states that Aldrovandi’s herbarium serves as a record of the initial changes in the European plant life and environments.

A significant aspect of this change is the large number of foreign species being introduced. When the collection was originally established, only 4% of the flowers were native to America and were primarily found in private or botanical gardens. Through early exploration in Central and South America, plants such as sweet peppers and courgettes were brought to Europe. As a result, there has been a 1,000% rise in non-native American flowers, highlighting the increasing significance of trade between America and Europe during the Renaissance period.

The head researcher, Dr. Fabrizio Buldrini of the University of Bologna, expressed surprise at the significant contrast found. He stated that the notable increases are worrisome as they clearly indicate the significant impact of humans.

The team led by Buldrini conducted a comparison between the flora gathered by Aldrovandi and those collected by Cocconi (1883) and Emilia-Romagna (1965-2021). They focused on the flat lands near the River Po and its smaller rivers, allowing for comparisons to be made between the various datasets.

The information also indicates the impact of the “little ice age” that lasted until the mid-1800s. Species that typically thrive at high altitudes, such as the silver cranesbill, were discovered at lower elevations of 800 meters above sea level by Cocconi. The mountain buttercup, which is currently only found above 1,000 meters, was once found at a much lower altitude of 300 meters during the “little ice age”.

Aldrovandi played a significant role in the establishment of the city’s botanical garden, one of the first in Europe. Many significant collections were amassed during his time and in the years that followed, solidifying Bologna’s reputation as a hub for modern botany and herbaria.

Starting in the 1970s, an effort has been made to create a complete map of the region’s plant life, leading to a database containing over 500,000 entries.

In general, the researchers emphasized the significance of preserved flower collections. They noted that there is a current tendency in the scientific community to overlook these collections, considering them to be outdated, inconvenient, and burdensome to maintain. However, according to Buldrini, this perspective is incorrect. Herbaria serve as essential and irreplaceable sources of data for numerous research areas.

According to the Index Herbariorum, there are 390 million specimens in global collections. Buldrini stated that disregarding them would be equivalent to disregarding our historical archives, monuments, or art collections.

Find more age of extinction coverage here, and follow biodiversity reporters Phoebe Weston and Patrick Greenfield on X (formerly known as Twitter) for all the latest news and features

Source: theguardian.com