25 years later

Jacek Kazimierczak

CEO of Lepidopterra

Have you ever wondered if the loss of biodiversity is real or how much we have already lost? For most people who have been observing nature for at least 10 to 15 years, this is tangible. Even common species are less numerous. Many local species have already disappeared. The variety of butterflies decreases every year. At the same time, new species of migrants are emerging in Europe, especially from the south and southeast. However, this does not compensate for the losses in any case.

In our case, it has been 28 years since we started observing butterflies and. The story begins in Łódź, located in central Poland, the fourth largest city in the country. Or rather on its outskirts. It is worth noting that central Poland was already one of the poorest regions of Poland in butterfly species. It includes a highly urbanised agglomeration surrounded by monocultural, intensively cultivated fields with scattered forests, both deciduous and coniferous, which occupy about 7% of the area. Meadows and scrubs are rare and under constant pressure. In 2029, it will be 100 years since the publication of the first records from the region. By then, we want to be ready to publish a full report on changes in local biodiversity.

Over the course of 100 years, many studies have been carried out in the region, however, it is extremely difficult to measure changes in butterfly diversity. The main reason is that the area of research was defined differently. In some cases, it concerns only the city of Łódź within its administrative borders, in other cases it is an agglomeration or even an area of 70 kilometers. In most cases, there is no data on the number of specimens observed. These factors make calculations and comparisons almost impossible.

"Since the middle of the twentieth century, the biodiversity of butterflies and moths has decreased by 27%, while 15% of species have already disappeared"

For the above reasons, we decided to dig out notebooks from our archives and present them to you. Moreover, we plan to visit the same places, at the same time in 2023, to show how it has all changed. We called it "25 years later" because it looks more even, secondly, in the first few years, we made very accurate field notes containing species, places, dates, temperature and quantity, which means there is less risk of confusion. We plan to adjust the exact site visit time to weather conditions, as each year is different. It is important, as most sources focuses only on species and place, while other data such as quantity is also a huge value.

In 2021 a team of scientists led by Tim Laussmann published an article "Lost and found: 160 years of Lepidoptera observations in Wuppertal (Germany)". This interesting research is based on work of amateur entomologists who have been observing the moth and butterfly fauna for decades. It turned out that since the middle of the twentieth century, the biodiversity of butterflies and moths has decreased by 27%, while 15% of species have already disappeared. The local fauna has grown by 2.4%, which means that as a result of climate and habitat changes, new species are also emerging.

Let see how it all changed in Łódź, Poland!

Time remaining until next field survey after 25 years in Łódź


25 years later - after overwintering

On April 10, 2023, we conducted our first field visit as part of the "25 years later" series. Read more to see the results!

Chalk, gypsum and limestone grasslands

Gypsum, chalk and limestone grasslands are also extremely valuable habitats. It creates exceptional conditions for many butterflies, moths and other species.

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