The figure of 1,147 butterflies of 28 species counted in 2025 contrasts sharply with the 2,207 observed the previous year, according to data collected within the Catalan Butterfly Monitoring Scheme (CBMS). This scientific project analyzes the evolution of butterflies across the Network of Natural Parks of Catalonia.

The census at Turó de Baldiri is carried out using a fixed route of nearly two kilometers, surveyed weekly for 30 weeks, between March and September. Experts warn that this decline is not an isolated event but reinforces a negative trend detected in recent years, now also affecting generalist species.

Although species like the Lulworth Skipper and the Wall Brown remain abundant, nine species did not exceed five individuals throughout the season, indicating ecological fragility. Studies point to the primary causes as the impact of climate change, with droughts and extreme heat, and the progressive closure of vegetation.

The Parc de la Serralada Litoral emphasizes that continued scientific monitoring is essential to understand the phenomenon and implement appropriate management measures. The status of butterflies, considered bioindicators, reflects an environmental imbalance that demands urgent action to preserve biodiversity in Maresme.