The monitoring, framed within the Catalan Butterfly Monitoring Scheme (CBMS), registered this 2025 a total of 1,147 butterflies of 28 species, a figure significantly lower than the 2,207 specimens counted in 2024. This sharp decline was specifically detected around the Turó de Baldiri.

Park experts indicate that this reduction is not an isolated event but reinforces a negative trend observed in recent years. While the decline initially affected more specialist species, the 2025 data shows that the drop now impacts generalist and common species in Maresme as well.

Studies primarily point to the impact of climate change, evidenced by extreme heat episodes and recurrent droughts, and the loss of open habitats. The progressive closure of vegetation reduces the meadows and pastures favorable for these insects.

The status of butterflies, considered bioindicators of environmental health, reflects an ecological imbalance affecting other species and highlights the need to implement adequate management measures to preserve biodiversity in the Serralada Litoral Park.