Solsona tower and nearby bunkers ranked top bat refuges

The Solsona tower continues to serve a defensive role of sorts — not against catapults or foreign soldiers, but as an important refuge for biodiversity.

The Catalan Institution of Natural History analysed 29 man-made cavities across the Alt Urgell and Cerdanya regions, including disused bordes, bunkers, mines, abandoned buildings and hermitages. The survey, focused initially on anthropic cavities before moving on to natural caves, aimed to study the presence of chiropterans (bats) and to interpret both diversity and abundance rather than produce a simple species list.

Using a relatively new index that also takes vulnerability into account, researchers identified two sites of very high conservation value; one of these is the Solsona tower in Castellciutat. The relative lack of human disturbance at the tower helps explain its rich assemblage of species, according to Pere‑Miquel Parès, a veterinarian and member of the institution. Scattered bunkers in the area also emerged as heavily used refuges and are considered to require the highest conservation priority.

The team recorded several notable species. Long‑eared bats were common, and three species of horseshoe bats were present in abundance. Forest species such as the barbastelle appeared in small numbers. The study did not detect clearly high‑mountain species, for example Vespertilio, which is typically associated with higher elevations.

The findings are intended to inform concrete conservation and management measures rather than remain purely descriptive. The institution argues the approach could be extrapolated to other counties to guide protection efforts more broadly.

To present the project and, if possible, recruit more volunteers to expand fieldwork, the institution will hold an open virtual meeting next Thursday.