A complex and highly specialised conservation intervention has made it possible to save the last remaining population of the great capricorn beetle in the Milan area. Thanks to the collaboration between researchers from the University of Milano-Bicocca, professional arborists, philanthropic organisations and PLIS Parco dei Mughetti, a large oak tree, now dead but still essential as a habitat, was transferred from IRCCS San Raffaele Hospital to a protected area suitable for the survival of the species.
The operation, carried out by the interdisciplinary BioTreeversity group, composed of Claudia Canedoli and Emilio Padoa-Schioppa from the University of Milano-Bicocca, arborist Davide Corengia from VerticalVerde and researcher Elisa Cardarelli from the University of Pavia, represents an exemplary case of active conservation of a priority species under the Habitats Directive.
A protected species that survives only thanks to large oak trees
Cerambyx cerdo, known as the great capricorn beetle, is a wood-boring beetle associated almost exclusively with large mature oak trees containing areas of decaying wood. The species is in severe decline throughout Europe because of the reduction in dead wood and forestry management practices that tend to remove mature trees.
The population living at IRCCS San Raffaele Hospital had been monitored for years by Milano-Bicocca researchers. The oak tree, now dead, contained numerous developing larvae. The removal of the tree — necessary for safety reasons — would have resulted in the destruction of the entire population.
A highly delicate technical and scientific intervention
The relocation of the trunk required complex work: from the preliminary monitoring of the animals and the stability assessment and structural analysis of the tree to the identification of the relocation site. These stages were accompanied by the equally complex management of the authorisation process, involving notification to the Lombardy Region and a derogation authorised by the Italian Ministry of the Environment and Energy Security, following an opinion from ISPRA, as well as logistical planning with Milan’s IRCCS San Raffaele Hospital and the companies involved.
The wood and adult Cerambyx beetles were transported and placed in the designated area within Parco dei Mughetti, allowing the species to complete its biological cycle. The Park has taken custody of the trunk, undertaking to ensure that the wood remains in situ for the number of years required for the larvae to mature.
This intervention arose from the collaboration between Milano-Bicocca and IRCCS San Raffaele Hospital, which not only prevented the removal of the senescent tree, but also actively contributed to planning the operation, demonstrating sensitivity towards biodiversity.
The operation was made possible thanks to the financial sponsorship of Fondazione Cariplo, which funded part of the logistical costs. The entire project was carried out through the initiative and coordination of the scientific research community, which contributed its own resources together with support from several private organisations, including Maisons du Monde Foundation.
«This intervention demonstrates that biodiversity conservation is made up of concrete actions, not abstract principles,» said Emilio Padoa-Schioppa of the University of Milano-Bicocca. «Saving a population of Cerambyx cerdo means protecting a precious fragment of our ecological history. Without senescent oak trees, many species disappear silently. Today, we chose not to let that happen.»
«We have been monitoring this population for around two years and, following the initial analyses, it became clear that relocation was the only solution capable of ensuring the beetles’ long-term survival,» added Claudia Canedoli. «Through BioTreeversity, a valuable network of collaborations between researchers, companies and professionals in the sector has been consolidated over the years, without which interventions of this kind would not be possible. The entire conservation project was complex, but we were determined not to allow yet another tree to follow the usual process of removal and disposal. We now have a positive story to tell, which we hope can serve as an inspiration.»
Parco dei Mughetti: a new beginning
PLIS Parco dei Mughetti, characterised by mature oak woodland and dead wood, provides an ideal habitat for Cerambyx cerdo. The relocated tree has been placed in a protected and monitored area. Over the coming months and years, the researchers and the Park will monitor the emergence of the adults and their possible colonisation of new trees.
The intervention represents a model that can be replicated in other urban contexts. The presence of habitat trees and dead wood is often overlooked in urban green-space management policies, but conserving these elements is one of the keys to genuine biodiversity conservation in cities and to supporting fundamental ecological cycles.