Towards the development of taxon-specific indices for the European Alps

The European Alps are among the richest biodiversity hotspots of global importance. Yet, their unique and fragile ecosystems make this area particularly vulnerable to intensified land use and climate change, requiring urgent action to identify priority areas for restoration and conservation.  

Long-term biodiversity data are essential tools for developing representative ecological indicators and indices that can detect environmental change driven by anthropogenic activities, including shifts caused by climate change. Furthermore, existing indicators and indices typically focus on lowland ecosystems, or specific habitat types, leaving significant gaps in alpine contexts (e.g., the Farmland Bird Index and the European Grassland Butterfly Index). Additionally, biodiversity data across the European Alps remain highly fragmented due to variations in sampling protocols, or due to geographical patterns in species and expertise distribution. 

We propose an expert-based approach that follows the Essential Biodiversity Variables (EBVs) framework, integrated by a data-based approach linked to available taxon-specific long-term monitoring datasets across the European Alps. Our aim is to develop a comprehensive baseline biodiversity dataset that facilitates the identification of representative indicators, and the development of indices for the entire European Alpine region. Using responses from targeted questionnaires focused on different taxa, we will map where different monitoring methods and programs exist for each taxonomic group, to reveal geographical gaps where additional biodiversity monitoring is needed. Moreover, the questionnaires' results will reveal quantitative and qualitative methodological information about long-term monitoring schemes in force across the Alps.

Preliminary findings from the questionnaires revealed that butterflies are the most monitored pollinators group in the European Alps. In addition, only a few, long-term monitoring projects run on pollinating insects and birds include sampling locations above the 2,500 m asl, highlighting an urgent need for increased monitoring effort at higher elevation, especially targeting the alpine environment. These insights can help integrate existing guidelines aimed at effectively monitoring taxonomic groups or species (see the recently updated guidance for aligning public and private practices with the EU Pollinator Monitoring Scheme - EUPOMS) or provide a foundational resource for stakeholders interested in initiating long-term monitoring of other taxa (i.e., mammals and birds), making any newly-developed biodiversity monitoring efforts more compatible with ongoing initiatives across the European Alps.