Developing and testing approaches to monitor subterranean biodiversity in karst

Subterranean species represent a unique and irreplaceable part of Europe's biodiversity, for which there is no single monitoring approach. In the Sub-BioMon project we will address this problem and develop standardised protocols for monitoring the status of subterranean biodiversity in karst areas in Europe. We will test methods that can be applied in different geographical areas and allow meaningful spatial and temporal comparisons. The project includes analytical and practical approaches, the definition of biogeographical regions at different geographical scales, and field testing of methods, including new approaches using DNA barcoding and environmental DNA (eDNA) for species detection and identification. Caves are listed as a special habitat under the EU Habitats Directive, so they need to be regularly monitored and their status reported. However, there are no standardised procedures to compare and review the conservation status and trends of this habitat in the EU. Caves as habitats require specific approaches that cannot be easily adopted from other habitat types. The project will look at them from a new angle: as important habitats for many surface species and as windows into larger subterranean habitats for exclusively subterranean species. The project will look at them from a new angle: as important habitats for many species on the surface and as windows into larger underground habitats for exclusively subterranean species. The results of the project are therefore relevant to a wide range of stakeholders, from international to national and local levels, as well as to the professional and wider public. Karst areas do not follow national boundaries; common examples include karst aquifers that are recharged in one country, while ecosystem services such as drinking water use are in a neighbouring country. Subterranean habitats and biodiversity are thus an example where international cooperation is crucial for their management and protection.

Monitoring the status of biodiversity, especially in habitats where endemism is high and species are rare, is a major research challenge. This is particularly true for monitoring species in subterranean habitats, namely those that live exclusively underground. There are no uniform and widely accepted methods for monitoring the status of subterranean biodiversity, and the monitoring protocols used in some places have limited use in international comparisons. The project will develop and test methods with the aim of defining minimum standards for monitoring and comparing subterranean biodiversity. We will investigate appropriate approaches to the selection of caves for monitoring subterranean biodiversity, the effectiveness of field work methods, analytical approaches, as well as test the applicability of eDNA and DNA barcoding methods for the identification and detection of selected subterranean species or communities. The international team will allow comparisons of different natural conditions, as subterranean biodiversity is unevenly distributed in Europe, with peaks of species richness in the southern parts of the continent.

Slovenia is the cradle of speleobiology, with the first scientific descriptions of subterranean animals (human fish, small-necked beetle) coming from its territory, which stimulated the development of this new discipline of biology. In addition, karst as well as non-karst subterranean environments in Slovenia represent the areas with the highest species diversity in the world. However, even in Slovenia, no methods have been developed and established for monitoring subterranean biodiversity, with the exception of a bat monitoring programme (many species use caves as roosts). Considering that most of the subterranean species are narrow endemics, many known from only one cave, monitoring and caring for this part of the biodiversity is also a concern for the world natural heritage. It is in Slovenia's interest to establish internationally comparable methods for monitoring subterranean biodiversity in order to be able to launch a programme of monitoring of this remarkable biodiversity; it is, after all, bound to do so by European and national legislation.