Functional diversity of Niphargus (Amphipoda: Niphargidae) in the DinaridesPremate, Ester (Avtor) Fišer, Cene (Mentor) subterranean amphipodsgroundwater ecosystemsfunctional traitsfunctional morphologybiodiversitywestern BalkanFunctional diversity (FD) is a facet of biodiversity complementing taxonomic (TD) and phylogenetic (PD) diversity, which accounts for the diversity of organismal functions within ecosystems and is assessed using functional traits. Inclusion of FD in ecological, evolutionary, and conservation-related studies is ever-increasing, but our knowledge on functional traits and FD in groundwater remains limited. In this work, we explored FD in groundwater ecosystems of the Dinarides, a global subterranean biodiversity hotspot, using amphipods of the genus Niphargus as a model system. We reviewed and extended the current knowledge on morphological functional traits in Niphargus. We organized all available data in an openly available dataset, which represents the first such collection of functional trait data for amphipods and for groundwater taxa. We used this dataset as a basis for further studies of FD. We examined the evolution of functional traits in Niphargus and found that some of the traits evolve interdependently. This causes a lower FD within habitats than expected but preserves potential for further diversification of the genus. Next, we assessed spatial FD patterns in the western Balkans. We combined multiple facets (FD, PD, TD) and organizational levels (individual-level metrics, α- and β- diversity) and inferred the drivers of β diversity. The patterns of different facets were incongruent on both α- and β- levels. The dominant component of β diversity was replacement and the main driver of β diversity was geographic distance across all facets. Lastly, we evaluated current indirect protection of groundwater biodiversity in the region. We found that priority species and biodiversity hotspots are not adequately protected. Our results highlight the importance and informativeness of FD in groundwater research and holistic biodiversity assessments. This work provides the foundation for further usage of FD in groundwater ecology and conservation. We discuss potential future research directions, including extension of the functional trait dataset, inference of community assembly mechanisms, research on drivers of biodiversity patterns and potential usage of Niphargus in biomonitoring.[E. Premate]20262026-04-02 07:15:11Doktorsko delo/naloga181338sl