Paleoecology of the late Pleistocene avifauna from Marlera (Istria, Croatia) with notes on the voles record

The Eastern Adriatic Coast, owing to its karstic nature, features numerous Quaternary cave sites that mostly date to the Pleniglacial - Late Glacial or Holocene (Marine Isotope Stages 2–1). In this paper, we present a well-preserved small-vertebrate assemblage from the Marlera fossil-cave site (southern Istrian Peninsula), dated to Marine Isotope Stage 3. Taxonomical and paleoecological analyses were conducted on bird and arvicoline assemblages. Further, detailed taphonomic analyses were performed on bird bones and arvicolins subsample. Avifaunal remains were divided into two distinct assemblages: Assemblage I (upper sediment unit), characterized by species preferring open and dry habitats, and Assemblage II (lower sediment unit), that also includes aquatic taxa. The most likely agents of accumulation for bird species not roosting or nesting in the cave were small carnivores and falcons, as reflected in skeletal-part frequencies and gnaw marks. The arvicoline record reveals a productive, karstic mosaic of open grasslands and woodland patches, with Microtus species signaling both dry steppe and locally moist, densely vegetated microhabitats. This faunal structure, combined with the taphonomic evidence and integration of regional paleoclimatic and paleoenvironmental data, shows that the southern Istrian part of the Great Adriatic Plain during MIS 3 was a productive, mostly open landscape with scattered trees and freshwater features. These results significantly contribute to our understanding of the region's paleoecology of this climatically dynamic period.