Petar Crnčan’s research while affiliated with Croatian Natural History Museum and other places

The Mediterranean is characterised by high biodiversity and numerous endemic species. These species are not only present in natural habitats, but also inhabit areas under human influence, such as agricultural lands. In the biodiversity assessment of Mediterranean vineyards and olive orchards within Zadar County, in Croatia, we identified eight endemic species with Mediterranean distribution, six with a Balkan Peninsula distribution, four with Dinaric Alps distribution and three species rare and endangered in Europe. Alongside these species, we have recorded five new species for Croatian fauna, many of those identified by combining morphological characteristics and the DNA barcoding tool. Araneae and Coleoptera contributed the highest number of endemic species and groups with new record were the following: Coleoptera, Diptera and Araneae. Compared to other sites, an olive orchard with ecological pest management (EPM), surrounded by natural ecosystems, had the highest ratio of endemic and rare species. Our findings emphasise that agricultural lands in the Mediterranean can be habitats for endemic and rare species and that future biodiversity research of these habitats is highly important, to monitor potential biodiversity changes and motivate future species and ecosystem conservation.

Alien aquatic macroinvertebrates, especially invasive crustaceans and molluscs, have heavily impacted native species and ecosystem processes in freshwaters worldwide. Knowledge on alien species distribution is necessary to understand their dispersal dynamics and prevent future invasions, and to predict and reduce undesirable impacts. Literature data on alien macroinvertebrate species (AMS) in Croatia are sparse and a complete inventory of alien macroinvertebrates in Croatian freshwaters has never been conducted. The aim of this study was to present a database of AMS in Croatian freshwaters and to analyse their origin, pathways of introduction and distribution. The AMS database was built based on literature data and the authors’ unpublished data, and included a total of 1,411 records from 689 sites across Croatia. In total, 29 AMS were recorded until 2019, belonging to five major taxonomic groups: subphylum Crustacea (16 species) and phyla Mollusca (7 spp.), Annelida (4 spp.), Cnidaria (1 sp.), and Platyhelminthes (1 sp.). The area of origin of most species is the European Ponto-Caspian region (19 spp., 66%), and the rest originate from North America (5 spp.), Asia (4 spp.) and New Zealand (1 sp.). The most important pathways of unintentional primary introductions were stowaway-shipping (20 spp., 69%) and contaminant-fish stocking (6 spp., 21%). All 29 AMS species were found in the Black Sea Basin (Danube Basin) and five of those were also recorded in the river catchments of the Adriatic Sea Basin. For most AMS, the Sava and Drava Rivers are the main river corridors for their westward spread from the Danube. Since studies of AMS dispersal mechanisms are lacking and only a few studies report the impacts of invasive AMS in Croatia, future studies should be focused on the dispersal dynamics and ecological impact of invasive macroinvertebrates in Croatian freshwaters.

This paper presents the results of a malacological survey of the largest Croatian lake - Vrana Lake and its surroundings in Vrana Lake Nature Park. Altogether 21 species of aquatic non-marine molluscs (15 gastropods, 6 bivalves) have been recorded. Out of all recorded species, only 10 were documented in Vrana Lake, probably due to the higher salinity of water in the lake. A population of the endangered gastropod Anisus vorticulus was found in Benča Lake.

The Chinese pond mussel Sinanodonta woodiana is an invasive bivalve species present in the flowing and standing waters of most of Europe. Field research conducted from 2007 to 2011 indicated that this species has colonised the entire eastern part of Croatia, and that its spread westward is continuing. During our study, S. woodiana was recorded at 54 localities.