The Croatian Natural History Museum (Croatian: Hrvatski prirodoslovni muzej) is the oldest and biggest natural history museum and the main body for natural history research, preservation and collection in Croatia. Located on Dimitrije Demeter Street in Gornji Grad, one of the oldest neighbourhoods of the Croatian capital Zagreb, it owns one of the biggest museum collections in Croatia, with over 2 million artefacts, including over 1.1 million animal specimens. It was founded in 1846 as the "National Museum". The National Museum was later split up into five museums, three of which were in 1986 merged as departments of the newly named Croatian Natural History Museum. The museum contains a large scientific library open to the public, and publishes the first Croatian natural history scientific journal, Natura Croatica.The permanent display of the Croatian Natural History Museum consists of mineralogical, petrographical and zoological collections, as well as two permanent exhibits in the atrium: the Rock Map of Croatia and the Geological Pole. It is home to the remains of the Neanderthal from Krapina. As of 2021, the museum is closed pending the completion of reconstruction following the 2020 Zagreb earthquake.
Coastal systems, such as those of the Eastern Adriatic Coast, are complex archives where marine and terrestrial influences can hinder paleoclimate reconstruction. Here, we present a new lake sediment record from coastal karst Lake Velo Blato and use stable isotopes and compositional analysis of ostracod assemblages to reconstruct Holocene paleoclimate and paleoenvironmental changes. Ostracod assemblages revealed three ecological groups: brackish (Cyprideis torosa), freshwater (Cypridopsis vidua), and wetland (Limnocythere inopinata, Darwinula stevensoni), indicating that salinity is the main ecological driver, while processes related to lake succession are secondary. Stable isotope composition of calcite suggests the wettest climate conditions between 8100 and 7500 cal yr BP, coinciding with the development of a freshwater lake. Marine influence is evidenced between 7500 and 6300 cal yr BP, marked by a transition from freshwater (Candona neglecta, Cypridopsis vidua, Paralimnocythere psammophila) to brackish (Cyprideis torosa, Candona angulata, Heterocypris salina) ostracod assemblages, which persisted throughout the Middle to Late Holocene. However, shifts in carbon isotopes around 2100 cal yr BP indicate a significant environmental change, coinciding with a transition from a brackish lake to a shallow wetland. Climatically, warm and dry conditions prevailed during the Roman and Medieval Warm Periods, while wetter conditions have dominated since the Little Ice Age. This study provides a high-resolution record of Holocene paleoclimate and paleoenvironmental change, offering a valuable contribution to understanding coastal systems of the Eastern Adriatic region.
The aquatic species Ludwigia peploides (Kunth) P.H. Raven (family Onagraceae ) is an invasive alien species of Union concern, i.e. included on “the Union list” since 2016 (European Commission 2016), according to the European Union Regulation No. 1143/2014 (European Union 2014). It is native to Americas, Australia and east Asia, with four subspecies recognized today (POWO 2026). In Europe, the species is associated with the formation of dense stands in slow-flowing and stagnant freshwater habitats, where it can alter habitat structure, reduce native biodiversity and affect water quality (Di Lernia et al. 2025). Its invasion success is largely driven by high ecological plasticity and multiple reproductive strategies. The species was recorded in Croatia eight years ago (Buzjak and Sedlar 2018), yet its distribution and infraspecific identity remain insufficiently resolved. In 2025, several new populations were discovered that are morphologically different from the one first reported. One recently discovered population was analysed in detail and can be unambiguously assigned to Ludwigia peploides subsp. montevidensis (Spreng.) P.H.Raven (Fig. 1. This determination is based on a consistent set of morphological characters. In contrast, at the first reported Croatian locality, population was re-sampled and re-examined in the field and subsequently in the laboratory. This population shows morphology predominantly like L . peploides subsp. glabrescens (Kuntze) P.H.Raven, particularly capsule length (up to ~40 mm) and number of seeds per locule (15–17), both of which correspond to diagnostic traits in existing identification keys. However, it also exhibits a mixture of characters, including sparse indumentum on upper stem portions and occasional pubescence on fruits and tepals (Fig. 1). Herbarium specimens deposited in the herbaria ZA and ZAGR, representing previously published records identified only at species level, show similar glabrescens -like morphology. This combination of traits suggests that key diagnostic characters traditionally used to delimit subspecies within L. peploides may not be fully stable. The incongruent morphological pattern may reflect either a higher degree of infraspecific plasticity than previously recognized, or a partial overlap of diagnostic traits among subspecies.
Effective sealing of glass jars used in natural history wet collections is critical for long-term specimen preservation. The selection of an appropriate sealant is a long-known challenge in wet collections management. For a new permanent exhibition at the Croatian Natural History Museum, we decided to use ground-glass-stopper jars, but faced limited time at the outset of the project to select a suitable sealant. We therefore compared nine different sealants that included silicone, wax-based sealants, as well as several commercially available greases and rubbers. Our evaluation focused on key criteria relevant to long-term exhibition use: aesthetic appearance, handling properties and sealing performance. Based on its advantages over the other sealants and its established use in other wet collections, we selected the beeswax–colophony mixture to seal exhibition jars. Although highly effective, this sealant requires skill and is relatively time-consuming to apply. Therefore, we refined the application protocol for the commercial beeswax–colophony mixture, which will serve as practice-based guidance for sealing glass jars and cylinders with ground-glass stoppers. Our comparative assessment also offers practical guidance for curators and collection managers seeking appropriate sealants for exhibition purposes.
Morphometric analyses of well-preserved specimens of Crassostrea gryphoides (Schlotheim, 1813) housed at the Croatian Natural History Museum (CNHM) were performed using two different measurement methods. Shell height (H), curved shell height (H’), shell length (L), curved shell length (L’), ligament height (HLig), curved ligament height (H’Lig), ligament length (LLig), curved ligament length (L’Lig) and shell width (W) were measured by a digital calliper and by an elastic ribbon. Their relations were tested in order to select the best methods to distinguish the morphotypes. The obtained results represent a solid base for future studies of oyster ecology.
The newly renovated Croatian Natural History Museum is a dynamic, inclusive space for knowledge and experience. The modern exhibits support multi-layered education based on interactivity, interpretation, and inspiration. By observing the displays and engaging with digital tools, multimedia, and tactile elements, visitors become participants in a story where knowledge is conveyed not only through information but also through personal experience. The focus is on accessibility, interactivity, and inclusivity, attracting new audiences – middle-aged and older individuals, previously marginalized communities, the growing number of foreign nationals living in Croatia, and tourists. Through innovative exhibition concepts and new technologies, education within this framework also fosters social change – the museum becomes a gathering place for the local community and a center for lifelong learning. This approach creates opportunities for new knowledge – not only about the natural specimens on display, but also about identities, ecology, and the contemporary challenges of climate change.
