In cooperation with the Natural History Museum Rijeka, we supplemented our exhibition Bioinspired science with new exhibits inspired by nature in the Gorski kotar.
Exhibit: How do bats see in the dark?
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Bats, which live in Gorski kotar, hunt insects at night. In the colder part of the year, bats hibernate in caves, dens, and attics due to lack of food. Many species of bats live in Croatia, e.g. great horseshoe bat (Rhinolophus ferrumequinum), southern horseshoe bat (Rhinolophus euryale), pygmy bat (Pipistrellus pipistrellus), forest bat (Pipistrellus nathusii), long-eared bat (Plecotus auritus), long-winged bat (Miniopterus schreibersi), great bat (Myotis myotis), or broad-eared bat (Barbastella barbastellus).
Echolocation of bats Bats have small eyes and see much worse than, for example, humans, but they have developed a method of using sound that allows them to fly and find food in complete darkness, called echolocation. Bats produce sound impulses through their mouths or noses (eg, horseshoe bats) and collect information about their surroundings by listening to the echoes. By listening to echoes, a bat can determine the position, speed of movement, size, shape and composition of objects in its environment.
Bioinspiration Humans have developed many useful technologies that mimic the technique of echolocation. Some of them are sonar, ultrasound medical examination, …
Bats that shout and bats that whisper Bats can be broadly characterized by their echolocation calls as shouting bats (loud bats) and whispering bats (silent bats). Screaming bats forage in open spaces and produce sounds of 110 decibels, equivalent to a car alarm or the volume of a symphony orchestra. Whisperers collect insects from the leaves of trees and produce sounds of 60 decibels, corresponding to the volume of human speech.
Not all bats echolocate. About 70% of all bat species in the world can echolocate. Also, bats are not the only animals that use echolocation. Whales and several species of shrews, tenrecs and woodpeckers use a similar technique. Most bat echolocations occur outside the range of human hearing. People can hear from 20 Hz to 15-20 kHz depending on age. Bat sounds can vary from 9 kHz to 200 kHz. Some bat sounds can be heard by humans (for example, the species Tadarida teniotis – Mediterranean free-tailed bat). The squeals and screeches that bats make in their roosts are not the sounds they use for echolocation.
Exhibit: Meadows of Gorski Kotar
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The plants of the Gorski kotar meadows are important for the ecosystem, and here we will give one example. Salvia pratensis, commonly known as meadow sage, plays a significant role in the ecosystems of Gorski kotar. Meadow sage is a source of nectar for a variety of flower visitors, including pollinators such as wild and domestic bees, butterflies, flies and other groups of insects. Pollinators are key to the reproduction of many plants, maintaining and contributing to biodiversity within and between ecosystems. The plant provides habitat and food for many invertebrates. Their presence in meadows and grasslands supports a diverse community of organisms, creating balanced community systems. Historically, meadow sage has been used for medicinal purposes, such as treating eye irritations and sore throats. In some regions, sage is endangered due to habitat loss and changes in land use.
To assess the biodiversity of the habitat, to understand its effects and protection, that is, to study evolution, it is necessary to determine the boundaries between individual species of organisms as accurately as possible. The genus Salvia is known for its diversity. It covers approx. 1000 species worldwide. The diversity of this genus refers not only to polymorphism, but also to reproductive strategies, secondary metabolites and roles in ecosystems. Salvia pratensis is especially morphologically variable, which contributes to the problem of distinguishing individual taxa, especially in the area of the NW Adriatic.
Balant, M., et al. (2019). “In search of an identity for Salvia bertolonii (Lamiaceae).” Phytotaxa 413(2): 117-136.
Exhibit: Hydroelectric power plants and their influence
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Croatia and Gorski Kotar have great potential for obtaining energy from rivers and lakes using hydroelectric power plants. Hydropower relies on the water cycle, which is powered by the sun, which makes it a renewable energy source and does not emit greenhouse gases or other pollutants during operation, which helps reduce air pollution and mitigate climate change. Dams that are built to create sufficient water supplies for hydroelectric power provide flood control, irrigation support, and clean drinking water. Hydroelectric power plants are extremely important for electricity production because they allow a quick reaction when a larger amount of energy is needed and enable cheap energy storage for future needs.
Unfortunately, there are also bad impacts on the environment. Dams and reservoirs can hinder the migration of aquatic organisms, change the natural water temperature and river flow characteristics, negatively affecting local ecosystems. Below the power plant, river courses often have very little water when the power plant is not operating and extremely rapid surges of water when the power plant is generating electricity, which destroys habitats for organisms that cannot adapt to such conditions. Reservoirs can also cover important natural areas, agricultural land, or archaeological sites and can lead to the relocation of communities. In Gorski kotar, we have hydropower plants Zeleni vir, Lepenica and Fužine hydropower plants. Water reservoirs in Gorski kotar are also used by hydropower plants built closer to the sea. Scientific research is carried out continuously to reduce negative impacts on the environment and nature and unnecessary losses during energy production.
Numeričke simulacije hidrauličkih tranzijenata u crpnoj hidroelektrani Fužine. J Škifić, B Crnković, N Črnjarić-Žic. Građevinar 74 (02.), 135-143, 2022. 2022.
L Sopta, S Maćešić, N Črnjarić-Žic, S Družeta, J Škifić… – 2005
Exhibit: Flooding
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Riverbed inundation simulations are crucial for several reasons. Flood simulations help to understand and assess flood risk. By predicting the extent and impact of potential floods, authorities can develop effective risk management strategies to protect communities and infrastructure. Accurate flood simulations are essential for creating early warning systems. These systems can provide timely warnings to the population and emergency services, enabling rapid evacuation and preparations, thereby reducing the risk to human life. They inform urban and regional planning by identifying flood-prone areas based on flood simulations and recorded previous events. This information is critical for designing flood-resistant infrastructure, zoning regulations, and land-use planning to minimize flood damage. Simulations can predict how floods will affect natural habitats, water quality and soil erosion, allowing for better conservation with reduced restoration efforts. By preventing or mitigating flood damage, simulations can save significant economic costs associated with property damage, business interruptions, and recovery efforts. They also help to optimize the allocation of resources for flood defense measures. Investing in such research contributes to broader scientific knowledge and provides data on hydrological and hydraulic processes.
L Sopta, S Vuković, N Črnjarić-Žic, S Družeta, J Škifić… – 2003
Exhibit: Trees in Computer Graphics
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Fractal pattern generating is indeed a natural mechanism observed in the growth of various organisms. Fractals are self-similar patterns that repeat themselves at different scales, and can be found in many biological structures and processes. Fractal patterns are not only aesthetically pleasing but offer several functional advantages:
fractal structures can increase the use of space and resources,
enabling organisms to adapt to their environment,
the self-similar nature of these patterns means that damage to one part of the structure does not necessarily endanger the entire system,
fractals provide a simple set of rules for growth and development, allowing complex structures to emerge from simple processes.
Because of these good properties, trees in computer games can be generated using fractal algorithms! This method is quite popular in computer graphics for creating realistic and complex natural structures such as trees. Fractal algorithms, such as the L-system (Lindenmayer system), are often used for this purpose. L-systems use recursive rules to simulate the branching patterns of trees, producing highly detailed, natural-looking results. By adjusting parameters such as branch length, angle, and depth of recursion, developers can create a wide variety of tree shapes and sizes.
Another approach uses Perlin noise, which is often used in the procedural generating process. Perlin noise can help create the irregularities and variations seen in natural tree structures, adding realism. These techniques not only increase the visual appeal of games, but also optimize performance by allowing the procedural generation of large forests without the need to manually model each tree.
Exhibit: Lynx and genetics
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The reintroduction of the lynx to Croatia was a significant effort for its conservation, in the last few years additionally encouraged by the LIFE Lynx project. This initiative aims to increase the genetic diversity and stability of the endangered Dinaric lynx population.
Historically speaking, lynxes were exterminated in Croatia at the beginning of the 20th century due to excessive hunting. The first reintroduction attempt took place in 1973, when six lynxes from the Slovak Carpathians were released into Slovenia. Over time, the offspring of these individuals spread to Croatia.
In recent years, the LIFE Lynx project has been instrumental in further strengthening the population. Since 2019, several lynx have been released into various Croatian national parks, including Risnjak and Paklenica. These efforts are key to increasing genetic diversity and reducing the risk of interbreeding within families.
Reintroduced lynxes play a vital role as top predators, helping to maintain ecosystem stability and enhance biodiversity. Their presence also supports local tourism, providing opportunities for wildlife viewing and nature activities.
Sindičić, M., Polanc, P., Gomerčić, T. et al. Genetic data confirm critical status of the reintroduced Dinaric population of Eurasian lynx. Conserv Genet14, 1009–1018 (2013). https://doi.org/10.1007/s10592-013-0491-x
