Geoethics Supporting Karst-Based Geotourism Modelling: Assessing Karst Geosites and Management Practices in Serbia and Montenegro

Aleksandar Antić¹; Mike Buchanan¹; Milica G. Radaković²; Miloš Marjanović²; Giuseppe Di Capua^1,3; Silvia Peppoloni^1,3; Slobodan B. Marković^2,4,5,6; Velibor Spalević⁷; Rastko Marković⁸; Nemanja Tomić²

 ¹International Association for Promoting Geoethics, Via di Vigna Murata 605, 00143 Rome, Italy

²Department of Geography, Tourism and Hotel Management, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 3, 21000, Novi Sad, Serbia

³Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Rome, Italy

⁴Division of Geochronology and Environmental Isotopes, Institute of Physics – Centre for science and Education, Silesian University of Technology, Gliwice, Poland

⁵Serbian Academy of Sciences and Arts, Kneza Mihaila 35, Beograd 11000, Serbia

⁶Institute for interdisciplinary and multidisciplinary studies, University of Montenegro, Cetinjska 2, 81000 Podgorica, Montenegro

⁷Biotechnical Faculty, University of Montenegro, Mihaila Lalića 15, 81000, Podgorica, Montenegro

⁸Faculty of Sciences, Department for Geography, University of Niš, Višegradska 33, 18000, Niš, Serbia

 Correspondence: a.antic994@gmail.com

Abstract: This study presents the development of a comprehensive Karst Geoethics Assessment Model (KGAM) that integrates karst vulnerability, conservation practices, and tourism utilisation to promote geoethical approach to International Best Practice (IBP), ensuring appropriate karst site management. The primary goal is to assess the performance from a geoethical perspective of sustainable management strategies for geologically significant destinations. As a case study, eight karst geosites in Serbia and Montenegro were subject to evaluation using four sets of indicators: Karst Vulnerability (KV), Human Activities (HA), Conservation Efforts (CE), and Geoethical Tourism Performance (GTP). Results reveal a range of vulnerabilities, conservation statuses, and tourism practices across the geosites, highlighting significant challenges, particularly in waste management, biodiversity loss, and geoethical awareness of local communities. Whilst a few geosites demonstrate robust conservation efforts and low human interference, others face high vulnerabilities from tourism and urban activities. The study emphasizes the need for specialised management strategies, educational programs, and geoethical practices to ensure the sustainable management and conservation of karst geosites. Recommendations for targeted interventions, stakeholder involvement, and geoethical tourism promotion are provided to improve the long-term sustainability of these unique landscapes.

Keywords: geoethics; geoethical assessments; karst systems; geotourism.

 1.       Introduction

The affirmation of attractive geological landscapes allows for the emergence of geotourism—a special interest form of tourism, which provides value to destinations through interpretation and distribution of knowledge (Hose, 2006; Dowling, 2013; Tessema et al., 2021). Geotourism focuses on and presents geologically significant destinations, which often include karst areas. With the emergence of geotourism, karst landscapes are becoming more frequently visited (Newsome et al., 2012; Dowling, 2013; Dowling & Newsome, 2017), this represents one of the constant challenges for the conservation and sustainable management of karst regions. Therefore, it is crucial to understand, assess and potentially prevent various forms of degradation within karst environments, which can be a result of tourism activities. In the case of geotourism, activities can be conducted in particularly vulnerable areas where anthropic activities can significantly threaten biotic and abiotic karst systems. Thus, implementing responsible management and maintenance of these destinations is a necessity (Hooper et al., 2005; Williams et al., 2020; Pourfaraj et al., 2020). Responsible tourism practices have been promoted globally, through declarations by international organisations (for example, the Cape Town Declaration on Responsible Tourism¹, 2002). This declaration emphasises dangers of nature-based tourism, consequences that can threaten both subterranean and terrestrial geobiodiversity, social implications (the relationship between tourists and local/host communities) as well as the importance of sustainable utilisation of natural and cultural heritage (Isaac, 2014).

Although meaningful, declarations of this type seem limited, in the sense that they do not provide sufficient guidance for the management of destinations of a particular form of tourism, such as geotourism. Current global geoconservation efforts are mostly reflected in UNESCO's mission to institutionally position and affirm geoheritage on the tourist market through standardisation and issuance of geopark status. Geoparks represent defined areas that encompass sites and landscapes of international geological significance (Herrera-Franco et al., 2021). Their goal is to emphasize the conservation and interpretation of geological heritage through various means, including geotourism, education programs, interpretation centres, and outreach activities. Geoparks can be officially recognized by UNESCO's Global Geoparks Network, which supports and coordinates the establishment and management of geoparks worldwide (Singh et al., 2021). With the establishment of geoparks, geotourism gains advantages that can enable a significant increase in sustainable protection measures and the promotion of (geo)ethically responsible behaviours towards geodiversity and biodiversity.

Given that karst landscapes are known for their high level of vulnerability, both from natural processes and from anthropogenic activities, it is necessary to strive for effective assessments and sustainable management measures and objectives (Telbisz et al., 2015; Powell et al., 2018; Parise et al., 2018; Ruban, 2018; Wang & Xiao, 2020). Dynamic interaction between surface and subsurface karst features enhances this vulnerability, as alterations on the surface can lead to environmental degradation in the subsurface and vice versa (Unklesbay & Vineyard, 1992; Herrera-Silveira et al., 2013). Therefore, it is necessary to establish responsible and ethically adequate management strategies that enable karst protection with appropriate education and visits. Karst-based geotourism can be defined as a specialised form of geotourism that focuses on unique geological karst features and landscapes, associated with the karst terrain. These geosites offer insights into karst geomorphology, climatology, limnology, hydrology, biology, palaeontology, palaeoanthropology, karstology and speleology, providing opportunities for scientific exploration and education.

As pressures of geotourism and land use intensify, safeguarding the integrity of karst environments has become an important aspect of these destinations, which demands a focused effort to address (geo)ethical considerations (Antic et al., 2020; Zafeiropoulos et al., 2021; Breg Valjavec et al., 2022). For example, the endemicity of biodiversity within karst environments represents a unique feature for geotourism destinations but also demands great necessity for rigorous sustainable conservation legislation (Krobicki et al., 2006; Gelvez-Chaparro et al., 2018). Karst regions hold invaluable opportunities for exploration and appreciation, but their fragile ecosystems require protective management to ensure their long-term preservation. Thus, balancing conservation with economic activities is essential to safeguard the rich biodiversity and geodiversity of karst environments for future generations, for local communities, researchers, tourists and managers.

Geoethics plays a pivotal role in promoting responsible behaviours within karst terrain management. It empowers geoscience communities, researchers, policymakers, local populations, visitors, and stakeholders to adopt principles of responsibility while embracing values such as stewardship, sustainability, and the minimisation of human impact. Geoethics encourages the protection, conservation, and sustainable enhancement of Earth's geological heritage. As Peppoloni & Di Capua (2021) point out, these principles are essential in ensuring that the management and utilization of such unique terrains align with ethical standards that prioritize long-term preservation.

Karst landscapes, characterised by their distinctive geological formations, fragile ecosystems, and vital water resources, are often vulnerable to human activities. Improper management can lead to environmental degradation, loss of biodiversity, and destruction of valuable natural and cultural heritage. Therefore, incorporating geoethical principles into land-use planning and environmental policies is not only a matter of scientific responsibility but also a societal one (Peppoloni & Di Capua, 2023). By following geoethical guidelines, geoscientists and other involved parties contribute to minimizing the negative effects of human actions, safeguarding these areas for future generations.

Moreover, emphasising responsible practices in managing geoheritage sites serves both cultural and practical purposes. Culturally, it provides a means to disseminate geological knowledge, IBP to the broader public, fostering a deeper understanding of Earth's dynamic karst processes by highlighting the intrinsic value of natural features like karst terrains. Practically, it enhances public awareness and engagement with geoheritage, which is vital for fostering a collective sense of responsibility toward environmental conservation. Engaging local communities in this process is crucial, as it helps to establish a sustainable approach to land management that respects both ecological and cultural sensitivities. This partnership strengthens the connection between people and their environment, promoting a sense of stewardship that extends beyond mere regulation (Peppoloni & Di Capua, 2015; Bobrowsky et al., 2017; Peppoloni et al., 2019; Peppoloni & Di Capua, 2023).

In addition to guiding professional practices, geoethics extends responsibility to geotourists, who are encouraged to embrace ethical conduct, respect local cultures, and minimize their ecological footprint (Gordon, 2018). Tourists visiting karst terrains have the potential to impact these sensitive environments, adopting geoethical behaviour ensures that they contribute positively to both the preservation of natural landscapes and the well-being of local communities. Responsible geotourism aligns with the broader goals of geoethics by promoting awareness, education, and minimal environmental disruption.

Geoethics also underscores the importance of international cooperation in managing karst terrains and promoting geotourism sustainability. The complex challenges associated with karst management—such as pollution control, habitat preservation, and water resource management—demand a united global effort. By fostering collaboration across borders, geoethical principles help to create a framework for shared responsibility, encouraging countries and regions to work together toward common conservation goals. With the promotion of responsible practices that minimise the risk of environmental degradation and habitat destruction, geoethics ensures that both scientific study and sustainable karst-based geotourism can continue in harmony with environmental protection.

The Cape Town Statement on Geoethics (Di Capua et al., 2017) highlights the importance of enhancing geoheritage, emphasizing that it integrates scientific, cultural, and social factors which hold intrinsic social and economic value. It recognizes the need to strengthen the connection between people and their environment, fostering a sense of belonging that encourages ethical stewardship. By embracing these principles, geoscientists, policymakers, tourists, and communities can all contribute to the preservation of Earth's geological heritage, ensuring that these valuable sites remain protected for future generations.

Therefore, it can be concluded that geoethics provides a critical foundation for managing karst terrains responsibly. It enables stakeholders to take an integrated approach to conservation, blending scientific insights with ethical considerations to ensure that these fragile landscapes are managed sustainably. By fostering a culture of awareness, education, and stewardship, geoethics not only safeguards geoheritage but also helps build a more informed and engaged society. This society, in turn, becomes capable of making decisions that respect both the environment and the communities that depend on it, whether through local initiatives or global cooperation.

Following these considerations, this paper aims to create a first comprehensive assessment model that will consider the dynamic interaction between karst vulnerability, conservation practices and tourism utilisation, as a constructive way to promote geoethical approaches to karst site management. The main purpose of conducting our karst-based geotourism modelling is to assess the geoethical performance of sustainable management structures related to geologically significant destinations. As a case study, we will analyse eight karst geosites in Serbia and Montenegro. The modelling includes an evaluation of four sets of indicators: karst vulnerability (KV), human activities (HA), conservation efforts (CE) and geoethical tourism performance (GTP). The modelling was performed on all important karstic geosites located in Serbia and Montenegro.

2. Study Area

Here we describe four karst terrain sites from Serbia: one intermittent spring, one karst spring, one cave system, one rock arch complex, and four sites from Montenegro: one cave system, one dry polje, one cave spring, one estavelle.

 

Figure 1. Selected karst geosites in Serbia and Montenegro. Limestones layer according to Asch, 2003.

 

2.1. Homoljska Potajnica – KG1 (Serbia)

Homoljska Potajnica (Figure 2a), is one of three rare intermittent springs in Serbia (Miljković, 2018; Miljković et al., 2019). It was first protected by law in 1961 as a natural monument, and in 1995 this intermittent spring was designated as a first-category, hydrological natural monument of exceptional significance. The spring is located on the southern slope of the Homolje Mountains (44°16'47.9"N 21°48'40.7"E) in Eastern Serbia, on the left bank of the Potajnička River, nine meters above the riverbed. The nearest village is Selište, from where several roads lead to the intermittent spring. The geological composition of the surrounding hills is diverse, ranging from Miocene, Pliocene Lake sediments and Upper Jurassic limestones to Ordovician metamorphic rocks. There are occurrences of gabbro of unknown age (Miljković, 2018). HP was first mentioned by Cvijić (1896), who visited the site three years earlier, and was later studied by Marković (1963), Gavrilović (1967), and Miljković (1980, 2006). In more recent research, Miljković (2018) observed that the spring remained active for 47-51 minutes, followed by a 7-hour and 15-minute pause. Previous studies have reported varying conclusions on the spring's dynamics. The active phase can last anywhere from 14 to 55 minutes, except for a 2011 event, when the spring remained active for 24 hours at full capacity. This rare event also triggered the activation of another spring, located 2 meters above the Homoljska Potajnica. Conversely, the dry phase can last from 39 minutes to 7 hours and 15 minutes. Notably, in 1964, the spring remained dry for 24 hours (Petrović & Petrović, 1997). It is suggested that the water reservoir is fed by multiple sources due to the variable dynamics of the spring. Researchers also measured the spring's dimensions and found that it had shifted 2 meters backwards due to 70 years of erosion. The bifurcated channels inside HP, described by Cvijić (1896), were destroyed as a result of this erosion (Gavrilović, 1967). Using turbidity as an indicator, it was confirmed that part of the water from the nearby Ponornica River contributes to filling the reservoir of Homoljska Potajnica (Gavrilović, 1967).

2.2. Mlava Spring – KG2 (Serbia)

Petrović & Petrović (1997) point to the existence of 1360 springs in the karst area of Eastern Serbia. It covers an area of 3.321 km², from which 2.840 km² does not have surface water. The springs are a consequence of contact between different rock types and the karst area within the Serbian Carpathians. However, only 86 of these springs have a discharge larger than 0.1 m³/s, and one of the most important, is the spring of river Mlava (Figure 2b), which is protected as a first-category hydrological natural monument in 1979 (Miljković, 2018). It is located on the southern part of Žagubica village (44°11'29.8"N 21°47'02.3"E), filling a sinkhole, on absolute height of 314 m. The sinkhole is formed on the contact of Lower Cretaceous limestones with Neogene lake sediments. The perimeter of the sinkhole is 93 m, the depth is estimated to be 73 m. Since karst in Eastern Serbia is relatively shallow, there is a correlation between the rainfall and spring discharge. The maximum water discharge on Mlava Spring occurs after the snow melt is combined with heavy rainfall. The absolute discharge was measured in 1910 and estimated to be 70 m³/s (Lutovac, 1935). Minimum discharge is measured in 1950 and was 0.25 m³/s (Dukić, 1975). During the summer when temperatures are higher, the aridity increases in the region (Radaković et al., 2019), the spring discharge is at its lowest. The average discharge for the period 1966-2010 is 1.96 m³/s. However, water temperature is shown to vary from 10.0°C to 10.6°C throughout the year (Petrović & Petrović, 1997). A portion of the spring water is used for a fishpond. The remainder flows over the artificial dam forming the confluence with Tisica stream creating the River Mlava. Water in Mlava Spring comes from different sources. Partially, from the area of nearby sunken streams on the northern slopes of Beljanica. Several times in history the spring dried out during the following years: 1893, 1957, 1971 (Miljković, 2018). This happens if the underground channels get filled with sediments which stop the water from flowing. Activation of these channels can cause local earthquakes or tremors (Miljković, 1992). Next to the Mlava spring is a hotel with a capacity for 70 guests, and it also possesses a restaurant and parking.

 2.3. Vetrena Dupka cave – KG3 (Serbia)

Vetrena Dupka Cave is located on the left side of Jerma valley (43°00'29.8"N 22°38'13.0"E), above the village of Vlasi in the southeastern part of Serbia, close to the border with Bulgaria. The cave entrance is exposed to the west, which can be reached by the narrow path through the forest on Vlasi mountain. The entire length of the cave is estimated to be 4.150 m. The cave system forms two parts, a very narrow and meandering channel and a vertical sinkhole called Pešterica. The entrance of the cave is located 420 m above sea level. It starts with a 40 m-long chamber, which ends in a blocky boulder choke (BC) of collapsed limestone. The only way to advance further through the cave is to pass through the BC in a very narrow downward-leading passage. Once the BC part is navigated, one can easily walk through the meandering channel until reaching the groundwater table. Pešterica sinkhole is 160 m deep, and it serves as a swallet hole for the continuum of the Berovička River, which creates the meanders within the cave and accumulates fluvial sediments within. Pešterica pit is located 720 m above sea level. The shape of pit is simple as it only has two smaller shelves on the side walls. The lower part of the pit has the remains of fluvial erosion (Petrović & Petrović, 1997).

 2.4. Vratna rock arch complex – KG4 (Serbia)

Rock arches can form through various erosional processes in karst terrains. They are specifically linked to running water and remnants of relict caves (or deroofed caves). These features are relatively rare, therefore, serve as attractive tourist destinations. In Eastern Serbia, there are several notable rock arches, including Osanička, Valja, Samar, Rajska, and Vratna. The Vratna Arch Complex (Figure 2c), being close to a monastery from XIV century, is the most visited one, which was the reason for selecting it for this assessment. The rock arch shares its name with the Vratna River, a right tributary of the Danube. Cvijić, a pioneer karst researcher, described this site as remnants of cave ceilings under which the Vratna River once flowed as an underground river. He suggested that the first phase of their formation involved the development of sinkholes in the cave ceiling, allowing other erosional forces to act on the cave's interior. Over time, the original cave channel became unrecognizable, leaving only two arches—Velika (large) and Mala (small)—standing proud above the river (44°22'56.2"N 22°20'17.4"E). The rock arch in the upper part of the Vratna River, known as Suva prerast (a Serbian term for a rock arch), likely originated from a sinkhole at the junction between differing Jurassic rocks (44°23'02.3"N 22°18'36.0"E). At this point, the Vratna River disappears underground via a swallow hole after encountering limestone. Ćalić-Ljubojević (2000) described the VAC above the Vratna River and estimated the length of the original cave to be at least 150 meters, a figure close to the earlier estimate of 160 meters (Petrović & Petrović, 1997). This length is derived from the distance and width between the Mala and Velika rock arches. Interestingly, a 305-meter-long cave developed within the Velika rock arch. There is ongoing debate as to whether this cave was once connected to the main cave channel, which no longer exists (Gavrilović, 1998; Ćalić-Ljubojević, 2000). There are two touristic path options for visiting this geosite. One path follows the highest parts of the terrain so the arches can be seen from above, while the second path follows the alluvial plain, and is more difficult to cross. This is due to the different depths of the river (at some sections the water is not present at the surface), and meandering character of the Vratna River. In one section of the valley where the sides are almost vertical, the path is the most dangerous,  reminiscent of via ferrata. In the Vratna River valley, multiple caves are present on the sides of the river adding to the picturesque scenery of this geosite.

 

Figure 2. Assessed karst geosites in Serbia (a) Homoljska potajnica intermittent spring; (b) Mlava spring; (c) Suva arch, part of the Vratna arch complex.

2.5. Đalovića cave – KG5 (Montenegro)

The Bjelopoljska Bistrica River flows through the Đalovića Gorge, forming four whirlpool potholes, in which the longest cave in Montenegro is located (43°04'23.7"N 19°55'23.6"E). It is formed in carbonate sediments of Ladinian and probably Anisian age (Radusinović & Pajović, 2024). This cave has two names, Pećina nad Vražjim firovima (Cave above the Devil's Whirlpool) (Nešić, 2015) or Đalovića Cave (ĐC), which is sometimes written in the literature as Djalovića (Djurović, Lješević, 1994). The nearest town is Bijelo Polje, and the closest village is Đalovići. Since the discovery of the cave in 1987 by the Belgrade Mountaineering Association. Several expeditions have measured the length of the cave, thus various lengths have been reported: 11.7 km (Belgrade Mountaineering Association),17.5 km (Madžgalj, 2013) and 20 km (Vujačić et al, 2024). ĐC has three entrances, of which the main entrance is 835 m above sea level (Djurovic, Djurovic, 2021), while the other entrances are smaller (Radojičić, 2015). Almost all speleothem types are present, some over 15 m high with halls over 30 m high. According to online data from Academic Speleologic and Alpinistic Club (ASAK) from Belgrade, the explored part of the ĐC consists of four parts: the Lake Channel, the Great Labyrinth, the Great Channel and a network of channels connecting the upper and lower levels. Permanent and seasonal lakes in the Lake Channel, were created by natural dams show clear signs of erosion and low accumulation. The Great Labyrinth is a complex of about fifteen channels of different sizes and heights, with significant chemical deposits. The Great Canal is characterized by its large dimensions, including impressive stalagmites, lakes, sand deposits of an underground river and water siphons (hypogenic speleogenesis). The connecting channels link the upper and lower cave levels, which are divided into two hydrographic zones, with the upper level being mostly dry and the lower part being in a transition zone. There are plans to build a cable car to the main entrance of the cave. Some work has already been started in the front part of the cave, but much remains to be done.

 

Figure 3. Assessed karst geosites in Montenegro (a) Nikšić polje, (b) Gornjepoljski Vir estavelle, (c) Sopot spring on the Adriatic shore.

 2.6. Nikšić polje – KG6 (Montenegro)

The second largest city in Montenegro, Nikšić (42°46'44.6"N 18°56'57.8"E), is located within the Nikšić karst Polje (Figure 3a). There are several poljes in Montenegro such as Cetinje, Grahovo and Dragalj, but none of them has such a high population like Nikšić (over 58,000 according to Lješević, Doderović, 2020). The absolute altitude of the polje is between 602 m and 661 m. The area is 66.1 km². In the northern part, it is 2.5 km wide, but 15 km in the south. Trebjesa, the 751 m high hill in the centre of the town of Nikšić, consists of Triassic dolomites. All geological units follow the northwest-southeast direction of the Dinaric Alps, except for the Quaternary sediments that cover the surface of NP. Since the Nikšić polje was surrounded by the Pleistocene glaciers on mt. Maganik, Moračke mt., Vojnik (Hughes et al. 2011), there are also glaciofluvial sediments (Nikolić et al., 2024). Beneath it are cretaceous limestones (Radojičić, 1952). The main river flowing through the NP is the Zeta, a right tributary of the Morača River. It disappears via swallet in the southern part of NP near Norin and reappears (resurgent) on the surface at the hydropower plant “Perućica” (307 MW) through the spring called Glava Zete (Head of Zeta) (Milanović et al., 2018). In the southern parts of NP, there were several sinkholes of the Zeta River, but they were filled with sediments (Radušinović, Pajović, 2024). The capacity of the Slivlje depression is estimated at 150 m³/s, and 252 m of underground channel have been explored (Ćulafić, Krstajić, 2024). The total underground flow of the Zeta River is about 5 km long, and the entire Zeta River is 89 km long (Milanović et al., 2018). Hydrological research in Nikšić polje led to the construction of three lakes: Slanjsko, Vrtac and Krupac, from which water is used in the Perućica hydropower plant. Before there were these lakes, NP was periodically flooded in autumn and spring (Stevanović, 2010). A total of 330 springs, 880 sinkholes, 30 estavelle and one intermittent spring are described in NP (Barović, 2024).

 2.7. Sopot spring – KG7 (Montenegro)

Sopot Spring (Figure 3c) is located near the town of Risan, on the main road from Risan to Herceg Novi, 40 m above the Adriatic Sea (42°30'49.1"N 18°40'53.6"E). When the SS is not active it looks like a cave next to the road. When it is active, groundwater comes from the cave and flows under the bridge to the Adriatic Sea. Near its discharge point into the Adriatic Sea, the submarine karst spring Risanska Vrulja releases groundwater from the karst aquifer system. It can sometimes be seen on the surface of the Adriatic Sea when the underground water pressure is higher than the pressure of the sea water above the spring. The discharge from SS can exceed 100 m³/s (Stevanović et al., 2022) and sometimes 150 m³/s (Mandić et al., 2017). The channel of the cave from which the water emerges has been explored over a length of 380 m. The entrance to the cave is 4 m high and 10 m wide. When the spring is active, the underground water reaches a height of 40 m above sea level, while when the spring is dry, the seawater penetrates about 500 m into the spring channels (Stevanović, 2010). Directly above the Sopot Spring is the protected forest of laurel (Laurus nobilis) and oleander (Nerium oleander) (Mandić et al., 2017). When the SS, associated with Risanska vrulja, is active, it provides a spectacular scenery for anyone driving on this sector, thus a parking and a viewpoint are made close to the site. The site can be reached by a local bus from the city of Risan.

 2.8. Gornjepoljski Vir estavelle – KG8 (Montenegro)

Radojičić (1952) described the estavelle (or inversac) near the village Vir in the Nature Preserve (42°50'46.9"N 18°55'01.8"E). The name Gornjepoljski refers to the sector of Gornjepolje (upper polje) of Nature Preserve. Estavelle is a specific form of sinkhole in karst areas, which acts as a spring and as a sinkhole depending on water availability in the area. It looks like a lake which suddenly disappears through the sinkhole in the summertime with a loud sound of cracking noise. For most of the year, Gornjepoljski Vir (Figure 3b) looks like a lake with a diameter of 85 m and an average depth of 30 meters. From May to September, it acts as a ponor, receiving inflow from the Sušica River at a rate of 0.1 to 0.5 m³/s. Following the first heavy autumn rains, the lake's water becomes turbulent and rapidly drains into the ponor. After 20 to 50 minutes, muddy, turbid water resurfaces from underground, refilling the lake and flowing down the Sušica riverbed into the Nikšić polje. This cycle repeats itself consistently every year (Bonacci, 2012).

3. Methodology

The goal for utilizing this newly developed assessment model is composing strategies that can enhance the geoethical preservation of our karstic geoheritage. The methodology employed in this study is based on previously utilised models in geosite evaluations (Zouros, 2005; Reynard et al., 2007; Vujičić et al., 2011; Cigna & Pani, 2013; Tomić & Božić, 2014; Brilha, 2016; Tomić & Košić, 2020; Antić et al., 2022). The Karst Geoethics Assessment Model (KGAM), which was used in this paper, represents an innovative approach to assessing karstic geoheritage, consisting of four groups of indicators: Karst Vulnerability (KV), Human Activities (HA), Conservation efforts (CE) and Geoethical Tourism Performance (GTP). All indicators have their own sub-indicators that are given values (grades) from 1 to 5 (1–lowest value and 5–highest value, Table 1). KV consists of 7 sub-indicators, HA includes 4 sub-indicators, CE includes 7 and GTP includes 6 sub-indicators. Therefore, modelling included the use of 4 indicators, which are comprised of 24 sub-indicators.

The assessment process comprises of three distinct stages. In the initial phase, the authors evaluated and assigned scores to the selected karst geosites in Serbia and Montenegro based on the sub-indicators within the four established indicator groups (Table 1).Subsequently, in the second stage, experts evaluate and provide importance factors (Tomić & Božić, 2014) for each sub-indicators within the assessment model. The importance factors are average scores given by experts (1–5) in surveys. Each sub-indicator has its own importance factor, representing the experts' collective assessment of its significance within the model. The third stage includes calculating the final ratings for the investigated karst geosites. Authors' ratings were multiplied by the previously established importance factors determined by experts. Therefore, the final ratings incorporates both the authors' opinions and the input from experts in the fields of karstology.

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KGAM can be defined according to the following equation:

 

KGAM = KV + HA + CE + GTP

(1)

Since each group of indicators consists of sub-indicators, factors in equation (1) can be calculated through the following set of equations:

KVi = i, where 1 ≤ KVSIi ≤ 5

(2)

 

HAp = p, where 1 ≤ HASIp ≤ 5

(3)

 

CEm = m, where 1 ≤ CESIm ≤ 5

(4)

 

GTPn = n, where 1 ≤ GTPSIn ≤ 5

(5)

Here, KVi, HAp, CEm and GTPn represent the scores assigned by the authors, while KVSI_i represents 7 sub-indicators of karst vulnerability levels (i = 1,…,7), HASI_p represents 4 sub-indicators of human activity levels (p = 1,…,4), CESI_m represents 7 sub-indicators of conservation efforts (m = 1,…,7) and GTPSI_n represents 6 sub-indicators of geoethical tourism performance levels (n = 1,…,6).

Each Importance Factors (IF) respectively for KV, HA, CE and GTP (KV_if, HA_if, CE_if and GTP_if) is defined as follows:

(6)

 

(7)

 

(8)

 

(9)

where, Iv_i, Iv_p, Iv_m and Iv_n represent numerical ratings assigned by each expert to individual sub-indicators related to KV, HA, CE and GTP. E is the total number of experts in the survey.

Finally, the KGAM equation with the importance factor is defined and shown in the following form:

 

KV =

(10)

 

HA =

(11)

 

CE =

(12)

 

GTP =

(13)

 

The results of the assessment are shown in 6 different matrices, which present the relationship between all the indicators developed in this study. The results of this methodology should provide insights into the current state of the evaluated karst geosites. The maximum attainable scores for all indicators are determined based on the comprehensive scoring system employed in the assessment method. For KV and CE, with their 7 sub-indicators, the maximum score per site is 175, calculated by multiplying the highest possible score (25) with each sub-indicator. Similarly, for HA, which consists of 4 sub-indicators, the maximum score is 100 and for GTP the maximum score per site is 150.

Table 1. Karst-based Geoethics and Geotourism Modelling

Indicators	Sub-indicators	Description	Scores
			1	2	3	4	5
Karst Vulnerability (KV)	Geological hazard (KV1)	Geological hazards specific to the geosite (e.g., collapse features, subsidence).	High occurrence of significant geological hazards with immediate threats.	Moderate occurrence of geological hazards with some localized impacts.	Occasional occurrence of geological hazards with manageable risks.	Negligible occurrence of geological hazards with no significant impacts.	No recorded geological hazards.
	Soil erosion risk (KV2)	The presence and extent of soil erosion.	Soil erosion rates are extremely high, resulting in irreversible damage.	Significant soil erosion with threats to karst environments.	Soil erosion rates are low and manageable due to effective land management practices.	Soil erosion is minimal, with stable soil conditions and erosion processes occurring at a negligible rate.	No soil erosion risk.
	Water availability (KV3)	Existence of surface waters and/or groundwaters.	Complete absence of water, neither on the surface nor underground. Without water movement, the ecosystem is degraded, erosion is pronounced, and there is no formation of karst structures.	Water is present only underground but does not circulate. This stagnation can lead to pollution and poor conditions for the karst ecosystem. Water does not contribute to the formation or maintenance of karst structures.	Occasional streams that appear seasonally or after heavy rainfall. Water temporarily flows but quickly disappears. It is insufficient for the long-term sustainability of the ecosystem, though it may contribute to temporary flushing of the karst.	Water continuously flows through underground streams, helping to shape cave formations, sustain the ecosystem, and provide constant sediment flushing. The karst system has a stable presence of water but without significant impact on surface flows.	The presence of permanent surface streams, springs, and underground flows that are constantly in motion. These water flows support stable ecosystems, shape karst formation, and ensure long-term circulation and resource renewal, which is ideal for karst systems.
	Water quality (KV4)	The quality of fluvial or subterranean waters within karst environments.	Extremely high levels of contamination (biological, chemical, or physical).	Some pollution from nearby land use (agriculture, industry, etc.).	Healthy ecosystem, but with slight degradation.	High water quality with low contamination levels.	Utmost water quality, essentially free from contamination.
	Waste, litter (KV5)	Improper disposal of waste in karst environments.	Large amounts of rubbish are visible, and the ecosystem is significantly disrupted, with possible toxic contamination and risks to the health of visitors and natural species.	Significant amounts of waste, including plastic and metal debris, paper, glass, and potentially hazardous chemicals (e.g., batteries).	Waste is present to a greater extent, but mostly paper, smaller plastic, and organic waste. The ecosystem is noticeably affected, but the damage is not irreversible.	Minimal waste, mostly small debris like paper or plastic items left on rare occasions. The ecosystem is almost untouched, and the damage is limited and easily remediated.	No waste present. There are no visible signs of human activity in terms of rubbish, and the ecosystem functions without disturbance.
	Biodiversity loss (KV6)	Potential shifts in vegetation distribution and habitat suitability.	High probability of significant shifts in vegetation distribution and habitat suitability.	Moderate probability with potential changes.	Low probability with minor potential changes.	Negligible probability with  potential for minimal changes.	No probability of shifts in vegetation distribution and habitat sustainability.
	Climate-related hazards (KV7)	Vulnerability of the geosite to climate-related hazards (e.g., increased erosion, altered precipitation patterns).	High vulnerability to climate-related hazards resulting in severe impacts.	Moderate vulnerability with potential impacts.	Low vulnerability with  potential for minimal impacts.	Negligible vulnerability with minor potential impacts.	No vulnerability to climate-related hazards and no impacts.
Human Activities (HA)	Frequency of human activities (HA1)	Frequency of human activities within the karst geosite.	High frequency of human activities causing extensive disturbance.		Occasional/rare human activities resulting in minor disturbances.		No observable human activities.
	Intensity of human activities (HA2)	Intensity of human activities within the karst geosite.	Intense human activities causing severe environmental degradation.		Low to moderate intensity of human activities with minor alterations.		No observable human activities.
	Rural infrastructure (HA3)	Rural infrastructure in karst environments.	Dense rural infrastructure with intensive agricultural practices, poor waste management, and significant environmental effects.	Extensive rural infrastructure with high agricultural intensity.	Basic infrastructure with moderate agricultural activities.	Extremely limited rural infrastructure with minimal agricultural or land use activities.	None
	Urban infrastructure (HA4)	Urban infrastructure in karst environments.	Dense urban centres with high levels of pollution, extensive infrastructure, and severe environmental effects.	Moderate-sized urban areas with noticeable pollution and waste management challenges.	Basic infrastructure and moderate controls on pollution and waste.	Extremely limited urban infrastructure with effective pollution controls.	None
Conservation efforts (CE)	Effectiveness of protection status (CE1)	Effectiveness of protection status or conservation zones.	Ineffective protection measures with significant threats to biodiversity and geological features.		Effective protection resulting in the preservation of most biodiversity and geological features.		Highly effective protection measures ensuring the preservation of all critical aspects.
	Compliance (CE2)	Compliance with regulations and management best practice plans to preserve the natural and cultural heritage of the geosite.	Non-compliance with regulations and management plans, leading to widespread degradation.		Moderate compliance, with occasional violations but overall adherence to regulations.		Full compliance, with strict adherence to regulations and management plans.
	Monitoring (CE3)	Monitoring programs to track changes in environmental conditions and assess the effectiveness of conservation measures.	Absence of monitoring programs, resulting in limited understanding of environmental changes.		Basic monitoring programs in place, providing valuable insights into environmental conditions.		Utmost value of monitoring systems, offering real-time data and continuous assessment without environmental impact.
	Management strategies for conservation (CE4)	Integration of monitoring data and research findings into adaptive management strategies for conservation	Lack of integration, resulting in ineffective management responses to changing conditions.		Moderate integration, with occasional adjustments based on monitoring findings.		Full integration, with adaptive management practices fully informed by monitoring data.
	Enforcement mechanisms (CE5)	Enforcement mechanisms to prevent unauthorized activities and minimize human impacts.	Weak enforcement, allowing widespread unauthorized activities and degradation.		Moderate enforcement, resulting in occasional violations but overall control of unauthorized activities.		Stringent enforcement, preventing any unauthorized activities within the geosite.
	Restoration efforts (CE6)	Restoration efforts targeting degraded habitats or areas impacted by human disturbance within the geosite.	Absence of restoration efforts, with degraded habitats left untreated.		Moderate restoration efforts, resulting in partial recovery of degraded habitats.		Comprehensive best practice restoration projects, fully restoring degraded habitats to their natural state.
	Community involvement (CE7)	Community involvement and support for habitat restoration initiatives.	Minimal community involvement, with little support for habitat restoration efforts.		Moderate community involvement, with active support from stakeholders.		Extensive community involvement, with enthusiastic support and active participation in habitat restoration projects.
Geoethical Tourism Performance (GTP)	Promotion (GTP1)	Promotion of ethical behaviours and responsible tourism practices among visitors and tourism operators within the geosite.	Minimal promotion of ethical behaviours, with widespread irresponsible tourism practices.		Moderate promotion of ethical behaviours, with ongoing efforts to encourage geoethical and responsible tourism practices.		Comprehensive promotion efforts, resulting in universal adherence to geoethical guidelines and responsible behaviours among tourists.
	Education (GTP2)	Development of educational programs and interpretive materials to raise awareness about the geological, ecological, and cultural significance of the geosite.	Limited educational programs and interpretive materials, with minimal efforts to raise awareness.		Adequate development of best practice educational programs and interpretive materials, reaching a moderate audience.		Utmost value of  best practice  educational programs and interpretive materials, reaching all visitors and stakeholders.
	Principles (GTP3)	Integration of geoethical principles and conservation messages into visitor interpretation and outreach efforts.	No integration of geoethical principles.		Low to moderate integration, with clear communication of current conservation messages alongside tourism promotion.		Full integration, with geoethical best practice principles and conservation messages central to all tourism efforts.
	Collaborations (GTP4)	Collaboration with educational institutions and organizations to promote environmental education and advocacy within the geosite.	Minimal collaboration, with limited partnerships and outreach efforts.		Moderate collaboration, with active partnerships and joint initiatives to promote sustainable environmental education.		Comprehensive collaboration, with close ties to educational institutions and organizations driving impactful environmental education, sustainability and best practice advocacy campaigns.
	Community engagement (GTP5)	Engagement of local communities in decision-making processes and conservation efforts related to the geosite.	Limited engagement, with local communities excluded from decision-making processes and conservation efforts.		Moderate engagement, with efforts to include local communities in decision-making processes and conservation initiatives.		Extensive ongoing engagement, with local communities leading decision-making processes and actively contributing to conservation efforts.
	Local involvement (GTP6)	Opportunities for local participation in tourism planning, interpretation, and economic benefits sharing.	Limited opportunities for local participation, with economic benefits primarily accruing to external stakeholders.		Moderate opportunities for local participation, with efforts to ensure equitable sharing of economic benefits.		Extensive opportunities for local participation, with local communities fully involved in tourism planning and economic benefits sharing, leading to inclusive and sustainable development.

4. Results

The results of the KGAM model are presented in Table 2 and Figures 4-9. Table 2 presents the results of the KGAM model, related to the evaluation of various indicators, sub-indicators, and importance factors for selected karst geosites (KG1-Homoljska potajnica; KG2-Mlava river spring; KG3-Vatrena Dupka cave; KG4-Vratna rock arches; KG5-Đalovica cave; KG6-Niksić Polje; KG7-Sopot Spring; KG8-Gornjepoljski Vir estavelle). It calculates the total scores for each sub-indicator and provides the sum of scores for broader categories like "Karst Vulnerability," "Human Activities," "Conservation Efforts," and "Geoethical Tourism Performance."

 

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