Colombia is characterized by presenting numerous resources in underground ecosystems, which are sensitive sites with special features within karstic landscapes. Santander is located in the central northern part of Colombia and contains not extensive explored extensive network of underground systems associated with highly fossiliferous carbonate rocks of the Cretaceous Rosablanca Formation, which is characterized by a very rich geodiversity exokarst and endokarst geoforms and biodiversity. Unfortunately, there is no environmental awareness in the community or action plans oriented to conservation and use of these underground systems.

Keywords: karst, Santander, natural heritage, ecosystems, geoconservation.

Colombia contains numerous resources in underground ecosystems, which are sensitive sites with special features within landscapes referred as karstic environments.¹ Geospeleology is the branch of the earth sciences that is dedicated to the study of underground cavities. This science is very recent in Colombia and dates back to the early 18^th century, when Humboldt visited the Iconozo Bridge, the Grotto of Alfonza and the Cave of Los Ladrones, department of Tolima.² However, Vélez was the first in exploring the caves of Moniquirá, (Boyacá). Since then, underground cavities have been object of interest by different authors.^3‒8 It must be developed for the benefit of the communities that own them to boost the industry based on tourism, water, scientific and educational aspects. Thanks to the caves, the scientists can know the climate of the past to understand climate change, learn about evolution because the most important archaeological and paleontological finds have been made in the caverns, and generate education and environmental awareness. There are several studies on cave heritage and management.^9,10 Geotourism is a relatively new concept in the tourism industry, which has emerged as a rapidly growing form of tourism.¹¹ Several authors,^12‒17 have defined geotourism. According to Servati and Qasemi,¹⁸ geotourism, as a subcategory of tourism, which is considered one of the new methods in providing tourism attraction (is a relatively new concept in tourism industry which has considerable growth in recent decade. Underground systems are significant elements of geoheritage and, therefore, they should be included catalogue of geosites.¹⁹ There are different studies on cave heritage and management.^9,10,20‒22 The karst system of Santander has approximately seventy (70) underground cavities associated with the Cretaceous Rosablanca Formation, which consists highly fossiliferous marine mudstones and limestones.²³ Underground systems represent unique natural laboratories and incredible landscapes from which, visitors can gain exceptional knowledge about the karstic dynamics. National Geographic has adopted the term “Geoeducation” to describe education about our world, providing students with a global understanding of how to work at local, regional and global levels. However, the concept of Geoeducation is not known in Colombia, because it has not been given importance to geosciences. Geoeducation plays an important role in integrating local communities to improve their quality of life, providing social equity. Geoconservation has steadily become an established concept^24,25 which refers to the conservation and sustainable management of geological/geomorphological heritage sites of special interest for education and research. According to Stephens et al.,²⁶ a geoconservation plan implemented for caves, can be based on excellent features of caves, which are important for education, research and eco/geo-tourism. The aim of this paper is to promote the geotourism and geoeducation practices around underground systems in Santander for geoconservation purposes.

The Cretaceous Rosablanca Formation, according to its current structural characteristics, morphology, relief and climate, and morphodynamic processes, constitutes an active karstic system.²⁷ It overlaps concordantly Los Santos Formation and is in transitional contact with the overlying Paja and Ruitoque formations.²³ Different studies^28‒30 have been carried out on this geological unit, particularly in relation to its stratigraphy and sedimentation environment. It consists of dolomitic limestones and evaporitic limestones with few intercalations of rocks of terrigenous origin in the lower part,³¹ biomicrites, marls and shales in the middle part²⁹ and sandstones and biosparitic rudstones with large bivalves in the upper part.²⁸ Santander shows one of the largest developments of karstic environments in Colombia. Figure 1 illustrates the location of the main occurrences of karst in Santander and the main exokart and endokarst features.

The valuation of underground systems has been performed according to the guidelines of the Instituto Geológico y Minero de España (IGME), which has been adopted by the Colombian Geological Service (CGS) for the characterization of the nation's geological heritage, valuing the elements that conform it according to the evaluation parameters. The evaluation of underground systems in Santander was carried out applying the valuation guideliness adopted by the CGS, according to their particular scientific, didactic and tourism interest for the development of projects and initiatives.³² A characterization of underground cavities led to speleometric maps and speleotematic catalogs was made. The periods of the karst cycles have been characterized taking into account the classification of Llopis-Llado.³³ The study of speleothems, tectonic indicators and karst associated to the underground cavities will serve to deepen the interpretations of the origin and evolution of the karstic regions in Santander, highlighting its geological importance, in order to generate educational and touristic activities that have the consequence of conservation of it, a virtual ethical signal linked to a QR code emphasizing the active geological processes that can be seen in it and its importance, along with an annex of the map of the caves as an aid to tourists to have an idea of ​​how they should behave, which is a viable alternative due to the tourist occurrence of each cave and lack of control at the entrance, as well as a permanent tour guide of the activities of geotourism that could be developed there with a good planning and implementation in an ideal scenario that would have as repercussions improvements and contributions to the economic and social development of the region. Underground georoutes have been performed, taking into account the use of personal protective equipment, the guidelines for the correct exploration of the karst system, the principles of geology, the speleothems and their formation, the karst geoforms, the basic hydrogeology and the importance of the natural and cultural heritage in order to develop geotourism and geoeducation activities, sensitizing the participants to perform good practices during the development of these activities in order to contribute to the geoconservation of the underground ecosystems and, therefore, to the sustainable development of the region. Therefore, the results can include the mineralogical characterization of speleothems that would contribute to the development of an architectural analysis for the reconstruction of paleoclimates, the didactic and informative material so that the visitors get a richer visit in terms of scientific education, the development of geoeducation and geotourism training activities.

Figure 1 Geographical location of the main occurrences of karst in Santander and exokart and endokarst features.

Geoconservation of underground ecosystems

In Colombia, there are numerous underground ecosystems, which, however, are not regulated or monitored by government guidelines or assisted by corporations and environmental entities, despite the wealth of fauna they contain and the tourism and sports possibilities they offer.³⁴ Deterioration of caves and speleothems directly due to tourist activities and vandalism has been observed,³⁵ which consequently induce a great harm to the equilibrium of the ecosystem. Activities such as mining, disposal of garbage, bonfires, dumping of sewage, indiscriminate tourism, destruction of speleothems and pictograms, graffiti on walls and ceilings, looting of archaeological material and little legislation for their protection have severely affected the underground ecosystems,³⁴ which, according to Anh-Duc & García-Guinea³⁶ are highly dynamic and understanding of their environment requires immediate methodological attention. Therefore, it is very important to keep in mind that for purposes of geoconservacion it is necessary to raise awareness among those who are going to participate in the activities of geotourism and geoeducation that comply with norms of good practices to avoid the deterioration of these subterranean ecosystems (Figure 2).

Figure 2 Geoconservation of underground systems.

Numerous underground systems in Santander municipalities, such as Zapatoca, Los Santos, Rionegro and El Peñón, can be considered as representative speleosites due to their exceptional values, standing out for their spatial development, richness and diversity of speleothems, underground streams and lakes and paleontological or archaeological remains. It is hoped to obtain strategic alliances with different entities that allow to expand these works to new municipalities and cavities of the department, taking into account the great Karstic potential that the entire department has. Karst sciences and geospeleology have enormous potential and must be known to scientists because of their great importance and ability to understand phenomena such as climate change and contribute to the sustainable development of regions.

The authors gratefully acknowledge the laboratories of the School of Geology and the Central Laboratory of the Universidad Industrial de Santander, and their technical and professional staff for assistance with data acquisition. Authors also thank members of the Research Group in Basic and Applied Geology and the Student Research Group in Geological Heritage for their helpful discussions and constructive comments. We express thanks to anonymous reviewers for helpful comments and suggestions of this manuscript. We are most grateful to the above-named people and institutions for support.

The authors declare that there are no conflicts of interest.

None.

1. Sánchez‒Botello CR, Jiménez‒Velandia G, Ríos‒Reyes CA, et al. Geological occurrence of the Ecce Homo Hill´s Cave, Chimichagua (Cesar), Colombia: an alternative for socio‒economic development based on geotourism. International Journal of Hydrology. 2018;2(5):618‒628.
2. Humboldt A. Sites of the mountain ranges and monuments of the indigenous peoples of America. Gaspar. Madrid. 1810. 439 p.
3. Correal G, Van der Hammen T. Summary of the results of an archaeological survey in the Cave of Los Guacharos, department of Huila. Revista de Antropología, Universidad de Los Andes, Bogotá. 1988;4(2):255‒271.
4. Acero D, Velandia F, Ramirez J. Geospeleology in the NW of the Guanentina province. Santander department, XI Colombian Congress of Geology, Bucaramanga. 2007.
5. Muñoz‒Saba Y, Gonzáles I, Calvo N. Cavernas de Santander Colombia. Colombian Geology Magazine of the National University of Colombia Bogotá D.C. 2013;1‒325.
6. Hoyos M, Muñoz‒Saba Y. Caverns in Santander: fauna and strategic use, XI Colombian Congress of Geology, Bucaramanga. 2007.
7. Casallas‒Pabon D, Hoyos M, Muñoz‒Saba Y, et al. Caverns of Santander Colombia. Field Guide, Publisher: Field Guide Series of the Institute of Sciences National University of Colombia, No. 13. 2013;57‒62.
8. Manco‒Jaraba DC. Description of the environmental impacts caused by misuse in the Sabana de León Cavern and Coco Loco Cave in the municipality of Manaure, Serranía de Perijá, Department of Cesar (Colombia). XVI Colombian Congress of Geology and III Symposium of Explorers. Santa marta Colombia. 2017;23:25‒34.
9. Jiménez‒Sánchez M, Domínguez‒Cuesta MJ, Aranburu A, et al. Quantitative indexes based on geomorphologic features: A tool for evaluating human impact on natural and cultural heritage in caves. Journal of Cultural Heritage. 2011;12(3):270‒278.
10. Roberts N. The Cultural and Natural Heritage of Caves in the Lao PDR: Prospects and Challenges Related to Their Use, Management and Conservation. The Journal of Lao Studies, Special Issue. 2015;113‒139.
11. Turner S. Promoting UNSECO global geoparks for sustainable development in the Australian‒Pacific region. Alcheringa: An Australasian Journal of Paleontology. 2006;30(1):351‒365.
12. Newsome D, Dowling RK. Geotourism: The Tourism of Geology and Landscape. Oxford: Goodfellow Publishers. 2010.
13. Hose TA. The English origins of geotourism (as a vehicle for geoconservation) and their relevance to current studies. Acta Geographica Slovenica. 2011;51(3):343–359.
14. Vasiljevic DA, Markovic SB, Hose TA, et al. The introduction to geoconservation of loess‒palaeosol sequences in the Vojvodina region: significant geoheritage of Serbia. Quaternary International. 2011;240(1‒2):108‒116.
15. Ollier C. Problems of geotourism and geodiversity. Quaestiones Geographicae. 2012;31:57–61.
16. Newsome D, Dowling R, Leung YF. The nature and management of geotourism: a case study of two established iconic geotourism destinations. Tourism Management Perspectives. 2012;2‒3:19‒27.
17. Gray M. Geodiversity. Valuing and conserving abiotic nature. Chichester: Wiley Blackwell; 2013. 495 p.
18. Servati MR, Qasemi A. Geotourism Strategies in Fars. Journal of Geographical Space. 2018;2:6.
19. Cocean G. Preliminary considerations upon the main types of speleosites in the Apuseni Mountains (Romania). Romanian Review of Regional Studies. 2015;11(2):107‒114.
20. Smith MJ, Burns GJ. Australia’s crystalline heritage: issues in cave management at Jenolan Caves. Helictite. 2011;40(2):27‒34.
21. Cigna A, Forti P. Caves: The Most Important Geotouristic Feature in the World, Campinas, SeTur/SBE. Tourism and Karst Areas. 2013;6(1):9‒26.
22. Aljerf L. Change theories drift conventional tourism into ecotourism. Acta Technica Corvininesis ‒ Bulletin of Engineering. 2015;8(4):101‒104.
23. Morales LG. General Geology and oil occurrences of the Middle Magdalena Valley, Colombia. In: Weeks LG, editor. Habitat of Oil: A Symposium: Tulsa, Oklahoma. American Association of Petroleum Geologists. 1958;641–695.
24. Sharples C. Geoconservation in forest management – principles and procedures. Tasforests. 1995;7:37–50.
25. Burek C. The importance of Quaternary geoconservation. Quad Newsletter. 2012;126:25–33.
26. Stephens M, Hodge S, Paquette J. Geoconservation of Volivoli Cave, Fiji: A Prehistoric Heritage Site of National Significance. Geoheritage. 2013;5(2):123–136.
27. Moreno JM, Salazar L, Rodríguez G, et al. Geosleological recognition in the province of Vélez Santander. XI Colombian Congress of Geology, Bucaramanga. 2007.
28. De Julivert Z. Petrographic Study of the Limestones of the Rosablanca Formation of the Mesa de los Santos Region. (Cordillera Oriental, Colombia). Boletín de Geología Universidad Industrial de Santander. 1963;15:5‒34.
29. Guerrero J. A proposal on the Classification of System Tracts: Aplication to the Allostratigraphy and Sequence Stratigraphy of the Cretaceous Colombian Basin. Part 1: Berriasian to Hauterivian. Geología Colombiana. 2002;20:3‒25.
30. Mendoza JE, Moreno JM, Rodríguez G. Rosablanca Formation Karstic Systems lower Cretaceous in Vélez Santander Province, Colombia. Revista Geología Colombiana. 2009;34(1):35‒44.
31. Guzmán G. The Aetostreon couloni and Ceratostreon boussingaulti Infracretaceous Griffids, from the Rosablanca Formation, as Indicators of marine oscillations. Cretaceous Project: Special Geological Publications of Ingeomins. 1985;16:1–16.
32. Zafra D, Rodríguez K, Gelvez J, et al. Characterization of the karst cycle periods of the Las Alsacias Cavern for geoconservation purposes based on geoeducation in the municipality of Zapatoca, Santander. Colombian Congress of Caving and VIII Caving Congress of Latin America and the Caribbean. San Gil. 2018.
33. Llopis‒Llado N. Fundamentals of karst hydrogeology (Introduction to geospeleology). Editorial Hermann Blume, Madrid. 1970.
34. Ríos‒Reyes CA, Manco‒Jaraba DC, Castellanos‒Alarcón OM. Geotourism in caves of Colombia as a novel strategy for the protection of natural and cultural heritage associated to underground ecosystems. Biodiversity International Journal. 2018;2(5):464‒474.
35. Manco‒Jaraba DC. Analysis of the environmental impacts caused by misuse in the Sabana de León Cavern and Coco Loco Cave in the municipality of Manaure, Serranía de Perijá, department of Cesar. Specialization Thesis in Environmental Engineering, Universidad Industrial de Santander. 2014;68.
36. Anh‒Duc T, García‒Guinea J. Vulnerability, pressures, and protection of karst caves and their speleothems in Ha Long Bay, Vietnam. Environmental Earth Sciences. 2014;71(11):4899–4913.