03_Koynova_05_21.indd UDC 598.112.11:504.064.3(1-18:497.2) CITIZEN SCIENCE ASSISTED MONITORING PROVIDES NEW DATA CONCERNING THE DISTRIBUTION OF THE BULGARIAN BENT-TOED GECKO, MEDIODACTYLUS DANILEWSKII STRAUCH (GEKKONIDAE, SQUAMATA), IN NORTH-EAST BULGARIA T. Koynova1*, P. Marinova1, N. Nikolov2, M. Kaschieva1, C. Chernikov3, V. Velkova4, N. Natchev1,5 1Department Biology, Faculty of Natural Sciences, Shumen University, Universitetska 115, 9700 Shumen, Bul- garia 2Didactics of Sports, Faculty of Pedagogics, Shumen University, Universitetska 115, 9700 Shumen, Bulgaria 3Zoo Razgrad, Severen blv., 7200 Razgrad, Bulgaria 4Faculty of Pharmacy, Medical University Varna, Tz. Osvoboditel 84, 9000 Varna, Bulgaria 5Department of Integrative Zoology, Vienna University, Althanstrasse 14, Wien 1090, Vienna Austria *Corresponding author E-mail: t.koynova@shu.bg T. Koynova (https://orcid.org/0000-0001-9044-6708) Citizen Science Assisted Monitoring Provides New Data Concerning the Distribution of the Bulgarian Bent-toed Gecko, Mediodactylus danilewskii (Gekkonidae, Squamata), in North-East Bulgaria. Koynova, T., Marinova, P., Nikolov, N., Kaschieva, M., Chernikov, C., Velkova, V., Natchev, N. — Th e Bulgarian Bent-toed Gecko (Mediodactylus danilewskii Strauch, 1887) is one of the two species of geckos inhabiting the territory of Bulgaria. In the recent years, new information on its distribution was published and big amount of data were collected. We organized an information platform for sharing data on the biology and live-range of M. danilewskii in inland North-East Bulgaria. Th is gecko is a highly synanthropic species which is oft en observed by citizens. Here we report on four new observation spots and also confi rm the presence of the species from recently published localities. All data were recorded by volunteers, hence we discuss on the methods for documentation of the specimens and the critical role of the citizen science to assess the range of distribution of the species. Key words: volunteers, observation, documentation, population, new locality, gecko. Introduction Th e genus Mediodactylus Szczerbak and Golubev, 1977 is widespread from the Mediterranean region to Central Asia ( Ananjeva et al., 2006) and includes fi ve species — M. kotschyi; M. orientalis; M. danilewskii; M. bartoni and M. oertzeni ( Kotsakiozi et al., 2018). Th e gecko Mediodactylus danilewskii is a small lizard with total length of 11 cm (see Stojanov et al., 2011). Th e species is highly synanthropic and inhabits almost exclusively human settlements in Bulgaria ( Beshkov & Nanev, 2002). Th ese geckoes are thigmothermic, have a rather cryptic behavior and are active predominantly during the night (Stojanov et al., 2011). Th ese characteristics make them a challenging object for monitoring. Oft en the professional scientists are limited in time and resources, so the methods of the “citizen science” can be applied for the purposes of time-consuming monitoring missions ( Th eobald et al., 2015; Kobori et al., 2016). Some forms of “citizen science” may represent a volunteer-based Zoodiversity, 55(5):381–386, 2021 DOI 10.15407/zoo2021.05.381 382 T. Koynova, P. Marinova, N. Nikolov, M. Kaschieva, C. Chernikov, V. Velkova, N. Natchev monitoring and possess the potential to solve problems concerning personnel limitations ( McClure et al., 2020). Th e volunteers may support the researchers using methodologies developed by professional scientists ( Trumbull et al., 2000; Silvertown, 2009). With proper training, citizens are able to provide accurate and reliable information ( Darwall & Dulvy, 1996; Newman et al., 2003). In addition, the modern technologies allow those citizens in access to advanced data collection and reporting tools, thus reducing data submission errors and eff orts ( Starr et al., 2014). In the recent years, interest in citizen science projects is growing globally ( Bonney et al., 2014; Peters et al., 2015; Hecker et al., 2018). In the ecological monitoring, the citizen science has a long and positive history and nowadays become more and more popular. Th e new information technologies allow for growing number of volunteers to contribute in gaining more information concerning the general biology of a variety of species ( Bonney et al., 2014; Kobori et al., 2016). Actually, the monitoring of biodiversity is one of the scientifi c fi elds, in which the citizen naturalists readily cooperate with the professional specialists (see Miller-Rushing et al., 2020). To date there are a lot of citizen science projects that involve collection of data on herpetofauna distribution (Cosentino et al., 2014; Petrovan & Schmidt, 2016; Deutsch et al., 2017, Rowley et al., 2019). Learning is a very useful benefi t of volunteering and it is oft en a motivation to support such activities ( Ryan et al., 2001; Bruyere & Rappe, 2007; Stepenuck & Green, 2015). Furthermore, public engagement with the environment can lead to behavioural change within the human society ( McKinley et al., 2017). Th e main goal of the present study was to involve volunteers in the investigation of the Bulgarian Bent- toed Gecko populations in inland North-East Bulgaria. We used the help of citizen science as an eff ective complement to fi eld surveys to collect data and to document the expansive distribution of M. danilewskii in the region. Material and methods In inland North-Eastern Bulgaria (except two populations near the Danube River), the Bulgarian Bent-toed Gecko was observed for the fi rst time in 2015 by a local hobby naturalist from Shumen town. We started immediately an organized observation of the population and established a data sharing platform at the website of the Biology Department (FNS, Shumen University) for collecting new information concerning the distribution of the species. Since 2015 we organized a group of volunteers from diff erent settlements in northeastern Bulgaria and since 2016, we also monitored some social platforms for information sharing. For correct identifi cation we had prepared a photographic guide for M. danilewskii (see fi g. 1). As a model organism we used one of the specimens detected in the town of Razgrad. For detailed photographic documentation we use a Canon EOS 60D with a macro lens Canon EF 100mm f/2.8 Macro USM (Canon Inc., Ota City, Tokyo, Japan) and a Sony RX 10 III (Sony Electronics Corporation, Minato, Tokyo, Japan). Th e most important morphological characteristics of the species were provided by Stojanov et al. (2011): small and oval dorsal tubercles; 5 to 8 W-formed dark dorsal stripes (normally 6); 4 to 9 preanal pores (normally 7); 1–3 prismatic postanal tubercles; the cranial tubercles are positioned above the ear opening. Results and discussion On the base of our previous researcher on M. danilewskii in North-Eastern Bulgaria ( Koynova et al., 2017) and the observations we currently made, we estimate that citizen involvement could be a very useful tool to complement the picture of the distribution of the species in this part of the country. Since 2015 we started to monitor the presence of the species in the region and thanks to the eff orts of all involved specialists and volunteers, we were able to gather valuable data. We confi rmed the distribution and the presence of permanent living population in Shumen town (see Koynova et al., 2020; Koynova & Natchev, 2020). Geckos are among the species that are most oft en translocated and are able to establish extralimital populations ( Kraus, 2009). Our observations confi rm this information and in- dicate on the expansive distribution of M. danilewskii in northeastern Bulgaria. In the pres- ent study we provide data on new registrations in sites with previously reported presence and represent data on four completely new sites of distribution – Razgrad, Dobrich, Ivan- ski, Osmar (fi g. 2). For the population in Razgrad we report presence confi rmation from 2016, 2017, 2019 and 2020 from four diff erent localities. For Dobrich were reported mul- tiple observations on subadult and adult specimens from two spots in the town. New data were provided for Ivanski and Osmar villages (Shumen District). One recently documented specimen confi rmed the presence of the species in Novi Pazar town (see also Koynova 383Citizen Science Assisted Monitoring Provides New Data Concerning the Distribution of the Bulgarian... et al., 2020). We collected also data from six new localities of the spe- cies in Shumen town (additional to the data provided by Koynova et al., 2017; Koynova et al., 2020; Koynova & Natchev, 2020). All new reported observations are as- sociated to low profi le buildings of 1 to 3 fl oors with exception of the geckos from Dobrich, where they were recorded on a 5 fl oored build- ing (table 1). We were able to confi rm the presence of M. danilewskii on the newly recorded spots by the help of photographic materials, which were supplemented to the observa- tion reports of the volunteers. In general, these lizards are very hard for photo documentation, because they are tiny and mostly night ac- tive. Normally, they behave rather shy and it is diffi cult to be ap- proached. A good and detailed photo shot normally demands proper illumination, the use of ex- pensive bright-aperture telescopic lenses, camera body with a large sensor and the use of a tripod (see fi g. 1). Th e documentation of details at the level of single scales is possible only by the use of macro-photography and in most cases demands the capture and immobilization of the specimen (fi g. 1). However, a high- resolution picture from dorsal view can contribute for the successful species indication Fig. 1. Morphological indicators for photograph-based identifi - cation of the Bulgarian Bent-toed Gecko (M. danilewskii): a — dorsal view of an adult specimen: white arrows indicate the six W-formed dorsal stripes, red arrows indicate the small and round dorsal tubercles, black arrows indicate the two prismatic postanal tubercles, red ellipse indicates the position of the cloacal opening on the ventral site of the body; b — ventral view of the cloacal region of the lizard: pale-blue arrows indicate the position of the seven preanal pores, the white asterisk indicates the cloacal open- ing, black arrows indicate the two prismatic postanal tubercles; c — close up picture of the head in right dorso-lateral plane: pale- rose arrows indicate the position of the cranial tubercle above the ear opening (indicated by an yellow asterisk); Picture performed by the use of Canon EOS 60D with micro lens EF 100 mm/2.8, illumination LedLenser T16 by 6000-8000K. T a b l e 1 . Coordinates of the newly recorded specimens of M. danilewskii in North East Bulgaria Place Coordinates (Datum, WGS 84) Name Dobrich 43.55232° N, 27.82891° E; 255 m a .s. l. Nelly Raycheva 43.57746° N, 27.82803° E; 197 m a. s. l. Nelly Raycheva Razgrad 43.52482° N, 26.52362° E; 206 m a. s. l. Chavdar Chernikov 43.52661° N, 26.52124° E; 203 m a. s. l. Chavdar Chernikov 43.52841° N, 26.52308° E; 202 m a. s. l. Chavdar Chernikov 43.51955° N, 26.52808° E; 249 m a. s. l. Djanan Isufova Ivanski 43.14486° N, 27.03489° E; 105 m a. s. l. Pavlina Marinova Osmar 43.21711° N, 26.85822° E; 174 m a. s. l. Nikolay Nikolov Shumen 43.27721° N, 26.91167° E; 265 m a. s. l. Aydin Hatibov 43.27408° N, 26.90809° E; 272 m a. s. l. Svilena Ivanova 43.23921° N, 26.93214° E; 184 m a. s. l. Stoyan Stoyanov 43.26403° N, 26.94092° E; 205 m a. s. l. Todorka Todorova 43.26869° N, 26.92109° E; 259 m a. s. l. Nikolay Nikolov 43.28228° N, 26.89981° E; 314 m a. s. l. Ralitsa Balkanska Novi Pazar 43.34139° N, 27.16639° E; 152 m a. s. l. Sevinch Basri 384 T. Koynova, P. Marinova, N. Nikolov, M. Kaschieva, C. Chernikov, V. Velkova, N. Natchev of the geckos. Only the registration of the preanal pores demands a picture in ventral view. Actually, the location of the cloacal opening can be estimated from a dorsal image and such a picture would allow for the precise count of the dorsal W-formed stripes between the occipital region and the origin of the tale. By the use of proper illumi- nation, the position of the cranial tu- bercles and the characteristics of the dorsal tubercles can be recognized on a high-resolution picture from dorsal view (fi gs 1 and 3). Th e increased in- tensity of the light and the stabiliza- tion of a small-sensor camera (e. g., a bridge camera or a smart phone cam- era) may improve dramatically the quality of the picture as a document confi rming the presence of the Bulgar- ian Bent-toed Gecko (see fi g. 3). Conclusions Th e crucial role of the volunteers in collecting data on the occurrence of the Bulgarian Bent-toed Gecko in inland North-East Bulgaria is demon- strated by the fact, that all documen- tations of the presence of the species were performed by citizens. Th e in- volvement of hobby environmentalist in non-avian monitoring programs is a relatively new procedure for Bulgar- ia. Especially for near future in studies of synanthropic species or species with wide distribution (some amphibian, reptiles, and mammals), we expect intensive development of citizen science platforms in Bulgaria. Several initiatives like the ongoing monitoring of M. danilewskii provided already valuable results and represent a solid base for the further involvement of citizen science volunteers in diff erent ecological investigations. Th is work was partly supported by the Research Fund of the Konstantin Preslavsky University of Shumen (Grant No. RD-08-67/25.01.2021) and Bulgarian Ministry of Education and Science under the National Program for Research “Young Scientists and Postdoctoral Students”. We are thankful to all volunteers for their work. References Ananjeva, N. B., Orlov, N. L., Khalikov, R. G., Darevsky, I. S., Ryabov S. A., Barabanov, A. 2006. An atlas of the reptiles of Northern Eurasia: Taxonomic diversity, distribution, conservation status. Pensoft Publishers, Sofi a, 1–245. Fig. 2. Schematic map of the confi rmed and new sites of distribution of the Bulgarian Bent-toed Gecko in North-East Bulgaria. Black spots represent the confi rmed locations and the grey spots represent the newly recorded localities. Th e scale bar represents 10 km. Fig. 3. Morphological indicators for photograph based iden- tifi cation of the Bulgarian Bent-toed Gecko (M. danilewskii): white arrows indicate the six W-formed dorsal stripes; red arrows indicate the small and round dorsal tubercles; the black arrow indicates the right prismatic post-anal tubercles; the red ellipse indicates the position of the cloacal opening; pale rose arrows indicate the position of the cranial tuber- cle above the ear opening (indicated by an yellow asterisk); Picture performed by the use Sony RX 10 III, illumination LedLenser T16 by 600–8000K. 385Citizen Science Assisted Monitoring Provides New Data Concerning the Distribution of the Bulgarian... Beshkov, V., Nanev, K. 2002. Th e amphibians and reptiles in Bulgaria. Pensoft , Sofi a–Moscow, 1–120 [In Bul- garian]. Bonney, R., Shirk, J. L., Phillips, T. B., Wiggins, A., Ballard, H. L., Miller-Rushing, A. J., Parrish, J. K. 2014. Next steps for citizen science. Science, 343, 1436–1437. doi: 10.1126/science.1251554 Bruyere, B., Rappe, S. 2007. Identifying the motivations of environmental volunteers. Journal of Environmental Planning and Management, 50 (4), 503–516. https://doi.org/10.1080/09640560701402034 Cosentino, B. J., Marsh, D. M., Jones, K.S., Apodaca, J. J., Bates, C., Beach, J. 2014. Citizen science reveals wide- spread negative eff ects of roads on amphibian distributions. Biological Conservation, 180, 31–38. https:// doi.org/10.1016/j.biocon.2014.09.027 Darwall, W. R., Dulvy, N. K. 1996. An evaluation of the suitability of non-specialist volunteer researchers for coral reef fi sh surveys. Mafi a Island, Tanzania — a case study. Biological Conservation, 78, 223–231. https://doi.org/10.1016/0006-3207(95)00147-6 Deutsch, C., Bilenca, D., Agostini, G. 2017. In Search of the Horned Frog (Ceratophrys ornata) in Argentina: Complementing Field Surveys with Citizen Science. Herpetological Conservation and Biology, 12(3), 664– 672. http://www.herpconbio.org/Volume_12/Issue_3/Deutsch_etal_2017.pdf Hecker, S., Haklay, M., Bowser, A., Makuch, Z., Vogel, J., Bonn, A. 2018. Citizen Science: Innovation in Open Science, Society and Policy. UCL Press, London, 1–542. Kobori, H., Dickinson, J. L., Washitani, I., Sakurai, R., Amano, T., Komatsu, N., Kitamura, W., Takagawa, S., Koyama, K., Ogawara, T., Miller-Rushing, A. J. 2016. Citizen science: a new approach to advance ecology, education, and conservation. Ecological Research, 31, 1–19. doi: 10.1007/s11284-015-1314-y Kotsakiozi, P., Jablonski, D., Ilgaz, C., Kumlutaş, Y., Avcı, A., Meiri, S., Itescu, Y., Kukushkin, O., Gvoždík, V., Scillitani, G., Roussos, S. A., Jandzik, D., Kasapidis, P., Lymberakis, P., Poulakakis, N. 2018. Multilocus phylogeny and coalescent species delimitation in Kotschy’s gecko, Mediodactylus kotschyi: hidden diver- sity and cryptic species. Molecular Phylogenetics and Evolution, 125, 177–187. https://doi.org/10.1016/j. ympev.2018.03.022 Koynova, T., Tzankov, N., Popgeorgiev, G., Naumov, B., Natchev, N. 2017. A new distribution record of the Kotschy’s Gecko (Mediodactylus kotschyi) from inland north-eastern Bulgaria. Herpetology notes, 10, 1–2. https://www.biotaxa.org/hn/article/view/23029/25867 Koynova, T., Doichev, D., Natchev, N. 2020. New data on the distribution of the Bulgarian Bent-toed Gecko (Mediodactylus danilewskii Strauch, 1887) in Shumen town (NE Bulgaria). Biharean Biologist, 14 (2), 122–124. http://biozoojournals.ro/bihbiol/cont/v14n2/bb_e202302_Koynova.pdf Koynova, T., Natchev, N. 2020. MEDIODACTYLUS DANILEWSKII (Mediterranean Th in-toed Gecko). DIET. Herpetological Review, 51 (4), 51. Kraus, F. 2009. Alien reptiles and amphibians: a scientifi c compendium and analysis. Springer, Netherlands, 1–569. McClure, E. C., Sievers, M., Brown, C. J., Buelow, C. A., Ditria, E. M., Hayes, M. A., Pearson, R. M., Tulloch, V. J. D., Unsworth, R. K. F., Connolly, R. M. 2020. Artifi cial Intelligence Meets Citizen Science to Supercharge Ecological Monitoring. Patterns (New York), 1 (7), 100109. https://doi.org/10.1016/j.patter.2020.100109 McKinley, D. C., Miller-Rushing, A. J., Ballard, H. L., Bonney, R., Brown, H., Cook-Patton, S. C., Evans, D. M., French, R. A., Parrish, J. K., Phillips, T. B., Ryan, S. F., Shanley, L. A., Shirk, J. L., Stepenuck, K. F., Weltzin, J. F., Wiggins, A., Boyle, O. D., Briggs, R. D., Chapin, S. F., Hewitt, D. A., Preuss, P. W., Soukup, M. A. 2017. Citizen science can improve conservation science, natural resource management, and environmen- tal protection. Biological Conservation, 208, 15–28. https://doi.org/10.1016/j.biocon.2016.05.015 Miller-Rushing, A., Primack, R., Bonney, R., Albee, E. 2020. Th e history of citizen science in Ecology and Con- servation. In: Lepczyk, C., Boyle, O., Vargo, T., eds. Handbook of Citizen Science in Ecology and Conserva- tion. University of California Press, 17–23. Newman, C., Buesching, C. D., Macdonald, D. W. 2003. Validating mammal monitoring methods and as- sessing the performance of volunteers in wildlife conservation — ‘‘Sed quis custodiet ipsos custodies?’’. Biological Conservation, 113, 189–197. https://doi.org/10.1016/S0006-3207(02)00374-9 Peters, M., Eames, C., Hamilton, D. 2015. Th e use and value of citizen science data in New Zealand. Journal of the Royal Society of New Zealand, 45(3), 151–160. https://doi.org/10.1080/03036758.2015.1051549 Petrovan, S. O., Schmidt, B. R. 2016. Volunteer conservation action data reveals large-scale and long-term negative population trends of a widespread amphibian, the Common Toad (Bufo bufo). PLoS ONE, 11:e0161943. https://doi.org/10.1371/journal.pone.0161943 Rowley, J., Callaghan, C., Cutajar, T., Portway, C., Potter, K., Mahony, S., Trembath, D., Flemons, P., Woods, A. 2019. FrogID: Citizen Scientists Provide Validated Biodiversity Data on Frogs of Australia. Herpeto- logical Conservation and Biology 14 (1), 155–170. http://www.herpconbio.org/Volume_14/Issue_1/Row- ley_etal_2019.pdf Ryan, R. L., Kaplan, R., Grese, R. E. 2001. Predicting Volunteer Commitment in Environmental Steward- ship Programmes.  Journal of Environmental Planning and Management, 44 (5), 629–648. https://doi. org/10.1080/09640560120079948 Silvertown, J. 2009. A new dawn for citizen science. Trends in Ecology & Evolution, 24, 467–471. https://doi. org/10.1016/j.tree.2009.03.017 386 T. Koynova, P. Marinova, N. Nikolov, M. Kaschieva, C. Chernikov, V. Velkova, N. Natchev Starr, J., Schweik, C. M., Bush, N., Fletcher, L., Finn, J., Fish, J., Bargeron, C. T. 2014. Lights, camera…Citizen science: Assessing the eff ectiveness of smartphone-based video training in invasive plant identifi cation. PLoS ONE, 9:e111433. https://doi.org/10.1371/journal.pone.0111433 Stepenuck, K. F., Green, L. T. 2015. Individual- and community-level impacts of volunteer environmental monitoring: A synthesis of peer-reviewed literature.  Ecology and Society, 20 (3), 19. https://www.jstor. org/stable/26270236 Stojanov, A., Tzankov, N., Naumov, B. 2011. Die Amphibien und Reptilien Bulgariens. Edition Chimaira, Ger- many, 1–582 [In German]. Th eobald, E. J., Ettinger, A. K., Burgess, H. K., DeBey, L. B., Schmidt, N. R., Froehlich, H. E., Wagner, C., HilleR- isLambers, J., Tewksbury, J., Harsch, M. A., Parrish, J. K. 2015. Global change and local solutions: tapping the unrealized potential of citizen science for biodiversity research. Biological Conservation, 181, 236–244. https://doi.org/10.1016/j.biocon.2014.10.021 Trumbull, D. J., Bonney, R., Bascom, D., Cabral, A. 2000. Th inking scientifi cally during participation in a citizen-science project. Science Education, 84, 265–275. https://doi.org/10.1002/(SICI)1098- 237X(200003)84:2%3C265::AID-SCE7%3E3.0.CO; 2-5 Received 13 June 2021 Accepted 1 September 2021