by Maisie Mitchell
– Heloderma charlesbogerti, commonly known as the Guatemalan beaded lizard, is arguably already one of the most misunderstood species on the planet, despite only being classed as one in 2013[1]; when it comes to local folklore, the beaded lizard is so notoriously mythologised that it’s often killed on sight[2]. With only around 200 left in the wild[3], you might ask whether saving this species is really worth the effort.
An adult Guatemalan beaded lizard. Photo by Angeldeleon7, CC BY 3.0. via Wikimedia Commons
The thing is, we wouldn’t just be saving one species—H. charlesbogerti is considered to be an umbrella species[4], meaning its conservation will also protect other species[5,6]. In 2015, conservationists Daniel Ariano-Sánchez and Gilberto Salazar released a paper detailing the yearly movements and behaviour of H. charlesbogerti. They observed 32 lizards for two years, having attached radio transmitters to six of them so they could be properly identified and tracked.
Ariano-Sánchez and Salazar noticed that the home range—where an individual lives, hunts and mates[7]—of H. charlesbogerti varies in size between the wet (June-October) and dry (November-May) seasons. It’s much larger in the wet season, when H. charlesbogerti is active, than in the dry season, when the lizard undergoes aestivation, a process a bit like hibernation[4].
While active, H. charlesbogerti frequently moves between shelters, preying on eggs and sometimes small mammals[4]. This could be the reason for the increase in home range size: it’s thought that the size of a home range is relative to how many resources an animal needs[8], and a bigger area could mean more opportunities for food and shelter.
Motagua spiny-tailed iguana (Ctenosaura palearis) eggs are a usual snack for H. charlesbogerti. C. palearis lays its eggs in April, just at the end of H. charlesbogerti’s aestivation period. This coincides with a spike of H. charlesbogerti activity, possibly because the beaded lizard will eat the iguana’s eggs as a way to tide it over after aestivation until birds start laying eggs at the start of the wet season[4]. Like H. charlesbogerti, C. palearis is endangered[9]—conservation of this species could actually help the Guatemalan beaded lizard population to survive[4,10].
How can all this research help protect H. charlesbogerti from extinction? Firstly, we can use information gained by observing its activity within a home range to identify resources that are less readily available; this can inform how we manage the land around its habitat, so these resources aren’t reduced more than necessary[4]. In addition, more information will mean that locals can be educated further about this lizard, so they’re less likely to exterminate it[2] and may even be encouraged to protect it[3].
While the focus of Ariano-Sánchez and Salazar’s paper was conserving the Guatemalan beaded lizard, it can potentially also help other species[4]. For example, around 77% of the underground shelters H. charlesbogerti uses are dug by mammals, especially skunks and nine-banded armadillos[4]—while none of these species are endangered[11,12,13,14], anything that benefits the Guatemalan beaded lizard will probably benefit them too[4].
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References
1 Reiserer, R.S., Schuett, G.W. & Beck, D.D. (2013) Taxonomic reassessment and conservation status of the beaded lizard. Heloderma horridum, 74-96.
2 Domínguez-Vega, H., Monroy-Vilchis, O., Manjarrez, J. & Balderas-Valdívia, C.J. (2017) Aversive hunting and sight frequency ecology of Beaded lizards (Squamata: Helodermatidae). Perspectives in Ecology and Conservation, 15(1), 47-51. 10.1016/j.pecon.2016.11.003
3 Ariano-Sánchez, D. (2006) The Guatemalan beaded lizard: endangered inhabitant of a unique ecosystem. Iguana, 13(3), 178–183.
4 Ariano-Sánchez, D., & Salazar, G. (2015) Spatial ecology of the endangered Guatemalan Beaded Lizard Heloderma charlesbogerti (Sauria: Helodermatidae), in a tropical dry forest of the Motagua Valley, Guatemala. Mesoamerican Herpetology, 2(1), 64-74.
5 Fleishman, E., Murphy, D.D. & Brussard, P.F. (2000) A new method for selection of umbrella species for conservation planning. Ecological applications, 10(2), 569-579. 10.1890/1051-0761(2000)010[0569:ANMFSO]2.0.CO;2
6 Frankel, O.H. & Soulé, M.E. (1981) Conservation and evolution. Cambridge: Press Syndicate of the University of Cambridge.
7 Burt, W.H. (1943) Territoriality and home range concepts as applied to mammals. Journal of mammalogy, 24(3), 346-352. 10.2307/1374834
8 Perry, G. & Garland Jr, T. (2002) Lizard home ranges revisited: effects of sex, body size, diet, habitat, and phylogeny. Ecology, 83(7), 1870-1885.
9 Ariano-Sánchez, D., Gil-Escobedo, J., del Valle, E. & Pasachnik, S.A. (2019) Ctenosaura palearis. The IUCN Red List of Threatened Species 2019. Available at: https://www.iucnredlist.org/species/44192/129419077#external-data [Accessed 1 December 2020].
10 Cotí, P. and Ariano-Sánchez, D. (2008) Ecology and traditional use of the Guatemalan black iguana (Ctenosaura palearis) in the dry forests of the Motagua Valley, Guatemala. Iguana, 15(3), 142-149.
11 Helgen, K., Reid, F. & Timm, R. (2016) Spilogale angustifrons. The IUCN Red List of Threatened Species 2016. Available at: https://www.iucnredlist.org/species/136636/45221538 [Accessed 1 December 2020].
12 Helgen, K. (2016) Conepatus leuconotus. The IUCN Red List of Threatened Species 2016. Available at: https://www.iucnredlist.org/species/41632/45210809 [Accessed 1 December 2020].
13 Cuarón, A.D., González-Maya, J.F., Helgen, K., Reid, F., Schipper, J. & Dragoo, J.W. (2016) Mephitis macroura. The IUCN Red List of Threatened Species 2016. Available at: https://www.iucnredlist.org/species/41634/45211135 [Accessed 1 December 2020].
14 Loughry, J., McDonough, C. & Abba, A.M. (2014) Dasypus novemcinctus. The IUCN Red List of Threatened Species 2014. Available at: https://www.iucnredlist.org/species/6290/47440785 [Accessed 1 December 2020].
15 Angeldeleon7, CC BY 3.0. Available at: https://commons.wikimedia.org/wiki/File:HelodermaHCharlesbogerti.JPG [Accessed January 27th 2021].
