Herpetology Notes, volume 11: 387-389 (2018) (published online on 09 May 2018)

Predator activity associated with flavomarginatus burrows

Sara Valenzuela-Ceballos1, Gamaliel Castañeda-Gaytán1,* and Ernesto Becerra1

Due to being endemic, and because their fossorial in Mexico (due that we were searching for vertebrate habits apparently increase the presence and abundance of associated to the burrows, we did not take numerous other species, ��� ����������������, Gopherus into account the sex of the bolson tortoise burrows flavomarginatus (Legler, 1959), ���������������������� inhabitants). Active burrows were selected based on flagship and keystone species for the Mapimi Biosphere external characteristics according to Auffenberg and Reserve (Aguirre et al., 1997). �urrows of this species Franz (1982) and Cox et al. (1987). Observations of can measure over five meters in length and have a depth predators included coyotes (Canis latrans Say, 1823), of 1.6 meters (Auffenberg, 1969, Morafka, 1982, Aguirre bobcats (Lynx rufus Schreber, 1777), foxes (Urocyon et al. 1984). These burrows provide a thermal gradient cinereoargenteus Schreber, 1775 and Vulpes macrotis that ranges between 42°C at the entrance to 28°C at 30 Merriam, 1888), badgers (Taxidea taxus Schreber, cm inside (Morafka, 1982). Due to these characteristics, 1777) and skunks (Mephitis mephitis Schreber, 1776). such burrows are an attractive place for other vertebrate These species appeared regularly on photographs that and invertebrate species looking for refuge. Thirty- showed them near the burrows, apparently looking for six vertebrates have been observed occasionally, prey. Among the burrow entrance observations two temporarily or seasonally occupying the burrows of predation events were recorded during 2014, the first G. flavomarginatus, (Valenzuela-Ceballos unpublished was the predation of a black tail-hare (Lepus californicus data). The importance of burrows of other Gopherus Gray, 1837) by a coyote (Canis latrans) (Figure 1). for facilitating the occurrence and trophic The hare was taking refuge inside of the burrow when interactions of multiple species is well documented; for it was caught. The second predation event was upon example, for the G. flavomarginatus sister taxa, Gopher a kangaroo rat (Dipodomys sp.) by a burrowing owl tortoises (G. polyphemus), 60 vertebrate species and (Athene cunicularia Molina, 1782) (Figure 2). The 302 invertebrate species were observed making use kangaroo rat was near the burrow’s entrance when the of their burrows (Jackson and Milstrey, 1989, Ashton burrowing owl chased it. and Ashton, 2008). However, similar associations burrows ����������������������������� and interactions at G. flavomarginatus burrows have for the abundance and interactions of a broad range not previously been published. To document species of species (Ashton and Ashton, 2008 and Catano and use and interactions at Bolson tortoise burrows we Stout, 2015). While Bolson tortoises and their burrows installed 9 cameras (Bushnell Trophy cam®, 8 mega have not had the same level of detailed studies, their pixel) directed towards nine active adult bolson tortoise burrow’s cooler microclimate in a region where daytime burrow entrances within the Mapimi Biosphere Reserve summer temperatures regularly exceed species’ thermal tolerances (Morafka, 1982), plus the abundance of predator activity at the burrow entrances argue that Bolson tortoises and their burrows may play a similar, keystone species role in the Chihuahuan Desert. The regular visitation of predators at Bolson tortoise burrows

1 Facultad de Ciencias Biológicas, Universidad Juárez del Estado suggests that these sites probably are suitable not just as de Durango, Gómez Palacio, Durango, México. a refuge for vertebrates, but also provide an important * Corresponding author. E-mail: [email protected] predator / prey interaction. 388 Sara Valenzuela-Ceballos et al.

Figure 1. The picture shows a hare (Lepus californicus) being predated by a coyote (Canis latrans) on the entrance of a Bolson tortoise burrow.

Figure 2. Burrowing owl (Athene cunicularia) with a kangaroo rat (Dipodomys sp.) prey at the entrance of a Bolson tortoise burrow. Predator activity associated with Gopherus flavomarginatus burrows 389

References Catano P.C., Stout I. J. (2015). Functional relationships reveal keystone effects of the gopher tortoise on vertebrate diversity Aguirre G, Adest GA, Morafka DJ (1984) Home range and in a longleaf pine savanna. Biodiversity Conservation 24: 1957- movement patterns of the Bolson Tortoise, Gopherus 1974. flavomarginatus. Acta Zoológica Mexicana 1: 1–28. Cox J, Inkley D, Kautz R (1987) Ecology and habitat protection Aguirre, G., D. J. Morafka, and G. A. Adest. 1997. Conservation needs of gopher tortoise (Gopherus polyphemus) populations strategies for the Bolson Tortoise, Gopherus flavomarginatus, in found on lands slated for large-scale development in Florida. the Chihuahuan Desert. Proceedings: conservation, restoration, Florida Game and Freshwater Fish Commission Non-game and management of tortoises and – An International Wildlife Program Technical Report 4: 69. Conference, pp. 333-338. New York and Tortoise Society, Jackson D.R., Milstrey E.G. (1989). The fauna of gopher tortoise New York, New York. burrows. In: Gopher tortoise relocation symposium proceedings, Ashton, R. E., Ashton, P. S. (2008). The Natural History and p. 86-98. Diemer, J.E., D.R. Jackson, J.L. Landers, J.N. Layne Management of the Gopher Tortoise. Gopherus polyphemus. and D.A. Wood, eds. Florida Game and Fresh Water Fish Auffenberg W, Franz R (1982) The status and distribution of the Commission Nongame Wildlife Program Technical Report No. gopher tortoise (Gopherus polyphemus). In: Bury R (Ed.) North 5, Tallahassee. American Tortoises: Conservation and Ecology. US Fish and Morafka D. (1982). The status and distribution of the bolson Wildlife Service (Washington, DC), Wildlife Research Report tortoise. In: North America tortoises: conservation and ecology, 13: 95–126. p. 71-94. Bury, R.B., ed. Auffenberg W. (1969). Tortoise behavior and survival. Rand McNally, Chicago, II.

Accepted by Eric Munscher