Herpetology Notes, volume 14: 985-994 (2021) (published online on 28 July 2021) Movements of Western Alligator Snapping Turtles, Macrochelys temminckii (Testudines, Chelydridae), in an urban ecosystem: Buffalo Bayou, Houston, Texas Eric Munscher1,2, Valeria Gladkaya1, Jeff Stein1,2, Brian P. Butterfield3, Rachel Adams4, Jordan Gray1, Arron Tuggle1,2, Andrew S. Weber1,5, Kelly Norrid6, and Andrew Walde1 Abstract. Little is known about many life history traits of the Western Alligator Snapping Turtle, Macrochelys temminckii, including the species’ ecology within urban ecosystems. Our study population inhabits waterways of Houston, Texas, the third-largest city in the United States. We conducted a telemetry study on 19.5 km of the Buffalo Bayou that laterally bisects inner metropolitan Houston. Ten radio transmitters were attached to six male and four female M. temminckii. Turtle movements were monitored biweekly between November 2018 and May 2020, except when the area experienced excessive water fluctua- tions and flooding. We recorded a total of 242 turtle locations. Turtles were almost always associated with structure (fallen logs, vegetative banks, cut banks) and showed strong preference for areas of the bayou exhibiting greater tree canopy/in-channel debris. Many observations documented turtles at the same locations throughout the study period, at times with multiple individ- uals sharing the same location. Pooled mean linear range for all turtles was 575.4 m. Males and females moved for 284–2285 m and 686–4226 m, respectively, with females averaging both greater movement distances as well as total observed range. Turtle movement increased in early spring, peaked in late spring, and decreased to little or no movement in the summer and winter months. Compared to most previously published data on the species, this population showed more limited movement. This could be due to physical barriers, including man-made structures (dams, bridges, and other flood control structures). These data could help with future conservation efforts for this species in the Houston area and other urbanized habitats, including minimizing habitat alteration/destruction throughout their associated waterways, and aiding in the preservation of undervalued urbanized ecosystems. Keywords. Urban ecology, home range, radio-tracking, bayou, conservation Introduction needs including searching for food, mates, nesting or nursery habitat, or to flee from predation and other Understanding animal movement patterns within the unfavourable environmental conditions (Mueller and ecosystems they inhabit has for decades been a core Fagan, 2008; Bodie and Semlitsch, 2000). tenet of ecology and conservation biology (Mueller Specific habitat usage by animals within an ecosystem and Fagan, 2008; Millar and Blouin-Demers, 2011). is of great interest to ecologists and conservation Animals move within ecosystems to meet life history biologists because it can provide valuable insight into the specific requirements of a species within that ecosystem (Harless et al., 2010), and what the cost/benefits are 1 Turtle Survival Alliance, 1030 Jenkins Road, Suite D, of those movements. By tracking species movements Charleston, South Carolina 29407, USA. over time, essential habitat types can be identified 2 SWCA Environmental Consultants, 10245 West Little York and management plans for these core/critical habitats Road, Suite 600, Houston, Texas 77040, USA. can be developed (Millar and Blouin-Demers, 2011). 3 Freed-Hardeman University, 158 East Main Street, Henderson, However, studying movement patterns of many species Tennessee 38340, USA. is problematic because these studies are expensive, time 4 Houston Zoo, 6200 Hermann Park Drive, Houston, Texas 77030, USA. consuming, labour intensive, and can be in difficult-to- 5 National Park Service, 274 River Road, Beach Lake, access study areas. Therefore, movement patterns for Pennsylvania 18405, USA. many species are not well known and represent gaps in 6 Texas Parks and Wildlife Department, 14320 Garrett Road, our understanding of their basic life histories. Houston, Texas 77044, USA. Movement patterns and habitat use are not well * Corresponding author. E-mail: [email protected] known for many freshwater turtle species. However, © 2021 by Herpetology Notes. Open Access by CC BY-NC-ND 4.0. these data are important because many turtle species 986 Eric Munscher et al. worldwide are experiencing population declines (e.g., on media such as iNaturalist, Vertnet, and Facebook, Gibbons et al., 2000; Lovich et al., 2018). Of the 359 with no long-term studies establishing population recognized extant turtle species, 187 (approximately demographics (Munscher et al., 2020). Alligator 52%) are considered Threatened according to criteria of snapping turtles are generally described as ranging as the International Union for the Conservation of Nature far west as the Trinity River watershed (Dixon, 2013) (IUCN), and 127 (approximately 35%) are considered but were recently discovered in Harris and Montgomery Endangered or Critically Endangered (Stanford et al., Counties (Munscher et al., 2020). The State of Texas 2020). These declines are a result of, but not limited to, added the Western Alligator Snapping Turtle to the state habitat loss and degradation, climate change, pressure list of protected species in 1987 (Texas Secretary of from illegal harvest, mesopredators, and overcollection State, 1987), and in 2018 elevated its status to Imperiled for the pet and meat trades, as well as for traditional (R2 rank; Munscher et al., 2020). However, unlike medicine trades (Turtle Taxonomy Working Group, other hard-shelled turtles, M. temminckii rarely bask, 2017; Lovich et al., 2018; Rhodin et al., 2018; Stanford are generally nocturnal, and typically spend most of the et al., 2020). For conservation efforts to be successful time submerged, rarely coming on to land (Pritchard, for species, key aspects of their life history, such as 1989; Hibbitts and Hibbits, 2016). These behavioural movement and habitat use, must be identified, and characteristics have led to a potential perceived decline monitored. Habitat and species management plans can in some parts of their range, though trapping efforts only be successful if all critical habitats and life history suggest that some populations may be more numerous stages are considered. than originally believed (Hibbitts and Hibbitts, 2016; One notable group thought to be in decline, for which Munscher et al., 2020). Recent surveys, in combination a comprehensive understanding of spatial movements with verified observations, have documented the species is lacking, includes members of the North American in 37 Texas counties, with unverified records from genus Macrochelys. This genus has two recognized another four counties (Rudolph et al., 2002; Dixon, species (Thomas et al., 2014), the Suwannee Alligator 2013; Munscher et al., 2020). Snapping Turtle (M. suwanniensis) and the Western Data on the movement of alligator snapping turtles, Alligator Snapping Turtle (M. temminckii). The while one of the more studied aspects of these species, Suwannee Alligator Snapping Turtle ranges from is still limited to a few studies across a large range northwestern peninsular Florida into southern Georgia, (Sloan and Taylor, 1987). Anecdotal observation data whereas the Western Alligator Snapping Turtle ranges and more robust studies do occur outside of Texas, but from the Florida Panhandle to eastern Texas and north as of the time of this writing no such data exist for M. into eastern Missouri and southern Illinois (Pritchard, temminckii within the state of Texas. Pritchard (1989) 1989; Thomas et al., 2014; Enge et al., 2014). Both stated that alligator snapping turtles were “habitual species have been documented as living in a variety upstream wanderers,” and that “certain individuals of freshwater habitats including lakes, rivers, canals, may wander upstream for decades.” In addition, Ernst swamps, and bayous (Sloan and Taylor, 1987; Pritchard, and Barbour (1972) stated that this species seems to be 1989; Munscher et al., 2020). Large freshwater turtle sedentary and seldom moved long distances (Sloan and species, including alligator snapping turtles, exhibit low Taylor, 1987). Shipman (1991) observed individuals recruitment, slow growth, and long generation times, remaining inactive and sedentary for up to eight days life history traits which make localized populations at a time. More detailed studies have been conducted on vulnerable to exploitation (Gibbons, 1987; Iverson, this species’ movement patterns in Louisiana, Missouri, 1991; Ernst and Lovich, 2009). Both alligator snapping Kansas, Oklahoma, and Florida (Riedle et al., 2006; turtle species have been heavily impacted by legal Enge et al., 2014). These studies showed that, in contrast collection and illegal poaching (Pritchard, 1989; to what was originally believed regarding its movement Huntzinger et al., 2019; Munscher et al., 2020). patterns, this species is capable of extensive movements Until recently M. temminckii was not known to inhabit throughout its aquatic habitats (Riedle et al., 2006). urban ecosystems. However, this species was recently The objective of this study was to describe the documented from the urban flood system (bayou) movement patterns of the Western Alligator Snapping waterways of Houston, Texas (Munscher et al., 2020). In Turtle in the Houston waterway area. These data will Texas, much of what is known about the species’ range be compared to