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Movement and Fate of Translocated and In Situ Southeastern Pocket Gophers
J.T. Pynne, Jonathan M. Owens, Steven B. Castleberry, Nikole L. Castleberry, and Robert Brinkman

Southeastern Naturalist, Volume 18, Issue 2 (2019): 297–302

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Southeastern Naturalist 297 J.T. Pynne, J.M. Owens, S.B. Castleberry, N.L. Castleberry, and R. Brinkman 22001199 SOUTHEASTERN NATURALIST 1V8o(2l.) :1289,7 N–3o0. 22 Movement and Fate of Translocated and In Situ Southeastern Pocket Gophers J.T. Pynne1,*, Jonathan M. Owens2, Steven B. Castleberry1, Nikole L. Castleberry3, and Robert Brinkman4 Abstract - Geomys pinetis (Southeastern Pocket Gopher) is absent from much of its historic distribution due to reductions in suitable habitat, which consists largely of open Pinus (pine) systems. Restored open pine habitat represents an opportunity to reestablish Southeastern Pocket Gophers into areas within their historic distribution through translocation. Using radio telemetry, we documented evidence of avian predation on experimentally translocated Southeastern Pocket Gophers and no predation on non-translocated individuals. Translocated individuals exhibited greater movement rates, including aboveground movements, likely exposing them to increased predation risk. Introduction Geomys pinetis Rafinesque (Southeastern Pocket Gopher) (hereafter, Pocket Gopher) historically occurred in the Coastal Plain of Alabama, Georgia, and Florida (Pembleton and Williams 1978). Although historically common in appropriate habitat, the current distribution consists of small, scattered populations isolated by habitat fragmentation (GDNR 2015). In response to declining populations, all 3 states in the range list the Pocket Gopher as a high-priority species in their state wildlife action plans (GDNR 2015). Pocket Gophers are largely associated with the Pinus palustris Mill. (Longleaf Pine)–Aristida stricta Michx. (Wiregrass) ecosystem (Golley 1962), which has been reduced to less than 3% of its previous extent (Landers et al. 1995). Recent focus on restoring Longleaf Pine and other open pine communities of the southeastern Coastal Plain (Van Lear et al. 2005) represents the opportunity to reestablish Pocket Gopher populations. However, given the fragmentation of current populations and limited dispersal abilities (Warren et al. 2017), natural recolonization into restored habitat is unlikely. Translocation may represent a viable option for establishing Pocket Gopher populations into restored pine habitat (Griffith et al. 1989). Herein, we report observations on the movements and fate of translocated compared to nontranslocated southeastern Pocket Gophers. Methods We conducted our study in the Sandhills ecoregion of the southeastern Coastal Plain at Plant Vogtle in Burke County, GA. We identified 2 Pocket Gopher source 1D.B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602. 2Durham, NC 27703. 3Georgia Museum of Natural History, University of Georgia, Athens, GA 30602. 4Oglethorpe Power Corporation, Waynesboro, GA 30830. *Corresponding author - Manuscript Editor: Andrew Edelman Southeastern Naturalist J.T. Pynne, J.M. Owens, S.B. Castleberry, N.L. Castleberry, and R. Brinkman 2019 Vol. 18, No. 2 298 populations and a translocation site with suitable habitat but no sign of an extant population (Fig. 1). The translocation site was separated from both source sites by ≥5 km. We trapped Pocket Gophers from 14 December 2010 to 25 January 2011 using traps, as described by Connior and Risch (2009a) and Hart (1973). While gophers were anesthetized under continuously inhaled sevoflurane, we surgically implanted 4-g VHS radio transmitters (Model V1/116, Sirtrack Tracking Solutions, New Zealand) subcutaneously between the scapulae (Connior and Risch 2009b). We performed capture, handling, and surgery under Georgia Department of Natural Resources scientific collection permit number 29-WBH-10-191 and University of Georgia Institutional Animal Care and Use Committee proposal number A2010 11- 582-Y1-A0. Figure 1. Locations of Southeastern Pocket Gopher capture and relocation sites at Plant Vogtle, Burke County, GA, 2010–2011. Inset map shows the historical species distribution. Southeastern Naturalist 299 J.T. Pynne, J.M. Owens, S.B. Castleberry, N.L. Castleberry, and R. Brinkman 2019 Vol. 18, No. 2 We released 5 randomly selected radio-tagged Pocket Gophers at the translocation site and released 4 back into their source burrow (hereafter, in situ). We released translocated individuals into a 0.5-m diameter by 0.5-m deep hole provisioned with carrots, potatoes, and turnips. We located all Pocket Gophers weekly for up to 16 weeks post-release using a telemetry receiver (TRX-2000S, Wildlife Materials Inc., Carbondale, IL) and a 3-element Yagi antenna, and recorded individual locations using a hand-held GPS unit. We used ArcGIS 9.3 (ESRI, Redlands, CA) to determine 3 movement metrics for each individual: initial movement (distance from the release point to the first telemetry location taken ~1 week later), movement rate (mean distance between all recorded locations), and farthest distance moved from release point. Sex determination in Pocket Gophers based on external morphology is unreliable (Baker et al. 2003); thus, we did not consider sexes separately. Results We were able to locate the telemetry signal of all 5 translocated individuals upon our initial location attempt except for 1 individual, for which we did not observe any evidence of mounding activity. We were unable to detect the telemetry signal of 1 translocated individual after the initial location, but we continued to observe mounding activity, suggesting transmitter failure. We did not attempt to re-trap any individual due logistical constraints and the difficulty of trapping Pocket Gophers (Connior and Risch 2009a). For the remaining 3 translocated individuals, we documented evidence of 2 predation events 7 d and 17 d postrelease. We recovered the carcass of 1 individual and observed that the surgical incision had been reopened and muscle had been picked from bone suggesting avian predation. Although unlikely, it is possible the individual died aboveground and was consumed post mortem. We found only the transmitter from the other individual at the base of a large tree. We successfully located the 5th translocated individual several times; it continued mounding activity after an above-ground dispersal movement. This individual was still alive at the end of the tracking period (16 weeks). We documented no evidence of predation on in situ Pocket Gophers, but excavated a transmitter that was apparently extruded from the surgery site from 1 individual. We do not know the fate of this individual, but we documented no mounding activity following transmitter recovery, suggesting that it died from transmitter-related complications. We were unable to detect the signal from another in situ Pocket Gopher after 9 weeks, but observed continued mounding activity, suggesting transmitter failure. Our movement analyses were based on Pocket Gophers with ≥5 locations (mean = 9.3, range = 5–15; n = 3 translocated, n = 4 in situ). Mean initial movement distance (translocated = 78.6 ± 34.3 m [mean ± SE], in situ = 23.2 ± 5.6 m), movement rate (translocated = 4.8 ± 3.3 m, in situ = 1.9 ± 0.9 m), and farthest distance moved (translocated = 98.4 ± 24.6 m, in situ = 44.5 ± 15.2 m) were all greater for translocated compared to in situ Pocket Gophers. Southeastern Naturalist J.T. Pynne, J.M. Owens, S.B. Castleberry, N.L. Castleberry, and R. Brinkman 2019 Vol. 18, No. 2 300 Discussion Although Pituophis spp. (pine snakes) are thought to be the primary predators of Pocket Gophers (Miller et al. 2012, Rudolph et al. 2002), other studies suggest that avian predation may also be common. Warren et al. (2017) documented Pocket Gopher mortality suggestive of avian predation. Several species of owls have been documented preying on Thomomys talpoides Richardson (Northern Pocket Gopher) (James and Barss 1985, Tyron 1943). Given their poor above-ground locomotory abilities, it is unlikely that the individual we failed to locate after translocation moved beyond detection. We surmise that either this individual was also predated and carried beyond transmitter range or the transmitter failed, though we never documented mounding by this individual. We observed no predation on in situ Pocket Gophers. Difference in predation rates observed may be due to increased movements exhibited by translocated individuals, exposing them to greater risk (Brown 1971, Van Vuren et al. 1997). Two translocated individuals made initial movements of 147 m and 57 m, respectively, which were the farthest movements recorded for those individuals. We suspect that initial movements of all translocated individuals were above ground, as all made movements >39 m and there was no mounding activity between the release site and the initial location. In contrast, initial movements of in situ gophers were smaller and likely underground in the existing burrow system. Other studies have indicated that translocated and in situ Pocket Gophers make aboveground dispersal movements (Connior and Risch 2010, Warren 2014). Another fossorial mammal, Otospermophilus beecheyi (Richardson) (California Ground Squirrel), makes extensive movements and lacks release-site fidelity after translocation (Van Vuren et al. 1997). Warren et al. (2017) documented only 2 predation events out of 17 radiotracked in situ Pocket Gophers. Although not quantified in this study, direction of initial movements in translocated individuals were not suggestive of homing. Homing attempts can lower translocation success (Van Vuren et al. 1997), but homing in Pocket Gophers is uncommon (Hansler et al. 2017, Warren 2014). Although based on a small sample size, our results suggest that predation due to increased aboveground movements of translocated Pocket Gophers may limit translocation success. If translocations are used to relocate agricultural nuisance individuals or repopulate extirpated areas, soft-release measures could reduce aboveground movements and lower predation risk (Van Vuren et al. 1997). Softrelease techniques may include construction of an extensive starter burrow prior to release, a wire cage or wooden coverboard placed over the starter hole, and fencing placed around the initial release area (Hansler et al. 2017). However, these measures are likely temporary because Pocket Gophers would eventually burrow below containment measures. Furthermore, Pocket Gophers would disperse below ground for foraging opportunities. Seasonal timing of translocation also may affect initial movements, and ultimately, translocation success (Bright and Morris 1994), but additional research is needed to determine optimal timing. Southeastern Naturalist 301 J.T. Pynne, J.M. Owens, S.B. Castleberry, N.L. Castleberry, and R. Brinkman 2019 Vol. 18, No. 2 Acknowledgments We thank Sonia Hernandez and Shaun Boone for implanting transmitters. John Jensen, Lara Mengak, Mike Murphy, Mike Odom and Sharon Swagger assisted with trapping and radiotelemetry. Mike Conner provided an early manuscript review. Literature Cited Baker, R.J., R.D. Bradley, and L.R. McAliley Jr. 2003. Pocket gophers. Pp. 276–287, In G.A. Feldhamer, B.C. Thompson, and J.A. Chapman (Eds.). Wild Mammals of North America. 2nd Edition. Johns Hopkins, Baltimore, MD. 1216 pp. Bright, P.W., and P.A. Morris. 1994. Animal translocation for conservation: Performance of dormice in relation to release methods, origin, and season. Journal of Applied Ecology 31:699–708. Brown, L.N. 1971. Breeding biology of the pocket gopher (Geomys pinetis) in southern Florida. American Midland Naturalist 85:45–53. Connior, M.B., and T.S. Risch. 2009a. Live trap for pocket gophers. Southwestern Naturalist 54:100–103. Connior, M.B., and T.S. Risch. 2009b. Benefits of subcutaneous implantation of radiotransmitters in pocket gophers. Southwestern Naturalist 54:214–216. Connior, M.B., and T.S. Risch. 2010. Home range and survival of the Ozark Pocket Gopher (Geomys bursarius ozarkensis) in Arkansas. American Midland Naturalist 164:80–90 Georgia Department of Natural Resources (GDNR). 2015. Georgia State Wildlife Action Plan. Georgia Department of Natural Resources, Social Circle, GA. 246 pp. Golley, F. 1962. Mammals of Georgia: A Study of their Distribution and Functional Role in the Ecosystem. University of Georgia Press, Athens, GA. 218 pp. Griffith, B., J.M. Scott, J.W. Carpenter, and C. Reed. 1989. Translocation as a species conservation tool: Status and strategy. Science 245:477–480. Hansler, T.P., S.E. Henke, H.L. Perotto-Baldivieso, J.A. Baskin, and C. Hilton. 2017. Shortdistance translocation as a management option for nuisance Maritime Pocket Gophers. Southeastern Naturalist 16:603–613. Hart, E.B. 1973. A simple and effective live trap for pocket gophers. American Midland Naturalist 89:200–202. James, S.W., and J.M. Barss. 1985. Predation by three owl species on Northern Pocket Gophers of different body mass. Oecologia 67:76–81. Landers, J.L., D.H. Van Lear, and W.D. Boyer. 1995. The Longleaf Pine forest of the southeast: Requiem or renaissance? Journal of Forestry 93:39–44. Miller, G.J., L.L. Smith, S.A. Johnson, and R. Franz. 2012. Home-range size and habitat selection in the Florida Pine Snake (Pituophis melanoleucus mugitus). Copeia 2012:706–713. Pembleton, E.F., and S.L. Williams. 1978. Geomys pinetis. Mammalian Species 86:1–3. Rudolph, D.C., S.J. Burgdorf, R.N. Conner, and C.S. Collins, D. Saenz, R.R. Schaefer, T. Trees, C.M. Duran, M. Ealy, and J.G. Himes. 2002. Prey handling and diet of Louisiana Pine Snakes (Pituophis ruthveni) and Black Pine Snakes (P. melanoleucus lodingi), with comparisons to other selected colubrid snakes. Herpetological Natural History 9:57–62. Tyron, C.A. 1943. The Great Gray Owl as a predator on pocket gophers. Wilson Bulletin 55:130–131. Van Lear, D.H., W.D. Carroll, P.R. Kapeluck, and R. Johnson. 2005. History and restoration of the Longleaf Pine–grassland ecosystem: Implications for species at risk. Forest Ecology and Management 211:150–165. Southeastern Naturalist J.T. Pynne, J.M. Owens, S.B. Castleberry, N.L. Castleberry, and R. Brinkman 2019 Vol. 18, No. 2 302 Van Vuren, D., A.J. Kuenzi, I. Loredo, and M.L. Morrison. 1997. Translocation as a nonlethal alternative for managing California Ground Squirrels. Journal of Wildlife Management 61:351–359. Warren, A.E. 2014. Ecology of the Southeastern Pocket Gopher (Geomys pinetis) in southwestern Georgia. M.Sc. Thesis. University of Georgia, Athens, GA. 79 pp. Warren, A.E., L.M. Conner, S.B. Castleberry, and D. Markewitz. 2017. Home range, survival, and activity patterns of the Southeastern Pocket Gopher: Implications for translocation. Journal of Fish and Wildlife Management 8:544–557.