Stopped Dead in Their Tracks: The Impact of Railways on Gopher Tortoise (<i>Gopherus polyphemus</i>) Movement and Behavior

Rautsaw, Rhett M.; Martin, Scott A.; Vincent, Bridget A.; Lanctot, Katelyn; Bolt, Marvin; Seigel, Richard A.; Parkinson, Christopher L.

doi:10.1643/ce-17-635

Cited by 15 publications

(6 citation statements)

References 28 publications

(40 reference statements)

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“…The berms form linear barriers and were built to divert rare flood events underneath the railroad, but inadvertently influence tortoise movements by diverting their travel routes toward large underpasses. Railroads are barriers to the movement of gopher tortoises [40], and our limited data suggest a similar relationship between railroads and the Mojave desert tortoise. Tortoises that follow the berms often end travel at the entrance to the culvert, where they presumably shelter underneath the large rocks used to raise the railroad above the desert floor (only one tortoise has been observed to be doing this during VHF relocation events; all other data for tortoises in the vicinity of the culverts come from GPS loggers).…”

Section: Discussionmentioning

confidence: 68%

“…Additionally, exclusion fences are typically erected around utility-scale energy infrastructure to prevent tortoises from returning to former home-ranges post-translocation. Research on the closely related gopher tortoise (Gopherus polyphemus) suggests that railroads may also serve as nearly impassable barriers to movement for tortoises [40]. Understanding how these disturbances affect desert tortoise movement and space use is critical in siting future anthropogenic development and designing and maintaining effective corridors within existing tortoise habitats.…”

Section: Introductionmentioning

confidence: 99%

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Using movement to inform conservation corridor design for Mojave desert tortoise

et al. 2020

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Background Preserving corridors for movement and gene flow among populations can assist in the recovery of threatened and endangered species. As human activity continues to fragment habitats, characterizing natural corridors is important in establishing and maintaining connectivity corridors within the anthropogenic development matrix. The Mojave desert tortoise (Gopherus agassizii) is a threatened species occupying a variety of habitats in the Mojave and Colorado Deserts. Desert tortoises have been referred to as corridor-dwellers, and understanding how they move within suitable habitat can be crucial to defining corridors that will sustain sufficient gene flow to maintain connections among populations amidst the increases in human development. Methods To elucidate how tortoises traverse available habitat and interact with potentially inhospitable terrain and human infrastructure, we used GPS dataloggers to document fine-scale movement of individuals and estimate home ranges at ten study sites along the California/Nevada border. Our sites encompass a variety of habitats, including mountain passes that serve as important natural corridors connecting neighboring valleys, and are impacted by a variety of linear anthropogenic features. We used path selection functions to quantify tortoise movements and develop resistance surfaces based on landscape characteristics including natural features, anthropogenic alterations, and estimated home ranges with autocorrelated kernel density methods. Using the best supported path selection models and estimated home ranges, we determined characteristics of known natural corridors and compared them to mitigation corridors (remnant habitat patches) that have been integrated into land management decisions in the Ivanpah Valley. Results Tortoises avoided areas of high slope and low perennial vegetation cover, avoided moving near low-density roads, and traveled along linear barriers (fences and flood control berms). Conclusions We found that mitigation corridors designated between solar facilities should be wide enough to retain home ranges and maintain function. Differences in home range size and movement resistance between our two natural mountain pass corridors align with differences in genetic connectivity, suggesting that not all natural corridors provide the same functionality. Furthermore, creation of mitigation corridors with fences may have unintended consequences and may function differently than natural corridors. Understanding characteristics of corridors with different functionality will help future managers ensure that connectivity is maintained among Mojave desert tortoise populations.

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Section: Discussionmentioning

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Using movement to inform conservation corridor design for Mojave desert tortoise

et al. 2020

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“…For example, agriculture tends to be aggregated in blocks, while roads and transmission lines have long narrow linear footprints that are often more evenly and widely distributed across landscapes. As a result, the influence of roads and transmission lines is likely to far exceed their surface footprint (Kuvlesky et al 2007), and these as well as railroads have the potential to impact long-term connectivity and genetics (Rautsaw et al 2018, Dutcher et al 2020. These linear features are clearly visible in our analyses (Fig.…”

Section: Limitations and Further Considerationsmentioning

confidence: 84%

Quantifying development to inform management of Mojave and Sonoran desert tortoise habitat in the American southwest

Carter

Nussear

Esque

et al. 2020

Endang. Species. Res.

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Two tortoise species native to the American southwest have experienced significant habitat loss from development and are vulnerable to ongoing threats associated with continued development. Mojave desert tortoises Gopherus agassizii are listed as threatened under the US Endangered Species Act, and Sonoran desert tortoises G. morafkai are protected in Arizona (USA) and Mexico. Substantial habitat for both species occurs on multiple-use public lands, where development associated with traditional and renewable energy production, recreation, and other activities is likely to continue. Our goal was to quantify development to inform and evaluate actions implemented to protect and manage desert tortoise habitat. We quantified a landscape-level index of development across the Mojave and Sonoran desert tortoise ranges using models of potential habitat for each species (152485 total observations). We used 13 years of Mojave desert tortoise monitoring data (4732 observations) to inform the levels and spatial scales at which tortoises may be affected by development. Most (66-70%) desert tortoise habitat has some development within 1 km. Development levels on desert tortoise habitat are lower inside versus outside areas protected by actions at national, state, and local levels, suggesting that protection efforts may be having the desired effects and providing a needed baseline for future effectiveness evaluations. Of the relatively undeveloped desert tortoise habitat, 43% (74030 km2) occurs outside of existing protections. These lands are managed by multiple federal, state, and local entities and private landowners, and may provide opportunities for future land acquisition or protection, including as mitigation for energy development on public lands.

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“…We therefore recommend future research to collect such data and investigate the immediate and long‐term ecological implications of such barriers to the elephant in the TCA. These could include implications on population dynamics, migration and home‐range patterns, access to food and water sources (Ito et al, 2013; Olson & van der Ree, 2015; Ruan et al, 2005), gene flow (Yu et al, 2017), bottlenecks in life‐history adaptation on calf survival (Bolger et al, 2008), deterioration in animal health ( See review in Iosif (2012) and Rautsaw et al (2018) and human–wildlife co‐existence strategies.…”

Section: Discussionmentioning

confidence: 99%

Effectiveness of wildlife underpasses and culverts in connecting elephant habitats: a case study of new railway through Kenya’s Tsavo National Parks

et al. 2021

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Transportation networks can be a major impediment to wildlife movements. We assessed the use of wildlife underpasses and culverts along a newly constructed railway in Kenya's Tsavo National Parks by African elephants (L. africana). We collared ten elephants with GPS satellite transmitters within 20 km of the railway in March 2016 and analysed their movement data to March 2019. Eight elephants used the underpasses although one did not cross the adjacent highway. The remaining two neither used the underpasses nor crossed the highway despite ranging in the vicinity. Their median speed significantly increased to 0.65 km/hr from 0.45 km/hr before crossing the railway, then slowed to 0.32 km/hr after crossing. Females in family groups moved faster than the lone bulls when using the underpasses. Seventy‐eight per cent of all crossings made were at night. The fast speeds and the nocturnal patterns are behavioural responses of elephants in risky landscapes or under stress. Disturbance from vehicles traffic on the adjacent highway and from newly developed human settlements may have limited use of underpasses. Wildlife crossing structures, signage and speed bumps along the highway; relocation of the illegal human settlements; and inter‐agency coordination are requisites for enhancing Tsavos' elephant habitat connectivity.

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Stopped Dead in Their Tracks: The Impact of Railways on Gopher Tortoise (Gopherus polyphemus) Movement and Behavior

Abstract: BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Cited by 15 publications

References 28 publications

Using movement to inform conservation corridor design for Mojave desert tortoise

Using movement to inform conservation corridor design for Mojave desert tortoise

Quantifying development to inform management of Mojave and Sonoran desert tortoise habitat in the American southwest

Effectiveness of wildlife underpasses and culverts in connecting elephant habitats: a case study of new railway through Kenya’s Tsavo National Parks

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