A New Approach to Conservation of the Mojave Desert Tortoise

Averill‐Murray, Roy C.; Darst, Catherine R.; Field, Kimberleigh J.; Allison, Linda

doi:10.1525/bio.2012.62.10.9

Cited by 30 publications

(16 citation statements)

References 28 publications

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“…The vast majority of threats to the species' persistence are associated with both widespread habitat loss or degradation and fragmentation due to human land uses Wildlife Service 2011, Tuma et al 2016). Moreover, conservation activities are difficult to achieve at a range-wide scale because development continues to occur at local scales and across multiple jurisdictional boundaries (Averill-Murray et al 2012).…”

Section: Introductionmentioning

confidence: 99%

A range‐wide model of contemporary, omnidirectional connectivity for the threatened Mojave desert tortoise

et al. 2019

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As habitat destruction leads to species extinctions globally, conservation planning that accounts for population‐level connectivity and gene flow is an urgent priority. Models that only approximate habitat potential are incomplete because areas of high habitat potential may be isolated, whereas intermixed areas of lower habitat potential may still be critical for maintaining connectivity between and among populations. We developed a range‐wide, omnidirectional (coreless) connectivity model and map for the threatened Mojave desert tortoise at a high spatial resolution (30 m), based on empirical movement data and a circuit‐theoretic approach to estimating connectivity. Specifically, we first estimated habitat potential (i.e., quality) for tortoise movement (as distinct from habitat potential more generally) across its range using hypotheses based on the published literature, linear mixed models, multiple environmental factors derived from remotely sensed data, and recent solar and wind development footprints. The resultant raster output was used to represent landscape conductance in a circuit‐theoretic model of connectivity, which relates the flow of electrical current through a circuit to the movement of tortoises through the landscape. We then modeled potential connectivity across the range of the tortoise using Circuitscape software and the Julia numerical programming language. Intermediate distances from minor roads, intermediate values of annual average maximum temperature, and increasing density of desert washes were among the strongest predictors of movement habitat quality. There was also strong evidence for increased habitat quality for movement with increasing amounts of vegetation cover. The resulting connectivity model and map was determined to accurately reflect important areas for tortoise movement, but we encourage others to do their own evaluation of the model within local areas of interest and as more data become available. Accordingly, the map can provide an important component to improve management decisions that have the potential to influence the conservation of connected desert tortoise populations throughout the range.

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Section: Introductionmentioning

confidence: 99%

A range‐wide model of contemporary, omnidirectional connectivity for the threatened Mojave desert tortoise

et al. 2019

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“…The few notable exceptions that have implemented scientifically-based mitigation translocation programs have yielded important insights to reduce future impacts for those species (Germano et al, 2015;Sullivan et al, 2015), and this provides an important example for solar development given its rapid pace. The federally protected Mojave desert tortoise (Gopherus agassizii) is an important representative organism that can be used to evaluate effects of solar development due to its wide distribution and potential for substantial displacement across targeted areas (Averill-Murray et al, 2012;Cameron et al, 2012;Lovich and Ennen, 2011). The desert tortoise is also vulnerable to exceeding its physiological limits (Morafka and Berry, 2002) and thus may be particularly sensitive to translocation in thermally extreme environments that are optimal for solar development.…”

Section: Introductionmentioning

confidence: 99%

Mitigation-driven translocation effects on temperature, condition, growth, and mortality of Mojave desert tortoise ( Gopherus agassizii ) in the face of solar energy development

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Farnsworth

Meyers

et al. 2016

Biological Conservation

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“…In the western U.S., one species impacted by utility-scale renewable energy development is the federally threatened Mojave desert tortoise ( Gopherus agassizii ) [ 11 ]. To offset potential impacts from construction and related human activities, translocation outside of project areas has become a tool used to manage wild tortoises as part of overall mitigation activities [ 12 ].…”

Section: Introductionmentioning

confidence: 99%

Short-Term Space-Use Patterns of Translocated Mojave Desert Tortoise in Southern California

et al. 2015

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Increasingly, renewable energy comprises a larger share of global energy production. Across the western United States, public lands are being developed to support renewable energy production. Where there are conflicts with threatened or endangered species, translocation can be used in an attempt to mitigate negative effects. For the threatened Mojave desert tortoise (Gopherus agassizii), we sought to compare habitat- and space-use patterns between short-distance translocated, resident, and control groups. We tested for differences in home range size based on utilization distributions and used linear mixed-effects models to compare space-use intensity, while controlling for demographic and environmental variables. In addition, we examined mean movement distances as well as home range overlap between years and for male and female tortoises in each study group. During the first active season post-translocation, home range size was greater and space-use intensity was lower for translocated tortoises than resident and control groups. These patterns were not present in the second season. In both years, there was no difference in home range size or space-use intensity between control and resident groups. Translocation typically resulted in one active season of questing followed by a second active season characterized by space-use patterns that were indistinguishable from control tortoises. Across both years, the number of times a tortoise was found in a burrow was positively related to greater space-use intensity. Minimizing the time required for translocated tortoises to exhibit patterns similar to non-translocated individuals may have strong implications for conservation by reducing exposure to adverse environmental conditions and predation. With ongoing development, our results can be used to guide future efforts aimed at understanding how translocation strategies influence patterns of animal space use.

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A New Approach to Conservation of the Mojave Desert Tortoise

Cited by 30 publications

References 28 publications

A range‐wide model of contemporary, omnidirectional connectivity for the threatened Mojave desert tortoise

A range‐wide model of contemporary, omnidirectional connectivity for the threatened Mojave desert tortoise

Mitigation-driven translocation effects on temperature, condition, growth, and mortality of Mojave desert tortoise ( Gopherus agassizii ) in the face of solar energy development

Short-Term Space-Use Patterns of Translocated Mojave Desert Tortoise in Southern California

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