Mapping potential effects of proposed roads on migratory connectivity for a highly mobile herbivore using circuit theory

Abstract

Migration is common worldwide as species access spatiotemporally varying resources and avoid predators and parasites. However, long‐distance migrations are increasingly imperiled due to development and habitat fragmentation. Improved understanding of migratory behavior has implications for conservation and management of migratory species, allowing identification and protection of seasonal ranges and migration corridors. We present a technique that applies circuit theory to predict future effects of development by analyzing season‐specific resistance to movement from anthropogenic and natural environmental features across an entire migratory path. We demonstrate the utility of our approach by examining potential effects of a proposed road system on barren ground caribou (Rangifer tarandus granti) and subsistence hunters in northern Alaska. Resource selection functions revealed migratory selection by caribou. We tested five scenarios relating habitat selection to landscape resistance using Circuitscape and GPS telemetry data. To examine the effect of potential roads on connectivity of migrating animals and human hunters, we compared current flow values near communities in the presence of proposed roads. Caribou avoided dense vegetation, rugged terrain, major rivers, and existing roads in both spring and fall. A negative linear relationship between resource selection and landscape resistance was strongly supported for fall migration while spring migration featured a negative logarithmic relationship. Overall patterns of caribou connectivity remained similar in the presence of proposed roads, though reduced current flow was predicted for communities near the center of current migration areas. Such data can inform decisions to allow or disallow projects or to select among alternative development proposals and mitigation measures, though consideration of cumulative effects of development is needed. Our approach is flexible and can easily be adapted to other species, locations and development scenarios to expand understanding of movement behavior and to evaluate proposed developments. Such information is vital to inform policy decisions that balance new development, resource user needs, and preservation of ecosystem function.

Quantifying Landscape Degradation Following Construction of a Highway Using Landscape Metrics in Southern Iran

“…Roads contribute to loss of biodiversity, both directly, through habitat fragmentation and degradation (Meijer et al, 2018;Silva et al, 2020;Fullman et al, 2021), reduced movement and gene flow (Epps et al, 2005;Cushman et al, 2010;Dean et al, 2019), increased risk of wildlife vehicle collisions (Mohammadi and Kaboli, 2016;Mohammadi et al, 2018;Saint-Andrieux et al, 2020;Borowik et al, 2021) and increased disturbance (Leblond et al, 2013;Iglesias-Merchan et al, 2018), and indirectly, via providing access for poaching (Clevenger et al, 2002;Ordiz et al, 2017;Kaszta et al, 2019;Carter et al, 2020).…”

Variation in winter site fidelity within and among individuals influences movement behavior in a partially migratory ungulate

“…Recent decisions have expanded the amount of TCH habitat available for oil and gas leasing and development [ 105 ] and approved new projects across the range of the herd (e.g., [ 36 , 106 ]). Understanding patterns of winter use and migration in areas proposed for development may allow analysis of potential impacts of proposed projects [ 107 ] as well as influence site selection and mitigation decisions. It is unknown how overwintering caribou in northern Alaska will respond to infrastructure and human activities, as most North Slope development to date has occurred outside of primary caribou winter range.…”

“…Understanding drivers of migration at both proximate and ultimate levels is key to understanding how they will be affected by changing environmental conditions [ 116 ]. As caribou face the pressures of a rapidly warming Arctic [ 117 ] and ongoing human development and activities [ 107 , 118 , 119 ], further research is needed to investigate what factors influence this diversity of caribou behaviors in Alaska and across the circumpolar Arctic.…”

Simulation modeling accounts for uncertainty while quantifying ecological effects of development alternatives

“…The WAH calves in the foothills of the Brooks Range mountains (Fig. 1), foraging in and around the NPR‐A during the summer and then largely migrating south for the winter (Dau 2015, Joly and Cameron 2019, Cameron et al 2020, Fullman et al 2021). The NPR‐A is also home to a diverse community of birds that migrate from as far as Antarctica (Andres et al 2012, Saalfeld et al 2013, Brown et al 2017) to breed and molt in lowland habitats throughout the NPR‐A (Liebezeit et al 2011, Andres et al 2012, Bart et al 2013, Amundson et al 2019).…”