Spatial Patterning of Prey at Reproduction to Reduce Predation Risk: What Drives Dispersion from Groups?

DeMars, Craig A.; Breed, Greg A.; Potts, Jonathan R.; Boutin, Stan

doi:10.1086/685856

Cited by 14 publications

(17 citation statements)

References 45 publications

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“…The effects of linear features on the movement of large terrestrial mammals are relatively well understood (Dyer et al, 2002; Whittington et al, 2004; Dickson et al, 2005; Latham et al, 2011; Whittington et al, 2011; McKenzie et al, 2012; Tremblay and Clair, 2009; DeMars et al, 2016; Dickie et al, 2017; Popp et al, 2018), but, here, we showed that anthropogenic linear features can also affect movement and space use of avian species during migration. Our approach was analytically nuanced, incorporating the affects of energy subsidies key to soaring movement into the the movement process.…”

Section: Discussionmentioning

confidence: 55%

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Novel step selection analyses on energy landscapes reveal how linear features alter migrations of soaring birds

Eisaguirre

Booms

Barger

et al. 2019

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Human modification of landscapes includes extensive addition of linear features, such as roads and transmission lines. These can alter animal movement and space use and affect the intensity of interactions among species, including predation and competition. Effects of linear features on animal movement have seen relatively little research in avian systems, despite ample evidence of their effects in mammalian systems and that some types of linear features, including both roads and transmission lines, are substantial sources of mortality. Here, we used satellite telemetry combined with step-selection functions (SSFs) designed to explicitly incorporate the energy landscape to investigate the effects of linear features and habitat on movements and space use of a large soaring bird, the golden eagle Aquila chrysaetos, during migration. Our sample consisted of 32 adult eagles tracked for 45 spring and 39 fall migrations from 2014-2017. Fitted SSFs indicated eagles had a strong general preference for south-facing slopes, where thermal uplift develops predictably, and that these areas are likely important aspects of migratory pathways. SSFs also revealed that roads and railroads affected movement during both spring and fall migrations, but eagles selected areas near roads to a greater degree in spring compared to fall and at higher latitudes compared to lower latitudes. During spring, time spent near linear features often occurred during slower-paced or stopover movements, perhaps in part to access carrion produced by vehicle collisions. Regardless of the behavioral mechanism of selection, use of these features could expose eagles and other soaring species to elevated risk via collision with vehicles and/or transmission lines. Linear features have been previously documented to affect the ecology of terrestrial species (e.g., large mammals) by modifying individuals' movement patterns; our work shows these effects on movement extend to avian taxa.

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Section: Discussionmentioning

confidence: 55%

“…Some linear features have negative effects that are unidirectional in predator-prey interactions. Seismic lines, for example, increase a predator’s (wolf) access to prey (caribou), negatively affecting prey but imposing no additional risk or harm to the predator (McKenzie et al, 2012; DeMars et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Novel step selection analyses on energy landscapes reveal how linear features alter migrations of soaring birds

Eisaguirre

Booms

Barger

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…The effects of linear features on the movement of large terrestrial mammals are relatively well understood (DeMars et al, 2016;Dickie et al, 2019;Latham et al, 2011;McKenzie et al, 2012;Whittington et al, 2004); here we provide evidence that anthropogenic linear features also affect movement and space use of avian species during migration. Our approach was analytically nuanced, incorporating the effects of energy subsidies key to soaring movement into the availability kernel.…”

Section: Discussionmentioning

confidence: 67%

Novel step selection analyses on energy landscapes reveal how linear features alter migrations of soaring birds

Eisaguirre

Booms

Barger

et al. 2020

Journal of Animal Ecology

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1. Human modification of landscapes includes extensive addition of linear features, such as roads and transmission lines. These can alter animal movement and space use and affect the intensity of interactions among species, including predation and competition. Effects of linear features on animal movement have seen relatively little research in avian systems, despite ample evidence of their effects in mammalian systems and that some types of linear features, including both roads and transmission lines, are substantial sources of mortality. 2. Here, we used satellite telemetry combined with step selection functions designed to explicitly incorporate the energy landscape (el-SSFs) to investigate the effects of linear features and habitat on movements and space use of a large soaring bird, the golden eagle Aquila chrysaetos, during migration. Our sample consisted of 32 adult eagles tracked for 45 spring and 39 fall migrations from 2014 to 2017. 3. Fitted el-SSFs indicated eagles had a strong general preference for south-facing slopes, where thermal uplift develops predictably, and that these areas are likely important aspects of migratory pathways. el-SSFs also provided evidence that roads and railroads affected movement during both spring and fall migrations, but eagles selected areas near roads to a greater degree in spring compared to fall and at higher latitudes compared to lower latitudes. During spring, time spent near linear features often occurred during slower-paced or stopover movements, perhaps in part to access carrion produced by vehicle collisions. 4. Regardless of the behavioural mechanism of selection, use of these features could expose eagles and other soaring species to elevated risk via collision with vehicles and/or transmission lines. Linear features have previously been documented to affect the ecology of terrestrial species (e.g. large mammals) by modifying individuals' movement patterns; our work shows that these effects on movement extend to avian taxa.

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“…, Rettie and Messier , DeMars et al. ). We assumed that when a wolf encountered a caribou cow with her calf, only the calf was killed.…”

Section: Wolf–caribou Encounter Modelsmentioning

confidence: 99%

“…DeMars et al. () used a wolf detection distance for calves of 1 km; we used detection distances of 0.5 or 1 km. Note that it is possible that encounters between wolves and prey are missed because we only simulate wolf positions every five minutes.…”

Section: Wolf–caribou Encounter Modelsmentioning

confidence: 99%

Slowing down wolves to protect boreal caribou populations: a spatial simulation model of linear feature restoration

et al. 2019

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In Canada, boreal caribou (Rangifer tarandus caribou) are declining in numbers, in part due to increased predation by wolves (Canis lupus). One management option to reduce wolf–caribou interactions and thus protect caribou is to remove man‐made linear features (LFs), structures such as roads, trails, and cut lines, which are used by wolves as traveling paths. Linear features increase wolf traveling speed and could additionally facilitate wolf entry into caribou habitat. Our goal was to quantify the expected effect of LF removal on caribou mortality and investigate whether this LF restoration could be a sufficient measure to stop caribou declines. We simulated the effects of LF restoration on caribou adult and calf survival in spatially explicit wolf–caribou encounter models. The models were parameterized using Global Positioning System (GPS) data, hidden Markov models (HMMs), and information from the published literature. Complete LF restoration decreased wolf traveling speed and thus reduced caribou mortality. The proportional reduction in adult caribou mortality ranged from 10 to 25% of its original value, and the proportional reduction in calf mortality ranged from 8 to 23%, depending on caribou density, number of wolf packs, kill probability given an encounter, and detection distance of wolves for caribou. Building on the model output, we used empirical caribou data to calculate the effects of reduced mortalities on the finite rate of annual population change, normalλ. Assuming that 25% or less of calf mortality was wolf‐related, normalλ stayed below one, that is, populations kept declining, even with complete LF restoration. With 50% of calf mortality due to wolves, caribou populations stopped declining (λ≥1) if adult and calf mortality were reduced by at least 19 to 24%. However, these values were not achieved in a majority of the parameter combinations in our study, not even with complete LF restoration. Given that LF restoration as a single measure is unlikely to stop boreal caribou populations from declining, we used a case example to illustrate how LF restoration could make a small contribution in a portfolio of short‐term and long‐term management options to reduce wolf predation on caribou.

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Spatial Patterning of Prey at Reproduction to Reduce Predation Risk: What Drives Dispersion from Groups?

Cited by 14 publications

References 45 publications

Novel step selection analyses on energy landscapes reveal how linear features alter migrations of soaring birds

Novel step selection analyses on energy landscapes reveal how linear features alter migrations of soaring birds

Novel step selection analyses on energy landscapes reveal how linear features alter migrations of soaring birds

Slowing down wolves to protect boreal caribou populations: a spatial simulation model of linear feature restoration

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