Spatial structure of reproductive success infers mechanisms of ungulate invasion in Nearctic boreal landscapes ...
1. Landscape change is a key driver of biodiversity declines due to habitat loss and fragmentation, but spatially shifting resources can also facilitate range expansion and invasion. Invasive populations are reproductively successful, and landscape change may buoy this success. 2. We show how modell...
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| Format: | Dataset |
| Language: | English |
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Dryad
2020
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| Online Access: | https://dx.doi.org/10.5061/dryad.xksn02vf2 https://datadryad.org/stash/dataset/doi:10.5061/dryad.xksn02vf2 |
| Summary: | 1. Landscape change is a key driver of biodiversity declines due to habitat loss and fragmentation, but spatially shifting resources can also facilitate range expansion and invasion. Invasive populations are reproductively successful, and landscape change may buoy this success. 2. We show how modelling the spatial structure of reproductive success can elucidate the mechanisms of range shifts and sustained invasions for mammalian species with attendant young. We use an example of white-tailed deer (deer; Odocoileus virginianus) expansion in the Nearctic boreal forest, a North American phenomenon implicated in severe declines of threatened woodland caribou (Rangifer tarandus). 3. We hypothesized that deer reproductive success is linked to forage subsidies provided by extensive landscape change via resource extraction. We measured deer occurrence using data from 62 camera-traps in northern Alberta, Canada, over three years. We weighed support for multiple competing hypotheses about deer reproductive success ... : We deployed 62 camera-trap sites (Reconyx PC900 HyperfireTM infra-red remote digital; Holmen, WI, USA) in a constrained stratified random design (Supplementary Information), sampled continuously between November 2011- November 2014, as in Fisher and Burton (2018); Fisher et al. (2020). Following Burton et al. (2015), we define 'site' as the average area used by a deer (seasonally, in a 3-month window), centered on the camera detection zone. We define 'study area' as the ca. 3500 km2 minimum convex polygon surrounding camera sites. Cameras were placed ca. 1m from the ground facing the wildlife trail and set to high sensitivity with 3-s delay. Spatial reproductive success We identified all camera trap images containing white-tailed deer and created a monthly detection-nondetection dataset with three states: breeding (fawns present in spring; hereafter “fawning”), non-breeding, or no deer detected. We discretized continuous camera sampling into monthly survey occasions. If a fawn(s) appeared in an image within ... |
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