Data from: Divergent estimates of herd-wide caribou calf survival: ecological factors and methodological biases ...
Population monitoring is a critical part of effective wildlife management, but methods are prone to biases that can hinder our ability to accurately track changes in populations through time. Calf survival plays an important role in ungulate population dynamics and can be monitored using telemetry a...
| Main Authors: | , , , |
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| Format: | Dataset |
| Language: | English |
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Dryad
2020
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.5061/dryad.xgxd254db https://datadryad.org/stash/dataset/doi:10.5061/dryad.xgxd254db |
| Summary: | Population monitoring is a critical part of effective wildlife management, but methods are prone to biases that can hinder our ability to accurately track changes in populations through time. Calf survival plays an important role in ungulate population dynamics and can be monitored using telemetry and herd composition surveys. These methods, however, are susceptible to unrepresentative sampling and violations of the assumption of equal detectability, respectively. Here we capitalized on 55 herd-wide estimates of woodland caribou (Rangifer tarandus caribou) calf survival in Newfoundland, Canada using telemetry (n = 1,175 calves) and 252 herd-wide estimates of calf:cow ratios (C:C) using herd composition surveys to investigate these potential biases. These data included 17 herd-wide estimates replicated from both methods concurrently (n = 448 calves and n =17 surveys) which we used to understand which processes and sampling biases contributed to disagreement between estimates of herd-wide calf survival. We ... : Staff from the government of Newfoundland and Labrador monitored 540 radio-collared woodland caribou calves across eight herds during the population growth phase (1979–1997) and 635 radio-collared calves across five herds during the population decline phase (2002–2014). Capture methods are described in Rayl et al. (2014) and Mumma et al. (2019). Staff from the government of Newfoundland and Labrador conducted 249 herd composition surveys for 26 woodland caribou herds across Newfoundland from 1979–2014, except for the years 1998–2001. Herd composition survey methods varied both temporally and spatially from 1979–2014 and we did not necessarily know the exact methodology used for a specific herd year. We summarize below a broad picture of the methods used. Between the months of September and December, observers (typically two plus the pilot) flew rotary-wing (and perhaps in earlier years, fixed-wing) aircraft over an area believed to be where herds were currently located. Occasionally, telemetry data were used ... |
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