10.5061/DRYAD.CC2FQZ652
Williams, Sara
0000-0001-6458-1316
University of Montana
Steenweg, Robin
Environment and Climate Change Canada
Hegel, Troy
Alberta Environment and Parks
Russell, Mike
Alberta Environment and Parks
Hervieux, Dave
Alberta Environment and Parks
Hebblewhite, Mark
University of Montana
Habitat loss on seasonal migratory range imperils an endangered ungulate
Dryad
dataset
2020
2021-01-11T00:00:00Z
2021-01-11T00:00:00Z
en
41869 bytes
3
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Endangered species policies and their associated recovery documents and
management actions do not always sufficiently address the importance of
migratory behavior and seasonal ranges for imperiled populations. Using a
telemetry location dataset spanning 1981 – 2018, we tested for changes in
prevalence of migratory tactics (resident, migrant) over time, switching
between tactics, shifts in seasonal space-use including migration
corridors, and survival consequences of migrant and resident tactics for
237 adult female endangered woodland mountain caribou in one population in
western Canada. Over more than three decades, the proportion of
individuals displaying annual migration to the low elevation forested
winter range declined from nearly 100% to 38%. Correspondingly, there was
a strong switch away from being migrant to being year-round residents at
high elevation. These behavioral changes corresponded to abandonment of
low elevation winter ranges in association with increasing levels of
anthropogenic land uses, including forestry and oil and gas developments.
Furthermore, there were no identifiable migration corridors to target for
migratory route protection. These shifts translated to lower survival
rates, particularly for caribou demonstrating resident tactics, consistent
with recent declines of the caribou population. That migrants switched to
residency in their largely undisturbed summer range, despite lower
survival, indicates maladaptive habitat selection consistent with recent
patterns of mountain caribou extirpations. Globally, endangered species
policies and their associated recovery plans and management actions often
do not explicitly consider the challenge of protecting migratory species.
Effective conservation of migratory species requires protecting critical
habitats needed for the entire life history of the species, including all
seasonal ranges and migratory habitat.
1. "RRPC_migation_class.csv": migration tactic classification
data for use in anlaysis of estimating probability of being migrant and
probability of switching tactic VHF or GPS radio collar locations used to
classify migratory tactic using net-squared displacement (NSD) models in
the ‘migrateR’ package in the program R (Bunnefeld et al., 2011; R Core
Team, 2019; Spitz, Hebblewhite, & Stephenson, 2017) using a single
location/day for individuals that had > 20 locations/year to ensure
model convergence using NSD. Other individuals’ movement trajectories were
not suitable for NSD models because of too few locations (e.g., VHF data)
or lack of a complete annual cycle (e.g. mortalities, collar failures,
etc.). To assess tactic for these latter individuals, we developed
decision rules based on successfully NSD classified individuals who showed
clear migration movements (Eggeman et al., 2016; see Supporting
Information). Decision rules for assigning migratory tactic: First, we
assumed all caribou spent summer (June – August) at high elevations
because no monitored caribou summered in low elevation areas. Thus, the
crucial test for migrant classification was whether we found even a single
location of an individual in winter (Jan – March) in lower-elevation
foothills. Conversely, if all an individual’s locations during winter
occurred in high-elevation range occupied during summer, we classified
this individual to be a high-elevation resident. In cases where migratory
tactic could not be determined, it was assigned as unknown. 2.
"RRPC_capture.csv": capture date information per individual for
use in survival analysis 3. "RRPC_fate.csv": fate information
per individual-year for use in survival analysis