Data from: Separating biological signal from methodological noise in home range estimates

Space use is commonly estimated in animal ecology. It has become a
cornerstone of evidence-based conservation planning, with animal tracking
increasingly used to underpin the designation of protected areas with high
conservation value. However, tracking technologies and analytical methods
may introduce biases in home range size estimates. We assessed these
potential biases using simulated tracking data and published home range
size estimates from empirical studies of animal tracking. We first
simulated animal movement data and added published location error
estimates for different technologies used for tracking sea turtles.
Location data were analysed using common space use estimation methods
(Minimum Convex Polygon, fixed and Autocorrelated Kernel Density
Estimation, Biased Random Bridge, and dynamic Brownian Bridge Movement
Model). Second, we reviewed home range size estimates obtained using
different technologies to track hawksbill (Eretmochelys imbricata) and
green (Chelonia mydas) turtles to assess the relative impacts on home
range estimates due to (i) tracking accuracy and (ii) analytical methods.
For both simulated data and empirical values of space use from the
literature (n = 90 studies), relatively large home range estimates tended
to be generated from lower-resolution Argos tracking compared to
higher-resolution Fastloc-GPS tracking. These findings reflect
inaccuracies in location data, providing spuriously large movements. For
example, Argos and Fastloc-GPS home range size estimates for adult green
turtles averaged 393 km2 and 53 km2, respectively (n = 64 and 39
individuals). For simulated data, biases introduced by tracking accuracy
had a far greater impact on home range size estimation than the analytical
method used, apart from when using Autocorrelated Kernel Density
Estimation (AKDE), which compensated for positional error very well. Our
results suggest that in many cases, hawksbill and green turtles have
relatively small home ranges (< 10 km2 and in some cases, <
1 km2), with this picture of their limited space use only emerging through
high-accuracy tracking. These general conclusions likely apply broadly
across taxa and will impact attempts to assess patterns of home range
sizes recorded for individuals across studies in different regions.