10.5061/DRYAD.C8234
Sacks, Benjamin N.
University of California, Davis
Statham, Mark J.
University of California, Davis
Wittmer, Heiko U.
Victoria University of Wellington
Data from: A preliminary range-wide distribution model for the Sacramento
Valley red fox
Dryad
dataset
2017
Sacramento Valley red fox
habitat
MaxEnt
Vulpes vulpes patwin
Holocene
2017-01-03T15:46:42Z
2017-01-03T15:46:42Z
en
https://doi.org/10.3996/072016-jfwm-057
210392 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
The Sacramento Valley red fox Vulpes vulpes patwin of California is a
newly named subspecies recently found to be distinct both from other
native red foxes and nearby introduced populations. The Sacramento Valley
red fox experienced a historical demographic bottleneck resulting in a
critically small genetic effective population size, causing concern over
its current status and management requirements, yet little is known about
its contemporary abundance, demographic trajectory, or habitat use. The
hot, arid Sacramento Valley contrasts starkly in climate and physiography
with the boreal habitats of other indigenous red foxes in western North
America, indicating the need to obtain information specifically on the
habitat requirements of this subspecies. A 3-y effort to locate
reproductive den sites throughout the Sacramento Valley resulted in 42
independent dens, which we used to obtain preliminary information on
habitat use and to develop a distribution model for this subspecies, and
28 Sacramento Valley red foxes killed by vehicles, which we used as
independent data to test the models. Foxes were present significantly more
than expected in grasslands and less than expected in wetlands and flooded
agriculture and also tended to occur in proximity to human development,
potentially as refuges from coyotes Canis latrans. We used Maxent to build
predictive models. The best model, which incorporated vegetation/land-use
classes and proximity to human development, identified 24% of the study
area as predicted-presence habitat, which contained 76% of the den sites
used to construct the model and 89% of independent locations used to test
the model. Our model greatly narrowed the area over which foxes are
predicted to occur and will facilitate future surveys to assess occupancy
and ultimately abundance and population trends.
FigureA1Locations of 42 Sacramento Valley red fox (Vulpes vulpes patwin)
den sites (black circles) and 28 road kills (red circles) in reference to
4 land-cover types used in Maxent modeling, Sacramento Valley, California,
2007–2009.SacksTableA1Locations and land-cover type coding of 42
Sacramento Valley red fox den sites used in Maxent
modelingSacksTableA2Locations of 28 native Sacramento Valley red fox road
killsFigureA2Locations of 70 Sacramento Valley red fox (Vulpes vulpes
patwin) den sites and road kills (black circles) in reference to
geographic landmarks and two Maxent model predicting distribution in the
Sacramento Valley, California: (A) the full model, based on vegetation
type, distance to grasslands, distance to development, and (B) a
2-variable model, based on vegetation type and distance to grasslands
(i.e., excluding distance to development). All data shown were collected
during 2007–2009.
California