Ecology of Red Fox

251 Pages·2005·3.01 MB·English

Ecology of Red Fox (Vulpes vulpes)
in the Lassen Peak Region of California, USA
by
John D. Perrine
Department of Environmental Science, Policy and Management
University of California, Berkeley
Fall 2005
Ecology of Red Fox (Vulpes vulpes)
in the Lassen Peak Region of California, USA

by

John Dixon Perrine III

B.S. (Vanderbilt University) 1991
M.S. (Miami University) 1995

A dissertation submitted in partial satisfaction of the

requirements for the degree of

Doctor of Philosophy
in

Environmental Science, Policy and Management

in the

GRADUATE DIVISION

of the

UNIVERSITY OF CALIFORNIA, BERKELEY

Committee in charge:

Professor Reginald H. Barrett, Chair
Professor Stephen R. Beissinger
Professor James L. Patton

Fall 2005
Ecology of Red Fox (Vulpes vulpes)
in the Lassen Peak Region of California, USA

© 2005

by

John Dixon Perrine III
1
Abstract

Ecology of Red Fox (Vulpes vulpes)

in the Lassen Peak Region of California, USA

by

John Dixon Perrine III

Doctor of Philosophy in Environmental Science, Policy and Management

University of California, Berkeley

Professor Reginald H. Barrett, Chair

The red fox population inhabiting California’s Cascade and Sierra Nevada
mountains (Vulpes vulpes necator) is listed as a State Threatened species, but its
management has been hindered by a lack of basic ecological information. I conducted a
comprehensive study of the red foxes in the Lassen Peak region to quantify their local
distribution, resource utilization, activity patterns, niche overlap with likely competitors
and genetic affinity with other red fox populations. The population was restricted to the
region’s highest elevations, occurring >1300 m and primarily within the western half of
Lassen Volcanic National Park. Red fox detections at camera traps in summer were
positively correlated with elevation, highway density and the detection of coyotes, and
were negatively correlated with shrub and herbaceous cover; in winter, detections were
positively correlated with elevation, highway density and mature closed-canopy forest
cover. Their diet was predominantly mammals, especially rodents and mule deer
(Odocoileus hemionus), supplemented by birds, insects and manzanita (Arctostaphylos
nevadensis) berries as seasonally available. Lagomorphs were virtually absent from the
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fox diet. Collared red foxes (n = 5) had large seasonal home ranges (95% MCP; mean =
2,564 ha in summer and 3,255 ha in winter). On average, summer locations were 479 m
higher than winter locations. Their summer range is likely unsuitable in winter due to
deep soft snow and the lack of lagomorphs, a critical winter food for many other red fox
populations, and these factors may limit the Lassen red fox population. Marten (Martes
americana) used the same habitat as the foxes but preyed upon smaller rodents and were
more diurnal. Coyotes (Canis latrans) were nocturnal like the foxes but were generally
at lower elevations and ate larger prey. The Lassen foxes all had the same mtDNA
haplotype, which was the most common haplotype among historic V. v. necator
specimens and was rare in the exotic fox populations from California’s lowlands.
Ecological and genetic evidence indicates that the Lassen red foxes are the native,
threatened V. v. necator, not exotic foxes dispersed from the lowlands. Additional
research is necessary to locate additional mountain red fox populations in California and
to identify the factors preventing their dispersal to the lowlands and vice versa.
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TABLE OF CONTENTS

Table of Contents..................................................................................................................i

List of Tables.......................................................................................................................ii

List of Figures.....................................................................................................................iv

Acknowledgements.............................................................................................................vi

Introduction..........................................................................................................................1

Chapter 1: Seasonal Food Habits of Red Fox, Coyote and Marten in the
Lassen Peak Region of Northern California..................................................15

Chapter 2: Distribution and Habitat Associations of Red Fox, Coyote and Marten
in the Lassen Peak Region as Indicated by Camera Trap Surveys................53

Chapter 3: Activity Patterns of Sympatric Red Fox, Coyote and Marten
in the Lassen Peak Region...........................................................................109

Chapter 4: Home Range and Habitat Use of Radio-Collared
Mountain Red Foxes....................................................................................131

Chapter 5: Red Fox Population Structure in California..................................................166

Conclusions: Niche Overlap Among Red Fox, Coyote and Marten in the
Lassen Region..........................................................................................190

Literature Cited................................................................................................................196

Appendix A: Measurements of Scats of Known Species Identity..................................215

Appendix B: TrailMaster Camera Protocol....................................................................217

Appendix C: Red Fox Locations and Home Ranges by Season.....................................221

Appendix D: Parasites of Lassen Red Fox.....................................................................233

Appendix E: Historical Taxonomy of California’s Mountain Red Foxes......................235
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LIST OF TABLES

Table 1: Field identity versus cytochrome-b identity of scats..........................................38

Table 2: Seasonal diet composition for Lassen red fox, coyote and marten.....................39

Table 3: Dietary niche overlap between pairs of Lassen carnivores................................42

Table 4: Seasonal dietary overlap among all three carnivores.........................................43

Table 5: Annual camera sampling effort in the Lassen region.........................................89

Table 6: CWHR communities represented in general cover types...................................89

Table 7: Variables used in the grid cell analyses..............................................................90

Table 8: Distribution of camera traps and carnivore detections by
CWHR community type....................................................................................91

Table 9: Detection of red fox and marten at camera traps in varying cover types...........92

Table 10: Detection statistics for each target species.......................................................93

Table 11: Univariate analysis of landscape variables in 2.6 km² cells.............................94

Table 12: Pairwise Pearson correlations among cell-level variables................................97

Table 13: Parameter estimates and odds ratios for terms in the landscape-only
model resulting from the stepwise logistic regression...................................100

Table 14: Comparative fit of models by species and season..........................................101

Table 15: Parameter estimates and odds ratios for the most parsimonious
multivariate models for red fox and coyote...................................................103

Table 16: Pairwise species associations at cameras within grid cells
where both species of the pair were detected.................................................104

Table 17: Number of telemetry fixes and monitoring dates for
radio-collared Lassen red fox.........................................................................123

Table 18: Distribution of seasonal detections of carnivores at
baited camera stations....................................................................................123
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Table 19: Was the number of detections proportional to the amount
of time in each diel period?............................................................................124

Table 20: Follow-up tests of whether species pairs were similarly
distributed within diel periods.......................................................................125

Table 21: Physical measurements at first capture for Lassen red foxes.........................157

Table 22: Number of locations, by type, for each collared red fox................................158

Table 23: Seasonal locations and home range size per collared red fox........................159

Table 24: Dates for seasonal home ranges......................................................................160

Table 25: Selection of cover types by individual red fox in summer.............................161

Table 26: Elevation of independent locations, by season...............................................162

Table 27: Elevation of aerial telemetry locations, by season..........................................162

Table 28: Vegetation characteristics of occupied rest sites in summer and winter........163

Table 29: Locality data for red fox specimens used in the genetic analysis...................185

Table 30: Distribution of cytochrome-b haplotypes among putative
red fox sub-populations..................................................................................188

Table 31: Matrix of pairwise FST values for California sub-populations
with ≥4 specimens..........................................................................................189

Table 32: Measurements of scats of known species identity..........................................215

Table 33: Fecal parasites of Lassen red fox....................................................................234
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LIST OF FIGURES

Figure 1: Red fox subspecies in North America.................................................................9

Figure 2: Study area relative to native and exotic red fox range in California.................10

Figure 3: Major vegetation types in the Lassen Peak region............................................11

Figure 4: Elevation in the Lassen Peak region.................................................................12

Figure 5: Places in and around the western half of Lassen Park that are
frequently mentioned in the text......................................................................13

Figure 6: Monthly snow depths in the Lassen region.......................................................14

Figure 7: Seasonal composition of Lassen carnivore scats by volumetric index.............44

Figure 8: Seasonal trends in diet composition for red fox, coyote and marten,
as composite food categories used for statistical testing.................................49

Figure 9: Seasonal diet trends for Cascade red fox..........................................................51

Figure 10: Camera sampling in the Lassen Peak region, 1992-2002.............................105

Figure 11: Distribution of seasonal camera sampling of 2.6 km² grid cells...................106

Figure 12: Distribution of red fox, marten and coyote detections in
summer grid cells.........................................................................................107

Figure 13: Distribution of red fox, marten and coyote detections in
winter grid cells............................................................................................108

Figure 14: Percentage of active telemetry bearings by hour for individual
Lassen red fox...............................................................................................126

Figure 15: Hourly distribution of red fox photographs at baited camera traps...............127

Figure 16: Comparison of red fox activity patterns generated from telemetry
bearings and from camera trap detections using an 8 hr time lag.................128

Figure 17: Hourly distribution of marten photographs at baited camera traps...............129

Figure 18: Hourly distribution of coyote photographs at baited camera traps
in summer.....................................................................................................130
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Figure 19: Study area boundary, defined as the 98% MCP around all fox locations.....164

Figure 20: Distance between independent telemetry points <24 hrs apart.....................165

Figure 21: Distribution of red fox specimens and 7 putative sub-populations in
California, relative to the range of the native Sierra Nevada red fox
and the exotic lowland red fox....................................................................183

Figure 22: Variable sites in the 354 bp region of the cytochrome-b gene in
red foxes from California, Nevada and Washington...................................184

Figure 23: Pairwise niche overlap among Lassen red fox, coyote and marten...............195

Figure 24: Distribution of scat length among Lassen red fox, coyote
and marten....................................................................................................216

Figure 25: Distribution of scat width among Lassen red fox, coyote and marten..........216

Figure 26: Fox locations, winter 1998............................................................................222

Figure 27: Summer 1998................................................................................................223

Figure 28: Winter 1999...................................................................................................224

Figure 29: Summer 1999................................................................................................225

Figure 30: Winter 2000...................................................................................................226

Figure 31: Summer 2000................................................................................................227

Figure 32: Winter 2001...................................................................................................228

Figure 33: Summer 2001................................................................................................229

Figure 34: Winter 2002...................................................................................................230

Figure 35: Summer 2002................................................................................................231

Figure 36: Winter 2003..................................................................................................232