Regional conservation planning is often guided by the use of focal species, whose
persistence can serve as a measure of the habitat elements to be maintained or enhanced
by conservation action. Here, I investigated the ecology of the American badger
(Taxidea taxus) as a focal species for regional conservation planning in California. First,
I investigated home range size and habitat use of nine radio-implanted badgers. At the
study site scale, home ranges were sited in grasslands, sandy/loamy soil types, and close
to recreational trails. Within their home range, badgers showed only a preference for
intermediate slopes over very steep slopes. Dens within badgers' home range were
associated with native grassland and scrub habitat, showed an avoidance of flat slopes,
and tended to be found within 500 meters of trails. Second, I examined the fine-scale
movement patterns of American badgers. Travel speeds were greater during the mating
season and spring than they were in the winter for both sexes. Vegetation type affected
the travel speed of males during the fall and spring; however, travel speed during the
mating season was not affected by vegetation type. Finally, I used occurrence data to
identify landscape factors affecting the population distribution of American badgers in
California, and to examine the factors associated with declines in badger occurrences
over time. Environmental features associated with badger occurrences and declines
varied by ecoregion: an association with grassland and shrub cover was detected in some
ecoregions, while an association with forest and woodland habitat was detected in others.
In remote ecoregions, human-altered habitats were positively associated with badger
occurrences. Declines in badger occurrences were associated with human-altered
landscapes in two ecoregions. These results will inform conservation planning by
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identifying 1.) area requirements for badgers, 2.) characteristics of habitat necessary for
their behavioral activities, and 3.) factors that may affect corridor efficacy in badger
habitat. Results also establish the geographic extent to which badgers should be
considered in regional conservation plans, and identify habitat factors specific to each
ecoregion that may affect badger persistence and thus their role as a focal species.
Protocol includes: canine scent surveys, badger sign surveys, scat DNA testing, hair snags, infrared cameras, and outreach efforts. Protocol from "Research Results of American Badgers in Western San Diego County, 2014".
Badgers (Taxidea taxus) are wide-ranging mid-sized predators associated with grassland and
upland habitats. Their large home ranges, low densities, and low fecundity make them particularly vulnerable to habitat fragmentation and road mortality. The American badger is a covered species under the San Diego Multiple Species Conservation Plan (MSCP) and has been identified by the San Diego Monitoring and Management Program (SDMMP) Connectivity Monitoring Strategic Plan as a target species for monitoring regional-scale functional connectivity of upland and grassland habitats and is considered to be at risk of loss from the SDMMP Management Strategic Plan Area (MSPA).
In 2015, we continued studies of the spatial and temporal use of habitats by the American badger by conducting monthly field sign and infrared (IR) camera surveys across seven focal sites in the County where we previously documented substantial and/or repeated badger activity; Volcan Mountain Ecological Reserve (ER), Santa Ysabel ER, Ramona Grasslands Preserve, Barnett Ranch Preserve, Marron Valley Cornerstone Lands, Rancho Guejito (privately owned), and the upper San Diego River and El Capitan Grande Reservation. Our objective was to determine if badgers use these areas annually and if so, to better document the duration and season(s) of activity.
In FY 2011, the California Department of Fish and Game (DFG) funded this initial study by a Natural Community Conservation Plan (NCCP) Local Assistance Grant (LAG) to determine if badgers still persist in the western portion of San Diego County. Survey sites were prioritized according to three criteria; 1) areas with historical and/or recent badger records, 2) conserved lands with priority given to MSCP and Multiple Habitat Conservation Plan (MHCP) lands, and 3) areas containing moderate to abundant grassland habitat.
We conducted canine scent surveys for American badger scat using a specially trained canine scent team from Conservation Canines (Heath Smith and Pips; University of Washington) from November 14 to December 14, 2011. We surveyed for badger scat across 32 sites within San Diego County and two sites in southern Riverside County. Pips had positive behavioral responses to scat at 13 sites. Using a badger specific DNA test, we were able to verify the scat collected to be that of the American badger at twelve sites: Marine Corps Base Camp Pendleton (Juliett and Oscar One), Fallbrook Naval Weapons Station, Daley Ranch in Escondido, Ramona Grasslands, Warner Springs Ranch, Whelan Lake, Crestridge Ecological Reserve, Santa Ysabel Ecological Reserve, Hollenbeck Canyon Wildlife Area, Marron Valley, and the Santa Rosa Plateau.
Because badgers are present within the western portion of the County, they are a suitable species for assessing upland connectivity by means of radio-telemetry. As a priority for research, we recommend follow-up focused surveys to identify target areas for future live-trapping and telemetry and to better define any areas with higher densities of badgers. We recommend development of a microsat
In 2014, we conducted a follow up study to the initial 2011 rapid assessment for the American badger. Our objectives were to identify target areas with potentially higher densities of badgers and to better assess the level of connectivity between known occupied areas. We conducted 30 canine scent surveys for badger scat (15 funded under Natural Community Conservation Plan (NCCP) Local Assistance Grant (LAG) Grant P1282109 and 15 funded by San Diego Association of Governments (SANDAG)) that included genetic testing of scat for species verification. We particularly focused on better characterizing badger activity at sites where fresh sign was found in 2011 and also surveyed suitable priority areas that had not been previously surveyed. From March 31 to May 9, 2014, we surveyed for badger scat and sign across 15 sites within San Diego County. We verified American badger at 8 of the sites (confirmed badger scat at 5 sites and badger burrows at 4 sites).
The purpose of this study was to examine the winter activities and burrow characteristics of
North American badgers (Taxidea taxus jeffersonii). At the northern range-limit of these
animals (British Columbia, Canada) winter is long and harsh and habitat patchy and atypical;
thus, badgers may respond to winter differently here than elsewhere. Using radio-telemetry
and remote-cameras, I documented winter activities of 16 badgers (12♀, 4♂) between 2007
and 2011. Similar to limited and anecdotal data collected elsewhere, badgers during winter
reduced home range 3.5 (SD = 0.6) km2 and movements 110.5 (SD = 12.2) m /day and
intensively used burrows 1.3 (SD = 0.8) burrows per winter.
The goals of this study were to (1) conduct a preliminary assessment of alternative DNA extraction protocols to provide efficient isolation of DNA from badger scat samples, and (2) to assess the utility of a microsatellite genetic assay using available published microsatellite loci for identifying individual badgers in San Diego County.
The native species of land mammals of California which currently do not have state or federal Threatened or Endangered Species status were investigated in order to identify those potentially threatened with extinction Investigations concentrated on determining historic and current distributions, habitat associations, population status, and the nature and proximity of threats of extinction. Information was developed primarily from the literature, museum records, and field notes, and from contacts with biologists with knowledge of current developments in the field.
The Southern California Mountains and Foothills Assessment: Habitat and Species
Conservation Issues provides detailed information about current conditions and
trends for ecological systems and species in the region. This information can be
used by land managers to develop broad land management goals and priorities
and provides the context for decisions specific to smaller geographic areas. The
assessment area covers 6.1 million acres, of which 56 percent are national forest
system lands. Over eighteen million people live in the coastal basin bordering the
assessment area.
