Vernon Bleich - Academia.edu (original) (raw)
Papers by Vernon Bleich
Wildlife Society Bulletin, Oct 1, 2006
... Morgart, JR, JJ Hervert, PR Krausman, JL Bright, and RS Henry. 2005. ... PAUL R. KRAUSMAN a ,... more ... Morgart, JR, JJ Hervert, PR Krausman, JL Bright, and RS Henry. 2005. ... PAUL R. KRAUSMAN a , STEVEN S. ROSENSTOCK b , JAMES W. CAIN III c . (2006) Developed Waters for Wildlife: Science, Perception, Values, and Controversy. ...
California fish and wildlife journal, 2019
California fish and wildlife journal, Aug 9, 2021
Journal of Mammalogy, May 30, 1975
Mammalia, Dec 28, 2021
Wild sheep (Ovis spp.) are of conservation concern throughout the Middle East. Little is known, h... more Wild sheep (Ovis spp.) are of conservation concern throughout the Middle East. Little is known, however, about the natural history or ecology of this taxon. To better understand size relationships among wild sheep occupying Iran, we analyzed results from 120 females collected from widely separated ecosystems. Morphometrics and body weights for all age categories of females occupying the Khosh-Yeilagh Wildlife Refuge in northeastern Iran were larger than those for the same age classes of females occupying Bamou National Park in southwestern Iran. Females from Bamou National Park, however, obtained adult body weight (x‾ = 25.8 ± 2.47 [SD] kg) at an earlier age than those from the Khosh-Yeilagh Wildlife Refuge (x‾ = 36.6 ± 3.21 kg). Ecological differences between these two areas suggest that net primary productivity, which is a function of numerous climatic and geographical factors, has been a primary force contributing to these results. Weights and measurements reported here provide the basic information for additional, more detailed research necessary to fully understand the evolutionary significance and management implications of these differences in body size and emphasize the conservation value of even the most basic natural history information.
Bulletin, Southern California Academy of Sciences, Apr 1, 2017
The Great Basin naturalist, 1988
Additional records of the spotted bat {Euderma inaculatum) from Inyo County and Shasta County, Ca... more Additional records of the spotted bat {Euderma inaculatum) from Inyo County and Shasta County, California, are reported. The latter record represents the northernmost locale for this species in California. A live adult male spotted bat {Euderma maculatum) with a fractured humerus was found on the ground at Lone Pine, Inyo County, California, on 10 August 1986. It later died in captivity. The specimen (CSULB 11834) was prepared as a skin with skull, fluidpreserved carcass, and stained glans penis and is deposited in the Mammal Collection at California State University, Long Beach. Standard measurements are: total length. 111 mm; tail length, 51 mm; hind foot, 11 mm; ear, 41 mm; forearm, 49 mm. The spotted bat had previously been reported from the Owens Valley, 60 miles north of Lone Pine at Bishop, Inyo County (Constantine et al. 1979). Vegetation in the Owens Valley is typical of the Great Basin, consisting primarily of sagebrush (Artemisia tridentata), saltbush {Atriplex spp.), greasewood (Sarcobatus vermiculatus), and rabbitbrush (Chrysothamnus nauseosus). The Owens Valley is in the rainshadow of the Sierra Nevada and is extremely arid. Another spotted bat was found alive in a garage at a residence in Palo Cedro, Shasta County, California, on 14 March 1983 and was taken to the Redding Office of the California Department of Fish and Game where the identification was confirmed by T. P. Stone. Final disposition of that specimen is unknown. This record extends the reported distribution of this species about 245 km NVf rom Reno, Washoe County, Nevada (Hall 1935), and 400 km SW from the Alvord Basin, Harney County, Oregon (McMahon et al. 1981). Vegetation at Palo Cedro consists largely of oak savannah (Quercus spp.); the area is more mesic than the Owens Valley. We thank E. and M. Muniz for calling our attention to the Lone Pine specimen and D. G. Huckaby for preparing it for deposition in the CSULB Mammal Collection.
California fish and wildlife journal, 2019
Bighorn sheep (Ovis canadensis) were extirpated from the San Rafael Mountains, Ventura County, Ca... more Bighorn sheep (Ovis canadensis) were extirpated from the San Rafael Mountains, Ventura County, California, about 1915, and remained so for 70 years. They were reintroduced to that range, which is near the western extreme of their historical distribution, in 1985 and 1987. We used aerial telemetry to investigate habitat selection by 18 bighorn sheep from 1985 to 1989. Resource selection showed some support for both sex and seasonal differences, but only seasonal variations appeared in the top model. Relative to availability, bighorn sheep selected locations clos
Wildlife Society bulletin, Jun 12, 2023
Tule elk (Cervus elaphus nannodes), the only North American elk endemic to California, once occur... more Tule elk (Cervus elaphus nannodes), the only North American elk endemic to California, once occurred throughout much of that state. Historically, the population numbered approximately 500 000, but that was reduced to critically low levels in the late nineteenth century as a result of habitat loss and commercial hunting. As recently as 1975, only 500 tule elk existed; recent efforts to reestablish this subspecies on historical ranges have resulted in a current population of at least 2700. Much of the previously suitable tule elk habitat has been altered by commercial development, or for agricultural uses. However, substantial tracts of suitable habitat remain in private ownership. In several instances, landowners have accepted translocated true elk in cooperative ventures with the California Department of Fish and Game.
Alces : A Journal Devoted to the Biology and Management of Moose, Aug 6, 2020
Biologists often must use incomplete information to make recommendations concerning harvest of la... more Biologists often must use incomplete information to make recommendations concerning harvest of large mammals. Consequently, those recommendations must draw on a firm understanding of the ecology of the species in question, along with selection of the most applicable population characteristics on which to base harvest—both essential components for prudent management. Density-dependent processes, which are ubiquitous among populations of large mammals, may be counterintuitive because of unexpected patterns in recruitment coincident with changes in population size. Misconceptions concerning population dynamics of ungulates also can occur when demographics are based solely on correlations with environmental factors. Further, the concept of a harvestable surplus can be misleading for managing ungulate populations, because of the parabolic relationship between population size and number of recruits—harvest determines the surplus rather than vice versa . Understanding consequences of mortality, especially relative components of compensatory or additive mortality, also is necessary. Knowledge of the proximity of an ungulate population to ecological carrying capacity ( K ) is required to fully assess whether most mortality is compensatory or additive. We describe selected life-history traits and population characteristics of ungulates useful in parametrizing where populations are in relation to K , thereby allowing for a reasonable harvest despite some uncertainty in population size. We advocate an adaptive-management approach while monitoring those life-history traits to evaluate the suitability of a particular harvest strategy.
Movement ecology, Apr 5, 2023
Animals select habitats based on food, water, space, and cover. Each of those components are esse... more Animals select habitats based on food, water, space, and cover. Each of those components are essential to the ability of an individual to survive and reproduce in a particular habitat. Selection of resources is linked to reproductive fitness and individuals likely vary in how they select resources relative to their reproductive state: during pregnancy, while provisioning young when nutritional needs of the mother are high, but offspring are vulnerable to predation, or if they lose young to mortality. We investigated the effects of reproductive state on selection of resources by maternal female desert bighorn sheep (Ovis canadensis nelsoni) by comparing selection during the last trimester of gestation, following parturition when females were provisioning dependent young, and if the female lost an offspring. We captured, and recaptured each year, 32 female bighorn sheep at Lone Mountain, Nevada, during 2016-2018. Captured females were fit with GPS collars and those that were pregnant received vaginal implant transmitters. We used a Bayesian approach to estimate differences in selection between females provisioning and not provisioning offspring, as well as the length of time it took for females with offspring to return levels of selection similar to that observed prior to parturition. Females that were not provisioning offspring selected areas with higher risk of predation, but greater nutritional resources than those that were provisioning dependent young. When females were provisioning young immediately following parturition, females selected areas that were safe from predators, but had lower nutritional resources. Females displayed varying rates of return to selection strategies associated with access to nutritional resources as young grew and became more agile and less dependent on mothers. We observed clear and substantial shifts in selection of resources associated with reproductive state, and females exhibited tradeoffs in favor of areas that were safer from predators when provisioning dependent young despite loss of nutritional resources to support lactation. As young grew and became less vulnerable to predators, females returned to levels of selection that provided access to nutritional resources to restore somatic reserves lost during lactation.
Wildlife Society Bulletin, Oct 1, 2006
ABSTRACT Thousands of wildlife water developments, commonly known as gallinaceous guzzlers or guz... more ABSTRACT Thousands of wildlife water developments, commonly known as gallinaceous guzzlers or guzzlers, have been installed throughout the western United States. In general, these units collect runoff from a concrete or other impervious surface and store that water in underground tanks. Water availability is limited to wildlife able to enter a small opening (approx. 20 cm in height) and crawl or walk down a sloped surface to the level of stored water. This design precludes use by large mammals. Moreover, wildlife occasionally may become entrapped in storage tanks, potentially fouling stored water. We developed a method of modifying gallinaceous guzzlers that allows large animals to access stored water and simultaneously decreases the probability of wildlife becoming entrapped in those guzzlers.
Journal of Wildlife Diseases, Jul 1, 1990
The skull of a mountain sheep (Ovis canadensis cremnobates) exhibiting osteoporosis was recovered... more The skull of a mountain sheep (Ovis canadensis cremnobates) exhibiting osteoporosis was recovered from San Diego County, California. This specimen also exhibited lateral asymmetry of the cranium and rostrum, malocclusion of molars, and mandibular asymmetry. Investigators are cautioned about potentially confusing lesions associated with chronic frontal sinusitis with lesions of osteoporosis in mountain sheep. To our knowledge this is the first report of osteoporosis in this species.
Fire Ecology, Dec 1, 2012
An isolated population of bighorn sheep (Ovis canadensis nelsoni) occupies fire-adapted chaparral... more An isolated population of bighorn sheep (Ovis canadensis nelsoni) occupies fire-adapted chaparral ranges in the San Gabriel Mountains, California, USA. During 1976 to 2006, the amount of high-suitability habitat on bighorn sheep winter-spring ranges resulting from fires (HSF) ranged from 670 ha to 3392 ha, and population estimates for sheep, which were correlated with HSF, ranged from 130 to 740 individuals. During the past 100 years, the majority of changes in the HSF were associated with a fire regime dominated by periodic large, wind-driven, high-intensity crown fires, which resulted in high variability in the HSF. Prior to European settlement, the fire regime likely included smaller, variable intensity fires that burned during summer, but that also would have influenced the HSF. The size of those smaller fires today is effectively constrained by current fire management strategies, including exclusion and suppression. We predicted that smaller summer fires would increase the amount of high-suitability habitat and reduce the variability observed in the HSF during contemporary times, and the outcomes of our comparisons were consistent with those predictions. Small fires can be implemented by prescription, and can help to stabilize and maintain a self-sustaining population of bighorn sheep in the San Gabriel Mountains.
Journal of Mammalogy, Aug 29, 1975
... ORLANDO A. SCHWARTZ AND VERNON C. BLEICH ... Temperature records for the same period from Bor... more ... ORLANDO A. SCHWARTZ AND VERNON C. BLEICH ... Temperature records for the same period from Borrego Valley (43.5 km north, 23.3 km west of the study area) show a mean high temperature in July of 43.1? C, and a mean low temperature in January of 1.6? ...
Journal of Range Management, 1983
Suggestions for improving the efficiency, dependability, and simplicity of the sand dams des&%ed ... more Suggestions for improving the efficiency, dependability, and simplicity of the sand dams des&%ed by Sivils and Brock (1981) are presented. Recommendations which may result in decreased installation and maintenance costs are included.
We used retrospective analyses to investigate cause-specific mortality and survivorship among 5 p... more We used retrospective analyses to investigate cause-specific mortality and survivorship among 5 populations of mule deer (N = 168 telemetered animals) wintering in the western Great Basin during 1986-1994. These populations existed under similar environmental conditions, but survivorship functions differed among them. Monthly survival ranged from 0.964 to 0.990, and annual survival ranged from 0.643 to 0.884. The proportion of deaths attributed to predation and malnutrition or anthropogenic causes did not differ among the 5 populations. Predation was the leading cause of mortality; mountain lions were responsible for approximately 90% of the deer killed by predators. No difference existed among these populations in the proportion of te1emetered deer that were killed by mountain lions, but proport ionally more females than males were killed by these large felids. Predation by mountain lions is the primary source of mortality and a widespread phenomenon among the populations of mule deer we investigated.
Journal of Mammalogy, May 19, 1995
ABSTRACT We studied aggression in the laboratory between two heteromyid rodents, Dipodomys agilis... more ABSTRACT We studied aggression in the laboratory between two heteromyid rodents, Dipodomys agilis and Dipodomys stephensi, to determine if dominance behavior could produce nonoverlapping habitat associations. D. stephensi, which is heavier than its opponent, initiated more attacks and retreated less frequently than did D. agilis. The average level of aggression shown by individual D. stephensi increased with body mass. The level of aggression shown by individual D. stephensi in a trial did not vary with the size or sex of the opponent, and individuals did not respond differently to these attributes of the opponent. Because D. stephensi is behaviorally dominant, we concluded that interspecific dominance could contribute to the observed association of D. agilis with coastal-sage-scrub habitat, but could not, by itself, restrict D. stephensi to annual grassland habitat.
Wildlife Society Bulletin, Jun 1, 2004
... Population dynamics of bighorn sheep in the San Gabriel Mountains, California, 19672002. Ste... more ... Population dynamics of bighorn sheep in the San Gabriel Mountains, California, 19672002. Stephen A. Holl, Vernon C. Bleich, Steven G. Torres. Abstract. ... Climate is Mediterranean, characterized by hot, dry summers and cool, moist winters. ...
Wildlife Society Bulletin, Oct 1, 2006
... Morgart, JR, JJ Hervert, PR Krausman, JL Bright, and RS Henry. 2005. ... PAUL R. KRAUSMAN a ,... more ... Morgart, JR, JJ Hervert, PR Krausman, JL Bright, and RS Henry. 2005. ... PAUL R. KRAUSMAN a , STEVEN S. ROSENSTOCK b , JAMES W. CAIN III c . (2006) Developed Waters for Wildlife: Science, Perception, Values, and Controversy. ...
California fish and wildlife journal, 2019
California fish and wildlife journal, Aug 9, 2021
Journal of Mammalogy, May 30, 1975
Mammalia, Dec 28, 2021
Wild sheep (Ovis spp.) are of conservation concern throughout the Middle East. Little is known, h... more Wild sheep (Ovis spp.) are of conservation concern throughout the Middle East. Little is known, however, about the natural history or ecology of this taxon. To better understand size relationships among wild sheep occupying Iran, we analyzed results from 120 females collected from widely separated ecosystems. Morphometrics and body weights for all age categories of females occupying the Khosh-Yeilagh Wildlife Refuge in northeastern Iran were larger than those for the same age classes of females occupying Bamou National Park in southwestern Iran. Females from Bamou National Park, however, obtained adult body weight (x‾ = 25.8 ± 2.47 [SD] kg) at an earlier age than those from the Khosh-Yeilagh Wildlife Refuge (x‾ = 36.6 ± 3.21 kg). Ecological differences between these two areas suggest that net primary productivity, which is a function of numerous climatic and geographical factors, has been a primary force contributing to these results. Weights and measurements reported here provide the basic information for additional, more detailed research necessary to fully understand the evolutionary significance and management implications of these differences in body size and emphasize the conservation value of even the most basic natural history information.
Bulletin, Southern California Academy of Sciences, Apr 1, 2017
The Great Basin naturalist, 1988
Additional records of the spotted bat {Euderma inaculatum) from Inyo County and Shasta County, Ca... more Additional records of the spotted bat {Euderma inaculatum) from Inyo County and Shasta County, California, are reported. The latter record represents the northernmost locale for this species in California. A live adult male spotted bat {Euderma maculatum) with a fractured humerus was found on the ground at Lone Pine, Inyo County, California, on 10 August 1986. It later died in captivity. The specimen (CSULB 11834) was prepared as a skin with skull, fluidpreserved carcass, and stained glans penis and is deposited in the Mammal Collection at California State University, Long Beach. Standard measurements are: total length. 111 mm; tail length, 51 mm; hind foot, 11 mm; ear, 41 mm; forearm, 49 mm. The spotted bat had previously been reported from the Owens Valley, 60 miles north of Lone Pine at Bishop, Inyo County (Constantine et al. 1979). Vegetation in the Owens Valley is typical of the Great Basin, consisting primarily of sagebrush (Artemisia tridentata), saltbush {Atriplex spp.), greasewood (Sarcobatus vermiculatus), and rabbitbrush (Chrysothamnus nauseosus). The Owens Valley is in the rainshadow of the Sierra Nevada and is extremely arid. Another spotted bat was found alive in a garage at a residence in Palo Cedro, Shasta County, California, on 14 March 1983 and was taken to the Redding Office of the California Department of Fish and Game where the identification was confirmed by T. P. Stone. Final disposition of that specimen is unknown. This record extends the reported distribution of this species about 245 km NVf rom Reno, Washoe County, Nevada (Hall 1935), and 400 km SW from the Alvord Basin, Harney County, Oregon (McMahon et al. 1981). Vegetation at Palo Cedro consists largely of oak savannah (Quercus spp.); the area is more mesic than the Owens Valley. We thank E. and M. Muniz for calling our attention to the Lone Pine specimen and D. G. Huckaby for preparing it for deposition in the CSULB Mammal Collection.
California fish and wildlife journal, 2019
Bighorn sheep (Ovis canadensis) were extirpated from the San Rafael Mountains, Ventura County, Ca... more Bighorn sheep (Ovis canadensis) were extirpated from the San Rafael Mountains, Ventura County, California, about 1915, and remained so for 70 years. They were reintroduced to that range, which is near the western extreme of their historical distribution, in 1985 and 1987. We used aerial telemetry to investigate habitat selection by 18 bighorn sheep from 1985 to 1989. Resource selection showed some support for both sex and seasonal differences, but only seasonal variations appeared in the top model. Relative to availability, bighorn sheep selected locations clos
Wildlife Society bulletin, Jun 12, 2023
Tule elk (Cervus elaphus nannodes), the only North American elk endemic to California, once occur... more Tule elk (Cervus elaphus nannodes), the only North American elk endemic to California, once occurred throughout much of that state. Historically, the population numbered approximately 500 000, but that was reduced to critically low levels in the late nineteenth century as a result of habitat loss and commercial hunting. As recently as 1975, only 500 tule elk existed; recent efforts to reestablish this subspecies on historical ranges have resulted in a current population of at least 2700. Much of the previously suitable tule elk habitat has been altered by commercial development, or for agricultural uses. However, substantial tracts of suitable habitat remain in private ownership. In several instances, landowners have accepted translocated true elk in cooperative ventures with the California Department of Fish and Game.
Alces : A Journal Devoted to the Biology and Management of Moose, Aug 6, 2020
Biologists often must use incomplete information to make recommendations concerning harvest of la... more Biologists often must use incomplete information to make recommendations concerning harvest of large mammals. Consequently, those recommendations must draw on a firm understanding of the ecology of the species in question, along with selection of the most applicable population characteristics on which to base harvest—both essential components for prudent management. Density-dependent processes, which are ubiquitous among populations of large mammals, may be counterintuitive because of unexpected patterns in recruitment coincident with changes in population size. Misconceptions concerning population dynamics of ungulates also can occur when demographics are based solely on correlations with environmental factors. Further, the concept of a harvestable surplus can be misleading for managing ungulate populations, because of the parabolic relationship between population size and number of recruits—harvest determines the surplus rather than vice versa . Understanding consequences of mortality, especially relative components of compensatory or additive mortality, also is necessary. Knowledge of the proximity of an ungulate population to ecological carrying capacity ( K ) is required to fully assess whether most mortality is compensatory or additive. We describe selected life-history traits and population characteristics of ungulates useful in parametrizing where populations are in relation to K , thereby allowing for a reasonable harvest despite some uncertainty in population size. We advocate an adaptive-management approach while monitoring those life-history traits to evaluate the suitability of a particular harvest strategy.
Movement ecology, Apr 5, 2023
Animals select habitats based on food, water, space, and cover. Each of those components are esse... more Animals select habitats based on food, water, space, and cover. Each of those components are essential to the ability of an individual to survive and reproduce in a particular habitat. Selection of resources is linked to reproductive fitness and individuals likely vary in how they select resources relative to their reproductive state: during pregnancy, while provisioning young when nutritional needs of the mother are high, but offspring are vulnerable to predation, or if they lose young to mortality. We investigated the effects of reproductive state on selection of resources by maternal female desert bighorn sheep (Ovis canadensis nelsoni) by comparing selection during the last trimester of gestation, following parturition when females were provisioning dependent young, and if the female lost an offspring. We captured, and recaptured each year, 32 female bighorn sheep at Lone Mountain, Nevada, during 2016-2018. Captured females were fit with GPS collars and those that were pregnant received vaginal implant transmitters. We used a Bayesian approach to estimate differences in selection between females provisioning and not provisioning offspring, as well as the length of time it took for females with offspring to return levels of selection similar to that observed prior to parturition. Females that were not provisioning offspring selected areas with higher risk of predation, but greater nutritional resources than those that were provisioning dependent young. When females were provisioning young immediately following parturition, females selected areas that were safe from predators, but had lower nutritional resources. Females displayed varying rates of return to selection strategies associated with access to nutritional resources as young grew and became more agile and less dependent on mothers. We observed clear and substantial shifts in selection of resources associated with reproductive state, and females exhibited tradeoffs in favor of areas that were safer from predators when provisioning dependent young despite loss of nutritional resources to support lactation. As young grew and became less vulnerable to predators, females returned to levels of selection that provided access to nutritional resources to restore somatic reserves lost during lactation.
Wildlife Society Bulletin, Oct 1, 2006
ABSTRACT Thousands of wildlife water developments, commonly known as gallinaceous guzzlers or guz... more ABSTRACT Thousands of wildlife water developments, commonly known as gallinaceous guzzlers or guzzlers, have been installed throughout the western United States. In general, these units collect runoff from a concrete or other impervious surface and store that water in underground tanks. Water availability is limited to wildlife able to enter a small opening (approx. 20 cm in height) and crawl or walk down a sloped surface to the level of stored water. This design precludes use by large mammals. Moreover, wildlife occasionally may become entrapped in storage tanks, potentially fouling stored water. We developed a method of modifying gallinaceous guzzlers that allows large animals to access stored water and simultaneously decreases the probability of wildlife becoming entrapped in those guzzlers.
Journal of Wildlife Diseases, Jul 1, 1990
The skull of a mountain sheep (Ovis canadensis cremnobates) exhibiting osteoporosis was recovered... more The skull of a mountain sheep (Ovis canadensis cremnobates) exhibiting osteoporosis was recovered from San Diego County, California. This specimen also exhibited lateral asymmetry of the cranium and rostrum, malocclusion of molars, and mandibular asymmetry. Investigators are cautioned about potentially confusing lesions associated with chronic frontal sinusitis with lesions of osteoporosis in mountain sheep. To our knowledge this is the first report of osteoporosis in this species.
Fire Ecology, Dec 1, 2012
An isolated population of bighorn sheep (Ovis canadensis nelsoni) occupies fire-adapted chaparral... more An isolated population of bighorn sheep (Ovis canadensis nelsoni) occupies fire-adapted chaparral ranges in the San Gabriel Mountains, California, USA. During 1976 to 2006, the amount of high-suitability habitat on bighorn sheep winter-spring ranges resulting from fires (HSF) ranged from 670 ha to 3392 ha, and population estimates for sheep, which were correlated with HSF, ranged from 130 to 740 individuals. During the past 100 years, the majority of changes in the HSF were associated with a fire regime dominated by periodic large, wind-driven, high-intensity crown fires, which resulted in high variability in the HSF. Prior to European settlement, the fire regime likely included smaller, variable intensity fires that burned during summer, but that also would have influenced the HSF. The size of those smaller fires today is effectively constrained by current fire management strategies, including exclusion and suppression. We predicted that smaller summer fires would increase the amount of high-suitability habitat and reduce the variability observed in the HSF during contemporary times, and the outcomes of our comparisons were consistent with those predictions. Small fires can be implemented by prescription, and can help to stabilize and maintain a self-sustaining population of bighorn sheep in the San Gabriel Mountains.
Journal of Mammalogy, Aug 29, 1975
... ORLANDO A. SCHWARTZ AND VERNON C. BLEICH ... Temperature records for the same period from Bor... more ... ORLANDO A. SCHWARTZ AND VERNON C. BLEICH ... Temperature records for the same period from Borrego Valley (43.5 km north, 23.3 km west of the study area) show a mean high temperature in July of 43.1? C, and a mean low temperature in January of 1.6? ...
Journal of Range Management, 1983
Suggestions for improving the efficiency, dependability, and simplicity of the sand dams des&%ed ... more Suggestions for improving the efficiency, dependability, and simplicity of the sand dams des&%ed by Sivils and Brock (1981) are presented. Recommendations which may result in decreased installation and maintenance costs are included.
We used retrospective analyses to investigate cause-specific mortality and survivorship among 5 p... more We used retrospective analyses to investigate cause-specific mortality and survivorship among 5 populations of mule deer (N = 168 telemetered animals) wintering in the western Great Basin during 1986-1994. These populations existed under similar environmental conditions, but survivorship functions differed among them. Monthly survival ranged from 0.964 to 0.990, and annual survival ranged from 0.643 to 0.884. The proportion of deaths attributed to predation and malnutrition or anthropogenic causes did not differ among the 5 populations. Predation was the leading cause of mortality; mountain lions were responsible for approximately 90% of the deer killed by predators. No difference existed among these populations in the proportion of te1emetered deer that were killed by mountain lions, but proport ionally more females than males were killed by these large felids. Predation by mountain lions is the primary source of mortality and a widespread phenomenon among the populations of mule deer we investigated.
Journal of Mammalogy, May 19, 1995
ABSTRACT We studied aggression in the laboratory between two heteromyid rodents, Dipodomys agilis... more ABSTRACT We studied aggression in the laboratory between two heteromyid rodents, Dipodomys agilis and Dipodomys stephensi, to determine if dominance behavior could produce nonoverlapping habitat associations. D. stephensi, which is heavier than its opponent, initiated more attacks and retreated less frequently than did D. agilis. The average level of aggression shown by individual D. stephensi increased with body mass. The level of aggression shown by individual D. stephensi in a trial did not vary with the size or sex of the opponent, and individuals did not respond differently to these attributes of the opponent. Because D. stephensi is behaviorally dominant, we concluded that interspecific dominance could contribute to the observed association of D. agilis with coastal-sage-scrub habitat, but could not, by itself, restrict D. stephensi to annual grassland habitat.
Wildlife Society Bulletin, Jun 1, 2004
... Population dynamics of bighorn sheep in the San Gabriel Mountains, California, 19672002. Ste... more ... Population dynamics of bighorn sheep in the San Gabriel Mountains, California, 19672002. Stephen A. Holl, Vernon C. Bleich, Steven G. Torres. Abstract. ... Climate is Mediterranean, characterized by hot, dry summers and cool, moist winters. ...