The Experts below are selected from a list of 30 Experts worldwide ranked by ideXlab platform
Daniel T Blumstein - One of the best experts on this subject based on the ideXlab platform.
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ecology and social behavior of golden marmots Marmota caudata aurea
Journal of Mammalogy, 1998Co-Authors: Daniel T Blumstein, Walter ArnoldAbstract:We studied golden marmots (Marmota caudata aurea), a little-studied, hibernating Eurasian sciurid, for 6 years at Dhee Sar, Pakistan, to evaluate their social behavior in light of existing thoughts about social evolution of marmots. Golden marmots most commonly were found in apparently monogamous associations (37/89 social groups consisted of one adult male and one adult female) but lived in larger groups containing up to seven adults, where group members shared a common home range and burrow system. When multiple adults lived together, contrary to the typical sciurid pattern, they lived in male-biased social groups. When multiple adult females shared a home range, only a single female in a given group lactated and weaned young. Reproduction was infrequent; >80% of social groups failed to wean a litter in any given year. Golden marmots delayed leaving their natal home range until after they had reached adult body size (2::3 years old) and were presumably sexually mature. Groups with mUltiple adults were largely a consequence of delayed dis persal. Resident marmots commonly tolerated adult immigrants. Golden marmots hiber nated socially; the active season of all members of a group was identical. Overwinter mortality of juveniles (30%) was higher than that of yearlings or adults « 10%). Some evidence of benefits from social hibernation was found; juveniles hibernating with only parents and littermate siblings suffered lower overwinter mortality than juveniles hibernat ing with other individuals. While general predictions about sociality in marmots were up held, an economic model combining defense costs and resource distribution failed to ex plain the mechanism of social monogamy.
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effects of vegetative variation on weaning success overwinter survival and social group density in golden marmots Marmota caudata aurea
Journal of Zoology, 1997Co-Authors: Daniel T Blumstein, J M FogginAbstract:We studied the effects of food resources on weaning success, overwinter survival, and social group density in golden marmots (Marmota caudata aurea), an Old World sciurid rodent. End-of-season standing crop, a measure of seasonal productivity, varied between marmot groups but seemed repeatable between years. We adjusted some of our measurements of potential food availability by marmot preferences because faecal analysis suggested that marmots foraged selectively. Some, but not all, measured fitness parameters were associated with variation in food availability. The probability of weaning young was associated with overall food availability the previous year, and there was a significant positive relationship between the early-season food resources and the proportion of years in which a group reproduced. Weaning date, a correlate of subsequent juvenile overwinter survival, was associated with overall food availability in the same year. Non-juvenile overwinter survival was weakly associated with food availability. Finally, marmot density was not associated with the availability of food resources. We suggest that obligate social behaviour may limit the degree to which demographic factors can track environmental variation.
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infanticide among golden marmots Marmota caudata aurea
Ethology Ecology & Evolution, 1997Co-Authors: Daniel T BlumsteinAbstract:Fifty-percent (36/72) of golden marmot (Marmota caudata aurea) pups that emerged above ground their first summer in Dhee Sar, Khunjerab National Park, Pakistan, died before their first hibernation. At least 22% (8/36) of this mortality was attributed to infanticide by new adult male group members. Carcasses were not cannibalized, thus infanticide probably was not a form of resource exploitation. Adult females who lost their entire litters to presumed infanticide were not more likely to breed in subsequent years; an observation inconsistent with infanticide being a form of sexual selection. Results are consistent with the hypothesis that males may kill unrelated pups to avoid providing care to unrelated young even though killed pups include potential future mates.
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cheek rubbing in golden marmots Marmota caudata aurea
Journal of Zoology, 1996Co-Authors: Daniel T Blumstein, S J HendersonAbstract:We studied the function of cheek-rubbing in golden marmots (Marmota caudata aurea) by combining observations of the external morphology of the orbital gland, observational studies of marmots cheek-rubbing, and experimental studies of marmots’responses to olfactory secretions from the orbital gland. Adult males had larger eyepatches–areas without hair above the orbital gland–than adult females. Both sexes produced sufficient glandular exudate to pool on the surface of the skin or fur above the orbital gland. Adult males cheek-rubbed more than adult females throughout the summer active season, but both males and females generally cheek-rubbed within 10m of a main burrow. Adult males responded more vigorously to the smells of non-group members of both sexes than to group members of either sex. Adult females responded more vigorously to the smell of non-group females than to non-group males or group members of either sex. Our results are consistent with the hypothesis that marmot cheek-rubbing functions to mark defended areas, possibly to minimize costs of aggressive interactions.
Klaus Hacklander - One of the best experts on this subject based on the ideXlab platform.
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responses of snow leopards wolves and wild ungulates to livestock grazing in the zorkul strictly protected area tajikistan
PLOS ONE, 2018Co-Authors: Khalil Karimov, Shannon Kachel, Klaus HacklanderAbstract:Long recognized as a threat to wildlife, livestock grazing in protected areas has the potential to undermine conservation goals, via competition, habitat degradation, human-carnivore conflict and disruption of predator-prey relationships. In the Strictly Protected Area Zorkul in Tajikistan (Zorkul Reserve), grazing is commonplace despite official prohibition, with potentially detrimental effects on local fauna, in particular, snow leopard Panthera uncia, wolf Canis lupus, brown bear Ursus arctos, argali sheep Ovis ammon, Asiatic ibex Capra sibirica, and long-tailed marmot Marmota caudata. To understand the impacts of grazing and associated human pastoralism on the large mammal community in Zorkul Reserve we used data from camera traps to build models of ungulate and carnivore site use intensity, and we investigated carnivore summer diets using microscopic scat analysis. While sample sizes limited our inference for several species, we found that site use of the most common ungulate, argali, decreased with proximity to herder’s camps, indicating possible displacement into sub-optimal habitats. However, no such pattern was present in carnivore site use. For wolf and snow leopard, the most frequently encountered prey items were argali and marmot, while bear depended almost exclusively on marmot. While current pastoralist practices in the reserve may not be incompatible with wildlife presence, our findings suggest that pastoralism may negatively impact ungulates by displacing them from otherwise suitable habitats, with unknown fitness consequences for ungulates or the predators that depend upon them. Managing Zorkul Reserve and other actively grazed protected areas to meet potentially competing demands of local pastoralist communities and conservation will require careful consideration of such interactions to minimize the risk of cascading negative impacts on wildlife.
Shannon Kachel - One of the best experts on this subject based on the ideXlab platform.
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responses of snow leopards wolves and wild ungulates to livestock grazing in the zorkul strictly protected area tajikistan
PLOS ONE, 2018Co-Authors: Khalil Karimov, Shannon Kachel, Klaus HacklanderAbstract:Long recognized as a threat to wildlife, livestock grazing in protected areas has the potential to undermine conservation goals, via competition, habitat degradation, human-carnivore conflict and disruption of predator-prey relationships. In the Strictly Protected Area Zorkul in Tajikistan (Zorkul Reserve), grazing is commonplace despite official prohibition, with potentially detrimental effects on local fauna, in particular, snow leopard Panthera uncia, wolf Canis lupus, brown bear Ursus arctos, argali sheep Ovis ammon, Asiatic ibex Capra sibirica, and long-tailed marmot Marmota caudata. To understand the impacts of grazing and associated human pastoralism on the large mammal community in Zorkul Reserve we used data from camera traps to build models of ungulate and carnivore site use intensity, and we investigated carnivore summer diets using microscopic scat analysis. While sample sizes limited our inference for several species, we found that site use of the most common ungulate, argali, decreased with proximity to herder’s camps, indicating possible displacement into sub-optimal habitats. However, no such pattern was present in carnivore site use. For wolf and snow leopard, the most frequently encountered prey items were argali and marmot, while bear depended almost exclusively on marmot. While current pastoralist practices in the reserve may not be incompatible with wildlife presence, our findings suggest that pastoralism may negatively impact ungulates by displacing them from otherwise suitable habitats, with unknown fitness consequences for ungulates or the predators that depend upon them. Managing Zorkul Reserve and other actively grazed protected areas to meet potentially competing demands of local pastoralist communities and conservation will require careful consideration of such interactions to minimize the risk of cascading negative impacts on wildlife.
J M Foggin - One of the best experts on this subject based on the ideXlab platform.
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effects of vegetative variation on weaning success overwinter survival and social group density in golden marmots Marmota caudata aurea
Journal of Zoology, 1997Co-Authors: Daniel T Blumstein, J M FogginAbstract:We studied the effects of food resources on weaning success, overwinter survival, and social group density in golden marmots (Marmota caudata aurea), an Old World sciurid rodent. End-of-season standing crop, a measure of seasonal productivity, varied between marmot groups but seemed repeatable between years. We adjusted some of our measurements of potential food availability by marmot preferences because faecal analysis suggested that marmots foraged selectively. Some, but not all, measured fitness parameters were associated with variation in food availability. The probability of weaning young was associated with overall food availability the previous year, and there was a significant positive relationship between the early-season food resources and the proportion of years in which a group reproduced. Weaning date, a correlate of subsequent juvenile overwinter survival, was associated with overall food availability in the same year. Non-juvenile overwinter survival was weakly associated with food availability. Finally, marmot density was not associated with the availability of food resources. We suggest that obligate social behaviour may limit the degree to which demographic factors can track environmental variation.
S J Henderson - One of the best experts on this subject based on the ideXlab platform.
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cheek rubbing in golden marmots Marmota caudata aurea
Journal of Zoology, 1996Co-Authors: Daniel T Blumstein, S J HendersonAbstract:We studied the function of cheek-rubbing in golden marmots (Marmota caudata aurea) by combining observations of the external morphology of the orbital gland, observational studies of marmots cheek-rubbing, and experimental studies of marmots’responses to olfactory secretions from the orbital gland. Adult males had larger eyepatches–areas without hair above the orbital gland–than adult females. Both sexes produced sufficient glandular exudate to pool on the surface of the skin or fur above the orbital gland. Adult males cheek-rubbed more than adult females throughout the summer active season, but both males and females generally cheek-rubbed within 10m of a main burrow. Adult males responded more vigorously to the smells of non-group members of both sexes than to group members of either sex. Adult females responded more vigorously to the smell of non-group females than to non-group males or group members of either sex. Our results are consistent with the hypothesis that marmot cheek-rubbing functions to mark defended areas, possibly to minimize costs of aggressive interactions.