Linking summer foraging to winter survival in yellow pine chipmunks (Tamias amoenus)

Kuhn, Kellie M.; Wall, Stephen B. Vander

doi:10.1007/s00442-008-1072-4

Cited by 39 publications

(48 citation statements)

References 47 publications

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“…However, they could have had access to some chemical cues expressed by flowers appearing in late April-May (Berger et al 1981). Second, chipmunks store enormous amounts of seeds in their burrows (Humphries et al 2002, Kuhn andWall 2008), which serves to decouple resource availability in their larder hoard from resource availability on the forest floor. For example, chipmunks had enough food in their burrows in a non-mast year to survive underground from July to May and presumably could have used these reserves to support current reproduction instead of survival for future reproductive opportunities.…”

Section: Discussionmentioning

confidence: 99%

Anticipation and tracking of pulsed resources drive population dynamics in eastern chipmunks

Bergeron

Réale

Humphries

et al. 2011

Ecology

162

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Abstract. Pulsed systems are characterized by boom and bust cycles of resource production that are expected to cascade through multiple trophic levels. Many of the consumers within pulsed resource systems have specific adaptations to cope with these cycles that may serve to either amplify or dampen their community-wide consequences. We monitored a seed predator, the eastern chipmunk (Tamias striatus), in an American beech (Fagus grandifolia) dominated forest, and used capture-mark-recapture analyses to estimate chipmunk vital rates and relate them to interannual variation in beech seed production. The summer activity and reproduction of adults anticipated autumn beech production, with high activity and intense reproduction occurring in summers prior to beech masts. Chipmunks also reproduced every spring following a beech mast. However, adult survival was independent of beech production. In contrast, juvenile survival was lower in years of mast failure than in years of mast production, but their activity was consistently high and independent of beech production. Population growth was strongly affected by the number of juveniles and therefore by beech seed production, which explains nearly 70% of variation in population growth. Our results suggest that a combination of resource-dependent reproduction and variable activity levels associated with anticipation and response to resource pulses allows consumers to buffer potential deleterious effects of low food abundance on their survival.

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Section: Discussionmentioning

confidence: 99%

Anticipation and tracking of pulsed resources drive population dynamics in eastern chipmunks

Bergeron

Réale

Humphries

et al. 2011

Ecology

162

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“…obs.). Other studies have documented how summer foraging is strongly correlated with over-winter survival in fossorial squirrels (Kuhn and Vander Wall 2008). Likewise, marmots must obtain sufficient food to replace reserves, breed and then build up reserves again for the next winter.…”

Section: Activity Budget Of Marmots and Pastoralism Effectsmentioning

confidence: 99%

“…This is because increased energy intake during summer active months is strongly correlated with winter survival and reproduction (Kuhn and Vander Wall 2008). Recent studies of other marmot species have found a relationship between increased body mass gained over the active season and survival during hibernation, reproduction rates, and subsequent litter and population size (Ozgul et al 2010;Tafani et al 2012).…”

Section: Introductionmentioning

confidence: 96%

Pastoralist disturbance effects on Himalayan marmot foraging and vigilance activity

Poudel

Spooner

Matthews

2015

Ecological Research

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Pastoralism is pervasive and has a long history across the rangelands of Trans-Himalaya. Disturbance associated with pastoralism can influence the behaviour of wild animals; hence, it is important to better understand its effects on wild animal behaviour. We compared the activity budget of the Himalayan marmot (Marmota himalayana) between areas experiencing both high and low levels of pastoralism, in the Upper Mustang region in Nepal. Scan sampling was used to collect diurnal activity budget data on adult marmots, whereas 2 min focal observations were made on foraging marmots to assess vigilance during foraging. Contrary to our prediction, there was no significant difference between areas of high and low pastoralism in terms of foraging behaviour. However, the vigilance activity of marmots was significantly influenced by the extent of disturbances associated with pastoralism. Marmots scanned the surroundings more often while foraging and spent more time scanning in high pastoralism sites as compared to marmots in low pastoralism sites. Although we found no direct negative effects of pastoralism on foraging time, marmots shifted the time of day when they foraged. This study suggests that marmots adjust their vigilance behaviour according to the environmental conditions in which they occur. These findings have important implications for the conservation of marmots in the wake of increasing pastoral activities and consequent increases in human-wildlife conflict in Nepal.

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“…For example, density-dependent changes in time spent foraging may be caused by concurrent changes in the frequency of antagonistic interactions (interference competition Creswell 1997; Rutten et al 2010), per capita resource abundance (Kuhn and Vander Wall 2008), the degree of heterogeneity in the distribution of resources (Monaghan and Metcalfe 1985), or perhaps increased heterospecific attraction that leads to increased predation risk (Lima et al 1985;Hik 1995). These potentially confounding influences can be explored by experimentally manipulating the density of free-ranging animals using food supplementation (Boutin 1990) and/or predator exclusion (Karels and Boonstra 2000) or by adding (Svensson and Sinervo 2000;Calsbeek and Smith 2007;Rutten et al 2010) or removing (Sillett et al 2004;Meylan et al 2007) conspecifics to a study area.…”

Section: Introductionmentioning

confidence: 99%

Behavioral responses of territorial red squirrels to natural and experimental variation in population density

Dantzer

Boutin

Humphries

et al. 2012

Behav Ecol Sociobiol

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The relative scarcity of studies at the intersection of behavioral and population ecology is surprising given the presumed importance of behavior in density-dependent population regulation. Here we tested whether North American red squirrels (Tamiasciurus hudsonicus) adjust their behavior in response to local population density and whether they use rates of territorial vocalizations in their local neighborhood to assess density. We examined these relationships using 18 years of live trapping and 20 years of behavioral data that were collected across natural variation in local population density. To disentangle the effects of population density on behavior from those due to changes in per capita food abundance or changes in the frequency of antagonistic interactions with neighbors, we also experimentally manipulated population density with long-term food supplementation as well as perceived population density with longterm playbacks of territorial vocalizations. The frequency with which squirrels emitted territorial vocalizations was positively associated with local population density. In contrast, antagonistic physical interactions observed between squirrels and territorial intrusions were rare and the frequency of intrusions was weakly and negatively, not positively, associated with population density. Squirrels experiencing naturally and experimentally high density conditions spent less time in the nest and feeding but more time being vigilant. Similar density-dependent changes in behavior were observed in response to our manipulations of perceived population density, indicating that vocalization rates and not physical interactions or food abundance were the mechanism by which squirrels assessed and responded behaviorally to changes in local density.

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Linking summer foraging to winter survival in yellow pine chipmunks (Tamias amoenus)

Cited by 39 publications

References 47 publications

Anticipation and tracking of pulsed resources drive population dynamics in eastern chipmunks

Anticipation and tracking of pulsed resources drive population dynamics in eastern chipmunks

Pastoralist disturbance effects on Himalayan marmot foraging and vigilance activity

Behavioral responses of territorial red squirrels to natural and experimental variation in population density

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