Spatial and elevational variation in fruiting phenology of a deciduous oak (<i>Quercus crispula</i>) and its effect on foraging behavior of the Asiatic black bear (<i>Ursus thibetanus</i>)

Nakajima, Ami; Koike, Shinsuke; Masaki, Takashi; Shimada, Takuya; Kozakai, Chinatsu; Nemoto, Yasuyuki; Yamazaki, Koji; Kaji, Koichi

doi:10.1007/s11284-011-0919-z

Cited by 21 publications

(17 citation statements)

References 34 publications

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“…Because signs of bears foraging for Q. crispula acorns in treetops have been observed in October (Nakajima et al. , ), the ingestion rate for consumption in treetops was used for September and October, while the ingestion rate for consumption on the ground was used for November.…”

Section: Methodsmentioning

confidence: 99%

“…We expected that the ingestion rate of Q. crispula acorns would differ substantially when bears feed in treetops versus when they feed on the ground because bears make the effort to climb trees to consume acorns and there is a great abundance of acorns in the crowns of the trees; therefore, we calculated the ingestion rate separately for these situations. Because signs of bears foraging for Q. crispula acorns in treetops have been observed in October (Nakajima et al 2012, the ingestion rate for consumption in treetops was used for September and October, while the ingestion rate for consumption on the ground was used for November. ❖ www.esajournals.org…”

Section: Calculating Intake Per Food Item Per Unit Of Timementioning

confidence: 99%

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Estimating the seasonal energy balance in Asian black bears and associated factors

et al. 2019

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Energy balance (i.e., energy intake minus energy expenditure) is an essential factor when evaluating an animal's nutritional state. We aimed to identify periods of the year that are most important for Asian black bears (Ursus thibetanus) in terms of energy balance. We estimated bears’ daily energy balance by estimating energy intake based on the energy content (kcal/g) of major food items, their average ingestion rate (g/min), and daily feeding time (min) and by estimating energy expenditure using an equation for the costs of resting, traveling, and feeding based on behavioral data of 34 bears fitted with GPS collars in central Japan. Because food habits of bears change seasonally, we estimated daily energy balance for each month. And, because bears change their feeding behavior depending on the availability of hard mast, we made separate estimations for years of good and poor mast conditions during autumn. We identified major food items from fecal analysis and calculated the gross energy content per unit for each item. Based on direct observation of bears feeding over 10 yr, we measured ingestion rates of the major food items; Quercus crispula acorns on the tree had the highest ingestion rate, whereas the values of other items did not show notable characteristics. The variability of energy expenditure rose moderately in good mast years, except for males. On the other hand, there was a bimodal pattern of energy intake and energy balance, declining from May to July, rising again from August to October, and declining in November. The peak of energy intake and energy balance was larger in good mast years than in poor mast years only for females, whereas the cumulative energy balance in good mast years was larger than in poor mast years for both sexes. After poor mast years, the cumulative energy balance of males becomes negative in February, during hibernation, and did not exceed zero until August, even if they could start feeding in May. Thus, further longitudinal studies that examine cumulative energy balance, rather than energy balance alone, are necessary to clarify the seasonal change in the nutritional state of Asian black bears.

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Section: Methodsmentioning

confidence: 99%

Section: Calculating Intake Per Food Item Per Unit Of Timementioning

confidence: 99%

Estimating the seasonal energy balance in Asian black bears and associated factors

et al. 2019

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“…In contrast, during those years when mast production is poor, the energy that bears can obtain is lower and there is much greater competition for the hard mast on the forest floor with other animals, such as mice (Shaw, 1968). This may make it necessary for bears to climb trees more frequently, eating the immature, poorer quality hard mast still remaining on the trees (Nakajima et al, 2012).…”

Section: Figurementioning

confidence: 99%

“…If more samples had been taken, differences might have shown up (e.g. it is known that Quercus species are preferred over C. crenata, in Nakajima et al, 2012). Differences among species need to be examined in more detail in future studies.…”

Section: Figurementioning

confidence: 99%

“…Previous studies have indicated that AFS are formed after the fruits of soft mast species have ripened, but in the case of hard mast species they are formed before the fruits have ripened (Koike, 2009;Nakajima et al, 2012). Bears make an effort to climb trees to feed on soft mast because the fallen fleshy fruits decay rapidly, becoming inedible on the ground (Koike, 2009), and they tend to visit trees with greater amounts of fruit .…”

Section: Introductionmentioning

confidence: 99%

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Detection of arboreal feeding signs by Asiatic black bears: effects of hard mast production at individual tree and regional scales

et al. 2018

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Arboreal feeding signs are among several field indicators of the use of tree crowns by the Asiatic black bear (Ursus thibetanus) to sit and eat fruit; however, it is unclear which factors influence this sign formation in hard mast species. Here, we investigated the influence of seed production by individual trees and at a regional scale by major hard mast species on the detection of arboreal feeding signs. For 7 years, we quantitatively assessed seed production by 374–481 trees each year of three dominant hard mast species (Quercus crispula, Quercus serrata and Castanea crenata) in the Ashio‐Nikko Mountains of central Japan and checked for the presence or absence of arboreal feeding signs in these trees. We estimated individual tree energy values and regional mast energy values across these three species and evaluated the influence of each factor on the detection probability of arboreal feeding signs. Arboreal feeding signs were more likely in individual trees with larger mast energy values and during poor mast years. There was no difference among species in the relative importance of individual tree energy or regional mast energy. Interaction of factors was also detected: the magnitude of the positive effect of individual tree energy on the detection of arboreal feeding signs was larger in poorer mast years, and the negative effect of regional mast energy was more conspicuous in the case of trees with greater mast energy. Thus, bears may maximize their feeding efficiency on hard mast in various ways, depending on regional mast availability; during poor mast years, bears are more likely to climb trees with higher individual tree energy values and leave arboreal feeding signs. Arboreal feeding signs cannot be used as an indicator of bear density unless both individual tree energy and regional mast energy values are monitored.

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Relatively stable response of fruiting stage to warming and cooling relative to other phenological events

Jiang

Wang

Meng

et al. 2016

Ecology

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The timing of the fruit-set stage (i.e. start and end of fruit set) is crucial in a plant's life cycle, but its response to temperature change is still unclear. We investigated the timing of seven phenological events, including fruit-set dates during 3 years for six alpine plants transplanted to warmer (+ ~3.5 °C in soils) and cooler (-~3.5 °C in soils) locations along an altitudinal gradient in the Tibetan area. We found that fruit-set dates remained relatively stable under both warming and cooling during the 3-years transplant experiment. Three earlier phenological events (emergence of first leaf, first bud set, and first flowering) and two later phenological events (first leaf coloring and complete leaf coloring) were earlier by 4.8-8.2 days °C -1 and later by 3.2-7.1 days °C -1 in response to warming. Conversely, cooling delayed the three earlier events by 3.8-6.9 days °C -1 and advanced the two later events by 3.2-8.1 days °C -1 for all plant species. The timing of the first and/or last fruit-set dates, however, did not change significantly compared to earlier and later phenological events.Statistical analyses also showed that the dates of fruit set were not significantly correlated or had lower correlations with changes of soil temperature relative to the earlier and later phenological events. Alpine plants may thus acclimate to changes in temperature for their fruiting function by maintaining relatively stable timings of fruit set compared with other phenological events to maximize the success of seed maturation and dispersal in response to short-term warming or cooling.Keywords: phenological sequence; seed-production stage; alpine plants; early-spring flowering plants; mid-summer flowering plants; temperature change; Tibetan plateau Accepted ArticleThis article is protected by copyright. All rights reserved. IntroductionMost studies of the response of phenological events to temperature have been based on the analysis of events early or late in the season such as leaf onset, first flowering, and senescence (Walker et al. 2006, Amano et al. 2010, Yu et al. 2010Shen et al. 2011; Piao et al. 2011;Cook et al. 2012;Wolkovich et al. 2012;Wang et al. 2014a). Plants may face trade-offs between the adjustment of one phenological event to temperature and the timing of subsequent events during the growing season (Post et al. 2008;Sherry et al. 2007Sherry et al. , 2011 Haggerty and Galloway 2011; Dorji et al., 2013;CaraDonna et al. 2014;Wang et al. 2014b). This is illustrated by Fig. 1. Changes of flowering dates may alter the timing of fruit maturation, whereas fruit phenology in turn determines seed maturation and dispersal, which further feeds back on the diversity of species in an ecosystem (Primack 1987). The response of timing of fruiting to warming relative to other phenological events is still unclear because of inconsistent results from different plant species (Post et al. 2008; Haggerty and Galloway 2011;Sherry et al. 2007) and because few studies have analyzed the effects from both warming an...

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Spatial and elevational variation in fruiting phenology of a deciduous oak (Quercus crispula) and its effect on foraging behavior of the Asiatic black bear (Ursus thibetanus)

Cited by 21 publications

References 34 publications

Estimating the seasonal energy balance in Asian black bears and associated factors

Estimating the seasonal energy balance in Asian black bears and associated factors

Detection of arboreal feeding signs by Asiatic black bears: effects of hard mast production at individual tree and regional scales

Relatively stable response of fruiting stage to warming and cooling relative to other phenological events

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