Using stable isotopes to understand the feeding ecology of the Hokkaido brown bear (<i>Ursus arctos</i>) in Japan

Matsubayashi, Jun; Morimoto, Junko; Mano, Tsutomu; Aryal, Achyut; Nakamura, Futoshi

doi:10.2192/ursus-d-12-00015.1

Cited by 18 publications

(20 citation statements)

References 46 publications

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“…Quinn et al (2009) reported that 49% of chum (Oncorhynchus keta) and pink (Oncorhynchus gorbuscha) salmon captured by bears (genus Ursus L., 1758) were carried into the riparian forests in southeastern Alaska [91]. The consumption of salmon by species varied widely among bears, age class, sex, and location [92,93]. Studies have shown that bears transferred MDN to terrestrial systems through excrement and urine [94] and to riparian forests by physically moving salmon carcasses [91] via foraging activities to enhance soil nitrogen pools, and thus beneficial to many other terrestrial organisms including plants, beetles, flies, and birds [95][96][97][98][99][100][101][102][103].…”

Section: Impacts Of Aquatic Resource Subsidies On Specific Terrestriamentioning

confidence: 99%

Importance of Riparian Zone: Effects of Resource Availability at Land-water Interface

Xiang¹,

Zhang²,

Richardson³

2017

Riparian Ecology and Conservation

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Riparian zone provides a variety of resources to organisms, including availability of water and subsidies. Water availability in riparian areas influences species distribution and trophic interaction of terrestrial food webs. Cross-ecosystem subsidies as resource flux of additional energy, nutrients, and materials benefit riparian populations and communities (e.g. plants, spiders, lizards, birds and mammals). However, aquatic ecosystems and riparian zones are prone to anthropogenic disturbances, which change water availability and affect the flux dynamics of cross-system subsidies. Yet, we still lack sufficient empirical studies assessing impacts of disturbances of land use, climate change and invasive species individually and interactively on aquatic and riparian ecosystems through influencing subsidy resource availability. In filling this knowledge gap, we can make more effective efforts to protect and conserve riparian habitats and biodiversity, and maintain riparian ecosystem functioning and services.

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Section: Impacts Of Aquatic Resource Subsidies On Specific Terrestriamentioning

confidence: 99%

Importance of Riparian Zone: Effects of Resource Availability at Land-water Interface

Xiang¹,

Zhang²,

Richardson³

2017

Riparian Ecology and Conservation

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“…However, compared with larger females, small females may cope better with poor nutritive conditions and thus experience less stress by avoiding males spatiotemporally (Steyaert et al 2013a(Steyaert et al , 2013b. Many previous studies have shown that females with cubs change their habits to reside in safer areas that are less frequently occupied by male bears (Dahle and Swenson 2003;Rode et al 2006;Steyaert et al 2013a) and meet their maintenance requirements by feeding on a lower quality diet (Ben-David et al 2004;Steyaert et al 2013b;Matsubayashi et al 2014). Thus, the trade-off between growth and risk of infanticide should affect the relationship between body size and diet quality in female subpopulations.…”

Section: Discussionmentioning

confidence: 99%

“…1). The major components of the diet of the Hokkaido brown bears are C 3 herbs, C 3 fruits, agricultural crops, insects, Sika deer, and salmon (Sato et al 2005;Matsubayashi et al 2014), although salmon consumption occurs in a limited zone in eastern Hokkaido (Ohdachi and Aoi 1987;Sato et al 2005;Matsubayashi et al 2014). Corn (Zea mays L.) is the only C 4 plant consumed by the bears; it is the most frequently eaten agricultural crop (Sato et al 2005).…”

Section: Study Sitementioning

confidence: 99%

“…The stable carbon and nitrogen isotope ratios were measured with commercial equipment (ANCA-IRMS; Europa Scientific Integra, UK) at the University of California, Davis, California, USA, and the overall estimated measurement error was <0.1‰ for ␦ 13 C and <0.2‰ for ␦ 15 N. The stable carbon and nitrogen isotope data for the bears in subpopulation No. 8, which were measured using a Finnigan MAT 252 mass spectrometer (Finnigan MAT, Bremen, Germany) connected to a Fisons NA1500 elemental analyzer at Hokkaido University, were obtained from Matsubayashi et al (2014). The estimated measurement error was <0.1‰ for ␦ 13 C and <0.2‰ for ␦ 15 N. …”

Section: Sample Preparation and Stable Isotope Analysesmentioning

confidence: 99%

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Testing for a predicted decrease in body size in brown bears (Ursus arctos) based on a historical shift in diet

et al. 2016

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A recent study found a historical decline in the proportion of meat in the diet of brown bears (Ursus arctos L., 1758) in the Hokkaido Islands, Japan. Because feeding habits are strongly correlated with the body size of animals, the shift in diet should have led to a decrease in the size of these bears. To predict the effects of this dietary shift on the skeletal size in bears, we correlated the femur length in Hokkaido brown bears with the carbon and nitrogen stable isotope values from bone samples and predicted the historical change in their body size. The variation in the femur lengths of the male and female subpopulations was positively correlated with their ␦ 15 N values, but not with their ␦ 13 C values, and the explanatory power of the constructed model was higher in males than in females. Based on the model and the ␦ 15 N values for historic and modern bears, the skeletal size of bear subpopulations in eastern Hokkaido was estimated to have decreased by 10%-18% for males and 8%-9% for females. Our results suggest that a historical dietary shift caused the decrease in the size of the Hokkaido brown bears.Key words: dietary shift, body size, brown bear, stable isotope, downsize, Ursus arctos. Résumé :Une étude récente établit une baisse historique de la proportion de viande dans le régime alimentaire des ours bruns (Ursus arctos L., 1758) dans les îles d'Hokkaido (Japon). Comme les habitudes d'alimentation sont fortement corrélées à la taille du corps des animaux, ce changement de régime devrait avoir mené à une diminution de la taille de ces ours. Afin de prédire les effets de ce changement de régime sur la taille des squelettes d'ours, nous avons corrélé la longueur du fémur d'ours bruns d'Hokkaido aux valeurs d'isotopes stables du carbone et de l'azote d'échantillons d'os et prédit le changement historique de la taille de leur corps. Les variations de la longueur des fémurs des sous-populations de mâles et de femelles présentaient une corrélation positive avec les valeurs de ␦ 15 N, mais pas avec les valeurs de ␦ 13 C, et la puissance explicative du modèle construit était plus grande pour les mâles que pour les femelles. À la lumière du modèle et des valeurs de ␦ 15 N pour les ours passés et actuels, il est estimé que les tailles des squelettes de sous-populations d'ours dans l'est d'Hokkaido ont diminué de 10 % à 18 % pour les mâles et de 8 % à 9 % pour les femelles. Nos résultats donnent à penser qu'un changement historique du régime alimentaire a causé une diminution de la taille des ours bruns d'Hokkaido. [Traduit par la Rédaction] Mots-clés : changement du régime alimentaire, taille du corps, ours brun, isotope stable, réduction de la taille, Ursus arctos.

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“…We made the following 60 predictions according to our previous findings [18]: (1) brown bear predation on cicada 61 nymphs occurs more frequently in the plantations than in the natural forest; (2) the 62 density of cicada nymphs is higher in the plantations than in the natural forest; The SWH has one of the highest densities of brown bear in the world [21]. Within the 81 study site, food items of the brown bears change across seasons; that is, herbaceous 82 plants are consumed in spring, herbaceous plants, ants and cicada nymphs are 83 consumed in summer, and Q. crispula acorns and anadromous salmon are consumed in 84 autumn [18,22,23]. Within the study area at least 11 individual bears were preying on 85 cicada nymphs, including two subadults, two solitary female adults, and three females 86 with cubs [18].…”

mentioning

confidence: 99%

Emergence of a novel interaction between brown bear and cicada due to anthropogenic habitat modification

Tomita

Hiura

2020

Preprint

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13Novel species interactions have generally emerged in ecosystems that are highly 14 modified by human activities. Anthropogenic habitat modification, such as 15 afforestation, is one possible driver of novel species interactions; however, empirical 16 evidence remains scarce. In this study, we show that a novel predator-prey interaction 17 between the brown bear (Ursus arctos) and nymphs of a cicada species (Lyristes 18 bihamatus) is generated by anthropogenic habitat modification. We evaluated the 19 frequency of brown bear predation on cicada nymphs and the density of cicada 20 nymphs between natural forests and plantations, which are a typical type of human-21 modified habitat. We found that brown bear predation on cicada nymphs occurred 22 only in the plantations. The density of cicada nymphs in the plantations was 23 significantly higher than in the natural forest. Our results indicate that the plantation 24 leads to the emergence of the bear-cicada interaction due to increasing the density of 25 cicada nymphs. The study draws attention to the overlooked effects of anthropogenic 26 habitat modification on species interactions. 27

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Using stable isotopes to understand the feeding ecology of the Hokkaido brown bear (Ursus arctos) in Japan

Cited by 18 publications

References 46 publications

Importance of Riparian Zone: Effects of Resource Availability at Land-water Interface

Importance of Riparian Zone: Effects of Resource Availability at Land-water Interface

Testing for a predicted decrease in body size in brown bears (Ursus arctos) based on a historical shift in diet

Emergence of a novel interaction between brown bear and cicada due to anthropogenic habitat modification

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