Food webs in Mongolian grasslands: The analysis of 13C and 15N natural abundances |
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| Authors: | Ayato Kohzu T Iwata M Kato J Nishikawa Eitaro Wada N Amartuvshin |
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| Institution: | 1. National Institute for Environmental Studies , Japan kohzu@ecology.kyoto-u.ac.jp;3. Faculty of Engineering , University of Yamanashi , Japan;4. Graduate School of Human and Environmental Studies , Kyoto University , Japan;5. Center for Ecological Research , Kyoto University , Japan;6. Japan Agency for Marine-Earth Science and Technology , Japan;7. Institute of Botany, Mongolian Academy of Science , Mongolia |
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| Abstract: | Overgrazing often lowers species richness and productivity of grassland communities. For Mongolian grassland ecosystems, a lack of detailed information about food-web structures makes it difficult to predict the effects of overgrazing on species diversity and community composition. We analysed the δ13C and δ15N signatures of herbaceous plants, arthropods (grouped by feeding habit), wild and domestic mammals, and humans in central Mongolia to understand the predominant food-web pathways in this grassland ecosystem. The δ13C and δ15N values of mammals showed little variation within species, but varied considerably with slope position for arthropods. The apparent isotopic discrimination between body tissue and hair of mammals was estimated as 2.0 ‰ for δ13C and 2.1 ‰ for δ15N, which was large enough to cause overestimation of the trophic level of mammals if not taken into account when using hair samples to measure isotopic enrichment. |
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| Keywords: | carbon-13 food selectivity grazing food chain herbaceous plants isotope ecology nitrogen-15 spatial scale trophic enrichment |
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