Using Stable Isotopes to Analyze Food Partitioning of Two Small Rodent Communities in He-huan Mountains
Date Issued
2012
Date
2012
Author(s)
Yeh, Wei-Ting
Abstract
Coexisting species may occupy different ecological niche in food resource utilization. We used stable carbon and nitrogen isotope techniques to analyze the food partitioning of rodent communities ( Taiwan vole: Microtus kikuchii, Formosan mouse: Apodemus semotus, and White-bellied rat: Niviventer culturatus ) in the alpine meadow and fir forest in the He-huan mountains. Rodent furs and potential food sources ( plants, fungi, and invertebrates ) were sampled in growing and non-growing seasons during 2009-2010 in both habitats, followed by carbon and nitrogen isotopic analyses. SIAR ( Stable isotope analysis in R ) was used to calculate the percentage contribution of food sources to the consumers. Three aspects were examined: habitat, seasonal, and species differences, along with food niche width measures to reveal variations within the populations. Habitat difference focused on coexistent species: Taiwan voles had similar trends in both seasons, with meadow individuals consuming more plants than forest ones. Formosan mice in the forest differed from the meadow ones, with forest individuals using fungi as their main food sources. Seasonal difference in diets only existed in Taiwan voles and white-bellied rats in forest, with more invertebrates consumed in non-growing than growing seasons. For species comparison, Taiwan voles ate more plants than other species in both habitats and less fungi in the forest. Besides, white-bellied rats consumed more animal sources than others in non-growing seasons. Formosan mice had wider food niche width than other species in both habitats, but seasonal differences existed. Overall, the three species did partition their food resources. The results also revealed that fungi might play an important role in rodents’ diet in the forest in He-huan mountains.
Subjects
food partitioning
stable isotopes
Microtus kikuchii
Apodemus semotus
Niviventer culturatus
Type
thesis
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