科研之友
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摘要
Bats are important ecosystem service providers, and therefore most relevant for both lowland and highland habitats, particularly in the tropics. Yet, it is poorly understood to what extent they perform large-scale movements, especially movements along mountain slopes. Here, we studied the movement ecology of the potentially migratory species Miniopterus natalensis at Mount Kilimanjaro in Tanzania. We analysed stable isotope ratios of C (delta C-13), N (delta N-15) and H (delta H-2) in keratin of sedentary frugivorous and insectivorous bats captured between 800 and 2,400 m above sea level to establish elevational gradients of stable isotope ratios in consumer tissues. We expected correlations between stable isotope ratios of the non-exchangeable portion of H in fur keratin and the elevation of capture site, but not necessarily for delta C-13 and delta N-15. Yet, in bats of both feeding ensembles, we found delta N-15 of fur keratin to correlate positively with the elevation of capture sites but not delta H-2. In frugivorous bats, delta C-13 increased with increasing capture elevation as well. By looking at intra-individual variation of delta C-13 and delta N-15 in fur keratin and wing membrane tissues of sedentary Rhinolophus cf. clivosus and of the potentially migratory species M. natalensis, we gathered evidence that M. natalensis migrates seasonally between low and high elevations along the slopes of Mount Kilimanjaro. Finally, based on an isoscape origin model we estimated that M. natalensis captured before and after the cold period at around 1,800 m above sea level originated from around 1,400 m a.s.l. or lower. Thus, we received convergent results in support of seasonal elevational movements of M. natalensis, probably in search for cold hibernacula at higher elevations of Mount Kilimanjaro.
- 出版日期2014-3
