文章基本信息

标题：31° South: Dietary niche of an arid‐zone endemic passerine
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作者：Ângela M. Ribeiro ; Ben Smit ; M. Thomas P. Gilbert 等
期刊名称：Environmental DNA
电子版ISSN：2637-4943
出版年度：2019
卷号：1
期号：2
页码：109-118
DOI：10.1002/edn3.13
出版社：Wiley
摘要：Balancing energy budgets are thought to be challenging for birds living in arid ecosystems because food supplies are low and unpredictable, and climatic conditions extreme. Thus, to ensure they obtain sufficient energy to fuel daily energetic budgets, birds may need to adjust their diets and become less selective (generalist) as conditions become harsher. To test this hypothesis, we used DNA metabarcoding to characterize both the prey availability (from pitfall traps) and the dietary content (from fecal samples) of several conspecific populations of a semi‐ and arid‐endemic insectivorous bird, the Karoo scrub‐robin ( Cercotrichas coryphaeus ) across a climatic gradient. Our results showed that Coleoptera, Hymenoptera, Orthoptera, and Lepidoptera were the main prey. When accounting for their presence as available prey, Coleoptera and Hymenoptera were preferred in all regions, whereas robins avoided Orthoptera and Lepidoptera in all but the most arid region. Although the different populations live in regions that vary with regards to productivity and thermoregulatory demands, we found that the dietary niche breadth (Bs) of the three populations was intermediate to low, and did not differ significantly. As a whole, our findings show that regardless of environmental harshness these insectivores have similar dietary niches, suggesting that large dietary plasticity is fundamental for their survival in energy‐depauperated ecosystems.
关键词：arid ecosystems;arthropods;birds;dietary niche;DNA‐barcoding;high‐throughput sequencing