Landcare Research, Lincoln, Canterbury 7640, New Zealand.
Proc Natl Acad Sci U S A. 2013 Oct 15;110(42):16910-5. doi: 10.1073/pnas.1307700110. Epub 2013 Sep 30.
Knowledge of extinct herbivore community structuring is essential for assessing the wider ecological impacts of Quaternary extinctions and determining appropriate taxon substitutes for rewilding. Here, we demonstrate the potential for coprolite studies to progress beyond single-species diet reconstructions to resolving community-level detail. The moa (Aves: Dinornithiformes) of New Zealand are an intensively studied group of nine extinct herbivore species, yet many details of their diets and community structuring remain unresolved. We provide unique insights into these aspects of moa biology through analyses of a multispecies coprolite assemblage from a rock overhang in a montane river valley in southern New Zealand. Using ancient DNA (aDNA), we identified 51 coprolites, which included specimens from four sympatric moa species. Pollen, plant macrofossils, and plant aDNA from the coprolites chronicle the diets and habitat preferences of these large avian herbivores during the 400 y before their extinction (∼1450 AD). We use the coprolite data to develop a paleoecological niche model in which moa species were partitioned based on both habitat (forest and valley-floor herbfield) and dietary preferences, the latter reflecting allometric relationships between body size, digestive efficiency, and nutritional requirements. Broad ecological niches occupied by South Island giant moa (Dinornis robustus) and upland moa (Megalapteryx didinus) may reflect sexual segregation and seasonal variation in habitat use, respectively. Our results show that moa lack extant ecological analogs, and their extinction represents an irreplaceable loss of function from New Zealand's terrestrial ecosystems.
了解已灭绝食草动物群落结构对于评估第四纪灭绝对更广泛生态系统的影响以及确定适当的分类群替代物以重新引入野生动物至关重要。在这里，我们展示了粪化石研究有可能超越单一物种的饮食重建，从而解决群落水平的细节问题。新西兰的恐鸟（鸟类：恐鸟目）是一组经过深入研究的九个已灭绝的食草动物物种，但它们的饮食和群落结构的许多细节仍然没有得到解决。我们通过对来自新西兰南部山区河谷一处崖壁上的多物种粪化石组合的分析，提供了有关这些恐鸟生物学方面的独特见解。使用古 DNA（aDNA），我们鉴定了 51 个粪化石，其中包括来自四个同域恐鸟物种的标本。粪化石中的花粉、植物大化石和植物 aDNA 记录了这些大型鸟类食草动物在灭绝前 400 年（约公元 1450 年）的饮食和栖息地偏好。我们利用粪化石数据开发了一个古生态位模型，其中根据栖息地（森林和河谷草本植物区）和饮食偏好对恐鸟物种进行了分区，后者反映了体型、消化效率和营养需求之间的比例关系。南岛巨型恐鸟（Dinornis robustus）和高地恐鸟（Megalapteryx didinus）广泛的生态位可能分别反映了性隔离和栖息地使用的季节性变化。我们的研究结果表明，恐鸟没有现存的生态类比，它们的灭绝代表了新西兰陆地生态系统功能的不可替代损失。
