New Zealand scientists are using fossilised moa poo (coprolites) to study the diets and habitats of the large flightless native birds, which became extinct around 500 years ago.
Examination of coprolites
A research team examined over 50 pieces of fossilised excrement of four different moa species (Aves dinornithiformes) gathered from a rock overhang in a montane river valley in southern New Zealand. The research team, led by paleoecologist Dr Jamie Wood from Landcare Research, was able to extract pollen, fossilised plant materials and ancient plant DNA spanning some 400 years prior to the avian herbivore’s extinction.
Variation between species
The authors found there was substantial variation between species, with different species having differing habitats and dietary preferences, showing the relationship 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,” write the researchers in their published research paper.
Ecological impacts of moa’s extinction
The researchers say that the moa's extinction led to widespread ecological change in New Zealand plant-based ecosystems. Moa were very large and as such played a major role in shaping the structure and composition of vegetation communities. They also provided vital ecosystem functions such as seed dispersal, with whole seeds often found in their poo. “Our results show that moa lack extant ecological analogues [existing animals that fill the same role as the extinct birds], and their extinction represents an irreplaceable loss of function from New Zealand’s terrestrial ecosystems.”
Knowledge of extinct herbivore community structuring is useful for the researchers in assessing the wider ecological impacts of Quaternary extinctions. This can help them understand which animals would be suitable replacements if an area was to be ‘rewilded’.
Coprolites provide unique insights
Coprolites provide unique insights into the plant taxa consumed over a discrete time period by extinct herbivores and have typically been used to reconstruct the diets of single herbivore species. Through ancient DNA, pollen and plant macrofossil analyses of 51 coprolites deposited by four species of extinct herbivore in a single rock shelter, we show the potential for coprolites to also resolve broader paleoecological questions around niche partitioning of extinct sympatric herbivore species and prehistoric herbivore community structure. Such information can help in our understanding of late Quaternary ecosystem functioning and the ecological consequences of prehistoric extinctions, as well as helping to inform rewilding efforts,” write the authors.
The research was published in the 15 October 2013 edition of the Proceedings of the National Academy of Science of the United States of America (PNAS).
The scientists in this article are paleoecologists. Your students may like to view this video clip, What’s an ecologist?, in which Professor Stephen Wing talks about the role of an ecologist and the types of research questions ecologists try to answer.
Meet Dr Marcus Vandergoes, a paleoecologist at GNS Science.
UPDATE: Read about research results released in June 2021 on a new sample of fossilised moa poo from a little bush moa in Fiordland, which is estimated to be 6,800 to 4,600 years old. Based on this, researchers, including Dr Wood, believe moa might have played a previously unknown role in spreading ground fern spores throughout the bush.