Coprolite deposits reveal megaherbivore moa

The consequences of extinction of Pleistocene megafauna symbolize the origin of plant growth and reproduction traits which have significant implications for interpretations of conservation measures in the contemporary world. The deficiency of dietary data for mega-herbivore species hinders scientific verification of these issues. New Zealand is forms the favorable ecosystem for effective ecological reconstruction. The terrestrial ecosystem in New Zealand was free of mammal species except for the three species of bats and it was dominated by 10 species of avian mega-herbivore.

Moa coprolites potentially provided dietary information for ten moa species. The present vegetation of Central Otago, one of the study areas is highly modified by anthropogenic burning, extensive clearing of land for pastoralism and alien species of grass and weeds. DNA analysis of coprolite revealed that all moa taxa consumed 30 species plants with strong dominance of herbs and subshrubs. This analysis revealed that different moa species in the same habitat fed on similar range of plant species. The relative abundance of different plant types varied slightly within species. Assemblages of seed from coprolite bearing sediment horizons in central Otago provided a proxy for palaeovegetation communities thus providing a peculiar opportunity for assessing plant taxa preferences of moa. The data suggested that herbs and subshrubs formed a larger part of the diet of moa. It further revealed that the moa utilized rockshelters and caves for shelter, roosting and nesting. Some of the variations in plant macrofossil content between individual coprolites were due to seasonal diet variation, with fruitseed being widely available during summer months but less common during winter. Coprolites and gizzards contained plant taxa representing at least eight plant growth forms hypothesized to be responses to moa-browsing and included divarication, toxicity, photosynthetic stems, prostrate-filiramulate habit, fibrous leaves, stinging hairs and low nutrient status, hence confirming that plants with these characteristics were part of moa diet and supported the co-evolution hypotheses. New Zealand has four dryland spring annual herbs including Ceratocephala pungens and Myosurus minimus novae-zelandiae both of which are endangered and lack dispersers.

In conclusion, the coprolite data strongly refute the idea that modern populations of introduced ungulates compete with moa since the coprolites show that moa ate high proportions of plant taxa that are avoided by ungulates and several others that are potentially toxic to mammals. such as e.g. Coriaria Ranunculaceae). In contrast, the data revealed that in some non-forest habitat types, the feeding ecologies of moa are similar to existing ratites that inhabit open habitats.


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