What links extinct moas, colorful truffles, and climate change?

New Zealand, known for its unique wildlife and flora, holds many secrets from the past. One of them was revealed by a recent study in Biology Letters: the extinct upland moas (Megalapteryx didinus) were not only majestic birds, but also played a central role in dispersing colorful, truffle-like fungi such as Gallacea scleroderma. These fungi, which still grow in New Zealand today, are crucial to the ecological balance of its forests.

Mycophages and symbioses: how animals and fungi shape New Zealand’s forests

Mycophages—animals that consume fungi—play a key role in dispersing fungal spores. In regions without a mammal-dominated fauna, such as New Zealand, birds likely took on this function. However, direct evidence for this assumption is limited, because since humans settled New Zealand in the 13th century, 41 percent of native bird species have gone extinct. The moas are one of the most prominent examples of this loss—and with them, an important ecological function disappeared.

Ectomycorrhizae, such as truffles, porcini, or fly agarics, serve an important function in forest ecosystems because they grow in symbiosis with trees or shrubs: the fungi provide plants with nutrients and water from the soil and, in return, receive sugar from photosynthesis as an energy source. Ectomycorrhizal fungi themselves cannot photosynthesize and therefore depend on these carbohydrates.

One example is the bright violet, truffle-like fungus Gallacea scleroderma. Its striking coloration likely helped it be noticed and dispersed more easily by birds such as moas. This symbiosis contributes significantly to forest stability and resilience, especially under changing climatic conditions.

Moas as irreplaceable spore dispersers

Fossil dung samples from caves in northwestern Nelson show that upland moas consumed not only colorful truffles such as Gallacea scleroderma, but also other ectomycorrhizal fungi such as Russula macrocystidiata and Rossbeevera pachydermis. The analysis also showed that fungal spores were present in the dung samples at high concentrations, suggesting that moas actively ate these fungi. With long digestion times and extensive movements, these flightless birds transported fungal spores over large distances and played a crucial role in dispersing them.

Interestingly, there is evidence that other moa species, such as the South Island giant moa and the bush moa (Anomalopteryx didiformis), also consumed fungi. Earlier analyses of fossil dung samples from these species revealed traces of ectomycorrhizae. However, these findings were less specific and did not show the taxonomic precision or the clear evidence for truffle-like species found in the current study.

Consequences of the loss for New Zealand’s forests

With the extinction of moas in the 15th century—caused mainly by hunting—not only did fascinating bird species disappear, but so did key players in New Zealand’s ecosystems. Studies show that today’s native birds in New Zealand rarely consume fungi, while introduced mammals such as rats and deer primarily disperse exotic fungal species. This threatens the diversity of endemic fungi such as colorful truffles. Without sufficient spore dispersal, these fungi could go extinct in the long term, weakening forest resilience. Invasive tree species that are less dependent on symbioses could be favored and displace native forests.

Conclusion: a delicate balance

Moas were indispensable partners for New Zealand’s forests and an example of how closely animal and plant species are linked in an ecosystem. Their loss shows how sensitive these networks are to disruptions such as biodiversity loss. Without moas and other native mycophages, the ecological balance risks tipping further. This could not only endanger native biodiversity, but also reduce forests’ resilience to the impacts of climate change.

Source

• Boast, A. P., Wood, J. R., Cooper, J., Bolstridge, N., Perry, G. L. W., & Wilmshurst, J. M. (2025). DNA and spores from coprolites reveal that colourful truffle-like fungi endemic to New Zealand were consumed by extinct moa (Dinornithiformes). Biology Letters, 21(2024). https://doi.org/10.1098/rsbl.2024.0440