Researchers from the University of Adelaide, New Zealand’s Manaaki Whenua-Landcare Research, and the University of Auckland have uncovered alarming findings regarding the kākāpō, a critically endangered parrot species. Their research indicates that over 80% of the parasites detected in kākāpō feces prior to the 1990s are no longer present. Modern populations no longer carry these parasites. This decline comes at the same time as major conservation successes for the species, starting with full-population management in the 90s.
Applying ancient DNA and cutting-edge microscopic techniques, the researchers examined fossil kākāpō poop over 1,500 years that had been preserved in a New Zealand cave. The analysis showed that nine of the original sixteen parasite taxa locally disappeared prior to the 1990s. Since that time, we’ve lost four more taxa and research to the grave. These findings shed light on a disturbing relationship. Perhaps unsurprisingly, the kākāpō population’s decline correlates almost perfectly with the hyper-speed loss of a great deal of native kākāpō parasite species.
The Role of Parasites in Ecosystems
The role of parasites in ecological communities has been largely underappreciated, or even completely ignored. As study co-author Dr. Jamie Wood explained, parasites are largely ignored in ecosystems and conservation. They are hugely important in holding the line and keeping the balance. He stated, “Despite their sometimes negative portrayal, parasites are increasingly appreciated for their ecological importance.”
Dr. Wood went on to explain the many ecological roles that parasites play. “Parasites are among the planet’s most ubiquitous, successful, and species-rich groups of organisms,” he said. “Nearly all free-living species harbor some parasites. Just like protecting against chronic diseases, gut bacteria can help maintain a robust immune system. Moreover, they jockey for position to remove exotic parasites that may threaten their hosts.
The study’s results underscore worries about the simultaneous crisis of disappearing biodiversity and climate change on these important organisms. Dr. Wood’s warning drew attention to the increasing rates of climate change, ecosystem alteration and biodiversity loss at a global scale. This trend reinforces the immediate need to understand how these changes are impacting dependent species, including parasites.
Significant Findings on Kākāpō Parasite Loss
These findings bring to light a chilling extent of parasite loss in kākāpō populations. Alexander Boast, lead author from Manaaki Whenua-Landcare Research, commented on the nature and scale of this decline which he said was surprising. He stated, “The level of parasite loss in kākāpō was greater than we had expected, and very few parasite species were found in both ancient and modern kākāpō populations.”
The ecological and evolutionary ramifications of this parasite extinction reach much further than the kākāpō. As a biologist, Dr. Wood was naturally concerned about the impact of such losses on host species. “The dependence of parasites on living hosts may make them susceptible to extinction,” he said. “Predictive models indicate that parasites may go extinct before their hosts during the coextinction process as opportunities to transmit between host individuals diminish.”
Given these results, the researchers argue that knowing how parasite communities are lost provides an important conservation tool. Photo by NASA As Dr. Wood pointed out, strongly documenting parasite extinction is an important first step in creating a “global parasite conservation plan”.
Implications for Conservation Efforts
The study’s findings could help inform future conservation approaches to protect the kākāpō and other endangered species. As kākāpō populations recover from near extinction, it is vital to consider the potential impact on their associated parasite communities.
Now, with that research published in Current Biology, we’re finally getting a fuller picture of the historical context behind those losses. The DOI for the study is 10.1016/j.cub.2025.07.009.
