Kākāpō (Strigops habroptila), Maud Island, New Zealand. Credit: Chris Birmingham/Department of Conservation (CC BY 2.0)
In an analysis of fossilised kākāpō droppings, researchers from Manaaki Whenua – Landcare Research in New Zealand have discovered that parasites found on the bird may be nearing extinction.
Although parasites are commonly thought of as negative they play a crucial role in balancing ecosystems, so their possible extinction is of great concern to scientists.
The kākāpō is a native New Zealand parrot with a large green body and an owl-like face. Despite having excellent climbing skills, these birds can’t fly. There are currently an estimated 241 kākāpō alive today.
In the mid-1990s, there were only 51 individual kākāpō known to be alive. Since then, kākāpō populations have been managed in sanctuaries and predator-free reserves as part of conservation efforts.
“Kākāpō are one of New Zealand’s most endangered species,” says Dr Andrew Digby, Science Advisor for Kākāpō/Takahē in the Department of Conservation’s Kākāpō Recovery Programme.
“However, this study shows that some of the parasites inhabiting kākāpō may be even more endangered than their host.”
To understand what happens to parasites when their host almost goes extinct, the research team analysed the ancient DNA and microfossil data of frozen and fossilised dung.
“Very few living species have coprolite records or have had their dung collected and frozen during their conservation,” says palaeoecologist Dr Janet Wilmshurst, the study’s co-author.
“Kākāpō have both, meaning they may be the only species in the world to have their parasite communities preserved across the entirety of their decline, and their ongoing recovery.”
Over 200 fossil dung samples and kākāpō droppings from 14 localities were analysed. Some of the fossils date back to more than 1,000 years ago.
The research team identified 16 parasite taxa qcross the pre-1990 samples. Only 3 of these were detected in the kākāpō population today – a loss of more than 80% of parasite groups.
The results, published in Current Biology, also revealed that, of the 7 possibly host-specific parasite taxa from pre-1990 samples, 4 may be extinct as the team did not observe them in modern kākāpō.
“The level of parasite loss in kākāpō was greater than we had expected, and very few parasite species were found in both pre-human and modern kākāpō populations,” says lead author and palaeoecologist Dr Alex Boast.
Even after the kākāpō were saved from near extinction and moved to conservation sanctuaries, the decline of parasites continued.
“It seems that endangered species everywhere may possess fractions of their original parasite communities,” says Boast.
The scientists suggest that the decrease in parasites may be due to there being fewer kākāpō that the parasites can live off. It may also be due to human interventions.
Over the past 50 years, the populations of 69% of monitored mammals, birds, amphibians, reptiles and fish around the world have declined. Recent estimates suggest biodiversity loss is occurring at a rate 10 to 100 times higher than the natural base line. This is largely the result of human activities and climate change.
While many conservation efforts are in place to reverse the impacts of deforestation and hunting, the researchers hope this study helps recognise how biodiversity loss can also impact the parasite population.
“This study emphasises just how important evidence from the past can be for informing conservation biology,” says Digby.