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Audio Dwindling carnivore numbers affecting ecosystems

Samantha Donovan

A new international study has found the dwindling numbers of big carnivores like lions, cheetahs, bears, wolves and dingoes is affecting whole ecosystems. The report's authors are urging countries to find new ways for humans and those animals to co-exist.


SIMON SANTOW: A new international study has revealed more about the role the world's big carnivores play in the environment.

Animals like dingoes, lions, cheetahs and bears don't just control the number of smaller predators, but they also benefit the environment in ways not previously understood.

Samantha Donovan reports.

SAMANTHA DONOVAN: The study looked at how big carnivores around the world affect ecosystems they live in.

Dr Mike Letnic from the University of New South Wales' Centre for Ecosystem Science is one of the study's co-authors.

MIKE LETNIC: What we found is, one, that these predators are declining, which is very unfortunate. And associated with their decline are these massive changes in the ecosystem. There's changes that we're beginning to understand really well, like eruptions in herbivore populations and smaller predators, but also there's these unexpected flow-on effects.

SAMANTHA DONOVAN: And what are some of those?

MIKE LETNIC: Well, increases in herbivore numbers mean that we have depletion of plant ecosystems and we lose plant cover, which has impacts for habitats for small animals.

SAMANTHA DONOVAN: In Australia, when you're talking about those herbivores, which animals would you mean?

MIKE LETNIC: Kangaroos, feral pigs, feral goats. And so we have enormous numbers of kangaroos in Australia where dingoes have been removed and that has flow-on effects because it reduces the amount of grass in the ecosystem.

SAMANTHA DONOVAN: Mike Letnic says the international carnivore study delivered some unexpected results.

MIKE LETNIC: We can have increases in human disease. So for example in the United States they've had outbreaks in deer numbers associated with loss of wolves and that has resulted in increases in tick numbers because ticks use deer for hosts. Ticks carry lime disease and lime disease is transferred to humans from ticks as well.

And also some very interesting work from Africa as well where hunting by people, hunting of large predators by people, has resulted in outbreaks in baboon numbers and baboons are an absolute nuisance. They eat the smaller wildlife but they're also competing with people for food because they're crop raiders. And it turns out that kids aren't going to school in parts of Africa because they have to guard the crops against raids by baboons.

SAMANTHA DONOVAN: The study is urging countries to look at how they can protect their large carnivores like the dingo.

Dr Letnic:

MIKE LETNIC: Well, it's very difficult to co-exist with dingoes. We want to hope that we can find ways to do that. And certainly in some parts of Australia novel approaches to I guess co-existing with dingoes are being trialled; for example, the use of guardian dogs to protect livestock while at the same time ward off dingoes.

SAMANTHA DONOVAN: So are you arguing that dingoes should be reintroduced to many areas of Australia or just the existing numbers protected?

MIKE LETNIC: I think reintroduction can be a very difficult thing to argue for, but what I would like to see in the future is perhaps find places where we can have dingoes, certainly where we try to preserve populations of dingoes that we've got and make sure that they don't disappear.

SAMANTHA DONOVAN: The research is published in today's edition of the journal Science.

SIMON SANTOW: Samantha Donovan.