Category Archives: Science communication

The Conversation: Thinking big gives top predators the competitive edge

By Thomas Newsome (Deakin University)

Dingoes could be the key to controlling red foxes and other invasive predators, but only if we encourage them in large enough numbers over a wide enough area, our research shows.

Dingoes can help manage devastating red fox and feral cat numbers, but only if we let enough of them live in key areas. Image credit Bobby Tamayo via The Conversation

Interest in re-introducing or restoring top predators, like dingoes and wolves, has been fuelled by recent studies demonstrating their important roles in their ecosystems. They can especially be vital in suppressing the abundance of lower-order competitors or “mesopredators”, like red foxes and possibly feral cats (which can have devastating effects on native species).

But researchers have found top predators aren’t always successful in reducing mesopredator numbers. Until now, such variation has been linked to human presence, land-use changes and environmental factors such as landscape productivity.

However, our research, published yesterday in Nature Communications, found that a key factor for success is high numbers of dingoes and wolves across their natural range.

The density effect

If you look at how species are typically distributed across a landscape – their range – ecological theory predicts there’ll be lower numbers at the outer edges of their range.

If you do need large numbers of top predators to effectively suppress mesopredators, the core of their range is potentially the best place to look.

We tested this idea, looking at the dingo in Australia and the grey wolf in North America and Europe. The mesopredators included the red fox in Australia, the coyote in North America and the golden jackal in Europe.

We used information from bounty hunting programs, as these provide data on predator numbers across a wide geographical area. In the case of Australia we used historic data from the 1950s, as this is the most recent reliable information about red fox and dingo distribution. The actual population numbers of red foxes and dingoes have changed substantially since then, but the nature of their interactions – which is what we were investigating – has not.

We determined that top predators exist in higher numbers at the core of their ranges in comparison to the edges. We then looked at mesopredator numbers across the range edges of their respective top predator.

The results, which were consistent across the three continents, suggest that top predators can suppress mesopredators effectively (even completely) but only in the core of their geographic range, where their numbers are highest.

In other words, abundant top predators can exert disproportionate mesopredator control once their numbers increase past a certain point.

The ‘enemy constraint hypothesis’

The relationship we uncovered is now formalised as the “Enemy Constraint Hypothesis”. It could apply to other predator dyads, where two animals compete for similar resources – even relationships involving parasites and pathogens.

Our findings are important for understanding species interactions and niches, as well as the ecological role of top predators. It could explain why other studies have found top predators have little influence on mesopredators: they were looking at the edge, not the core, of the top predators’ range.

How many top predators do we need?

Dingoes can be vital for reducing red fox and possibly feral cat numbers. In our case studies the ranges of each top predator were limited primarily by human use of the land and intensive shooting, trapping and poisoning.

Killing pack animals like dingoes can fracture social groups, potentially altering their natural behaviour and interactions with other species. Future studies on predator interactions therefore need to consider the extent to which the animals are acting in response to human intervention.

If we want to benefit from the presence of top predators, we need to rethink our approach to management – especially where they are subjected to broad-scale control, as the dingo is in some parts of Australia.

Changing our relationship with top predators would not come without its challenges, but high extinction rates around the world (and especially in Australia) clearly indicate that we urgently need to change something. If this includes restoring top predators, then we need to think big.

This article was originally published on The Conversation. Read the original article, including reader comments.

The Conversation

The Conversation

Capstone Editing: The trouble with academic grant applications

It’s time to look at the way academic grants are awarded. Image: Shutterstock

Regular successful grants are crucial for academic career advancement. Grants fund research, research leads to publications, and publications result in job security and promotion. But the likelihood of success is low, particularly for early-career researchers. Last year, the Australian Research Council (ARC) Discovery Projects, and National Health and Medical Research Council grants had a success rate around 18%, and ARC Linkage Projects around 30%.

A huge amount of effort is being dedicated to writing grants with very little chance of success.

How can we make this system better? My suggestions include prioritising funding for early-career researches, an expression-of-interest system to gauge the success of proposals, transparent and detailed feedback to unsuccessful applicants, and changing the timing of grant season so that is more family-friendly.

Read more on the Capstone Editing blog.

The Conversation: Bigfoot, the Kraken and night parrots – searching for the mythical or mysterious

In 2012 scientists succeeded in filming for the first time ever a giant squid in its natural habitat. Image credit: EPA / NHK / NEP / Discovery Channel / AAP

It’s remarkable how little we know about Earth. How many species do we share this planet with? We don’t know, but estimates vary from millions to a trillion. In some respects we know more about the Moon, Mars and Venus than we do about the ocean’s depths and the vast sea floors.

But humans are inquisitive creatures, and we’re driven to explore. Chasing mythical or mysterious animals grabs media headlines and spurs debates, but it can also lead to remarkable discoveries.

The recent photographing of a live night parrot in Western Australia brought much joy. These enigmatic nocturnal birds have been only sporadically sighted over decades.

Another Australian species that inspires dedicated searchers is the Tasmanian tiger, or thylacine. A new hunt is under way, not in Tasmania but in Queensland’s vast wilderness region of Cape York.

Other plans are afoot to search for the long-beaked echidna in Western Australia’s Kimberley region.

In the case of the thylacine, old accounts from the region that sound very much like descriptions of the species raise the prospect that perhaps Cape York isn’t such a bad place to look after all.

But in reality, and tragically, it’s very unlikely that either of these species still survives in Australia. For some species there is scientific research that estimates just how improbable such an event would be; in the case of thylacines, one model suggests the odds are 1 in 1.6 trillion.

Chasing myths

The study and pursuit of “hidden” animals, thought to be extinct or fictitious, is often called cryptozoology. The word itself invites scorn – notorious examples include the search for Bigfoot, the Loch Ness Monster or Victoria’s legendary black panthers.

Granted, it’s probably apt to describe those searches as wild goose chases, but we must also acknowledge that genuine species – often quite sizeable ones – have been discovered.

Remarkable discoveries of animals thought to be fantasies or long extinct include giant squid, mountain gorillas, okapi, Komodo dragons and coelacanths.

In some cases, like the giant squid, these animals have been dismissed as legends. The reclusive oarfish, for example, are thought to be the inspiration for centuries of stories about sea serpents.

Technology to the rescue

Finding rare and cryptic species is self-evidently challenging, but rapid advances in technology open up amazing possibilities. Camera traps now provide us with regular selfies of once highly elusive snow leopards, and could equally be used with other difficult-to-find animals.

Environmental DNA is allowing us to detect species otherwise difficult to observe. Animal DNA found in the blood of leeches has uncovered rare and endangered mammals, meaning these and other much maligned blood-sucking parasites could be powerful biodiversity survey tools.

Acoustic recording devices can be left in areas for extended time periods, allowing us to eavesdrop on ecosystems and look out for sounds that might indicate otherwise hidden biological treasures. And coupling drones with thermal sensors and high resolution cameras means we can now take an eagle eye to remote and challenging environments.

The benefits of exploration and lessons learned

It’s easy to criticise the pursuit of the unlikely, but “miracles” can and do occur, sometimes on our doorstep. The discovery of the ancient Wollemi pine is a case in point. Even if we don’t find what we’re after, we may still benefit from what we learn along the way.

I’ve often wondered how many more species might be revealed to us if scientists invested more time in carefully listening to, recording and following up on the knowledge of Indigenous, farming, and other communities who have long and intimate associations with the land and sea.

Such an approach, combined with the deployment of new technologies, could create a boom of biological discovery.

This article was originally published on The Conversation. Read the original article, including reader comments.

The Conversation

The Conversation

Capstone Editing: Crowd funding your research

Is crowd funding the future of grants for science and the arts?

I’ve successfully crowd funded two research projects: The Big Roo Count and Papua New Guinea’s mountain mammals, and learnt a few things along the way.

As well as an alternative source of income for research, crowd funding allows direct and immediate contact with the public. You carry them along on the way with you, which is how science should be.

Read more on the Capstone Editing blog.

The Conversation: Government needs to front up billions, not millions, to save Australia’s threatened species

By Don Driscoll (Deakin University) Bek Christensen (University of Queensland) and Euan Ritchie (Deakin University)

Southern cassowaries, orange-bellied parrots, Leadbeater’s possums, and Australia’s only purple wattle are among the threatened species the government is seeking conservation investment for under its recently released threatened species prospectus. The prospectus seeks business and philanthropic support in partnership with the government and community groups to raise around A$14 million each year.

Orange-bellied parrots are one of the species included in the government’s Threatened Species Prospectus. Image crdeit: JJ Harrison via Wikimedia Commons

The government has proposed 51 projects, costing from A$45,000 to A$6 million. At first glance the prospectus is a positive initiative.

But it also highlights that the current government is unwilling to invest what’s needed to assure the conservation of our threatened plants, animals and other organisms.

The good news

The government’s partial outsourcing of conservation investment and responsibility might have some benefit. Raising broader awareness about the plight of Australia’s threatened species, particularly among Australia’s leading companies and donors, could lead to valuable conservation gains. It could translate to pressure for greater financial investment in conservation and less damaging actions by big companies.

The prospectus includes an excellent range of critically important projects. These include seed banks for plants facing extinction, and projects to control feral animals and create safe havens for mammals and birds.

These projects could help to save species on the brink of extinction, such as the critically endangered Gilbert’s potoroo, the Christmas Island flying fox and the orange-bellied parrot.

The projects have a high chance of success. Community groups and government are already on board and ready to take action, if only the funds materialise.

Why do so many species need urgent help?

The State of the Environment Report released in early March shows that the major pressures on wildlife have not decreased since 2011 when the previous report was released. The prospects for most threatened species have not improved.

Habitat loss is still the biggest threat. The homes of many threatened species are continually under threat from developments. Coal mines threaten the black-throated finch, urban sprawl eats away at the last 1% of critically endangered Victorian grasslands, and clearing for agriculture has spiked in Queensland.

Feral animals are widespread and control programs have been inadequate. New diseases are emerging, such as the chytrid fungus that has devastated frog populations worldwide.

The horticulture industry, for example, introduced myrtle rust to Australia. The disease was poorly managed when it was first detected. It now infects more than 350 species of the Myrtaceae family (including eucalypts).

We have so many threatened species because national and state governments don’t invest enough money in protecting our natural heritage, and environmental protections have been rolled back in favour of economic development.

Show us the money

Over the past three years the federal government has invested A$210 million in threatened species. This annual investment of A$70 million each year is minuscule compared with the government’s revenue (0.017% of A$416.9 billion).

It includes projects under the National Landcare Program, Green Army (much of which didn’t help threatened species) and the 20 Million Trees program.

The A$14 million that the prospectus hopes to raise is a near-negligible proportion of annual revenue (0.003%).

Globally, the amount of money needed to prevent extinctions and recover threatened species is at least ten times more than what is being spent.

In Australia, A$40 million each year would prevent the loss of 45 mammals, birds and reptiles from the Kimberley region.

Can we afford it? The 2016 Defence White Paper outlines an expansion of Australia’s defence expenditure from A$32.4 billion in 2016-17 to A$58.7 billion by 2025, even though the appropriate level of investment is extremely uncertain.

We are more certain that our biodiversity will continue to decline with current funding levels. Every State of the Environment report shows ongoing biodiversity loss at relatively stable, low-level funding.

And what will happen if industry won’t open its wallets? Will the government close the funding gap, or shrug its shoulders, hoping the delay between committing a species to extinction and the actual event will be long enough to avoid accountability?

In the past few years we’ve seen the extinction of the Christmas Island forest skink, the Christmas Island pipistrelle, and the Bramble Cay melomys with no public inquiry. Academics have been left to probe the causes, and there is no clear line of government responsibility or mechanism to provide enough funding to help prevent more extinctions.

Popularity poll

Another problem is the prospectus’s bias towards the cute and cuddly, reflecting the prejudice in the Commonwealth Threatened Species Strategy. The strategy and prospectus make the assumption that potential benefactors are inclined to fork out for a freckled duck, but not for a Fitzroy land snail.

The prospectus includes almost half of Australia’s threatened mammals (listed under the Environment Protection and Biodiversity Conservation Act) and one-fifth of the threatened birds.

Other groups are woefully represented, ranging from 13% of threatened reptiles to just 1% of threatened plants and none of the listed threatened invertebrates. The prospectus does not even mention spectacular and uniquely Australian threatened crayfish, snails, velvet worms, beetles, butterflies, moths and other insects.

The allocation of funds is equally problematic. We found that birds received the most money (A$209,000 per species on average), followed by mammals and plants.

Raising new funds to help save iconic species is valuable, and can help other species. This focus on birds and mammals wouldn’t be a problem if the government were to pick up the tab for the less popular threatened species.

But it hasn’t. That means our threatened species program will continue to be exceptionally biased, while many more species vanish forever, with little acknowledgement.

We think that the prospectus, despite its biases, is a positive initiative. It is vital to engage society, including business and wealthy philanthropists, in the care of Australia’s natural heritage. But it also highlights how little the government is willing to invest in preserving our threatened wildlife and ecosystems.

This article was originally published on The Conversation. Read the original article, including reader comments.

The Conversation

The Conversation