Author Archives: Euan Ritchie

About Euan Ritchie

I apply ecological theory with good doses of field work to seek solutions to the challenges of conserving biodiversity.

YouTube: Carnivore conservation needs evidence-based livestock protection

A new study published in the peer-reviewed journal PLOS Biology reveals certain nonlethal methods are effective for managing predators in agricultural landscapes. Twenty-one authors from 10 nations reviewed 114 peer-reviewed scientific studies measuring the effectiveness of lethal and non-lethal methods for reducing carnivore predation on livestock. Livestock guardian dogs, livestock enclosures and fladry all were scientifically shown to be effective conflict deterrents.

 

Carnivore conservation needs evidence-based livestock protection

Authors: Lily M van Eeden, Ann Eklund, Jennifer R B Miller, José Vicente López-Bao, Guillaume Chapron, Mikael R Cejtin, Mathew S Crowther, Christopher R Dickman, Jens Frank, Miha Krofel, David W Macdonald, Jeannine McManus, Tara K Meyer, Arthur D Middleton, Thomas M Newsome, William J Ripple, Euan G Ritchie, Oswald J Schmitz, Kelly J Stoner, Mahdieh Tourani, Adrian Treves

Published in: PloS Biology

Abstract

Carnivore predation on livestock often leads people to retaliate. Persecution by humans has contributed strongly to global endangerment of carnivores. Preventing livestock losses would help to achieve three goals common to many human societies: preserve nature, protect animal welfare, and safeguard human livelihoods.

Between 2016 and 2018, four independent reviews evaluated >40 years of research on lethal and nonlethal interventions for reducing predation on livestock. From 114 studies, we find a striking conclusion: scarce quantitative comparisons of interventions and scarce comparisons against experimental controls preclude strong inference about the effectiveness of methods.

For wise investment of public resources in protecting livestock and carnivores, evidence of effectiveness should be a prerequisite to policy making or large-scale funding of any method or, at a minimum, should be measured during implementation.

An appropriate evidence base is needed, and we recommend a coalition of scientists and managers be formed to establish and encourage use of consistent standards in future experimental evaluations.

van Eeden LM, Eklund A, Miller JRB, López-Bao JV, Chapron G, Cejtin MR, Crowther MS, Dickman CR, Frank J, Krofel M, Macdonald DW, McManus J, Meyer TK, Middleton AD, Newsome TM, Ripple WJ, Ritchie EG, Schmitz OJ, Stoner KJ, Tourani M, Treveset A (2018) Carnivore conservation needs evidence-based livestock protection, PLOS Biology PDF DOI 

Reblog: Minister, why is the dingo no longer ‘fauna’ ?

ConservationBytes.com

dead dingoSo, a few of us have just submitted a letter contesting the Western Australia Government’s recent decision to delist dingoes as ‘fauna’ (I know — what the hell else could they be?). The letter was organised brilliantly by Dr Kylie Cairns (University of New South Wales), and she and the rest of the signatories have agreed to reproduce the letter in full here on ConservationBytes.com. If you feel so compelled, please voice your distaste of this decision officially by contacting the Minister (details below).

CJA Bradshaw

Honourable Stephen Dawson MLC
Minister for Environment; Disability Services
Address: 12th Floor, Dumas House
2 Havelock Street, WEST PERTH WA 6005
(minister.dawson@dpc.wa.gov.au)

cc: Department of Biodiversity, Conservation and Attractions (biodiversity@dbca.wa.gov.au)
cc: Brendan Dooley (brendan.dooley@dpc.wa.gov.au)

Dear Minister,

The undersigned welcome the opportunity to comment on and recommend alteration of the proposed section (9)(2) order of the Biodiversity Conservation Act…

View original post 1,247 more words

Australian Geographic: The extinction crisis: Australians call for a radical re-haul of environmental laws

Australia is failing to meet international obligations to protect our unique wildlife, experts say.

Recounting a list of Australian animals on the brink of extinction comes all too easily to Euan Ritchie, an Associate Professor in Wildlife Ecology and Conservation at Deakin University.

“Obvious examples include the orange-bellied parrot, which only has a few individuals left in the wild,” he says, referring to the multi-coloured grass parrot with a total population of less than 50 that migrates between Tasmania and mainland Australia…

Continue reading on the Australian Geographic website

The Conversation: Why the WA government is wrong to play identity politics with dingoes

Western Australian Minister for the Environment Stephen Dawson has declared that the dingo, Australia’s native canine, will no longer be classified as native. Image credit Leo via Flickr.

By Bradley Smith (CQUniversity Australia), Euan Ritchie (Deakin University) and Lily van Eeden, (University of Sydney).

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Australia’s Commonwealth Coat of Arms depicts two iconic native animals – the kangaroo and the emu. Both are unquestionably fair dinkum Aussies, unique to this continent and having lived here for a very long time. A “very long time”, according to Australian legislation (the EPBC Act 1999), is any species having been present since before the year 1400.

But in Western Australia, under the state’s Biodiversity Conservation Act 2016, no native animal is guaranteed protection. The Act includes a caveat whereby the relevant minister may determine that a native species is in fact, not.

This week, WA’s environment minister Stephen Dawson did just that, declaring that from January 1, 2019, the dingo, Australia’s native canine, will no longer be classified as native fauna.

The dingo does meet the federal government’s criterion, having lived in Australia as a wild canid for an estimated 5,000 years. But under the planned changes in WA, the dingo will lose its current listing as “unprotected fauna”, and will from next year be considered indistinguishable from either the common domestic dog or feral dogs.

What is a species anyway?

According to the biological species concept, a species is a group that has the ability to interbreed and produce viable, fertile offspring. Dingoes, dogs and other canids do interbreed (or “hybridise”), and indeed this is one of the key reasons why the pure dingo is listed as vulnerable by the International Union for the Conservation of Nature.

But this ability to hybridise is also one of the main justifications cited by the WA government in its decision to revoke the dingo’s citizenship (the fact sheet has since been removed from the website, but can be accessed here). The rationale is that if dingoes and dogs are technically the same species, why should dingoes get special treatment?

However, the biological species concept is problematic when applied to canids. If you lump dingoes and dogs together because they readily interbreed, then logically we must do the same for wolves, coyotes, jackals or other canids that can also interbreed (and have done for millenia).

It’s hard to imagine anyone seriously suggesting that a grey wolf and a pug are the same species. This suggests that this criterion alone is insufficient to solve the conundrum. Indeed, there are at least 32 different species concepts, clearly illustrating the difficulty of defining a single rule by which all organisms should abide.

Despite this, a recent paper that argues the biological species concept should be applied to dingoes, was cited as supporting evidence by the WA government. Adopting this narrow interpretation of taxonomy is perhaps somewhat premature. It ignores other investigations that provide evidence to the contrary. Given the contention around defining species, it seems unwise to determine the species status of dingoes independently of other, more comprehensive evidence and argument.

Distinguishing dingoes

All canids share similarities, but their differences are also many and marked. The dingo can be distinguished from other dogs in various ways: their appearance, anatomy, behaviour, their role in ecosystems, and their genetics (their evolutionary history and degree of relatedness to other species). Dingoes seem to be largely devoid of many of the signs of domestication.

It is therefore reasonable for the dingo to be considered separately from wolves and domestic dogs, while also acknowledging that they all occupy the same broad species classification, Canis lupus.

Having lived in Australia as free-living, wild populations for around 5,000 years almost exclusively under the forces of natural selection, and separately from any other dog lineage until European arrival, there is no notion of the dingo as a domestic animal gone feral. To classify dingoes as nothing more than “feral domestic dogs” expunges their unique, long and quintessentially wild history. Dingoes are not ecologically interchangeable with any other type of dog, either wild or domesticated.

Labelling the dingo as a feral domestic dog changes their legal status and removes any current obligations for developing appropriate management plans. This demotion of status could lead to intensified lethal control. Indeed, control may even be legally mandated.

In the absence of thylacines, mainland Tasmanian devils, and other apex predators, the ecological role that the dingo plays in the Australian landscape is vital. Dingoes help to control kangaroo and feral goat populations, and in some cases foxes and cats as well.

Given WA’s remoteness, it remains one of the few bastions of pure dingoes, and as such it presents an opportunity to seek ways to protect them rather than pave the way for their removal. The WA government’s decision also sets a dangerous precedent for the management of dingoes, and indeed other contentious native wildlife, elsewhere in Australia.

How we choose to classify plants and animals might sound like dry science. But it has genuine implications for policy, management and conservation. Our scientific naming systems are vital for helping to organise and understand the rich biological diversity with which we share the planet, but it is important to remember that these systems are informed not just by biology but also by our values.

In this case, economic and political interests appear to have been favoured over wildlife preservation, and given Australia’s unenviable conservation record this is deeply concerning.
The Conversation

ABC News: Dingoes to remain classified as non-native wild dogs under reform to Western Australian law

Widespread reforms to WA’s Biodiversity Conservation Act, expected next year, will not consider a change to the existing classification of a dingo as a wild dog, not native to Australia.

The iconic animals are considered no different to wild dogs and can be trapped or killed without permission in many places.

Dingoes are currently classed as unprotected native fauna and a declared pest, but the animals will be listed as non-fauna under widespread reform to the Act…

Continue reading on the ABC News website

The Conversation: A numbers game: killing rabbits to conserve native mammals

Controlling rabbit populations has a key role in conserving Australia’s native plants and animals

By Euan Ritchie (Deakin University), Damien Fordham (University of Adelaide), and Miguel Lurgi, (Centre national de la recherche scientifique)

This article was originally published on The Conversation. Read the original article.

Invasive species have a devastating effect on biodiversity. In Australia, introduced red foxes and feral cats have been implicated in the majority of the extinctions of the native mammal fauna, which has been decimated since European arrival.

But there’s a herbivore that also causes eco-catastrophe. Rabbits both compete with native animals for food and shelter and act as easy prey for abundant populations of cats and foxes. By over-grazing vegetation and reducing habitat complexity, they make hunting easier for introduced predators.

Food webs are complex. Because of this, once an invasive species is embedded in a food web, simply eradicating them without considering the potential knock-on effects to other species they interact with, could cause unintended and undesirable consequences. We modelled different rates of rabbit population reduction to assess what level of control might be best for aiding the conservation of native mammals and not causing negative outcomes.

Rabbit numbers boom and crash

Rabbits, famously, reproduce rapidly and can cope with a relatively high predation rate. This can cause “hyper-predation”, where rabbit-inflated cat and fox populations indirectly increase the predation pressure on native mammals. This is especially so when rabbit populations intermittently crash due to, for example, extreme environmental events (like severe and prolonged droughts) or disease. This causes predators to switch their diet and eat more native mammals.

This logically suggests that reducing rabbit numbers might thus help reduce cat and fox populations, by removing their abundant prey. Collectively this should benefit native plants and animals, including many threatened mammal species. However, ecosystem and pest management is a complex game.

When controlling rabbits we need to look beyond one or two species. We should consider the potential consequences for the entire ecological community, which ultimately depend on how changes in one species percolate through the network of ecological interactions between them.

Our new research, recently published in the Journal of Applied Ecology, set out to examine these questions in more detail. We consider other key players in Australia’s arid regions, such as kangaroos and dingoes, when looking at the effects of rabbit control on small native mammals. Our aim was to provide a better understanding of how changes in rabbit populations might affect other species via the food web.

We developed a multi-species ecological network model to describe and quantify how changing rabbit abundance can affect species on different feeding levels. In addition to rabbits, small native mammals, and mesopredators (cats and foxes), our model also considers apex predators (dingo) and large herbivores (kangaroo) as part of the Australian arid food web. This model allowed us to examine changes in predator-prey interactions (including potential prey switching and hyper-predation) and how these could affect the survival of native prey through time.

We found that removing rabbits at rates between 30-40% appeared to benefit small mammals. This is approximately the rate at which rabbits are currently managed in Australia using biocontrol agents (introduced diseases).

Rabbit control in Australia typically involves a “press and pulse” approach. Rabbit populations are suppressed via biocontrol (press) and periods of warren destruction and poisoning (pulse). Finding that reducing rabbit populations by around 40% seems most beneficial to small mammals is important, as it informs how and when we combine these strategies.

The 40% rate corresponds well with the disease-induced (press) mortality rate in rabbit populations due to rabbit haemorrhagic disease and myxomatosis. These are the primary biocontrol agents used in arid Australia to control rabbit populations.

Our study supports rabbit-reduction strategies that involve sustained “press” control, that kill a moderate portion of a rabbit population, with less frequent removal at higher proportions of the population.

To effectively manage invasive species, it’s important to focus on entire communities. Targeting single species might not be enough – every animal exists within a complex web of interactions.

There has been much focus by the current government on controlling feral cats, as a way to conserve many of Australia’s unique and threatened mammal species.

However, more focus could be devoted to protecting habitat cover and complexity, by reducing the land clearing and over-grazing that makes hunting easier. We can also manage rabbits sensibly to reduce competition for resources, and indirectly control cats and foxes.
The Conversation