The value of honours

When I awoke this morning at 3:50 to do an interview with ABC Overnights about drought and wildlife, there was an email in my inbox informing me that we’d had a new paper accepted in Royal Society Open Science.

Getting the ‘accepted’ email is always nice, but this one was particularly welcome because the study arose from an honours thesis.

At some Universities in Australia, including my own, students above a threshold in terms of undergrad marks can elect to do a further ‘honours’ year. In science, this is a 9-12 month period in which the student works closely with a supervisor and co-supervisors to carry out a scientific study. Honours is huge learning curve for students as they are exposed to the rigors of science, including scientific writing, statistical analysis, and interpreting findings in the face of uncertainty. I am a massive fan of the honours scheme because it allows students to dip their toe into science without too much commitment, allowing them to judge if a research career might be for them, while adding to their CV.

An important final step of an honours year is to get the work published in a scientific journal, allowing the research to be assessed for its validity and rigor as it passes through peer-review, and then ensuring the work is accessible to a broader readership. This can take time, often years. Fortunately, this year has been a good year for my past honours students, with six projects published so far and several others in review. A summary of these is provided below.

Webster, C., Massaro, M., Michael, D., Riley, J., Bambrick, D., Nimmo, D.G. (accepted). Native reptiles alter their foraging in the presence of the olfactory cues of invasive mammalian predators. Royal Society Open Science.

Carlin Webster did honours with me in 2017, co-supervised by Mel Massaro (CSU), Damian Michael (ANU), and Julia Riley (Macquarie University). Carlin studied the response of native reptiles (marbled gecko, Christinus marmoratus, and Boulenger’s skink, Morethia boulengeri) to the olfactory cues of a range of predators, both native and introduced. Our aim was to test the hypothesis that native lizards would be naïve to the olfactory cues of non-native predators, due to a lack of shared co-evolutionary history. The two non-native species—red foxes (Vulpes vulpes) and feral cats (Felis catus)—have co-occurred with our study lizards for <200 years. Despite this, we found that the two species of native reptile responded in a similar way to predators, regardless of their origin (native or introduced).

Geyle, H., Guillera-Arroita, G., Davies, H., Firth, R., Murphy, B., Nimmo, D.G., Ritchie, E.G., Woinarski, J., Nicholson, E. (accepted). Towards meaningful monitoring: a case study of a threatened rodent. Austral Ecology.

Hayley Geyle did honours in 2015, supervised by Emily Nicholson, and co-supervised by Euan Ritchie (Deakin University), Brett Murphy (Charles Darwin Uni), Gurutzeta Guillera-Arroita (Melbourne University), and me, with input from PhD student Hugh Davies (Melbourne University), Ron Firth and John Woinarski (Charles Darwin University). She employed power analysis developed by Guru and Jose Lahoz-Monfort to identify the optimal approach to monitoring the threatened brush-tailed rabbit rat (Conilurus penicillatus) on the Tiwi Islands (and yes, she got to do field work there too!).

Geschke, A., Bennett, A.F., James, S., Nimmo, D. G. (2018). Compact cities or sprawling suburbs? Optimising the distribution of people in cities to maximise species diversity. Journal of Applied Ecology.

Andy Geschke did honours with me in 2015, co-supervised by Andrew Bennett (LaTrobe) and Simon James (Deakin). Andy asked how can we best distribute people in urban landscapes in a way that minimises harm to biodiversity? To answer this question, Andy studied birds in residential Melbourne, and worked with myself and Simon to develop a mathematical optimization procedure that could answer the question. Andy found that approaches to urban development that do not include large conservation areas are suboptimal. This research was covered in The Gaurdian .

Davis, H., Ritchie, E.G., Avitabile, S., Doherty, T., Nimmo, D.G. (2018) Testing the assumptions of the pyrodiversity begets biodiversity hypothesis for termites in semi-arid AustraliaRoyal Society Open Science.

Hayley Davis did honours with me in 2014, co-supervised by Euan Ritchie (Deakin) and Sarah Avitabile (LaTrobe). Her interest in invertebrates took her to the Big Desert wilderness of north-western Victoria. Hayley tested the hypothesis that a diversity of fire histories across a landscape would increase the diversity of animal species, using termites as a case study. She found that most termite species occur across a wide range of fire histories, and so the hypothesis was ultimately rejected.

Geary, W., Ritchie, E.G., Lawton, J., Healey, T., Nimmo, D.G. (2018) Incorporating disturbance into trophic ecology: fire history shapes patterns of mesopredator suppression by an apex predator. Journal of Applied Ecology.

Billy Geary did honours in 2014, co-supervised by Euan Ritchie. Billy also worked in the Big Desert region, focusing on the region’s largest predator: dingoes. Billy examined how patterns of dingo occurred related to fire history, and whether patterns of fox occurrence supported the hypothesis that dingoes suppress foxes. The hypothesis was supported, as fewer foxes were recorded in areas that had many signs of dingo activity. By modelling the relationship between fire, dingoes and foxes, we showed how fire management could have flow-on effects on invasive predators. This research was summarised in a very neat infograph by Fuse Consulting covered by ABC News

Richardson, E., Nimmo, D.G., Avitabile, S., Tworkowski, L., Welbourne, D., Watson, S.J., Leonard, S. (2018) Camera traps and pitfalls: evaluating the effectiveness of two methods for surveying reptiles in semi-arid Australia. Wildlife Research.

Emily Richardson did honours in 2014, supervised by Steve Leonard, and co-supervised by Sarah Avitabile, Simon Watson (LaTrobe), and me, with help from Dustin Welbourne (UNSW). Emily tested the capacity for remote camera to survey for reptiles. She compared downward facing cameras with pitfall traps (a more conventional method for surveying reptiles). She found that cameras did quite well for detecting diurnal species, and outperformed pitfall traps for some larger species (e.g., goannas), but did not perform so well for nocturnal species.

 

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ARC success

I’m happy to say I had a double-dose of ARC success this round. First, I’ve been awarded an ARC Discovery Early Researcher Award (DECRA), starting next year. My project for the DECRA will take me to the heart of the western desert where I will work with collaborators (Prof Rebecca Bird and Assoc Prof Doug Bird [Penn State], Prof Chris Dickman [Sydney Uni] and Dr Euan Ritchie [Deakin]) to examine the potential for Indigenous land management to restore ecosystems. This research is also being funded by the Hermon Slade Foundation and the Ecological Society of Australia is covering the costs of my travel to the U.S to work with collaborators at Penn State as part of the ESA Wiley Next Gen Award.

Project description

Can Indigenous land management forestall an extinction crisis? This project aims to test the theory that a lack of Indigenous land management precipitated the collapse of Australia’s mammal fauna. Current rates of species extinction exceed background rates by 100-1000 times, because of changes to ecosystems by humans. Paradoxically, Australia’s most pressing extinction crisis could be due to too little human disturbance. This project will test Indigenous land management’s capacity to forestall further mammal declines and restore degraded ecosystems, and enhance Indigenous livelihoods. Anticipated outcomes include on-ground principles for integrating Indigenous knowledge into biodiversity conservation, and transformative insights on the interdependence of humans and their environment.

Second, I was named on a successful Linkage Infrastructure Equipment and Facilities (LIEF) grant along with fellow CSU researchers Dave Watson and Gary Luck. This LIEF (led by Paul Roe, QUT) is really exciting, aiming to set up a network of acoustic recorders across the country that will provide 24/7 surveillance of soundscapes across 450 sites. The data that will be generated will be a world-first and offer unprecedented insights into change across Australia’s ecosystems.

Project description

Australian Acoustic Observatory: A network to monitor biodiversity. This project aims to create a terrestrial acoustic sensor network comprising 450 listening stations across Australia. Acoustic sensing transforms environmental science by recording vocal species 24/7, providing spatial and temporal data for ecosystem monitoring and research. Australia has leading research expertise in this emerging field, which is relevant to its fragile and mega-diverse environment. This project is expected to enable and develop continental scale environmental monitoring, and the data generated will be made freely available to all online, enabling new science in understanding ecosystems, long-term environmental change, data visualisation and acoustic science.

PhD project: The effects of fire on biodiversity in north-central Victoria

PhD scholarships: The effects of fire on biodiversity in north-central Victoria

Charles Sturt University, Albury, NSW

Stipend: $26,288 (tax free) per year over 3 years plus a $5,000 top up.

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An opportunity exists for a student to undertake a PhD on the effects of fire on biodiversity in the Strathbogie ranges of north-east Victoria. The project will be supervised by Dr Dale Nimmo of the Institute of Land, Water and Society (ILWS) and the School of Environmental Science. Focal taxonomic groups could include mammals, birds, reptiles, plants (with co-supervision from Dr Jodi Price, CSU), or pollinators (with co-supervision from Dr Manu Saunders, CSU).

The project is supported by the Goulburn Broken CMA (Dr Jenny Wilson) and the Department of Environment, Land, Water and Society (Dr Jane Roots), with substantial opportunity for industry engagement.

As well as an annual stipend ($31,288 including top up) and considerable in-kind support, the student will have access to operating funds ($5,000 per year) to support travel and fieldwork.

Applicants must apply through Charles Sturt University for a relevant scholarship for doctoral studies e.g. Australian Post Graduate Award (APA) or CSU University Postgraduate Research Scholarship. Further details are at: http://www.csu.edu.au/research/scholarships

Potential candidates will need a First Class Honours, Masters degree with a research component, or equivalent.

Please contact Dr Dale Nimmo for further information: email: dnimmo@csu.edu.au (phone: 02 6051 9827).

Expressions of interest close 28th of October, 2016.

 

Invasive predators are eating the world’s animals to extinction – and the worst is close to home

Originally published on The Conversation. By Tim Doherty, Dale Nimmo, Al Glen, Euan Ritchie and Chris Dickman.

Invasive species are a threat to wildlife across the globe – and invasive, predatory mammals are particularly damaging.

Our research, recently published in Proceedings of the National Academy of Sciences, shows that these predators – cats, rats and foxes, but also house mice, possums and many others – have contributed to around 60% of bird, mammal and reptile extinctions. The worst offenders are feral cats, contributing to over 60 extinctions.

So how can we stop these mammals eating away at our threatened wildlife?

Counting the cost

Our study revealed that invasive predators are implicated in 87 bird, 45 mammal and 10 reptile extinctions — 58% of these groups’ contemporary extinctions worldwide.

Invasive predators also threaten 596 species classed as vulnerable, endangered or critically endangered on the International Union for the Conservation of Nature Red List. Combined, the affected species include 400 birds, 189 mammals and 149 reptiles.

Twenty-three of the critically endangered species are classed as “possibly extinct”, so the number of extinctions above is likely to be an underestimate.

Until now, these shocking statistics have been unknown, and the heavy toll of invasive predators on native biodiversity grossly underappreciated. Species extinctions attributed to invasive predators include the Hawaiian rail (Zapornia sandwichensis) and Australia’s lesser bilby (Macrotis leucura).

Australia’s lesser bilby, now extinct.

Who are the worst offenders?

We found that three canids (including the red fox and feral dogs), seven members of the weasel family or mustelids (such as stoats), five rodents, two primates, two mongooses, two marsupials and nine species from other families negatively impact threatened species. Some of these species, such as hedgehogs and brushtail possums, don’t immediately spring to mind as predators, yet they are known to prey on many threatened species.

Feral cats threaten the most species overall (430), including 63 that have become extinct. This equates to one-quarter of all bird, mammal and reptile extinctions – making the feral cat arguably the most damaging invasive species for animal biodiversity worldwide.

Five species of introduced rodent collectively threaten 420 species, including 75 extinctions. While we didn’t separate out the impacts of individual rodent species, previous work shows that black rats (Rattus rattus) threaten the greatest number of species, followed by brown rats (R. norvegicus) and Pacific rats (R. exulans).

The humble house mouse (Mus musculus) is another interesting case. Despite their small size, house mice have been recorded eating live chicks of albatrosses, petrels and shearwaters.

Other predators that threaten large numbers of species are the domestic dog (Canis familiaris), pig (Sus scrofa), small Indian mongoose (Herpestes auropunctatus), red fox (Vulpes vulpes) and stoat (Mustela erminea).

Invasive mammalian predators (clockwise from top left): feral dog, house mouse, stoat, feral pig, feral cat, brushtail possum, black rat, small Indian mongoose and red fox (centre). Clockwise from top-left: Andrey flickr CC BY 2.0 https://flic.kr/p/4M2E7y; Richard Adams flickr CC BY 2.0 https://flic.kr/p/7U19v9; Mark Kilner flickr CC BY-NC-SA 2.0 https://flic.kr/p/4D6LPe; CSIRO CC BY 3.0 http://www.scienceimage.csiro.au/image/1515; T. Doherty; Toby Hudson CC BY-SA 3.0 https://commons.wikimedia.org/wiki/File:BrushtailPossum.jpg; CSIRO CC BY 3.0 http://www.scienceimage.csiro.au/image/10564; J.M.Garg CC BY-SA 3.0 https://commons.wikimedia.org/wiki/File:Herpestes_edwardsii_at_Hyderaba.jpg; Harley Kingston CC BY 2.0 https://flic.kr/p/ceWFr7 (centre).

Island species most at risk

Species found only on islands (insular endemics) account for 81% of the threatened species at risk from predators.

The isolation of many islands and a lack of natural predators mean that insular species are often naive about new predators and lack appropriate defensive responses. This makes them highly vulnerable to being eaten and in turn suffering rapid population decline or, worse, extinction. The high extinction rates of ground-dwelling birds in Hawaii and New Zealand — both of which lack native mammalian predators — are well-known examples.

Accordingly, the regions where the predators threatened the greatest number of species were all dominated by islands – Central America and the Caribbean, islands of the Pacific, the Madagascar region, New Zealand and Hawaii.

Conversely, the continental regions of North and South America, Europe, Africa and Asia contain comparatively few species threatened by invasive predators. While Australia is a continent, it is also an island, where large numbers of native birds and mammals are threatened by cats and foxes.

Along with feral cats, red foxes have devastated native mammals in Australia. Tom Rayner

Managing menacing mammals

Understanding and mitigating the impact of invasive mammal predators is essential for reducing the rate of global biodiversity loss.

Because most of the threatened species studied here live on islands, managing invasive predators on islands should be a global conservation priority. Invasive predators occur on hundreds of islands and predator control and eradication are costly exercises. Thus, it is important to prioritise island eradications based on feasibility, cost, likelihood of success and potential benefits.

On continents or large islands where eradications are difficult, other approaches are needed. This includes predator-proof fencing, top-predator restoration and conservation, lethal control, and maintenance of habitat structure.

Despite the shocking statistics we have revealed, there remain many unknowns. For example, only around 40% of reptile species have been assessed for the Red List, compared to 99% for birds and mammals. Very little is known about the impact of invasive predators on invertebrate species.

We expect that the number of species affected by invasive predators will climb as more knowledge becomes available.


This article was co-authored by Al Glen from Landcare Research, New Zealand. Landcare Research is a government-funded research organisation that conducts research into a range of conservation issues, including pest management. It did not provide funding for this research

New project: Can Indigenous fire management restore mammal communities?

I’m excited to say that the Hermon Slade Foundation has thrown support behind my research for a second consecutive year. Last year it was for a project examining the long-term recovery of woodland bird communities following southern Australia’s Millennium Drought (2001-2009), building on previous work  in the region that documented shorter-term responses (see here, here, here, and a perspective piece it inspired here).

My first selfie
Professor Rebecca Bird from Penn State taking a Western Desert selfie with a Martu woman engaging in traditional fire management. Photo from http://anthpsuhendylab.squarespcace.com  

This time it is to initiate a study on the capacity for traditional Indigenous fire management to restore mammal communities. The project is in collaboration with Rebecca and Doug Bird from the Human Environmental Dynamics Lab at Penn State, USA, and Euan Ritchie from Deakin University. We will work in remote parts of the Western Desert of Western Australia, where Rebecca and Doug have done ground-breaking work (see here, here, here) on the fire regimes maintained by Indigenous communities and their impacts on native species. We will compare areas under active Indigenous fire management with areas where such management has long ceased to reveal the ecological consequences of an active, traditional fire regime. We are extremely grateful to the Hermon Slade Foundation for supporting this work, and I can’t wait for this collaboration to begin later in the year.

New paper: Does the Configuration of Roadside Vegetation Affect Woodland Bird Communities in Rural Landscapes?

A new paper from PhD student Mark Hall. This is actually Mark’s honours work, so it’s great to see it published (far too few honours theses make it to publication). Well done Mark!

Abstract

In agricultural regions worldwide, linear networks of vegetation such as hedges, fencerows and live fences provide habitat for plant and animal species in heavily modified landscapes. In Australia, networks of remnant native vegetation along roadsides are a distinctive feature of many rural landscapes. Here, we investigated the richness and composition of woodland-dependent bird communities in networks of eucalypt woodland vegetation along roadsides, in an agricultural region in which >80% of native woodland and forest vegetation has been cleared. We stratified sites in a) cross sections and b) linear strips of roadside vegetation, to test the influence on woodland birds of site location and configuration in the linear network (the ‘intersection effect’). We also examined the influence of tree size at the site, the amount of wooded vegetation surrounding the site, and the abundance of an aggressive native species, the noisy miner Manorina melanocephala. Birds were surveyed at 26 pairs of sites (cross section or linear strip) on four occasions. A total of 66 species was recorded, including 35 woodland species. The richness of woodland bird species was influenced by site configuration, with more species present at cross sections, particularly those with larger trees (>30 cm diameter). However, the strongest influence on species richness was the relative abundance of the noisy miner. The richness of woodland birds at sites where noisy miners were abundant was ~20% of that where miners were absent. These results recognise the value of networks of roadside vegetation as habitat for woodland birds in depleted agricultural landscapes; but highlight that this value is not realised for much of this vast vegetation network because of the dominance of the noisy miner. Nevertheless, roadside vegetation is particularly important where the configuration of networks create nodes that facilitate movement. Globally, the protection, conservation and restoration of such linear networks has an important influence on the persistence of biota within human-dominated landscapes.