Transition from the Anthropocene to the Minicene

24 09 2016
Going, going ...

Going, going … © CJA Bradshaw

I’ve just returned from a life-changing trip to South Africa, not just because it was my first time to the continent, but also because it has redefined my perspective on the megafauna extinctions of the late Quaternary. I was there primarily to attend the University of Pretoria’s Mammal Research Institute 50thAnniversary Celebration conference.

As I reported in my last post, the poaching rates in one of the larger, best-funded national parks in southern Africa (the Kruger) are inconceivably high, such that for at least the two species of rhino there (black and white), their future persistence probability is dwindling with each passing week. African elephants are probably not far behind.

As one who has studied the megafauna extinctions in the Holarctic, Australia and South America over the last 50,000 years, the trip to Kruger was like stepping back into the Pleistocene. I’ve always dreamed of walking up to a grazing herd of mammoths, woolly rhinos or Diprotodon, but of course, that’s impossible. What is entirely possible though is driving up to a herd of 6-tonne elephants and watching them behave naturally. In the Kruger anyway, you become almost blasé about seeing yet another group of these impressive beasts as you try to get that rare glimpse of a leopard, wild dogs or sable antelope (missed the two former, but saw the latter). Read the rest of this entry »

Outright bans of trophy hunting could do more harm than good

5 01 2016

In July 2015 an American dentist shot and killed a male lion called ‘Cecil’ with a hunting bow and arrow, an act that sparked a storm of social media outrage. Cecil was a favourite of tourists visiting Hwange National Park in Zimbabwe, and so the allegation that he was lured out of the Park to neighbouring farmland added considerable fuel to the flames of condemnation. Several other aspects of the hunt, such as baiting close to national park boundaries, were allegedly done illegally and against the spirit and ethical norms of a managed trophy hunt.

In May 2015, a Texan legally shot a critically endangered black rhino in Namibia, which also generated considerable online ire. The backlash ensued even though the male rhino was considered ‘surplus’ to Namibia’s black rhino populations, and the US$350,000 generated from the managed hunt was to be re-invested in conservation. Together, these two incidents have triggered vociferous appeals to ban trophy hunting throughout Africa.

These highly politicized events are but a small component of a large industry in Africa worth > US$215 million per year that ‘sells’ iconic animals to (mainly foreign) hunters as a means of generating otherwise scarce funds. While to most people this might seem like an abhorrent way to generate money, we argue in a new paper that sustainable-use activities, such as trophy hunting, can be an important tool in the conservationist’s toolbox. Conserving biodiversity can be expensive, so generating money is a central preoccupation of many environmental NGOs, conservation-minded individuals, government agencies and scientists. Making money for conservation in Africa is even more challenging, and so we argue that trophy hunting should and could fill some of that gap. Read the rest of this entry »

Eat a feral a week

22 03 2012

© Y. Sugiura

Just a quick post this week about something I’ve been contemplating for a while.

What if every Australian pledged to eat a feral animal a week?

Yes, I know that it’s a bit out of the pitch, and I’m sure not everyone would do it. Nor would it be physically possible for one person to eat an entire camel, buffalo or deer in a week – but hopefully you get the picture.

Why propose this? Australia is quite over-run with feral animals. Some quick stats:

Now we have, of course, many other ferals (cats, rats, foxes, mice), but I don’t think too many people would want to eat them. I have personally eaten feral pigs, camels, buffalo, goats, and red, fallow and sambar deer, mostly from my own research trips or from friends who hunt. Read the rest of this entry »

Where the sick buffalo roam

28 10 2011

It’s been some time coming, but today I’m proud to announce a new paper of ours that has just come out in Journal of Applied Ecology. While not strictly a conservation paper, it does provide some novel tools for modelling populations of threatened species in ways not available before.

The Genesis

A few years ago, a few of us (Bob LacyPhil Miller and JP Pollak of Vortex fame, Barry Brook, and a few others) got together in a little room at the Brookfield Zoo in the suburban sprawl of Chicago to have a crack at some new modelling approaches the Vortex crew had recently designed. The original results were pleasing, so we had a follow-up meeting last year (thanks to a few generous Zoo benefactors) and added a few post-docs and students to the mix (Damien FordhamClive McMahon, Tom Prowse, Mike Watts, Michelle Verant). The great population modeller Resit Akçakaya also came along to assist and talk about linkages with RAMAS.

Out of that particular meeting a series of projects was spawned, and one of those has now been published online: Novel coupling of individual-based epidemiological and demographic models predicts realistic dynamics of tuberculosis in alien buffalo.

The Coupling

So what’s so novel about modelling disease in buffalo, and why would one care? Well, here’s the interesting part. The buffalo-tuberculosis example was a great way to examine just how well a new suite of models – and their command-centre module – predicted disease dynamics in a wild population. The individual-based population modelling software Vortex has been around for some time, and is now particularly powerful for predicting the extinction risk of small populations; the newest addition to the Vortex family, called Outbreak, is also an individual-based epidemiological model that allows a population of individuals exposed to a pathogen to progress over time (e.g., from susceptible, exposed, infectious, recovered/dead). Read the rest of this entry »

Linking disease, demography and climate

1 08 2010

Last week I mentioned that a group of us from Australia were travelling to Chicago to work with Bob Lacy, Phil Miller, JP Pollak and Resit Akcakaya to make some pretty exciting developments in next-generation conservation ecology and management software. Also attending were Barry Brook, our postdocs: Damien Fordham, Thomas Prowse and Mike Watts, our colleague (and former postdoc) Clive McMahon, and a student of Phil’s, Michelle Verant. At the closing of the week-long workshop, I thought I’d share my thoughts on how it all went.

In a word, it was ‘productive’. It’s not often that you can spend 1 week locked in a tiny room with 10 other geeks and produce so many good and state-of-the-art models, but we certainly achieved more than we had anticipated.

Let me explain in brief why it’s so exciting. First, I must say that even the semi-quantitative among you should be ready for the appearance of ‘Meta-Model Manager (MMM)’ in the coming months. This clever piece of software was devised by JP, Bob and Phil to make disparate models ‘talk’ to each other during a population projection run. We had dabbled with MMM a little last year, but its value really came to light this week.

We used MMM to combine several different models that individually fail to capture the full behaviour of a population. Most of you will be familiar with the individual-based population viability (PVA) software Vortex that allows relatively easy PVA model building and is particular useful for predicting extinction risk of small populations. What you most likely don’t know exists is what Phil, Bob and JP call Outbreak – an epidemiological modelling software based on the classic susceptible-exposed-infectious-recovered framework. Outbreak is also an individual-based model that can talk directly to Vortex, but only through MMM. Read the rest of this entry »

Vodcast on killing for conservation

24 02 2010

The inaugural issue of Methods in Ecology and Evolution came out today (see first issue editorial) and I am very pleased not only that our paper (Spatially explicit spreadsheet modelling for optimizing the efficiency of reducing invasive animal density) made it into the the paper line-up (see previous post on the paper here), we also managed to score the journal’s cover image (buffalo image shown right: Asian swamp buffalo Bubalus bubalis introduced to Australia in the early 19th Century now populate much of the tropical north and cause severe environmental disturbances to savanna and wetland ecosystems. Despite a broad-scale cull of hundreds of thousands of free-ranging buffalo occurring in the 1980s and 1990s to eradicate brucellosis and tuberculosis, the population is recovering and continuing to threaten protected areas such as Kakadu National Park. A small wild harvest of several thousand buffalo occurs each year in Arnhem Land where mustering is aided by helicopters and on-ground vehicles. The buffalo pictured are housed in temporary holding pens and then shipped for live export. Photo credit: Jesse Northfield).

I also had the opportunity to chat with Journal Coordinator, Graziella Iossa, via Skype about the paper, and they have put up a YouTube vodcast of the interview itself. You can also check it out here.

Summary: Corey Bradshaw answers what is the main idea behind his work with co-authors, “Spatially explicit spreadsheet modelling for optimising the efficiency of reducing invasive animal density”. Further, he explains how their model advances methodology in ecology and evolution and finally shows how it could be applied by wildlife manager and practitioners with basic knowledge of computer models. Their Excel-spreadsheet ‘Spatio-Temporal Animal Reduction’ (S.T.A.R.) model is designed specifically to optimise the culling strategies for feral pigs, buffalo and horses in Kakadu National Park (northern Australia), but Corey explains how their aim was to make it easy enough for anyone to use and modify it so that it could be applied to any invasive species anywhere.

Congratulations to Editor-in-Chief Rob Freckleton, Graziella and the Associate Editors for a great first issue. Other titles include:

Keep them coming!

CJA Bradshaw

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Computer-assisted killing for conservation

12 01 2010

Many non-Australians might not know it, but Australia is overrun with feral vertebrates (not to mention weeds and invertebrates). We have millions of pigs, dogs, camels, goats, buffalo, deer, rabbits, cats, foxes and toads (to name a few). In a continent that separated from Gondwana about 80 million years ago, this allowed a fairly unique biota to evolve, such that when Aboriginals and later, Europeans, started introducing all these non-native species, it quickly became an ecological disaster. One of my first posts here on was in fact about feral animals. Since then, I’ve written quite a bit on invasive species, especially with respect to mammal declines (see Few people, many threats – Australia’s biodiversity shame, Shocking continued loss of Australian mammals, Can we solve Australia’s mammal extinction crisis?).

So you can imagine that we do try to find the best ways to reduce the damage these species cause; unfortunately, we tend to waste a lot of money because density reduction culling programmes aren’t usually done with much forethought, organisation or associated research. A case in point – swamp buffalo were killed in vast numbers in northern Australia in the 1980s and 1990s, but now they’re back with a vengeance.

Enter S.T.A.R. – the clumsily named ‘Spatio-Temporal Animal Reduction’ [model] that we’ve just published in Methods in Ecology and Evolution (title: Spatially explicit spreadsheet modelling for optimising the efficiency of reducing invasive animal density by CR McMahon and colleagues).

This little Excel-based spreadsheet model is designed specifically to optimise the culling strategies for feral pigs, buffalo and horses in Kakadu National Park (northern Australia), but our aim was to make it easy enough to use and modify so that it could be applied to any invasive species anywhere (ok, admittedly it would work best for macro-vertebrates).

The application works on a grid of habitat types, each with their own carrying capacities for each species. We then assume some fairly basic density-feedback population models and allow animals to move among cells. We then hit them virtually with a proportional culling rate (which includes a hunting-efficiency feedback), and estimate the costs associated with each level of kill. The final outputs give density maps and graphs of the population trajectory.

We’ve added a lot of little features to maximise flexibility, including adjusting carrying capacities, movement rates, operating costs and overheads, and proportional harvest rates. The user can also get some basic sensitivity analyses done, or do district-specific culls. Finally, we’ve included three optimisation routines that estimate the best allocation of killing effort, for both maximising density reduction or working to a specific budget, and within a spatial or non-spatial context.

Our hope is that wildlife managers responsible for safeguarding the biodiversity of places like Kakadu National Park actually use this tool to maximise their efficiency. Kakadu has a particularly nasty set of invasive species, so it’s important those in charge get it right. So far, they haven’t been doing too well.

You can download the Excel program itself here (click here for the raw VBA code), and the User Manual is available here. Happy virtual killing!

CJA Bradshaw

P.S. If you’re concerned about animal welfare issues associated with all this, I invite you to read one of our recent papers on the subject: Convergence of culture, ecology and ethics: management of feral swamp buffalo in northern Australia.

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ResearchBlogging.orgC.R. McMahon, B.W. Brook,, N. Collier, & C.J.A. Bradshaw (2010). Spatially explicit spreadsheet modelling for optimising the efficiency of reducing invasive animal density Methods in Ecology and Evolution : 10.1111/j.2041-210X.2009.00002.x

Albrecht, G., McMahon, C., Bowman, D., & Bradshaw, C. (2009). Convergence of Culture, Ecology, and Ethics: Management of Feral Swamp Buffalo in Northern Australia Journal of Agricultural and Environmental Ethics, 22 (4), 361-378 DOI: 10.1007/s10806-009-9158-5

Bradshaw, C., Field, I., Bowman, D., Haynes, C., & Brook, B. (2007). Current and future threats from non-indigenous animal species in northern Australia: a spotlight on World Heritage Area Kakadu National Park Wildlife Research, 34 (6) DOI: 10.1071/WR06056

Coming to grips with the buffalo problem

7 09 2009

Clive McMahon (left) & colleaguesA good friend and colleague of mine, Dr. Clive McMahon, is visiting Adelaide for the next few weeks from Darwin. We’re attacking a few overdue manuscripts and sampling a few of Adelaide’s better drops of value-added grape juice, so I asked him to do a guest post on about his work. So here it is, something perhaps even few Australians know much about, let alone overseas folks. If you can recall that very strange scene in the film Crocodile Dundee where the old croc hunter casts a gestured spell over a horned beast, then you’ll probably appreciate this post.

Yes, there are plenty of them in northern Australia

Invasive and feral species can be important drivers of biodiversity loss. Australia, like many other isolated islands has developed an ancient, unique and diverse ecosystem. This unique ecosystem has been under extreme pressure ever since humans arrived around 40000-60000 years ago. One of the more damaging and economically important introduced species in Australia is the Asian swamp buffalo (Bubalus bubalis). Ironically, swamp buffalo are listed as Endangered by the IUCN, and current estimates suggest that there are probably less than 4000 in their native habitats in Asia.

© B. Salu, Kakadu National Park

© B. Salau, Kakadu National Park

The first 16 buffalo were introduced to Australia in 1826 on Melville Island, and then to the mainland at Cobourg Peninsula a year later from Kupang (now West Timor, Indonesia). Another 18 buffalo were obtained from Kisar Island (northeast of modern Timor-Leste) and introduced to the Cobourg. In 1843, another 49 were introduced. When the first Cobourg settlement was abandoned in 1849, all the buffalo were released, and the population spread rapidly throughout the Northern Territory. Over the next 65 years, numbers and distribution increased to an estimated 350000 in the 1960s and 1970s and densities exceeded 25 km-2 in ‘prime’ habitat. However, the population was severely reduced during the 1980s and 1990s in parts of its range under the Brucellosis-Tuberculosis Eradication Campaign (BTEC). Although largely successful in eradicating buffalo from pastoral lands in the short term, there was no ongoing broad-scale management of numbers and the present-day population of free-ranging buffalo has recovered to former densities in some areas.

© C. Speed

© C. Speed

Buffalo were then and still are major problem in Australia due mainly to the environmental damage they cause, such as saltwater intrusion of wetlands and trampling of sensitive habitats, their potential threat to Australia’s livestock industry as hosts for disease, and the danger they pose to human safety. Given these ecological, economic and social impacts, there is an urgent need to manage buffalo numbers.

An important step to inform management of introduced and invasive species is to determine the history of introduction and quantify the rate of spread from introduction sites. Contemporary genetic techniques in conjunction with demographic and life history information are useful tools for understanding the dynamics, population structure, biology and colonisation dynamics of plants and animals, including invasive species such as buffalo.

We are currently in the final stages of providing the first detailed analysis of the buffalo population structure (demographic and genetic) to (1) establish the rate and most probable history of spread using detailed genetic information sampled from 8 sub-populations, (2) quantify the genetic distance and mixing rates between populations and (3) describe the age structure and therefore the demographic performance of this very successful invasive species.

Firstly to get an idea of genetic structure and relatedness, we collected a total of 430 small skin biopsies from buffalo across the Northern Territory, representing eight geographically distinct populations. To determine what has made the buffalo such a successful invader it is important to know the survival and breeding performance; we also constructed seven life tables based on culled samples at different densities and in different environments to work out what are the critical components of the population – i.e., where management intervention would be most successful.

As expected from a bottlenecked population, genetic variation is low compared to the that found in swamp buffalo from India and South East Asia. Despite this reduced genetic variation, the Australian population has thrived and spread outwards from introduction sites and into culled sites at high rates over the last 160 years (covering ~ 224 000 km2 in that time).

Although buffalo in Australia experienced two major periods of population reduction since their introduction, a small proportion (estimated at ~ 20 %) escaped the BTEC reduction in the eastern part of its north Australian range. BTEC did not operate with uniformity across the entire range of buffalo, concentrating its destocking efforts in a general area from the western coast of the Northern Territory to west of the Mann River in Arnhem Land, and south roughly to Kakadu National Park’s southern border. Coincidently and not surprisingly, it is in this area that we observe most migration activity.

The subpopulation structure detected here suggests that each population, while connected over generational time scales, generally remains in its immediate vicinity over the course of management-tractable periods. Therefore, management aimed at protecting Australia’s lucrative livestock industry trading under Australia’s disease-free status will benefit directly from this knowledge. For example, the localised introduction and subsequent rapid detection of disease could be efficiently managed from local culls because short-term movements of long-distance are less likely. Our results showcase how management of animals for disease control can be effectively informed via genetic studies and so avoid the need for expensive broad-scale intervention.

Our analyses of the age structure of buffalo reveals that buffalo have the capacity to recover swiftly after control because of high survival and fertility rates. Survival in the juvenile age classes was consistently the most important modifier of population growth. In populations where juvenile animals are harvested annually, fertility determined rebound potential. Thus, management aimed at long-term control of densities should focus primarily on the sustained culling of adult females and their offspring.

Given that numbers of buffalo are increasing and that buffalo are extremely well-adapted to the monsoonal tropics (unlike cattle, buffalo can maintain body condition and positive growth during times of food shortages), they are vulnerable to extended periods of harsh conditions. Climate change predictions herald increasing rainfall in the region, thereby potentially reducing the pressure on juvenile survival. As such, buffalo population growth could conceivably increase, making future management much more difficult. In essence, we need a large, evidence-based density reduction programme in place soon to prevent the worst ecological damage to Australia’s sensitive and unique ecosystems.

Check back here for announcements of upcoming publications arising from our work.

Clive McMahon & CJA Bradshaw

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