The march of the Cane toads

Despite the name of my blog, its not often I write a post about Cane toads!  But recently a study came out that uses modelling to propose an interesting solution to halt the progress of the Cane Toad across North-western Australia.

Identifying optimal barriers to halt the invasion of cane toads.Tingley R, Phillips B, Letnic M, Brown G, Shine R, Baird S. J Appl Ecol. 2013 Feb; 50(1):129-37

Our Review: Lonsdale M and Parry H, 2013.
F1000Prime.com/717979948#eval793471458
Cane toads! Is there any way of stopping their march across northern Australia? This paper uses spatial modeling to suggest an economically and technically feasible solution. The model shows not only the potential importance of man-made waterholes to the invasion process, but suggests a control strategy that targets just these key points in the landscape.

Although this approach doesn't take into account landscape heterogeneity in the dispersal kernel, it does acknowledge that dispersal is not a uniform process, in this case driven by a series of waterbodies as foci of the invasion front. The authors feel their estimates may be conservative due to their treatment of rainfall variability, but it could also be argued that they may underestimate spread from vehicle movement (particularly with the expansion of mining in the region), and the model assumes colonization is very rapid following the presence of two toads at a site. Both of these issues simply highlight the complexity of the simulation of invasion spread. The stochastic approach taken here, that allows for an exploration of the most likely scenarios in relation to a potential management solution, is a good one that could easily be extended both to incorporate more complexity and to simulate other biological invasions.

 Image from the paper (figure 1): "The study area in Western Australia. The black arrow in the lower left-hand corner shows the location of the De Gray River, which was used as an endpoint in all simulations. The dark grey region below the black arrow shows the extent of the Pilbara region. In the inset, only waterbodies that lie within the predicted distribution of toads (grey shading) are depicted."

The 100 worst

The Invasive Species Specialist Group (ISSG) is a global network of scientific and policy experts on invasive species.  They have developed a method of scoring invasive species to come up with a list of the 100 worst.  This was recently reduced to 99, as Rinderpest virus has been eradicated ('from the wild').  That leaves a spot remaining!  So, how to fill it?  Well, this is open for public debate on their website to find the new 100th villain.  Their criteria? Firstly, they developed a shortlist of 50, from:
-  Species with a high number of appearances on current 'hit lists', both international and national
-  Emerging threats: potential major impacts or rapid spread rates of species not currently problematic.

From these, they assigned a score of (i) spread - the number of continents already invaded, and (ii) impact: either ecological, economic and/or health.  Then, they eliminated those whose genus is already represented in the top 100, or those whose value can also be 'positive' (economic, ecological or health).  This leaves just 10 candidates...

I think my vote would probably go to the triffid-like Giant Hogweed Heracleum mantegazzianum, although the aquatic plants on the list also sound particularly threatening. 

However, it was a surprise to find the beautiful Lionfish Pterois volitans on there - I have often admired this in large aquariums although I was aware it is not one you would easily keep at home, being rather poisonous!  If this piscivorous fish becomes more widespread it's impact on populations of reef fish is anticipated to be enormous - as if there weren't enough threats to coral reefs already with climate change and coral bleaching.

Radio Interview: Pest Suppressive Landscapes

My first radio interview!  This is a summary of where we are at so far with our project on 'Pest Suppressive Landscapes'.  Particularly the relationship between insect pests and predators with non-crop vegetation in the landscape, and how this might be managed to better promote predators.

Please click here to access the mp3 of the interview.

 Image shows two of the 7km radius landscapes (circles) that we studied in Queensland.  We have four more landscapes, two in New South Wales and two in Western Australia. 

CSIRO TV

CSIRO TV has just launched:

This first episode showcases some of the great work by my fellow CSIRO scientists.  It includes an explanation of the role of CSIRO's deep space complex at Tidbinbilla in the recent Mars landing; a new invention of a safer cattle gate; details of one of the many important reports that CSIRO have produced on climate change, this one on the effects on the marine environment; and a showcase of some of the remote technology CSIRO has developed.  CSIRO has also developed remote technology for biosecurity through the virtual taxonomy laboratory at the Australian National Insect Collection.  This uses remote microscopes to link species identification requirements in remote locations with experts here in Australia. 

Stay tuned for more monthly video highlights of news and events from across the organization!

The publication strategy dilema

With the rise of open-access, rapidly publishing online journals academics publication strategy is becoming even more important.  These new journals do not necessarily have an impact factor but may well lead to high citations for individual articles given their more easily accessible nature.  The dilemma of where to publish to advance your academic career has never been greater.  This is well summarized in a recent article and subsequent reviews on F1000.

On plummeting manuscript acceptance rates by the main ecological journals and the progress of ecology.

Wardle DA.Ideas Ecol Evol. 2012 May 29; 5:13-5

Reviews on F1000:
Hector A: 2012. F1000.com/717950080#eval793153059
Norton D: 2012. F1000.com/717950080#eval793458341 

I particularly like the questions raised in the reviews as they are pertinent to my own publication dilemmas, where as an early career researcher I'm aware that I'm likely to be judged not only on the number of papers but also the impact factor or rank of the journal I publish in. 

• Is high selectivity (and rejection rates) at journals the best system for advancing science?
• Should a paper be judged by the journal it is in or would article-level metrics do a better job? 
• Do we need journals any more or would we be better with a repository in the Cloud? 
• Should all publicly-funded research be open access (as is increasingly the case in medicine)? 
• Are new initiatives, such as PLoS, Frontiers, eLife, and Faculty of 1000's new publishing initiative F1000 Research, the way forward? 
• Should academics in the 'more mature' stages of their careers, and for whom promotion is less of an issue, endeavor to publish research through these new publishing initiatives to counter the institutionalized emphasis on impact factor?
• why are we so focused on quantity and what happened to the in-depth research projects or reviews of key issues that used to be published?

I also appreciate David Norton's comment about the value of books, particularly as I have recently published a couple of book chapters and have the opportunity for more - but they tend to be viewed as somehow less worthy than papers:

"I was concerned recently to hear a colleague say that a book was less important than a traditional published paper in terms of research quality – but a book might reflect the results of many years work and provide a synthesis of a considerable body of research, including much reflection; surely this is of more value to ecology than simply publishing the latest bit of data that reaches publishable size that can squeezed out of an experiment or field trial?"

An important article

Its not often we highlight an article as 'exceptional', but we felt this refutation that eloquently counters some of the rather wild articles published recently which essentially tell us to stop making so much fuss about invasive species is an important one. 

The natives are restless, but not often and mostly whendisturbed.

D Simberloff, L Souza, MA Nuñez, MN Barrios-Garcia and W Bunn Ecology. 2012 Mar; 93(3): 598-607

Our Review: 

Parry H, Lonsdale M: 2012. F1000.com/717952323#eval793457754 

This paper provides some counter-evidence to the argument that native species are as likely to become problematic invaders as non-indigenous species. The authors examined the literature on plant invasions in the United States and found that a member of the naturalised non-native pool is 40 times more likely than the native species to be perceived as invasive.

It is important to note that, while 'invasive' means different things to different researchers in the literature, these authors are using it to mean spreading from the point of introduction into the natural or semi-natural habitat and having an effect on the resident species in the habitat. The authors used Web of Science literature searches to determine for the United States the proportion of native and non-native plant species that were recorded as invasive and to glean the reasons for invasions by native species. In addition to demonstrating that non-native species have far greater invasion risk than native species, they also found that the typical cause for invasiveness of native species was mainly anthropogenic environmental change, such as altered fire regimes and grazing regimes. In other words, it was unusual for native species to spontaneously invade under natural, unmodified environmental conditions.

All this provides an important counter-argument to the proposal that there is nothing special about non-native species per se, which has arisen in recent literature (e.g. [1]). According to Simberloff et al., non-native species clearly have a greater propensity to cause damage than natives, and we should use this information strategically, rather than ignore this important trait.

References:

[1] Don't judge species on their origins.

Davis MA, Chew MK, Hobbs RJ, Lugo AE, ..., Ehrenfeld JG, Grime JP, Mascaro J, Briggs JC Nature. 2011 Jun 9; 474(7350): 153-4

F1000 July review: Invasion and phenology

This month we chose to review a Nature paper, which presents data that perhaps poses more intriguing questions than it actually answers.


Extended leaf phenology and the autumn niche in deciduous forest invasions. Fridley JD. Nature. 2012; 485(7398):359-62

Our review:
Parry H, Lonsdale M: 2012. F1000.com/716398006#eval793002852

Invasion ecologists have invoked phenology as one explanation of the apparent success of non-indigenous forest species compared to native species. This paper shows that the invasion of forest species with canopies that persist later into autumn is resulting in a seasonal change in primary productivity that may rival climate change in size and extent. 


This paper shows a clear difference in autumn leaf fall timing for these two groups of species, where non-native invasives maintain their leaves for longer. In spring there is also more rapid bud/leaf formation by non-native invasives before canopy shading. This paper discusses whether this would constitute a competitive advantage (increased annual tree growth) or, in fact, a disadvantage (lack of nutrient resorption in autumn due to frost damage of leaves and subsequent nutrient loss). It would be interesting to compare the data from this study to the behaviour of these same non-native trees in their native range. They do not necessarily behave the same way – there may have been a selection process, or phenotypic plasticity, at play here. The role of phenotypic plasticity in invasion ecology had been suggested a long time ago {1} and has been the subject of recent literature {2}, with some novel suggestions on how it may operate geographically (e.g. see ref {3}).