Friday, 5 July 2013

Presentation at the 2013 Australian Summer Grains Conference

I recently presented some of the 'hot off the press' findings from our Grains Research and Development Corporation project 'Pest Suppressive Landscapes'The talk was given at the Australian Summer Grains Conference 2013 and uploaded to their website as part of the proceedings.  This is a fantastic way to share the work that we are doing and they have made a great job of the recording. 

Hazel Parry
Pest suppressive landscapes: Understanding the role of habitat on Rutherglen Bug populations

Tuesday, 2 July 2013

Plant invasions and extinction debts

I am rather behind on posting reviews to this blog, apologies!  We continue to review papers for F1000 and I will continue to do so with Mark Lonsdale even though his role is now changing at CSIRO (he has stepped down as chief of Ecosystem Sciences after serving a long and successful 'chiefdom'!) . 

At the end of April we highlighted the following article, particularly because it questions the timeframe over which we consider 'invasions' to play out: they are probably much longer than many of us have been thinking!

Gilbert B and Levine JM, Plant invasions and extinction debts.  Proc Natl Acad Sci U S A 2013, 110(5):1744-9 

Our review:  

The idea that invasive species are a distinct threat to biodiversity has been disputed in recent times. One of the lines of evidence adduced has been the paucity of examples of invasives driving native plant species to extinction [1]. This paper uses a combination of metapopulation modelling and field experiments to show that, for a suite of Californian native grasses, extinction due to competition from invasive grasses is a real possibility – it just takes time.

The authors demonstrate experimentally that the native grass populations retreat to refugia of ever smaller size and less favourable conditions, while the habitat between these refugia becomes less hospitable for seed production and establishment through competition with the invasives. Metapopulation models show that the populations become increasingly vulnerable to local extinction with less likelihood of recolonisation because of the distance from other viable seed sources.

Their modelling suggests that these extinctions may take hundreds of years to play out. While this is slow by comparison with direct habitat destruction and the likely impact of climate change, extinction is a long-term consequence of present, profound, and insidious changes to ecosystem processes.
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