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: F1000Prime.com/718000610#eval793474985
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.
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
