Readers of the Canberra Times will have seen the article about Kate
Grarock's research on Common Mynas in Canberra.
The paper to which it refers is Grarock, K, Tidemann, CR, Wood, J
& Lindenmayer, DB 2012, 'Is It Benign or Is It a Pariah?
Empirical Evidence for the Impact of the Common Myna Acridotheres
tristis on Australian Birds', PLoS One, vol. 7, no.
7, p. e40622.
It is available in free full text at
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0040622
.
The abstract reads:
There is widespread concern over the impact of introduced species on
biodiversity, but the magnitude of these impacts can be variable.
Understanding the impact of an introduced species is essential for
effective management. However, empirical evidence of the impact of
an introduced species can be difficult to obtain, especially when
the impact is through competition. Change in species abundance is
often slow and gradual, coinciding with environmental change. As a
result, negative impacts on native species through competition are
poorly documented. An example of the difficulties associated with
obtaining empirical evidence of impact due to competition comes from
work on the Common Myna (<italic>Acridotheres
tristis</italic>). The species is listed in the World’s top
100 worst invaders, despite a lack of empirical evidence of its
negative impacts on native species. We assessed the impact of the
Common Myna on native bird abundance, using long-term data both pre
and post its invasion. At the outset of our investigation, we
postulated that Common Myna establishment would negatively affect
the abundance of other cavity-nesting species and bird species that
are smaller than it. We found a negative relationship between the
establishment of the Common Myna and the long-term abundance of
three cavity-nesting species (Sulphur-crested Cockatoo, Crimson
Rosella, Laughing Kookaburra) and eight small bird species (Striated
Paradoxes, Rufous Whistler, Willie Wagtail, Grey Fantail,
Magpie-lark, House Sparrow, Silvereye, Common Blackbird). To the
best of our knowledge, this finding has never previously been
demonstrated at the population level. We discuss the key elements of
our success in finding empirical evidence of a species impact and
the implications for prioritisation of introduced species for
management. Specifically, prioritization of the Common Myna for
management over other species still remains a contentious issue.
Regards - David
--
David McDonald
1004 Norton Road
Wamboin NSW 2620
Australia
T: (02) 6238 3706
M: 0416 231 890
F: (02) 9475 4274
E: m("dnmcdonald.id.au","david");">
Blog: www.socialresearch.com.au/news.html
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