Dec. 14, 2012 — A study of closely-related
bird species has found that they do not coexist in the same region because they
remain too ecologically similar and will out-compete each other, not because of
geographical barriers or unsuitable habitats.
Oxford University scientists examined 'sister'
species -- species that are each other's closest relatives -- of the 'ovenbird'
family from South America. They compared data on when these species diverged
and where they live today and found that those that have been separated for
longest and have evolved very different beaks were able to coexist more rapidly
after they became two separate species.
The findings suggest that species displaced due
to climate change may not be able to survive in what appears to be a suitable
new habitat because a related species already living there will out-compete
them for resources.
A report of the research appears this week in Ecology
Letters.
'Competitive exclusion between species is
generally thought to be limited to relatively small spatial scales, such as
between individual birds or across local patches of habitat,' said Dr Alex
Pigot of Oxford University's Department of Zoology, lead author of the report.
'In our work we are able to show that competition is a major factor responsible
for excluding closely-related species from entire regions. The key was being
able to rule out other explanations like geographical barriers, such as rivers,
or unsuitable habitats from being the main barriers to 'sister' species
co-existing.'
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