Dear Marmamers,
The following paper on resource
partitioning in sympatric delphinids was recently published:
Parra,
G., J. 2006. Resource partitioning in sympatric delphinids: Space use and
habitat preferences of Australian snubfin and Indo-Pacific humpback dolphins.
Journal of Animal Ecology 75:862-874.
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1.
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Many species of delphinids co-occur in space
and time. However, little is known of their ecological interactions and the
underlying mechanisms that mediate their coexistence.
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2.
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Snubfin Orcaella
heinsohni, and Indo-Pacific humpback dolphins Sousa chinensis, live in sympatry
throughout most of their range in Australian waters. I conducted boat-based
surveys in Cleveland Bay, north-east Queensland, to collect data on the space
and habitat use of both species. Using Geographic Information Systems, kernel
methods and Euclidean distances I investigated interspecific differences in
their space use patterns, behaviour and habitat preferences.
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3.
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Core areas of use (50% kernel range) for both
species were located close to river mouths and modified habitat such as
dredged channels and breakwaters close to the Port of Townsville.
Foraging and travelling activities were the dominant behavioural activities
of snubfin and humpback dolphins within and outside their core areas.
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4.
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Their representative ranges (95% kernel range)
overlapped considerably, with shared areas showing strong concordance in the
space use by both species. Nevertheless, snubfin dolphins preferred slightly
shallower (1–2 m) waters than humpback dolphins
(2–5 m). Additionally, shallow areas with seagrass ranked high in
the habitat preferences of snubfin dolphins, whereas humpback dolphins
favoured dredged channels.
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5.
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Slight differences in habitat preferences
appear to be one of the principal factors maintaining the coexistence of
snubfin and humpback dolphins. I suggest diet partitioning and interspecific
aggression as the major forces determining habitat selection in these
sympatric species.
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The paper is available through the journal’s website: http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2656.2006.01104.x
Those without a subscription to the journal can request a
PDF copy from me: [EMAIL PROTECTED]
Cheers
Guido
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Guido J. Parra, PhD
Postdoctoral Fellow
School of Veterinary Science
University of Queensland
St Lucia, QLD 4072, Australia
Ph: (07) 3365-3066 Mob: 0437630843
Fax: (07) 3365-1255 Email: [EMAIL PROTECTED]
Webpage: http://www.uq.edu.au/vetschool/index.html?page=47564&pid=47559
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