Ricki Coughlan wrote:
when available, as far as I have been able to determine. In Tasmania, the
Bumble Bee has not caused significant harm to local nectarivores as it has a
preference for taking nectar when the day warms up a little - preferring
temperatures of around 10 degrees or more, if memory serves. Thus, the local
birds, insects and mammals have first dibs on the nectar in the cool early
Tasmanian mornings (many Australian plant species produce their nectar at
hours aimed to encourage their targeted or preferred pollenators and this is
generally in the nights or early mornings).
If I recall correctly from Andrew Hingston's presentation at the 2003
Birds Aus members day in Hobart, this is nearly but not quite correct.
Good old _Bombus terrestris_ is active at relatively low temperatures,
and gets in before the honeybees - coinciding with the main early
activity of nectarivorous birds. The bumblebee appears to exert quite a
significant impact on the standing nectar crop as far as Swift Parrots
are concerned in Tasmania at some sites. Swifties only breed to much
extent every second year; coinciding with the biannual peak in Blue Gum
flowering. This shows how tight the energy budget is down there.
Bumblebees are not ecologically benign in Tasmania, and are unlikely to
be on the mainland either. By the time they've completely colonised
Tasmania, their impacts might be more obvious (ie. possibly resulting in
decreased recruitment for Swift Parrots amongst other things).
Hopefully the precautionary principle will prevail.
--
=================================
Lawrie Conole
Senior Ecologist
Ornithology & Terrestrial Ecology
Ecology Australia Pty. Ltd.
Flora and Fauna Consultants
88B Station Street
FAIRFIELD VIC 3078 Australia
E-mail:
Internet: http://www.ecologyaustralia.com.au/
Ph: (03) 9489 4191; Mob: (0419) 588 993
Fax: (03) 9481 7679
ABN 83 006 757 142
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