HR: 15:45h
AN: NB44D-02    [Abstracts]
TI: Emerging aquatic insects affect riparian spider distribution and growth rates in a temperate rainforest
AU: * Marczak, L B
EM: laurie@interchange.ubc.ca
AF: University of British Columbia, 2424 Main Mall, Vancouver, BC V6T1Z4 Canada
AU: Richardson, J S
EM: john.richardson@ubc.ca
AF: University of British Columbia, 2424 Main Mall, Vancouver, BC V6T1Z4 Canada
AB: Emerging aquatic insects from streams provide a temporally shifting, alternative source of energy to riparian web-building spiders. The effects of dynamics in aquatic insect emergence on spider distributions are poorly understood. We manipulated the abundance of aquatic insects in riparian forests of British Columbia by excluding aquatic insects using a greenhouse type covering from May through the end of July. In the absence of manipulations, aquatic insect abundance generally peaks in July. The overall density of riparian spiders was reduced when aquatic insects were excluded in May and July but not in June. As in similar studies, tetragnathid spiders in particular showed a strong response to aquatic insect exclusion. The ideal free distribution predicts that organisms at low densities should have equal access to resources for growth to those at high densities. Using comparisons of body size low and high densities of animals we determined that tetragnathid abundance and growth patterns do represent an ideal free distribution.
DE: 9810 New fields (not classifiable under other headings)
DE: 9901 NABS Student Award - Basic Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly