Monday, December 10, 2007 - 9:17 AM

Does species sorting occur in spider colonization of old field saplings?

Carol Frost, and Chris Buddle, McGill University, Natural Resource Sciences, Macdonald Campus, 21,111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, Canada

Rate of spider colonization of the foliage of small trees in an old field was determined by removing all spiders from trees every four days throughout one summer. Spider colonization rate changed throughout the season, peaking late July to early August. Mechanism of spider colonization was determined by comparing colonization rate when cursorial immigration was prevented with that when both cursorial and aerial immigration were allowed. Cursorial immigration was prevented in one group of trees by painting sticky rings around the trunks, which spiders could not pass. Overall, there was no difference in the number of spiders collected from the trees in the two groups, suggesting that spiders generally move between trees aerially. Abundance, richness, and taxonomic composition were compared among spiders colonizing empty trees, and spiders established in foliage throughout the season. Spider abundance and richness in recently colonized trees were lower than in established spider assemblage trees, and recently colonized trees had fewer species than established spider assemblage trees. The most abundant colonizing species were also most abundant in established assemblages, and no colonizing species were excluded from established assemblages. These results suggest that spiders are dispersal limited in this context, and provide no evidence that species sorting or mass effects metacommunity paradigms explain patterns of spider abundance and richness in this system.

Species 1: Araneae