HR: 1330h
AN: NB33Q-11    [Abstracts]
TI: Vertical movements and colonisation patterns of stream invertebrates within the riverbed in a NW Italian stream
AU: * Fenoglio, S
EM: fenoglio@unipmn.it
AF: DISAV University of Piemonte Orientale, Via Bellini 25 I-15100, Alessandria, AL 15100 Italy
AB: There is a growing interest in the vertical dimension of streams. We examined vertical movements and colonisation patterns of stream macroinvertebrates within the substratum in the Caramagna Creek (NW Italy) We sampled the macrobenthos at three levels (0-5 cm, 5-10 cm, 10-15 cm) below the streambed using 56 artificial substrata (5x5x15 cm baskets filled with clean substratum). Traps from 1 to 28 were covered with a nylon net (mesh width 265 �m) except for the apex, allowing access exclusively from the top (T traps). Traps from 29 to 56 were covered with the same net, but in this case the only access was from the bottom (B traps). After 14, 28, 42 and 56 days, fourteen traps (seven T and seven B) were removed. Community richness and density considerably increased over time in both traps. Forty-one taxa colonised the riverbed traps, with significant differences between T and B traps. This study provides data about the presence of interesting vertical movements within the first layer of the riverbed, underlining the existence of patterns and preferential movement direction among macroinvertebrate taxa. The interstitial zone is an important habitat, playing an key role for the functioning of the entire lotic ecosystem.
DE: 9810 New fields (not classifiable under other headings)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly