HR: 1330h
AN: NB33N-07    [Abstracts]
TI: Responses of Meiofauna to Flooding in Stream Mesocosms Along a Gravelbed Stream in the Ozark Highlands
AU: * Reese, R A
EM: rareese@uark.edu
AF: University of Arkansas, Science and Engineering 622, Fayetteville, AR 72701 United States
AU: Brown, A V
EM: artbrown@uark.edu
AF: University of Arkansas, Science and Engineering 622, Fayetteville, AR 72701 United States
AB: We tested the responses of meiofauna to disturbance by flooding using stream mesocosms on the Illinois River, Arkansas (U. S. A.), a riffle/pool, gravelbed stream in the Ozark Highlands. For 18 days in July and August 2003, one group of stream mesocosms was not disturbed and two were subjected to flooding treatments; moderate/frequent, and severe/infrequent. On day eighteen core samples were taken of the gravel/sand substrate in the mesocosms. Planktonic samples taken entering the mesocosms identified prospective colonizers. Core samples taken from the natural stream bed served as reference meiofauna communities. Statistical differences in densities of meiofauna L^-1 of substrate were observed in ten of the 19 taxa and for total meiofauna. In all taxa where there were significant differences, the undisturbed stream mesocosms had significantly higher densities than at least one of the two disturbance treatments. Total meiofauna mean densities in the undisturbed treatments, 1809 ± 258 (2 s. e.), were significantly higher than both the moderate/frequent and the severe/infrequent mesocosms (F = 21.35, P < 0.000). Shannon's diversity index (H) was highest at the moderate/frequent disturbance regime. Four rare taxa were absent and evenness of the remaining meiofauna increased at the moderate/frequent treatment.
DE: 9810 New fields (not classifiable under other headings)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly