WATER-LEVEL AFFECTS GROWTH OF ENDANGERED NORTHEASTERN BULRUSH, SCIRPUS-ANCISTROCHAETUS SCHUYLER

The effect of four static water levels (-5, 0, +5, and +10 cm in relat ion to the soil surface) and five sites (origin of parent plant) on gr owth of the federally endangered northeastern bulrush, Scirpus ancistr ochaetus, was examined in a greenhouse experiment. Maximum live leaf h eight was not affected initially by water level. By mid-experiment, le af height was greater at higher water levels but did not differ among treatment water levels by the close of the experiment. Final biomass d id not differ among any treatment. The ratio of final root to shoot ma ss (R:S) decreased with an increase in water levels from 0 to 10 cm. T he ratio of final live shoot mass to dead shoot mass (LS:DS) was affec ted by both water level and site. LS:DS was lower in the two higher wa ter levels, suggesting a shorter leaf life span at these depths. Final LS:DS of plants from each site had a significant negative linear rela tionship with initial site plant mass, perhaps due to different develo pmental stages or ages of offshoots of plants collected from each site . Small differences in water depth were found to affect height, leaf l ife span, and R:S in this species while site-of-origin had little effe ct on growth under greenhouse conditions. Even moderate changes in wat er level therefore may be an important factor in growth of S, ancistro chaetus in the field and management decisions related to conservation of this species should take possible disturbances to the hydrologic re gime under consideration. (C) 1998 Elsevier Science B.V.