How native plant growth (height, density, biomass, and percent carbon, nitrogen, and phosphorus) is affected by Typha x glauca before litter accumulation.

Abstract

This was an observational study of native plant species along an invading Typha x glauca front during an eight week period in June through August; it was conducted to measure native plant productivity with and without the presence of T. x glauca before any litter had accumulated. Measurements were taken on three dates to record native plant species productivity in three zones of differening T. x glauca density (High, Low, and Not Present). C:N:P ratios for Juncus nodosus and Juncus balticus along the T. x glauca gradient were also analyzed and quantified. There was a visible trend from the High Density to Not Present Zone, with some native plant species having a significant negative correlation against T. x glauca density. Most native plant speices decrease in height, density, and mass as T. x glauca densities increase. Nitrogen levels decrease slightly in Juncus nodosus and Juncus balticus as T. x glauca densities increase, but there is no significant change in carbon or phosphorus. Once the effect of water depth on native plant growth had been taken into account, the effect of T. x glauca density on native plants productivity decreased, but did not completely disappear. T. x glauca density may still have a significant effect on some native species, but to state with certainty, ore studies are needed to sort out the effects of water depth and T. x glauca density on native plant species growth.