Factors influencing the distribution of aquatic plant communities in Irish canals

The aquatic plant communities in two Irish canals were examined between 1990 and 1994 to investigate the factors that influence plant species distribution and community structure. Four main aquatic plant groups were identified by TWINSPAN. Two groups were characterised by bankside vegetation, including Carex sp., Juncus bulbosus and Scirpus lacustris. Large mixed assemblages of emergent, floating leaved, free floating and submerged plant species characterised the third group. The fourth group was species poor and was dominated by Cladophora sp. Canonical Correspondence Analysis identified weed control history, total oxidised nitrogen, water colour, distance from feeder stream and distance from summit as the factors that potentially influenced the distribution of plant species. The results indicated that ongoing management practices did not significantly alter the overall structure and abundance of the plant communities during the study period.