Study

Assessing benthic barriers vs. aggressive cutting as effective yellow flag iris (Iris pseudacorus) control mechanisms

  • Published source details Tarasoff C.S., Streichert K., Gardner W., Heise B., Church J. & Pypker T.G. (2016) Assessing benthic barriers vs. aggressive cutting as effective yellow flag iris (Iris pseudacorus) control mechanisms. Invasive Plant Science and Management, 9, 229-234.

Actions

This study is summarised as evidence for the following.

Action Category

Use covers/barriers to control problematic plants: freshwater marshes

Action Link
Marsh and Swamp Conservation

Use cutting/mowing to control problematic herbaceous plants: freshwater marshes

Action Link
Marsh and Swamp Conservation
  1. Use covers/barriers to control problematic plants: freshwater marshes

    A replicated, randomized, paired, controlled, before-and-after study in 2014–2015 in two lakeshore marshes cleared of yellow flag iris Iris pseudacorus in British Columbia, Canada (Tarasoff et al. 2016) reported that the effect of covering plots on recolonizing vegetation depended on the water level. Statistical significance was not assessed. Initially, all study plots were completely covered by invasive yellow flag iris. This was clipped to ground level. One year later, in the intermittently flooded marsh, covered plots had approximately 7% vegetation cover (yellow flag iris seedlings and broadleaf cattail Typha latifolia; species cover not quantified). In contrast, open plots had 100% cover of yellow flag iris. Meanwhile, in the permanently flooded marsh, both covered and open plots had approximately 5% vegetation cover (yellow flag iris seedlings and broadleaf cattail; species cover not quantified). Methods: Nine pairs of plots (approximately 1 m2) were established in iris-dominated marshes on the shores of two lakes. In June 2014, yellow flag iris was cut to 0–4 cm above the sediment in all plots. Cuttings were removed. Then, one random plot/pair was covered with an impermeable rubber sheet for 150 days. Vegetation cover was surveyed in July 2015.

    (Summarised by: Nigel Taylor)

  2. Use cutting/mowing to control problematic herbaceous plants: freshwater marshes

    A replicated, randomized, paired, controlled, before-and-after study in 2014–2015 in two lakeshore marshes invaded by yellow flag iris Iris pseudacorus in British Columbia, Canada (Tarasoff et al. 2016) reported that the effect of cutting yellow flag iris on recolonizing vegetation depended on the water level. Statistical significance was not assessed. Before cutting, all study plots were completely covered by yellow flag iris. One year later, in the permanently flooded marsh, cut plots had only 5% vegetation cover (mixture of yellow flag iris seedlings and broadleaf cattail Typha latifolia; species cover not quantified) whilst uncut plots had 100% vegetation cover (yellow flag iris only). In the intermittently flooded marsh, both cut and uncut plots were completely covered by yellow flag iris. Methods: Nine pairs of plots (approximately 1 m2) were established in iris-dominated marshes on the shores of two lakes. In one random plot/pair, yellow flag iris was cut to 0–4 cm above the sediment. Cuttings were removed. The other plots were left uncut. Vegetation cover was surveyed in July 2015.

    (Summarised by: Nigel Taylor)

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