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Providing evidence to improve practice

Individual study: Survival of parrotfeather following simulated drawdown events

Published source details

Wersal R.M., Madsen J. & Gerard P. (2013) Survival of parrotfeather following simulated drawdown events. Journal of Aquatic Plant Management, 51, 22-26


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Parrot’s feather: Water level drawdown Control of Freshwater Invasive Species

A replicated, randomized, controlled, laboratory study conducted between 2008 and 2009 in the USA (Wersal et al. 2013) found that water removal in order to expose plants to drying during the summer (summer dry outs) reduced survival of parrot’s feather Myriophyllum aquaticum more than water removal during winter (winter dry outs). For four out of five comparisons, the survival of parrot’s feather plants exposed to dry outs of the same duration was lower in summer (0–75%) than in winter (68–80%). After a dry out of 12 weeks, parrot’s feather survival was 18% in summer and 78% in winter. Parrot’s feather shoots were propagated in 3.78 l pots placed inside 1100 l containers filled with water. Four containers, each with 10 pots, were exposed to dry outs of two, four, six, eight and 12 weeks duration, or no dry out, in each season. Winter dry out was initiated in January and summer dry out was initiated in July.