Parrot’s feather: Water level drawdown

How is the evidence assessed?
  • Effectiveness
    60%
  • Certainty
    30%
  • Harms
    0%

Study locations

Key messages

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. 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.

    Study and other actions tested
Please cite as:

Aldridge, D., Ockendon, N., Rocha, R., Smith, R.K. & Sutherland, W.J. (2020) Some Aspects of Control of Freshwater Invasive Species. Pages 555-87 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Control of Freshwater Invasive Species

This Action forms part of the Action Synopsis:

Control of Freshwater Invasive Species
Control of Freshwater Invasive Species

Control of Freshwater Invasive Species - Published 2017

Control of Freshwater Invasive Species Synopsis

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What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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