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Providing evidence to improve practice

Individual study: Control of New Zealand pygmyweed Crassula helmsii by covering with black polythene at The Lodge RSPB Reserve, Bedfordshire, England

Published source details

Wilton-Jones G. (2005) Control of New Zealand pygmyweed Crassula helmsii by covering with black polythene at The Lodge RSPB Reserve, Bedfordshire, England. Conservation Evidence, 2, 63-63


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Crassula helmsii: Use lightproof barriers to control plants Control of Freshwater Invasive Species

A before-and-after field trial in 2003-2004 at a single pond in Bedfordshire, UK (Wilton-Jones 2005) reported that covering plants with black polythene eradicated C. helmsii, but it recolonized the site within a year and no statistical tests were carried out. Before the trial C. helmsii was estimated to cover 5% of the pond, and was eradicated after the treatment. However, one year after the treatment finished C. helmsii had recolonized the pond. The authors suggest this was due to plants which survived in surrounding areas not covered by the polythene. The 12 m2 pond was covered with opaque black polythene weighed down with stones for six months between autumn 2003 and spring 2004.