Using sheep to control purple loosestrife (Lythrum salicaria)

Published source details Kleppel G.S. & LaBarge E. (2011) Using sheep to control purple loosestrife (Lythrum salicaria). Invasive Plant Science and Management, 4, 50-57.
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This study is summarised as evidence for the following.

	Action	Category
	Use grazing to control problematic plants: freshwater marshes Action Link

Use grazing to control problematic plants: freshwater marshes

A replicated, paired, controlled, before-and-after study in 2008 in a wet meadow invaded by purple loosestrife Lythrum salicaria and reed canarygrass Phalaris arundinacea in New York State, USA (Kleppel & LaBarge 2011) found that grazed paddocks had higher plant species richness and greater cover of non-invasive plants than ungrazed paddocks. After two months, grazed paddocks contained more plant species in total (grazed: 25; ungrazed: 20 species/20 m²) and per quadrat (grazed: 4.0; ungrazed: 2.6 species/0.25 m²). Grazed paddocks had lower cover than ungrazed paddocks of the key invasive species: purple loosestrife (grazed: 20%; ungrazed: 65%) and reed canarygrass (grazed: 20%; ungrazed: 50%). Accordingly, grazed paddocks had higher cover of other grass-like plants (40%) than ungrazed paddocks (20%). Before intervention, cover of these plant groups was statistically similar in paddocks destined for each treatment (loosestrife: 50%; canarygrass: 43–45%; other grass-like plants: 20–30%). Methods: Four pairs of 200-m² paddocks were established in an invaded wet meadow. Between 16 June and 3 August 2008, one plot/pair was rotationally grazed by sheep (two ewes/paddock for 2–3 days every two weeks). Detailed vegetation surveys were carried out after intervention (mid-August 2008; 20 quadrats/paddock). Cover was also surveyed before intervention (early June 2008).

(Summarised by: Nigel Taylor)