Wetland vegetation before and after experimental purple loosestrife removal
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Published source details
Morrison J.A. (2002) Wetland vegetation before and after experimental purple loosestrife removal. Wetlands, 22, 159-169.
Published source details Morrison J.A. (2002) Wetland vegetation before and after experimental purple loosestrife removal. Wetlands, 22, 159-169.
Actions
This study is summarised as evidence for the following.
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Physically remove problematic plants: freshwater marshes Action Link |
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Physically remove problematic plants: freshwater marshes Action Link |
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Use herbicide to control problematic plants: freshwater marshes Action Link |
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Physically remove problematic plants: freshwater marshes
A replicated, randomized, paired, controlled, before-and-after study in 1988–1991 in two wet meadows invaded by purple loosestrife Lythrum salicaria in New York State, USA (Morrison 2002) found that physically removing all vegetation had no significant effect on vegetation richness, diversity or overall cover three years later, but increased cover of grass-like plants and reduced cover of forbs. After three years and in both meadows, cleared and uncleared plots had statistically similar plant species richness (cleared: 8; uncleared: 7–8 species/m2), plant diversity (data reported as a diversity index) and overall vegetation cover (cleared: 79%; uncleared: 78–117%). However, cleared plots were dominated by grass-like plants (73–74% cover) and had little cover of forbs (overall: 6–9%; purple loosestrife: 2%), whereas uncleared plots had little cover of grass-like plants (26–39%) and had high cover of forbs (overall: 41–92%; purple loosestrife: 31–78%). Note that these differences were only statistically significant in one of the two meadows. For data on the cover of other individual plant species, see original paper. Before intervention and within each meadow, plots destined for each treatment had statistically similar total vegetation cover (99–153%), plant species richness (8–10 species/m2). plant diversity, grass-like plant cover (11–67%) and loosestrife cover (18–82%). In one meadow, overall forb cover was lower in plots destined for clearance (25%) than plots not destined for clearance (121%). Methods: In 1988, six pairs of 1-m2 plots were established across two loosestrife-invaded wet meadows. In September, all vegetation was dug up and removed from one random plot in each pair. These plots were also used in (3). Vegetation was not removed from the other plots. Plant species and their cover were surveyed before removal (August 1988) and three years after (September 1991).
(Summarised by: Nigel Taylor)
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Physically remove problematic plants: freshwater marshes
A replicated, randomized, paired, controlled, before-and-after study in 1988–1991 in two wet meadows that had been cleared of vegetation in New York State, USA (Morrison 2002) found that controlling regrowth of invasive purple loosestrife Lythrum salicaria (by pulling up seedlings and applying herbicide to large shoots) had no significant effect on plant species richness, diversity or vegetation cover. After three years, plots with and without control of loosestrife regrowth had statistically similar plant species richness (control: 7; no control: 8 species/m2), plant diversity (data reported as a diversity index), total vegetation cover (control: 67–82%; no control: 79%), grass-like plant cover (control: 60–75%; no control: 70–73%) and forb cover (control: 5–20%; no control: 8–10%). Purple loosestrife cover was 0% in plots where regrowth had been controlled, but still only 2% in plots where regrowth had not been controlled. For data on the cover of other individual plant species, see original paper. Before intervention and within each meadow, plots destined for each treatment had statistically similar plant species richness (8–9 species/m2), plant diversity, total vegetation cover (103–143%), grass-like plant cover (16–58%), forb cover (25–56%) and purple loosestrife cover (23–63%). Methods: In 1988, six pairs of 1-m2 plots were established across two loosestrife-invaded wet meadows. In September, all vegetation was dug up and removed from the plots. In six of the plots (one random plot/pair), loosestrife regrowth was controlled twice/year thereafter (pulling up seedlings and painting large shoots with glyphosate; the study does not distinguish between the effects of these interventions). In the other plots loosestrife regrowth was not controlled. These plots were also used in (2). Plant species and their cover were surveyed before initial removal (August 1988) and three years after (September 1991).
(Summarised by: Nigel Taylor)
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Use herbicide to control problematic plants: freshwater marshes
A replicated, randomized, paired, controlled, before-and-after study in 1988–1991 in two wet meadows that had been cleared of vegetation in New York State, USA (Morrison 2002) found that controlling regrowth of invasive purple loosestrife Lythrum salicaria (by applying herbicide to large shoots and pulling up seedlings) had no significant effect on plant species richness, diversity or vegetation cover. After three years, plots with and without control of loosestrife regrowth had statistically similar plant species richness (control: 7; no control: 8 species/m2), plant diversity (data reported as a diversity index), total vegetation cover (control: 67–82%; no control: 79%), grass-like plant cover (control: 60–75%; no control: 70–73%) and forb cover (control: 5–20%; no control: 8–10%). Purple loosestrife cover was 0% in plots where regrowth had been controlled, but still only 2% in plots where regrowth had not been controlled. For data on the cover of other individual plant species, see original paper. Before intervention and within each meadow, plots destined for each treatment had statistically similar plant species richness (8–9 species/m2), plant diversity, total vegetation cover (103–143%), grass-like plant cover (16–58%), forb cover (25–56%) and purple loosestrife cover (23–63%). Methods: In 1988, six pairs of 1-m2 plots were established across two loosestrife-invaded wet meadows. In September, all vegetation was dug up and removed from the plots (see Action: Physically remove problematic plants). In six of the plots (one random plot/pair), loosestrife regrowth was controlled twice/year thereafter (painting large shoots with glyphosate and pulling up seedlings; the study does not distinguish between the effects of these interventions). In the other plots, loosestrife regrowth was not controlled. Plant species and their cover were surveyed before initial removal (August 1988) and three years after (September 1991).
(Summarised by: Nigel Taylor)
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