Study

Control of Lepidium latifolium (perennial pepperweed) and recovery of native plants in tidal marshes of the San Francisco Estuary

  • Published source details Boyer K.E. & Burdick A.P. (2010) Control of Lepidium latifolium (perennial pepperweed) and recovery of native plants in tidal marshes of the San Francisco Estuary. Wetlands Ecology and Management, 18, 731-743.

Actions

This study is summarised as evidence for the following.

Action Category

Physically remove problematic plants: brackish/salt marshes

Action Link
Marsh and Swamp Conservation

Use herbicide to control problematic plants: brackish/salt marshes

Action Link
Marsh and Swamp Conservation

Use herbicide to control problematic plants: brackish/salt marshes

Action Link
Marsh and Swamp Conservation
  1. Physically remove problematic plants: brackish/salt marshes

    A replicated, randomized, paired, controlled, before-and-after study in 2005–2007 in three brackish and salt marshes invaded by pepperweed Lepidium latifolium in California, USA (Boyer & Burdick 2010) found that physically removing pepperweed before spraying herbicide increased native plant cover more than spraying alone. Averaged over the two years following intervention, cleared/sprayed plots had greater cover of native plants (year one: 26–124%; year two: 33–195%) than plots that were only sprayed (year one: 10–67%; year two: 19–113%). In contrast, cleared/sprayed plots had lower pepperweed cover (year one: 0–14%; year two: 5–44%) than plots that were only sprayed (year one: 2–60%; year two: 25–88%). Before intervention, plots destined for each treatment had statistically similar cover of native plants (10–33%) and pepperweed (90–100%). For data on the cover of other individual plant species, see original paper. Methods: In April 2005, five sets of 2 x 2 m plots were established each of three pepperweed-invaded marshes. In each set, there was one replicate where pepperweed was removed (including roots to 20 cm depth) before spraying regrowth with herbicide (1.25% glyphosate), and one replicate that was only sprayed with herbicide. Treatments were randomly allocated to plots. Vegetation cover was measured before (April 2005) and quarterly for two years after (April 2007) intervention, in 1-m2 quadrats.

    (Summarised by: Nigel Taylor)

  2. Use herbicide to control problematic plants: brackish/salt marshes

    A replicated, randomized, paired, controlled, before-and-after study in 2005–2007 in three brackish and salt marshes invaded by pepperweed Lepidium latifolium in California, USA (Boyer & Burdick 2010) found that plots sprayed with glyphosate herbicide typically had similar cover of native plants to unsprayed plots, over the two years following spraying. In most comparisons, total native plant cover was statistically similar in sprayed and unsprayed plots: eight of nine comparisons in year one (for which sprayed: 10–50%; unsprayed: 16–45%) and six of nine comparisons in year two (for which sprayed: 19–113%; unsprayed: 23–49%). Pepperweed cover was typically lower in sprayed than unsprayed plots: in nine of nine comparisons in year one (sprayed: 2–60%; unsprayed: 89–99%) and six of nine comparisons in year two (for which sprayed: 25–78%; unsprayed: 85–100%). Before intervention, plots destined for each treatment had statistically similar cover of native plants (10–33%) and pepperweed (90–100%). For data on the cover of other individual plant species, see original paper. Methods: In April 2005, five sets of 2 x 2 m plots were established in each of three pepperweed-invaded marshes. In each set, there was one sprayed replicate (1.25% glyphosate) and one unsprayed replicate. Treatments were randomly allocated to plots. Vegetation cover was measured before (April 2005) and quarterly for two years after (April 2007) spraying, in 1-m2 quadrats. This study shared part of the experimental set-up used in (3).

    (Summarised by: Nigel Taylor)

  3. Use herbicide to control problematic plants: brackish/salt marshes

    A replicated, randomized, paired, controlled, before-and-after study in 2005–2007 in three brackish and salt marshes invaded by pepperweed Lepidium latifolium in California, USA (Boyer & Burdick 2010) found that plots sprayed with glyphosate herbicide typically had similar cover of native plants to unsprayed plots, over the two years following spraying. In most comparisons, total native plant cover was statistically similar in sprayed and unsprayed plots: eight of nine comparisons in year one (for which sprayed: 10–50%; unsprayed: 16–45%) and six of nine comparisons in year two (for which sprayed: 19–113%; unsprayed: 23–49%). Pepperweed cover was typically lower in sprayed than unsprayed plots: in nine of nine comparisons in year one (sprayed: 2–60%; unsprayed: 89–99%) and six of nine comparisons in year two (for which sprayed: 25–78%; unsprayed: 85–100%). Before intervention, plots destined for each treatment had statistically similar cover of native plants (10–33%) and pepperweed (90–100%). For data on the cover of other individual plant species, see original paper. Methods: In April 2005, five sets of 2 x 2 m plots were established in each of three pepperweed-invaded marshes. In each set, there was one sprayed replicate (1.25% glyphosate) and one unsprayed replicate. Treatments were randomly allocated to plots. Vegetation cover was measured before (April 2005) and quarterly for two years after (April 2007) spraying, in 1-m2 quadrats. This study shared part of the experimental set-up used in (2).

    (Summarised by: Nigel Taylor)

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