Study

Revegetation of a wetland following control of the invasive woody weed, Mimosa pigra, in the Northern Territory, Australia

  • Published source details Paynter Q. (2004) Revegetation of a wetland following control of the invasive woody weed, Mimosa pigra, in the Northern Territory, Australia. Ecological Management & Restoration, 5, 191-198

Actions

This study is summarised as evidence for the following.

Action Category

Physically damage problematic plants: freshwater marshes

Action Link
Marsh and Swamp Conservation

Use prescribed fire to control problematic plants: freshwater marshes

Action Link
Marsh and Swamp Conservation

Introduce fragments of non-woody plants: freshwater wetlands

Action Link
Marsh and Swamp Conservation

Introduce seeds of non-woody plants: freshwater wetlands

Action Link
Marsh and Swamp Conservation

Introduce fragments of non-woody plants: freshwater wetlands

Action Link
Marsh and Swamp Conservation

Introduce seeds of non-woody plants: freshwater wetlands

Action Link
Marsh and Swamp Conservation

Use herbicide to control problematic plants: freshwater marshes

Action Link
Marsh and Swamp Conservation
  1. Physically damage problematic plants: freshwater marshes

    A study in 1998–2003 in a degraded floodplain marsh in the Northern Territory, Australia (Paynter 2004) reported that following herbicide application, physical damage and prescribed burning to control invasive mimosa Mimosa pigra, some herbaceous plants recolonized the site along with mimosa. After one year, cover of all vegetation other than mimosa was approximately 31–80%. This included 12–45% total cover of grasses/sedges. Mimosa cover was approximately 0–17%, depending on the area within the marsh. The number of new mimosa seedlings each year declined over time, from 1 seedling/m2 in the first year after intervention was complete, to <0.5 seedlings/m2 in the second and third years, then 0 seedlings/m2 in the fourth year. Methods: Three interventions were applied to a 100-ha patch of mimosa-dominated floodplain. In April 1998, the site was sprayed with herbicide (metsulfuron methyl). In October 1999, the dead vegetation was crushed using a chain tied between two bulldozers, then the site was burned (fire lasting several days). The study does not distinguish between the effects of these interventions. Vegetation was surveyed in the dry season (July–October), in up to three areas of the marsh (where no vegetation had been introduced) and for up to four years after intervention was complete. This study was in the same area as (2), but used a different experimental set-up.

    (Summarised by: Nigel Taylor)

  2. Use prescribed fire to control problematic plants: freshwater marshes

    A study in 1998–2003 in a degraded floodplain marsh in the Northern Territory, Australia (Paynter 2004) reported that following herbicide application, physical damage and prescribed burning to control invasive mimosa Mimosa pigra, some herbaceous plants recolonized the site along with mimosa. After one year, cover of all vegetation other than mimosa was approximately 31–80%. This included 12–45% total cover of grasses/sedges. Mimosa cover was approximately 0–17%, depending on the area within the marsh. The number of new mimosa seedlings each year declined over time, from 1 seedling/m2 in the first year after intervention was complete, to <0.5 seedlings/m2 in the second and third years, then 0 seedlings/m2 in the fourth year. Methods: Three interventions were applied to a 100-ha patch of mimosa-dominated floodplain. In April 1998, the site was sprayed with herbicide (metsulfuron methyl). In October 1999, the dead vegetation was crushed using a chain tied between two bulldozers, then the site was burned (fire lasting several days). The study does not distinguish between the effects of these interventions. Vegetation was surveyed in the dry season (July–October), in up to three areas of the marsh (where no vegetation had been introduced) and for up to four years after intervention was complete.

    (Summarised by: Nigel Taylor)

  3. Introduce fragments of non-woody plants: freshwater wetlands

    A replicated, randomized, paired, controlled, before-and-after study in 1999–2000 in a floodplain marsh in the Northern Territory, Australia (Paynter 2004) reported that 50% of plots planted with wick grass Hymenachne acutigluma runners contained wick grass after one year, but found that planting had no significant effect on vegetation cover. After one year, wick grass was present in 5 of 10 planted plots (at approximately 1% cover). Presence in unplanted plots was not clearly reported. Planted and unplanted plots had statistically similar cover of vegetation overall (approximately 90%), sedges and grasses overall (approximately 12%) and invasive mimosa Mimosa pigra (approximately 10%). Before planting, plots destined for each treatment had statistically similar cover of vegetation (<1%), dead mimosa stumps (15%) and bare mud (85%). Methods: In November 1999 (at the end of the dry season), fifteen 5 x 5 m plots were established (in five sets of three) on a degraded floodplain marsh. Mimosa had recently been cleared from the marsh using herbicide, crushing and burning. Then, 10 plots (two random plots/set) were planted with locally-collected wick grass runners (36 or 121 runners/plot). The other five plots (one random plot/set) were not planted. Vegetation was surveyed immediately before planting and approximately one year after (October 2000). This study used the same marsh as (4), but a different experimental set-up.

    (Summarised by: Nigel Taylor)

  4. Introduce seeds of non-woody plants: freshwater wetlands

    A replicated, randomized, paired, controlled, before-and-after study in 1999–2000 in a floodplain marsh in the Northern Territory, Australia (Paynter 2004) reported that only two of five sown herb species were present after one year, and found that sowing had no significant effect on vegetation cover. After one year, the only two sown species present in any sown plots were wick grass Hymenachne acutigluma (in 1 of 35 sown plots; approximately 1% cover) and water chestnut Eleocharis dulcis (in 5 of 20 sown plots; cover not reported). Wick grass was present in 0 of 15 unsown plots. Water chestnut was present in 1 of 10 unsown plots. Sown and unsown plots had statistically similar cover of vegetation overall (approximately 76–90%), sedges and grasses (approximately 12–27%) and invasive mimosa Mimosa pigra (approximately 10–17%). Before sowing, plots destined for each treatment had similar cover of vegetation (<1%), dead mimosa stumps (5–15%) and bare mud (85–95%). Methods: In November 1999 (end of the dry season), herb seeds (collected from local wetlands) were sown into 5 x 5 m plots in a degraded floodplain marsh. Mimosa had recently been cleared from the marsh using herbicide, crushing and burning. In one area, ten sets of three plots were established. Twenty plots (two random plots/set) were sown with seeds of five mixed species, including wick grass and water chestnut (1 g/species). In the other area, five sets of four plots were established. Fifteen plots (three random plots/set) were sown with wick grass seeds (1.25 g, 5 g or 12.5 g). All other plots were not sown. Vegetation was surveyed immediately before sowing and approximately one year after (October 2000). This study used the same marsh as (5), but different experimental set-ups.

    (Summarised by: Nigel Taylor)

  5. Introduce fragments of non-woody plants: freshwater wetlands

    A replicated, randomized, paired, controlled, before-and-after study in 2000–2003 in a floodplain marsh in the Northern Territory, Australia (Paynter 2004) found that plots planted with wick grass Hymenachne acutigluma runners contained more wick grass than unplanted plots over three years and had greater vegetation cover after three years, but supported similar mimosa germination rates. Immediately before planting, these plots had no vegetation cover. After one year, wick grass was more frequent and had greater cover in planted plots (present in 10 of 12 plots at 6% cover) than unplanted plots (present in 2 of 12 plots at <1% cover). Overall vegetation cover was statistically similar in planted plots (60%) and unplanted plots (66%). After three years, planted plots still had greater wick grass cover (24%) than unplanted plots (<2%) and now had greater overall vegetation cover (68%) than unplanted plots (50%). Finally, germination rates of invasive mimosa Mimosa pigra did not significantly differ between planted and unplanted plots in any year (see original paper). Methods: In July–September 2000 (at the end of the wet season), twelve pairs of 7.5 x 7.5 m plots were established on a degraded floodplain marsh. Mimosa had recently been cleared from the marsh using herbicide, crushing and burning. Then, one plot in each pair was planted with 16 locally-collected wick grass runners. The other plots were not planted. Vegetation was surveyed immediately before planting and in the following three dry seasons (July–October 2001–2003). This study used the same marsh as (3), but a different experimental set-up.

    (Summarised by: Nigel Taylor)

  6. Introduce seeds of non-woody plants: freshwater wetlands

    A replicated, randomized, paired, controlled, before-and-after study in 2000–2003 in a floodplain marsh in the Northern Territory, Australia (Paynter 2004) found that sowing seeds of three wetland herb species had no significant effect on their abundance or overall vegetation cover, or on germination rates of invasive mimosa Mimosa pigra. Immediately before sowing, plots had no vegetation cover. After one year, only one of three sown species (wick grass Hymenachne acutigluma) was present in sown plots. However, wick grass was present in the same proportion (17%) of sown and unsown plots. In three of three years after planting, sown and unsown plots had statistically similar cover of wick grass (sown: <2%; unsown: <2%), grasses/sedges overall (sown: 34–52%; unsown: 41–45%) and vegetation overall (sown: 40–76%; unsown: 50–76%). Finally, mimosa germination rates did not significantly differ between sown and unsown plots in any of the three years after sowing (see original paper for data). Methods: In July–September 2000 (at the end of the wet season), twelve pairs of 7.5 x 7.5 m plots were established on a degraded floodplain marsh. Mimosa had recently been cleared from the marsh using herbicide, crushing and burning. Then, one plot in each pair was sown with an equal mix of three herb species (2,667 g/ha of seeds collected from local wetlands). The other plots were not sown. Vegetation was surveyed immediately before sowing and in the following three dry seasons (July–October 2001–2003). This study used the same marsh as (4), but a different experimental set-up.

    (Summarised by: Nigel Taylor)

  7. Use herbicide to control problematic plants: freshwater marshes

    A study in 1998–2003 in a degraded floodplain marsh in the Northern Territory, Australia (Paynter 2004) reported that following herbicide application, physical damage and prescribed burning to control invasive mimosa Mimosa pigra, some herbaceous plants recolonized the site along with mimosa. After one year, cover of all vegetation other than mimosa was approximately 31–80%. This included 12–45% total cover of grasses/sedges. Mimosa cover was approximately 0–17%, depending on the area within the marsh. The number of new mimosa seedlings each year declined over time, from 1 seedling/m2 in the first year after intervention was complete, to <0.5 seedlings/m2 in the second and third years, then 0 seedlings/m2 in the fourth year. Methods: Three interventions were applied to a 100-ha patch of mimosa-dominated floodplain. In April 1998, the site was sprayed with herbicide (metsulfuron methyl). In October 1999, the dead vegetation was crushed using a chain tied between two bulldozers, then the site was burned (fire lasting several days). The study does not distinguish between the effects of these interventions. Vegetation was surveyed in the dry season (July–October), in up to three areas of the marsh (where no vegetation had been introduced) and for up to four years after intervention was complete. This study was in the same area as (7), but used a different experimental set-up.

    (Summarised by: Nigel Taylor)

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