Study

Effects of experimental disturbances on a tropical freshwater marsh invaded by the African grass Echinochloa pyramidalis

  • Published source details López Rosas H., Moreno-Casasola P. & Mendelssohn I.A. (2006) Effects of experimental disturbances on a tropical freshwater marsh invaded by the African grass Echinochloa pyramidalis. Wetlands, 26, 593-604.

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 cutting/mowing to control problematic herbaceous plants: freshwater marshes

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 replicated, randomized, paired, controlled study in a freshwater marsh in eastern Mexico (López Rosas et al. 2006) found that disking after cutting grass-invaded vegetation increased plant diversity (but not richness), typically had no significant effect on overall plant density, and increased the absolute and relative abundance of two common native plant species. After 4–8 months, cut/disked plots had higher plant diversity than plots that had only been cut (data reported as a diversity index). However, there was no significant difference between treatments in plant species richness (cut/disked: 7–10; cut only: 4–7 species/0.49 m2). Cut/disked plots supported a similar overall plant density to cut plots in two of three comparisons (for which cut/disked: 66–89; cut only: 67–120 individuals/0.49 m2). Two of five monitored native plant species had greater cover in cut/disked plots (Canada spikesedge Eleocharis geniculata: 26%; umbrella sedge Fuirena simplex: 10%) than cut plots (spikesedge: 0%; umbrella sedge: 1%). The same was true for relative abundance (above-ground biomass, measured after eight months only; see original paper for data). Invasive antelope grass Echinochloa pyramidalis had statistically similar cover under each treatment in two of three comparisons (for which cut/disked: 26–42%; cut only: 38–47%). Methods: In January (year not reported), seven pairs of 0.49-m2 plots were established in a degraded marsh, invaded by antelope grass. In all 14 plots, vegetation was cut to ground level. In one random plot/pair, the soil was then disked by hand (to 37 cm depth, until a “muddy, uniform consistency” was reached). This damaged rhizomes (underground horizontal stems). All of these plots were enclosed, underground, by a plastic barrier. Vegetation was surveyed between May and September later that year (biomass in September only).

    (Summarised by: Nigel Taylor)

  2. Use cutting/mowing to control problematic herbaceous plants: freshwater marshes

    A replicated, randomized, paired, controlled study in a freshwater marsh invaded by antelope grass Echinochloa pyramidalis in eastern Mexico (López Rosas et al. 2006) found that cutting the vegetation had no significant effect on overall plant density, richness or diversity, the relative abundance of common plant species, or the absolute abundance of common native plant species. After 4–8 months, cut and uncut plots contained a statistically similar overall plant density (six of six comparisons; cut: 56–126; uncut: 54–93 plants/0.49 m2), species richness (six of six comparisons; cut: 4–8; uncut: 3–5 species/0.49 m2) and diversity (two of two comparisons; data reported as a diversity index). Accordingly, all six monitored plant species had a similar relative abundance in cut and uncut plots (five native species, plus antelope grass; see original paper for data). The five native plant species had statistically similar cover in cut and uncut plots in 14 of 14 comparisons (both treatments: 0–19% cover/species). In contrast, antelope grass had lower cover in cut plots in five of six comparisons (for which cut: 38–92%; uncut: 94–100%). Methods: In January (year not reported), twenty-one 0.49-m2 plots were established (in seven sets of three) in a degraded marsh, invaded by antelope grass. In 14 plots (two random plots/set), vegetation was clipped to ground level. In seven of these, the most abundant native plant species was deliberately not clipped. In the final seven plots (one random plot/set), no vegetation was clipped. All 21 plots were enclosed, underground, by a plastic barrier. Vegetation was surveyed between May and September later that year (relative biomass in September only).

    (Summarised by: Nigel Taylor)

  3. Use herbicide to control problematic plants: freshwater marshes

    A replicated, randomized, paired, controlled study in a freshwater marsh invaded by antelope grass Echinochloa pyramidalis in eastern Mexico (López Rosas et al. 2006) found that spraying the vegetation with herbicide had no significant effect on overall plant density, richness or diversity, the relative abundance of common plant species, or the absolute abundance of common native plant species. After 4–8 months, sprayed and unsprayed plots contained a statistically similar overall plant density (six of six comparisons; sprayed: 57–81; unsprayed: 54–93 plants/0.49 m2), species richness (six of six comparisons; sprayed: 5–7; unsprayed: 3–5 species/0.49 m2) and diversity (two of two comparisons; data reported as a diversity index). Accordingly, all six monitored plant species had a similar relative abundance in sprayed and unsprayed plots (five native species, plus antelope grass; see original paper for data). The five native plant species had statistically similar cover in sprayed and unsprayed plots in 13 of 14 comparisons (both treatments: 0–19% cover/species). In contrast, antelope grass had lower cover in sprayed plots in four of six comparisons (for which sprayed: 22–78%; unsprayed: 99–100%). Methods: In January (year not reported), twenty-one 0.49-m2 plots were established (in seven sets of three) in a degraded marsh, invaded by antelope grass. Fourteen plots (two random plots/set) were sprayed with glyphosate herbicide (Roundup®). In seven of these, the most abundant native plant species was shielded with plastic tubes. The final seven plots (one random plot/set) were not sprayed. All 21 plots were enclosed, underground, by a plastic barrier. Vegetation was surveyed between May and September later that year (relative biomass in September only).

    (Summarised by: Nigel Taylor)

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