Study

Altering light and soil N to limit Phalaris arundinacea reinvasion in sedge meadow restorations

  • Published source details Iannone B.V. & Galatowitsch S.M. (2008) Altering light and soil N to limit Phalaris arundinacea reinvasion in sedge meadow restorations. Restoration Ecology, 16, 689-701.

Actions

This study is summarised as evidence for the following.

Action Category

Introduce nurse plants to aid focal non-woody plants: freshwater wetlands

Action Link
Marsh and Swamp Conservation

Add below-ground organic matter before/after planting 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
  1. Introduce nurse plants to aid focal non-woody plants: freshwater wetlands

    A replicated, randomized, paired, controlled, before-and-after study in 2004–2005 in two wet basins in Minnesota, USA (Iannone & Galatowitsch 2008) found that sowing potential nurse species along with target sedge meadow species did not increase the germination rate or abundance of the target species after one growing season. Sixteen weeks after sowing, the germination rate was significantly lower in plots with a high-diversity nurse crop (33%) than plots with a low-diversity nurse crop (51%) or no nurse crop (61%). Plots with a nurse crop had a lower total density of the target species (with: 370–1,000; without: 980–1,300 shoots/m2) and target grass-like plants (with: 150–660; without: 660–780 shoots/m2). The effect of nurse crops on the total density of target forbs depended on presence of invasive reed canarygrass Phalaris arundinacea and addition of sawdust (see original paper for details). The study also reported data on the abundance of individual target species. Nurse crops had significant effect on 9 of 10 target species, although this sometimes depended on nurse crop diversity, canarygrass presence, sawdust addition and the outcome metric. For example, 6 of 10 target species had lower cover in plots with a high-diversity nurse crop than plots with no nurse crop (data reported as cover classes; see original paper for full details). Methods: In May 2005, seeds of 10 target sedge meadow species were sown onto seventy-two 1-m2 plots (total 2,250 seeds/m2) across two experimental, vegetation-free wet basins. The plots were grouped in six sets of 12. At the same time, a nurse crop was sown onto 48 plots (eight random plots/set; total 2,100 seeds/m2). This contained either five species (24 plots) or one species (24 plots). Some plots had also been amended with sawdust (October 2004) or sown with reed canarygrass (May 2005). Target vegetation was surveyed for 16 weeks after sowing. Seedlings were counted in five 100-cm2 subplots/plot. Shoot density and cover were monitored across the whole of each plot. This study used the same site as (1), but a different experimental set-up.

    (Summarised by: Nigel Taylor)

  2. Add below-ground organic matter before/after planting non-woody plants: freshwater wetlands

    A replicated, randomized, paired, controlled, before-and-after study in 2004–2005 in two wet basins in Minnesota, USA (Iannone & Galatowitsch 2008) found that adding sawdust to plots before sowing a mixture of sedge meadow species typically had no significant effect on their germination or abundance after one growing season. Sixteen weeks after sowing, the germination rate was statistically similar in plots with sawdust (48%) and plots without sawdust (47%). The same was true in four of four comparisons at earlier dates. After 16 weeks, plots under each treatment contained a statistically similar total density of target species (sawdust: 460–1,300; no sawdust: 370–1,100 shoots/m2) and target grass-like plants (sawdust: 190–690; no sawdust: 150–780 shoots/m2). The effect of sawdust addition on the total density of target forbs depended on the presence/diversity of a cover crop (see original paper for details). The study also reported data on the abundance of individual target species. Sawdust addition had no significant effect on 5 of 10 species for any metric and in any conditions (see original paper for details). Methods: In October 2004, seventy two 1-m2 plots were established (in six sets of 12) across two experimental, vegetation-free wet basins. In half of the plots (6 random plots/set), the top 7 cm of soil was replaced with cedar Thuja sp. sawdust. The plots were then tilled. In May 2005, seeds of 10 target sedge meadow species were sown onto all 72 plots (total 2,250 seeds/m2). Some plots were also sown with other species, as cover crops and/or experimental invaders (reed canarygrass Phalaris arundinacea). Target vegetation was surveyed for 16 weeks after sowing. Seedlings were counted in five 100-cm2 subplots/plot. Shoot density and cover were monitored across the whole of each plot.

    (Summarised by: Nigel Taylor)

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

    A replicated, before-and-after study in 2004–2005 in two experimental wet basins in Minnesota, USA (Iannone & Galatowitsch 2008) reported that 33–61% of sown sedge meadow plant seeds germinated depending on the presence/diversity of a nurse crop, and that vegetation abundance after one growing season depended on the presence/diversity of a nurse crop, presence of an invasive plant species, sawdust addition and the outcome metric. For example, the total density of target (sown) sedge meadow species was lowest (370 shoots/m2) in plots with a high-diversity nurse crop and reed canarygrass Phararis arundinacea, but without added sawdust, and highest (1,300 shoots/m2) in plots without a nurse crop, but with reed canarygrass and added sawdust. The density of individual sown species ranged from 0 shoots/m2 (e.g. great blue lobelia Lobelia siphilitica under all conditions) to 490 shoots/m2 (prairie ironweed Vernonia fasciculata under one set of conditions). Methods: In May 2005, seeds of ten target sedge meadow species were sown onto seventy-two 1-m2 plots (total 2,250 seeds/m2) across two experimental, vegetation-free wet basins. The seeds were stored cold (4°C) and wet for four months before sowing. All plots were weeded for 10 weeks after sowing. For experimental reasons, 48 plots were also sown with a potential nurse crop (one or five species), 36 plots were sown with reed canarygrass, and 36 plots were amended with sawdust before sowing. Target vegetation was surveyed for 16 weeks after sowing. Seedlings were counted in five 100-cm2 subplots/plot. Shoot density and cover were monitored across the whole of each plot. This study used the same site as (2) and (3), but a different experimental set-up.

    (Summarised by: Nigel Taylor)

Output references
What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 18

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.


Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust