Carex seedling emergence in restored and natural prairie wetlands

Published source details Kettenring K.M. & Galatowitsch S.M. (2011) Carex seedling emergence in restored and natural prairie wetlands. Wetlands, 31, 273-281.
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This study is summarised as evidence for the following.

	Action	Category
	Chill seeds of non-woody plants before sowing: freshwater wetlands Action Link
	Introduce seeds of non-woody plants: freshwater wetlands Action Link

Chill seeds of non-woody plants before sowing: freshwater wetlands

A replicated, paired, controlled study in 2003–2004 in six prairie pothole wet meadows in Iowa, USA (Kettenring & Galatowitsch 2011) found that chilling sedge Carex spp. seeds increased germination rates for seeds sown in natural meadows, but not for seeds sown in restored meadows. In natural meadows and averaged across all four sown species, the germination rate was higher for chilled seeds (3%) than seeds kept at room temperature (<0.3%). However, the difference was only significant for one of four species when analyzed separately (bristly sedge Carex comosa; chilled: 3%; room temperature: <0.2%). In recently rewetted meadows, the germination rate did not significantly differ between treatments, whether averaged across species (chilled: 13%; room temperature: 9%) or analyzed for individual species (chilled: 9–17%; room temperature: 8–11%). Methods: In late spring 2003, wild-collected seeds of four sedge species were sown into the wet meadow zone of six prairie potholes (three natural and three rewetted one year previously). Within each pothole, eighteen 50-cm diameter plots/species were sown with 300 seeds. Nine plots/pothole received chilled seeds (kept at 1–5°C over the previous winter) whilst the other nine received unchilled seeds (kept at room temperature over the previous winter). Seedlings were counted for two growing seasons.

(Summarised by: Nigel Taylor)
Introduce seeds of non-woody plants: freshwater wetlands

A replicated study in 2003–2004 in six wet meadows in Iowa, USA (Kettenring & Galatowitsch 2011) reported that <1–21% of sown sedge Carex spp. seeds germinated within two growing seasons. A higher proportion of seeds germinated in recently rewetted meadows (7–21%) than natural meadows (<1–4%). For seeds sown in natural meadows in the spring, a higher proportion germinated when chilled over the previous winter than when kept at room temperature (see Action: Chill seeds before sowing). Within each wetland type and seed treatment, germination rate did not significantly differ between species (see original paper). Methods: In autumn 2002 and spring 2003, seeds of 4–5 sedge species were sown into the wet meadow zone of six prairie pothole wetlands (900–8,100 wild-collected seeds/species/pothole, split across 9–27 plots/species). Three meadows were natural and three had been rewetted one year previously (so were still developing vegetation, and had drier soil with no sedge seeds). Autumn-sown seeds were held in place with plastic mesh and barriers. Amongst spring-sown seeds, half had been chilled (1–5^°C) over the previous winter whilst half had been kept at room temperature. Seedlings that emerged from the soil were counted for two growing seasons.

(Summarised by: Nigel Taylor)