Ag. Van Der Valk et al., The restoration of sedge meadows: Seed viability, seed germination requirements, and seedling growth of Carex species, WETLANDS, 19(4), 1999, pp. 756-764
To better understand how to establish Carex species from seed in created an
d restored wetlands, a series of experimental studies was conducted on Care
x seed and seedlings. These studies included (1) the effect of seed age (1
to 18 months after collection) on viability and germination, (2) storage co
nditions (+4, -4 or +4/-4 degrees C; wet or dry) on seed germination, (3) s
oil moisture on seed germination, and (4) soil amendments (fertilizer, tops
oil, and compost) on seedling recruitment and growth. Seeds of Carex specie
s of several provenances would not germinate to any appreciable extent once
they were more than six months old. For Carex aquatilis, germination could
be increased by storing its seed at either 4 degrees C or -4 degrees C. Fo
r Carex lacustris and Carex stricta, seed germination decreased significant
ly, by about 50 to 100% in all 8 storage treatments. Germination of Carex s
tipata seed was highest in 1 cm of standing water, and its seed did not ger
minate in the driest soil moisture treatment. Carex stricta seed germinatio
n was not affected very much by soil moistures. No Carex spp. were recruite
d from seed in any of the field soil-amendment treatment plots. In both the
greenhouse and field, the addition of compost, topsoil, and fertilizer inc
reased the growth of Carex stricta In a greenhouse study, above ground, bel
ow ground, and total dry mass increased linearly with the percent compost a
dded. Our results suggest that the probability of establishing Carex spp. f
rom seed in created and restored wetlands in the Upper Midwest would be max
imized by using fresh seed, preferably seed produced earlier in the same gr
owing season; by keeping soil moisture levels as high as possible; and by r
aising the soil's organic matter content, if need be, through the use of su
itable soil amendments to levels found in natural sedge meadows.