ANTLFINGER, ANN E.* and DIANA BRADSHAW. Biology Department, University of Nebraska at Omaha, Omaha, NE 68182. - Seed germination and seedling establishment of Spiranthes cernua (Orchidaceae) in a native and a reestablished prairie.
Reintroduction of species can help restore diversity to damaged
ecosystems or reestablish organisms that are locally extirpated. In
this study, we investigated the feasibility of transplanting orchids
into prairies. Lab-germinated seedlings of Spiranthes cernua
were planted into the native Nine-Mile Prairie (Lincoln, NE) and the
reestablished Allwine Prairie Preserve (Omaha, NE) in 1998. We
examined the effect of planting location, season transplanted, and
herbivore protection on seedling survival and growth. There has been
limited success. One-third of the seedlings survived at Nine-Mile
Prairie (N=64) through 2000. In spring 2001, these seedlings were part
of a prescribed burn. After the fire, 14% were found aboveground. The
effect of the fire will be confirmed by the 2002 census. After four
years, only one seedling remains at Allwine Prairie (N=31). The low
survivorship may be due to soil, mycorrhizal or canopy differences
between native and reestablished prairies or physical disturbance of
the seedlings. In general, there was no effect of season or location
on survival. However, the mean total leaf area of spring-planted
seedlings was greater than those planted in the fall and location on a
slope at Nine-Mile Prairie also affected plant size. S. cernua
requires mycorrhizae for germination. In 1999, seeds were collected
from the native population and buried at Allwine Prairie in slide
holders containing fine-mesh cloth. One set was removed May-July 2000
and the status of 830 seeds recorded. Over 50% of the embryos had
swollen, 15% had ruptured the seed coat and one-third did not
germinate. This spring, the second replicate will be tested for
mycorrhizal infection. Transplanting small seedlings is
labor-intensive and may be an ineffective method of orchid
reintroduction, if our results are typical. This experiment does
provide important information about the demography of orchid
seedlings, which are difficult to locate in a mature prairie.
Key words: Orchidaceae, prairie, seed germination, seedling transplant, Spiranthes cernua