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Survival
In September, 4 months after our initial planting, the survival of
plugs was significantly greater than that of sprigs for all three
species (Table 3). Survival averaged over transplant type was about
65% for both Puccinellia and Spartina but only about 50% for Juncus.
Reevaluation of these May 1979 transplants 1 year after planting
indicated that significant mortality of both transplant types occurred
over winter (Table 3). Greater overwinter mortality occurred in plug
than in sprig transplants for both Puccinellia and Juncus . These
results suggest that whatever factors were causing mortality in the
sprigs were still affecting the plugs and that it was simply taking
longer to cause mortality in the larger transplant type. Overall
survival was less than 50% for both transplant types for all species,
but still significantly higher for plugs than for sprigs. These
relatively low survival percentages included plantings in unfavorable
(low elevation, exposed, poorly drained) locations, since we were
trying to determine response over a wide range of conditions. In the
more favorable sites, at about the elevation of the natural Juncus
marsh, survival of plug transplants was consistently above 70% for
Puccinellia . On those planting sites where 10% or more of the
transplants survived through the second year, plugs continued to
survive better than sprigs for Puccinellia and Juncus (Table 4). Of
all the 1979 transplants, only those of Puccinellia on the better sites
yielded survival values of greater than 60%.
TABLE 3. Percent survival at 4 and 12 months for two types of
transplants 3 for three species for the combined plantings
made at lie Grande and Kerlavos in May 1979.
Survival (%) by time" by type
Species 4 months 12 months
Sprig Plug Sprig Plug
Juncus