Skógræktarritið - 15.05.2001, Síða 170

Table 1. Relative cover (%) July 1991, Hardangervidda, for some plant species showing strong
changes between plots after transplantation. (Benedict and Wielgolaski 1992).
1 Plant species Lichen heath “Blueberry ” community
Vacc. myrtillus Self-transpl. 0 Transpl. to "blueberry" community 0 Self-transpl. 9.42 Transpl. to lichen heath 1.00
Vacc. vitis-idaea 19.00 2.42 0 5.42
Desch. flexuosa 0 2.50 9.75 3.42
Festuca ovina 5.73 4 0 0.75
Dicranium coll. 1.10 6.92 16.25 11.50
Cetraria nivalis 22.10 0.17 0.17 7.83
expected that reciprocal trans-
plantations between the two
communities within some years
would visualise changes in the
taxonomic composition. ln that
way the studies could give indi-
cations on possible vegetation
changes by climatic variation, for
instance due to the greenhouse
effect by C02 increase. The
response of the various plant
species does not reflect only the
influence of each stress factor
before and after the transplanta-
tion, but it also reflects the inter-
nal changes in the competition
within the community.
The two communities chosen in
the studies are both low growing
without deep roots. Therefore, the
mats could relatively easily be
moved from one place to another
without too much destruction of
the plants. About 10 cm thick veg-
etation mats in six replicates were
carried between the sites in 75 by
35 cm styroform boxes. Mats of
similar size were also transplant-
ed within each of the sites to see
the effect of destruction of tops of
roots by the transplantation itself
in comparison with vegetation on
untouched plots. Non-destructive
samplings by percentage cover-
age of the various plant species
were carried out at the time of
seasonal maximal above ground
biomass the first year of study,
after four years and after nine
years (Wielgolaski and Benedict,
1986; Benedict and Wielgolaski,
1992). Some rough estimates
were also done after 15 years.
Results and discussion
Less than 20% of the plants of
Vaccinium myrlillus (blueberry)
transplanted to the lichen heath
were alive after 4 years and even
half of that 9 years after trans-
plantation, given as relative
cover (Table 1). 15 years after
transplantation all blueberry
plants transplanted to the lichen
heath were dead. The reduction
also in biomass of the species by
transplantation was strongly
significant both when compared
with the control plots and with
the selftransplanted ones. The
biomass of V. vitis-idaea moved
from the lichen heath to the
blueberry heath was also strong-
ly reduced after 9 years. The
cover of the species at that time
was less than 13 % as high in the
transplanted as in the selftrans-
planted plots (Table I). Explana-
tions for the reduction in V. myr-
tillus by transplantation may be
both the draught and the windy
and cold, poorly snow covered
lichen heath. The death of
V. vitis-idaea at the blueberry com-
munity was more surprising, but
may have something to do with
the wetter soil conditions at the
site.
The two grass species
Deschampsia flezuosa and Festuca
ovina showed a similar, but less
dramatic response to reciprocal
transplantations between the
sites. Normally the first species
mentioned is favoured in areas of
good snow cover, the second in
dry, wind blown areas. Both
species, however, seemed to sur-
vive relatively well 9 years after
transplantation to other condi-
tions. About 1/3 of D. flexuosa
(measured as cover or biomass)
survived 9 years after transplan-
tation from the blueberry heath
to the wind blown lichen heath,
while F. ovina survived well after
transplantation to the wetter
blueberry community. However,
the last species showed a consid-
erably weaker flowering percent-
age when transplanted from its
natural site. This may probably
indicate a weaker fitness to the
more sheltered conditions.
Also some of the other vascu-
lar plants in the study not shown
in the table, gave interesting
responses to the transplanta-
tions. The dwarf Salix, S. herbacea,
was not naturally found in the
plots at the lichen heath, but sur-
vived well after transplantation
from the blueberry heath even 15
years after transplantation. How-
ever, S. herbacea transplanted to
the lichen heath did not flower.
This may indicate that good
168
SKÓGRÆKTARRITIÐ 2001 l.tbl.