M. Zobel et al., Small-scale dynamics of plant communities in an experimentally polluted and fungicide-treated subarctic birch-pine forest, ACTA OECOL, 20(1), 1999, pp. 29-37
Pollution from the Cu-Ni smelter at Monchegorsk, Kola peninsula, has result
ed in major changes in the plant communities surrounding the smelter. Howev
er, very little pollution reaches northern Finland, which makes it possible
to use this area for field experiments to study the mechanism of community
change under pollution load. A field experiment was established to study t
he possible effect of pollution on the subarctic forest community, with Cu-
Ni pollution and acid rain (AR) used as treatments. A fungicide (F)-treatme
nt was also added to estimate the significance of plant-fungus interactions
in community response. Floristic similarity decreased during the experimen
t, both within and between treatments. Cu-Ni- and AR-treatments did not hav
e any effect on species richness. The Cu-Ni treatment reduced significantly
the number of new species arrivals in plots, whereas the number of local e
xtinctions remained constant. The heavy metal treatment resulted in a decre
ase in the bryophyte cover. The cover of Linnea borealis increased slightly
due to the Cu-Ni-treatment, but decreased due to the AR-treatment. The F-t
reatment also resulted in a lower richness than in the untreated variant. A
gain, this effect was due to the reduced number of arrivals, whereas the nu
mber of local extinctions remained unchanged. The F-treatment also resulted
in a higher cover of bryophytes and dwarf shrubs. Changes in species richn
ess of subarctic understorey plant communities were mainly caused by the di
fferential arrival of species under different environmental conditions. As
the number of arrivals was negatively correlated to the F-treatment, the pr
esence of (presumably positive) interactions between vascular plants and fu
ngi may have an influence on the response of a community to pollution. (C)
Elsevier, Paris.