- Соковнина (Абдульманова) С.Ю. &. Эктова С.Н. [Sokovnina (Abdulmanova) S.U. &. Ektova S.N]
- Растительные ресурсы [Rastitelnye Resursy]
- 56(3): 221–240
- DOI: 10.31857/S0033994620030085
[in Russian with English summary:] Overgrazing caused by reindeer husbandry has been a serious problem for the regions of the boreal
and tundra zones for many years . Terricolous fruticose lichens are the most sensitive component of Northern
ecosystems [2, 8–10]. Currently, valuable forage lichens in the tundra zone of the Yamal Peninsula maintaining
high occurrence, have a low abundance. The greatest impact of reindeer grazing and trampling is typical
for summer pastures and driving paths. The study is aimed to estimation of the growth rate of Cladonia
lichen thalli on summer pastures of the Yamal and Gydan peninsulas with different levels of vegetation cover
degradation. The main objects of the study were valuable forage species of shrubby fruticose lichens – Cladonia
arbuscula (Wallr.) Flot, C. rangiferina (L.) F. H. Wigg, C. stellaris (Opiz) Pouzar & Vzda, C. stygia (Fr.) Ruoss.
In this research 2 gradients were considered: zonal and plant communities. Shrub tundra subzone: shrub tundra,
exposed tundra communities, hummock bogs. Typical tundra subzone: shrub tundra, exposed tundra
communities and hummock bogs. Arctic tundra subzone: dwarf shrub-lichen tundra, spotted grass-moss-lichen
tundra and hummock bogs. The growth rate was calculated as a ratio of lichen podetia height to the
number of branches , which characterizes lichen growth potential in the study area. And the growth rate
of the living part of lichen podetia  was estimated, to assess the potential of lichen productivity. This method
is recognized in the international scientific community [19, 20]) and confirmed by modern methods .
For analysis, we used one-factor or two-factor analysis of variance, methods of multivariate analysis, using
forward sorting, and univariate regression. In the study area, the growth rate of shrubby fruticose lichens varied
from 1.2 to 6.3 mm/ year. There is no significant decrease in lichen growth rate from south to north. The
lowest growth rate of shrubby fruticose lichens was observed in the communities of the southern (shrub) tundra.
That is in opposition to the expected maximum. The height of podetia in the southern (shrub) tundra is
21% lower than in the arctic. Arctic tundra communities exist under less impact. The height of the living part
of podetia in the zonal gradient does not change. However, the highest values were found in the southern
(shrub) tundra, which indicates a higher growth potential of lichens. The relative age of the podetia and its
living part vary insignificantly in the “south – north” gradient. In the southern (shrub) tundra in shrub plant
communities, model lichen species grow significantly faster. The density of shrubs is the single significant biotic
factor that positively affects the growth rate of lichens. In the plant community series of the northern
(typical) tundra differences in the growth rate were not revealed. The maximum growth rate was observed in
communities of hummock bogs and decreased in shrub tundra by 13% and in exposed tundra by another 6%.
The single significant biotic factor for the lichen growth rate is the thickness of the moss-lichen layer. With
an increase in pasture impacts, the contribution of lichen mat height to the growth rate variation increases
from 6 to 28%. In the arctic tundra subzone the growth rate of lichens in the hummock bogs is significantly
higher than in other types of plant communities. The lichen mat height and percentage cover of mosses are
significant biotic factors. The variation in the height and age parameters of the lichen podetia in the plant
communities gradient is similar to lichen growth rate changes. Among the model species, the minimum
growth rate and growth rate of the living part of podetia were revealed for C. stellaris, the species most sensitive
to trampling. However, the maximum values of the height and age of the living part of the podetia prove that
this species has the greatest potential for growth and production. The most resistant to pasture impact is
C. stygia, a species characterized by the maximum growth rates of the podetia and its living part, and maximum
height of the podetia.
Keywords: Yamal peninsula, Gydan peninsula, West Siberia, tundra zone, shrubby fruticose lichens, genus
Cladonia, growth rate, geographical gradient, ecological gradient, grazing influence.
- Tuesday, 02 May 2023 15:29