The effects of stand characteristics on reindeer lichens and range use by semi-domesticated reindeer

The study was carried out in Kuusamo (66°15'N, 29°05'E) and Inari (68°30'N, 28°15'E), northern Finland, where 24 and 22 Scots pine stands were studied respectively. Clear-cutting (logging residue) caused a decline in lichen biomass for some few years, but otherwise the age of the stand had no effect upon lichen biomass. Instead, a positive correlation was found between litter/logging residue and the mean height of lichens; in Kuusamo, logging residue decreased significantly with the age of the stand. Grazing pressure in terms of fecal group density increased with the age of the stand. The preference of old forests came visible also as a lower mean height of lichens, which eliminates the possibility that the preference of old forests is associated only to the use of arboreal lichens. In Inari, grazing pressure sharply increased after the stand had reached the age of 100 years despite scarce litter/logging residue and fair lichen ranges in younger forests; there prevailed a negative correlation between stand density and grazing pressure. It has been suggested that there might be three main reasons for reindeers preferring old forests: 1) hardening of the snow (because of winds) on clear-cut areas, 2) logging residue preventing digging for the food beneath the snow, and 3) poor visibility in young pine stands (Inari) which might increase predation risk.


Introduction
and Mattila (1981Mattila ( , 1988) stated that in Finnish reindeer management area there is no significant difference in lichen biomass in young (<70 yrs.) and older forests.On the other hand, there exists evidence that reindeer likely graze in old forests (R. Helle, 1984;Helle and Aspi, 1985).The question on availability of reindeer lichens is coming more important with the reduction of arboreal lichens caused in northern Finland by cuttings and air pollution (Kautto et al., 1986;Mattila, 1988;Helle et al., 1989).This paper deals with that obvious discrepancy between absolute (total biomass) and relative (biomass available to animals) lichen resources (see Andrewartha and Birch, 1954).

Study area
The study was carried out in Kuusamo If the grazing pressure in a known area is constant, the circle of radius, which contains at least one fresh item, is every year: (2) r f = V^I7~T were the Poisson parameter X denotes the mean number of items per circle of unit radius (see Pielou, 1977).If the fecal groups are observable only one year, then the distance from the random point to an old fecal group is the same as the distance to a fresh group.Generally, if fecal group is observable t years, then distance to an old group is: (3) r t = Vl/(tx \ ) Thus the ratio between old and fresh group in the stand is: (4) r t /r f =( ^I7(txx)/(V17X) and the age (t) of the fecal group is found to be: (

General features of study areas
The means for the main characteristics of the study areas are given in Table 1.

In
Fennoscandia, a major proportion of semidomesticated reindeer (Rangifer tarandus L.) confine themselves in winter in coniferous forests where timber is commonplace the main forest product.The impacts of wood production on winter ranges can be described briefly as followsreduces arboreal lichens (Usneaceae), since forests with abundant sources of them are normally older than 100 years (Mattila, 1979); arboreal lichens are used mainly in late winter when ground vegetation is not available to reindeer because of deep or hard snow.3. Reindeer lichens (Cladonia ssp.) are the most Rangifer, Special Issue No. 3, 1990.important component in the winter diet of reindeer.However, the opinions on the effects of forestry on lichen biomass and lichen use by reindeer are some what conflicting.

(
Calluna-Cladina type) in pine forests, were studied in 1983 and 1984.The size of the sample areas was 1 ha, and they were selected for the study on the basis of the estimated age of the stand in order to obtain a centre of the sample plot was measured separately to the nearest fresh (< 1 year) and old ( > 1 year) fecal group in 16 sample areas in Kuusamo in order to determine the average decomposition time for fecal groups.

Fig. 1 .
Fig. 1.The rate of decomposition of fecal groups in stands of various age.• = stands < 10 year; o = stands > 10 year The lower percent cover of lichens in Kuusamo is largely a result from heavier grazing pressure.In the late 1970's, the lichen range area per reindeer older than one year (close to animal number of winter herd) amounted in Kuusamo to 19 ha and in Inari to 68 ha.That explains also the lower mean height of lichens as well as the smaller proportion of Cladonia stellaris (0.3% vs. 33.7%,calculated from percent cover), whose poor resistence to heavy and frequently repeated grazing is well-known (Ahti, 1961).Also percent cover of mosses and litter was greater in Kuusamo.Most of litter in young stands was logging residue in both study areas.Material from Kuusamo comprised of younger regeneration areas, which might explain the abundance of logging residue.Reindeer lichens The characteristics of lichens were not dependent on the age of the stand in Kuusamo, whilst in Inari the mean height of lichens correlated negatively (r = -0.521,p < 0.05, df = 20) and percent cover positively (r = 0.445, p <.0.05, with the age of the stand.One should note, however, the drastic decline in lichen biomass in Kuusamo immediately after clearcutting (Fig. 2), when about 60% of the ground was

Fig. 2 .
Fig. 2. The age of the stand and lichen biomass in Kuusamo (A) and Inari (B).

Fig. 5 .
Fig. 4. The relationship between grazing pressure and the mean height of lichens in Kuusamo (A) and Inari (B).3E 1500

Table 1 .
General characteristics (mean +_ standard error) of the sample areas in Kuusamo and Inari.