Fróðskaparrit - 01.07.2004, Síða 38

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HABITAT PREFERENCES OF THE ARBUSCULAR MYCORRHIZAL FUNGI
OF THE FAROES COMPARED WITH OTHER PLACES
Aspect Altitude #A #B #C #D #BL #Other Sum PJ in soil (mg/kg) Temp. (°C) S- W # Clones # AM types
North Low 0 6 11 14 0 3 34 10.3 6 0.95 27 4
North High 21 0 11 0 16 4 52 13.8 3.5 1.19 50 4
South Low 2 1 7 0 0 2 12 26.0 6.8 0.80 10 3
South High 0 0 26 0 0 3 29 17.5 4 0 26 1
23 7 55 14 16 12 127
Chi-square calculations for all categories of AM fungal types: df = 15, chi-square: 123.478, p < 0.001
If only aspect is considered, then df = 5, chi-square = 54.052 and p < 0.001
If only altitude is considered, then df = 5, chi-square = 41.004 and p < 0.001
Table 1. Number of the main AM fungal types and a Chi-square test, indicating that al the AM fungal communities
vary according to both aspect and altitude. Further are listed the values of extractable phosphorus (method: Olsen
et al, 1954 and Banderis et al., 1976), means of onsite temperature loggings, number of clones for each aspect/
altitude category and the number ofAM fungal types.
um repens from a seminatural grassland at
the Macaulay Institute’s Sourhope field sta-
tion in Scotland, and concluded that the two
plant species host different AM fungi, but
that A. capillaris supported 21 different
AM types.
The Shannon-Wiener index (Table 1)
shows a very low diversity at high altitude
south-facing. The explanation might be that
at high altitude there is reasonable more ex-
tractable phosphate on the south-facing
sites than at the north-facing. There is also
S- w # Clones # AM types
High 1.30 76 4
Low 1.07 36 5
North 1.63 82 6
South 0.45 37 4
Table 2. Shannon-Wiener values when only altitude is
considered (row 1 and 2) and when only aspect is
considered (row 3 and 4).
a temperature difference which migth af-
fect the growth of both plant and fungi
(Table 1). The Shannon index was 1.71 for
the Sourhope grassland ecosystem (2 plant
species).
Studies comparing plants with fme ver-
sus coarse root systems show that plants
with fíne root systems might be less depen-
dent upon the mycorrhizal symbiont for
phosphate uptake than plants with coarse
roots (Newsham et al., 1995b). As most
grasses, Agrostis capillaris have a fine root
system, and might be able to control the
colonisation under “high” phosphate lev-
els.
There is higher diversity at the north-
facing sites, and at high altitude compared
with low altitude. These sites have in com-
mon lower temperature and lower phos-
phate content than low altitude and south-
facing sites. AM fungi are known to in-
crease the host plants phosphate uptake,