Fróðskaparrit - 01.01.1998, Blaðsíða 19

EIN OYGGJALÍVLANDAFRØÐILIG GREINING AV FLORUNI í FØROYUM
25
northern islands are significantly different
from the number of species of the remain-
ing islands (p<0.01). The deviations of the
southern islands in percent, however, are
not significantly larger than the other is-
lands (p>0.05).
The underlying cause why Fugloy has
not fewer species, may be due to an imper-
fection in the calculation method. The reg-
istration efforts carried out on Fugloy have
been greater than on other, northerly is-
lands, in relation to its area. In Hansen
(1966), it may be observed that Fugloy has
two stations where e.g. the more than dou-
ble-sized Svínoy has only one.
The height of the island is relevant, too.
In order to investigate whether high islands
have fewer species, the same test may be
applied. By a so-called high island, we un-
derstand an island which contains stations
in the high mountain zone, i.e. above 600
metres according to Hansen (1966). This
definition includes Suðuroy, Vágar,
Streymoy, Eysturoy, Kalsoy, Kunoy, Borð-
oy, Viðoy and Fugloy. There appears to be
a statistically reliable tendency for high is-
lands to have fewer species than low is-
lands.
We have been unable to establish
whether the northerly islands have a lower
number of species than anticipated on ac-
count of their location or their relief, but
most likely it is a combination of both fac-
tors.
In terms of the height of the islands, the
flora of the intermediate and mountainous
Area km2 Number of species Number of species acc.to S = cAz The null hypothesis % diff S = cAz % diff The null hypothesis
Suðuroy 166.0 238 202.0 224.7 17.8 5.9
Stóra Dímun 2.7 65 89.8 53.4 -27.6 21.8
Skúvoy 10.0 112 116.2 110.2 -3.6 1.7
Sandoy 112.1 222 187.0 210.1 18.7 5.7
Mykines 10.3 107 116.8 111.5 -8.4 -4.0
Vágar 177.6 211 204.7 227.1 3.1 -7.1
Hestur 6.1 118 105.4 87.9 12.0 34.3
Koltur 2.5 108 88.4 50.6 22.2 113.3
Nólsoy 10.3 145 116.8 111.5 24.1 30.1
Streymoy 373.5 221 237.0 252.3 -6.8 -12.4
Eysturoy 286.4 207 224.9 243.8 -8.0 -15.1
Kalsoy 30.9 139 145.1 158.3 -4.2 -12.2
Kunoy 35.5 151 149.1 164.1 1.3 -8.0
Borðoy 94.9 163 181.0 203.7 -9.9 -20.0
Viðoy 41.0 136 153.4 170.0 -11.3 -20.0
Svínoy 27.4 128 141.7 153.3 -9.7 -16.5
Fugloy 11.2 126 118.8 115.2 6.1 9.4
Lítla Dímun 0.8 12 70.6 19.8 -83.0 -39.4
I able 2. The number ofspecies in the Faroe Islands compared with the number of species in the Islands as
calculated by the two models S = cAzand the null hypothesis, based on the areas ofthe islands.
Talva 2. Talið á sløgum í Føroyum samanborið við talið á sløgum í íslandi, sum tey eru roknað út við tveimum
myndlum, S = cAz og null-hypotesuni, grundað á víddina á oyggjunum.