Fróðskaparrit - 01.01.1987, Síða 96

100
THE ECOLOGY OF SOME MARINE AND MARITIME LICHENS
5.2 Littoral fringe.
Verrucaria maura is the only species oc-
curring in this zone and is here used as an
indicator for the zone. The upper border
corresponds to the lower limit of Lichina
confinis and Caloplaca marina, and on
shaded places of Caloplaca thallincola.
Table 1 and 2 show that the zone is 1 m
wide at loc. 59.
In northern Ireland Lichina pygmaea, L.
confinis, and Verrucaria maura constitute
three distinct zones. Lichina confinis is
making the uppermost belt, Verrucaria
maura the middle and Lichina pygmaea the
lowermost belt. While Lichina confinis is
common in the Faroe Islands, Lichina pyg-
mea is only found once here.
5.3 The mesic supralittoral zone.
It appears from table 1 and 2 that Verru-
caria maura is still dominating in this zone.
At loc. 59 Lichina confinis shows some de-
gree of dominance in the lowermost part of
this zone, but at loc. 57 this species are less
dominating, but widespread through the
entire zone. Lecanora poliophea invades at
both localities and gives the zone a greyish
colour. Caliplaca thallincola, and C. mar-
ina are found sporadically. At loc. 59
Phaeophyscia orbicularis and Candelariella
vitellina were found. The zone is 3 m wide
at loc. 57 and 4 m wide at loc. 59.
Fletcher (1973) uses Caloplaca marina,
Catillaria chalybeia, Lecanora actophila,
L. helicopis, and Lichina confinis as indica-
tor for the zones. Chatillaria chalybeia and
Lecanora helicopis were not found in my
investigations, but they were collected
once in the Faroe Islands by Degelius
(1955). Lecanora helicopis does not occur
in the m.s.l. zone, but sparsely in s.s.l.
zone at loc. 59.
Lecanora poliophaea is just as abundant-
ly distributed here as in the s.s.l. Accord-
ingly it will not be used as an indicator.
Baldursdóttir (1985) found the same distri-
butional pattern for this species in Iceland.
So it is most appropriate to use Caloplaca
marina and Lichina confinis as indicators.
5.4 The submesic supralittoral zone.
Lecanora poliophaea is still dominant in
this zone, and Verrucaria maura is abun-
dantly distributed here, especially at loc. 59
(see fig. 4 and 5).
The foliose Xanthoria parietina obtains a
relatively constant distribution here, is
used as an indicator. Other foliose lichens
that invade this zone are Physcia tenella var
marina, Physcia caesia, Physcia sp., and
Phaeophyscia orbicularis. The last men-
tioned species is especially dominating at
loc. 59 but is more sparse at loc. 57.
Of other species that were found in this
zone, but not in the m.s.l. zones, the fol-
lowing can be mentioned: Lecanora atra,
Buellia coniops, and Candelariella vitellina.
Lecanora actophila is very sparse at loc.
59, and was not found at loc. 57. Ramalina
siliquosa was found occasionally at loc. 59,
but it was not found in this zone at loc. 57.
Fig. 4 and 5 show that this zone has a width
of 4 m at both localities.
5.5 The xeric supralittoral zone.
Anaptychia fusca is the only new lichen at
both localities. For the first time Caloplaca
festiva invades loc. 57 in this zone, but at
loc. 59 it invaded an area further away