Greinar (Vísindafélag Íslendinga) - 01.01.1967, Blaðsíða 67

63
Faxasker
Faxasker is to the north of Yztiklettur on Heimaey.
It is rather low, not more than 10 m above sea-level and
covered by the breakers in rough weather. There is a
shelter for shipwrecked seamen on the rock, and also a
light. Three species of vascular plants have been found
there, though only a few individual plants of each: Coch-
learia officinalis, Puccinélla maritima and Stellaria media.
Concluding remarks
In general the vegetation on the larger islets is pre-
dominated by the grasses, especially Festuca rubra, which
seems to be favoured by the environmental conditions
present.
The surface of the islands is generally sloping towards
the sea, preventing water from accumulating. During pe-
riods of drought, which can last for several weeks, the
soil may become so dry that only the highly drought-re-
sistant species survive.
In addition, the fertility level of the soil, the effect of
the velocity and frequency of winds, the splashing of sea
water, as well as the grazing of sheep, are important en-
vironmental factors ajid presumably account for the fact
that no woody plants grow wild on the islands, with the
exception of three woody species found on the lava of
Heimaey. The high precipitous cliffs, reaching consider-
able depths below sea level and thus devoid of gravel
beaches, exclude some coastal species and hinder disper-
sal by sea.
A review of the distribution of species in the principal
associations of the outer islands — the puffin colony and
the dry meadow land — shows the dominant species of the
former to be Festuca rubra, and of the latter, Agrostis
tenuis. On the margins of the puffin colonies Poa pratensis
is dominant.
>