during the summer. Evidence from other reindeer ranges indicate 
that when lichens are depleted, grasses and sedges are grazed ex- 
tensively during the winter (Palmer, 1929). 
On the dry flats where utilization by reindeer has been most 
intense and the lichen flora has been virtually eliminated, some 
wind erosion of the fine organic surface duff has taken place. The 
mineral soil is not as susceptible to wind erosion due to its high 
moisture content from frost thawing in summer and its frozen nature 
in winter. The surface character of the flats, with the raised 
hummocks of willow and intervening depressions occupied by the li- 
chens and sedges, also tends to preclude wind erosion. Frost boils 
are common throughout the flats and can be mistaken for erosion due 
to reindeer activity, particularly so when the imprints of several 
hooves remain in the firm mud of the boils. The windswept, vegetated 
ridge tops, which are segments of winter range, are more readily 
eroded by wind action when the vegetative cover is disrupted. On 
these sites both the plant cover and the layer of organic duff are 
much thinner than on the lower flats and the effect of feeding and 
trampling by reindeer is more pronounced. Evidence of moderate to 
severe wind erosion of both the organic surface layer and the finer 
mineral soil were encountered on the more exposed ridges where wind 
velocities are greatest. Figure 20 shows the effects of wind erosion 
in exposing the roots of Dryas and in the establishment of a pebble 
layer as the finer mineral soil has been blown away. 
Invasion of deteriorated lichen-willow-sedge range by other less 
desirable species has not occurred to a significant extent. Ona 
few of the more xeric low ridges and slopes, the impression is gained 
that Dryas and Empetrum have increased their area of surface cover- 
age as the destruction of the lichen growth exposes more mineral soil. 
However, the growth of dense mats of Dryas and Empetrum are restrict- 
ed in area and occur only on the dry and exposed ridge tops and old 
gravel flats adjacent to the beach. 
Extensive reindeer trails, such as are characteristic of long- 
used caribou range, are’not found on the island. Single trails have 
developed through narrow passes, in V-shaped canyons, and where lake 
shores crowd adjacent hillsides. Apparently, the movements of rein- 
deer on the island are dispersed and not usually en masse so that 
the parallel trails of migration found on caribou ranges have not 
developed here. 
CONCLUSIONS 
It is obvious, from the herd counts and the projected population 
growth curve (Fig. 2), that the reindeer on St. Matthew Island have 
rapidly increased in 13 years to occupy an apparently very favorable 
virgin range. At their present rate of increase, saturation of the 
2g 
