Biological Succession in Aleutians — BANK 
499 
Fig. 4. Temporary bog in the middle of a lowland meadow, Atka Island. Seepage from surrounding hillsides 
collects here, and plants typical of wet habitats invade the area. These plants include: Carex Lyngbyaei and other 
Carex spp., Flantago macrocarpa. Polygonum vhiparum, Platanthera dilatata, Juncus haltkus, Erlgeron perigrinus, 
Eriophorum Chamissonis, etc. 
these areas are inhabited by liverworts, Sphag- 
num capillaceum, S. Girgensohnii and other 
mosses, Saxifraga punctata subsp. insularis, 
Leptarrhena py roll folia, Viola Langsdorffi, Pin- 
guicula vulgaris, sometimes Scirpus spp., and 
Carex spp. Their growth often becomes ex- 
tensive and deep enough to necessitate a wide 
detour when walking across a hillside. These 
are usually temporary features, however, and 
such wet places, with their typical vegetation, 
constantly appear and disappear under the 
influence of fluctuating subsurface drainage 
patterns, which are in turn greatly affected 
by yearly variations in snow accumulation. 
True peat bogs, such as those common to 
parts of mainland Alaska and Canada, are 
not found in the Aleutians. Instead the bogs 
are of the type just described, formed from 
seepage, or are essentially low areas contain- 
ing water- saturated mud overlaid by scattered 
growths of sedges, Juncus spp., short grasses, 
and sometimes Sphagnum (Fig. 4). Usually 
such areas are shallow, but some are deep 
enough to completely mire large vehicles. 
Many such mud bogs are only a transitional 
stage for shallow ponds and meadows. I ob- 
served an amazingly quick replacement of 
Carex Lynghyei and Eriophorum Chamissonis by 
Calamagrostis canadensis var. Langsdorjfi and 
other grasses after one such bog was drained 
by military operations. 
Other evidences of instability are noticeable 
in stream ravines. Usually occurring here are 
ferns {Athyrium Filix-femina and Dryopteris 
spp.), grasses such as Deschampsia heringensis, 
mosses, Streptopus amplexifolius , Epilohium an- 
gusti folium var. macrophyllum, frequently Ar- 
temisia unalaskensis, and various umbellifers. 
The profuse vegetation frequently grows out 
over the stream and in time may entirely cover 
