The Coastal Tundra at Barrow 29 



(Type VI) is variable. This type includes the sparse vegetation of the 

 basins of low-centered polygons as well as the more abundant vegetation 

 of some pond margins. It has no woody species, and only a few lichens. 

 Saxifraga foliolosa is characteristic of the basins and CalUergon sarmen- 

 tosum is characteristic of the pond margins. Drepanocladus brevifolius is 

 common throughout this type. Low species diversity, thick organic mat, 

 and highly organic soils distinguish Type VI from the other meadow 

 types. Spring snow cover on this type is moderately deep and late to 

 recede. 



The vegetation type termed Arctophila pond margin (Type VII) is 

 also found in slow-flowing streams and is the most distinct of the princi- 

 pal types, although it occupies only Z^/o of the area. Woody plants and h- 

 chens are totally absent. Single-shooted graminoids, erect forbs and bry- 

 ophytes all contribute to this vegetation type, although the emergent 

 grass Arctophila fulva is characteristic. Ranunculus pallasii and Caltha 

 palustris are occasionally present. The pleurocarpous mosses CalUergon 

 giganteum and Drepanocladus brevifolius are the principal bryophytes. 

 Late in the growing season the substrate oi Arctophila pond margin may 

 occasionally become anaerobic and have a characteristic odor of hydro- 

 gen sulfide. 



The Cochlearia meadow (Type VIII) is a rudimentary community 

 that develops on recent alluvium in the creek bed that crosses the Biome 

 research area, where snow commonly accumulates and remains late in 

 the growing season. The sandy, moist alluvial soil of the Cochlearia mea- 

 dow thaws deeply and the active layer may exceed 1 m in late summer. 

 This vegetation type is floristically rich, but extremely variable. 

 Cochlearia officinal's, Phippsia algida and Stellaria humifusa are the 

 principal species present. 



The variations in vegetation and soil across microtopographic fea- 

 tures are a dominant aspect of the coastal tundra at Barrow. Many of the 

 following chapters deal with the structure and function of tundra organ- 

 isms across these unique landscape units. 



