13] VEGETATIONAL TYPES OF POLAR LANDS 4OI 



Sedge by the doubtfully specifically distinct Hoppner Sedge {Carex 

 suhspathacea), the same plants generally play a similar role in middle- 

 and high-arctic regions, though with increasing depauperation. It 

 seems probable that they are unable to alter their habitat markedly, 

 at least if and when it has reached the approximate level of the 

 highest tides, and consequently that they represent a subclimax 

 which will persist indefinitely. 



Another type of local climax is engendered by the perennial 

 manuring that takes place around the ' bird-cliffs ' where countless 



Fig. 126. — Luxuriant ' patchwork quilt ' of mixed and many-coloured Lichens 

 and Mosses developed near top of bird-cliflf. Northernmost point of Quebec, 

 overlooking Hudson Strait. Scale indicated by pack on left which is 60 cm. high. 



sea-birds nest every summer. Here unoccupied ledges may support 

 coarse Grasses and rank Scurvy-grass, the rock faces being covered 

 by Lichens, often of extraordinary size. The tops of the cliffs 

 typically support near their edges and in damp depressions a rich 

 grassy sward, and, stretching back for 100 metres or so, a luxuriant 

 and dense ' patchwork quilt ' of mixed and variously coloured Lichens 

 and Mosses. This is seen in Fig. 126 and is due to manuring 

 effects engendered apparently largely by scavenging Sea-gulls and 

 Birds-of-prey, though in some instances Foxes and Polar Bears are 

 also involved. The situation being usually very exposed, the 

 adjacent unmanured cliffs and hinterland are apt to be practically 

 barren and in striking contrast. More local manuring may also 



