474 F. S. Chapin III et al. 



Lemming 



peak year 



(0.01} 



■-r: 



0.21 



0.19 



Standing 

 dead 

 10 36) 19 



N(0 38l 



0.04 



Vase, 

 shoots 

 jMOIQ) 



0.21 



Exchangeable 



calcium 



295 



Rate during average year 

 ■ Rate during lemming high 



a. Calcium. 



Runoff? 



Exchangeable 



potassium 



13.8 



b. Potassium. 



