2,200 



JULY 

 1965 



JAN. 

 1966 



JULY 



Figure 1.— Standing crop of Juncus . Solid line represents observed values; broken line represents seasonal cycle cal- 

 culated on the basis of an assumed constant total biomass. 



These data on standing crop were sum- 

 marized in a simple compartmental model in 

 which X represents the content of the com- 

 partment and X the rate of transfer from the 

 compartment. 



The three compartments, live, dying, and 

 dead, were defined with the following equa- 

 tions: 



d(live)/dt = growth - rate of transfer to 

 dying compartment x standing 

 crop live (344 g./m.2) 

 d(dying)/dt = rate of transfer to dying com- 

 partment X standing crop live - 

 rate of transfer to dead com- 

 partment X standing crop dying 

 (504 g./m.2) 



GROWTH 



LIVt 

 ^344 g. 



TRANSFER 



Xj X Xj 



DYING 

 504 g. 



TRANSFER 



-A o X X ' 



DEAD 

 1,604 g. 



X, 



TRANSFER 



Xg X X3 



11 



