Figure 1
From: Population dynamics of plateau pika under lethal control and contraception control
The symmetrical effect of p and q on determining whether the plateau pika population dies out. If (p,q) locates in the domain D 0 then the population will persist and E2 exists always, otherwise the population may die out. When h = 1, if (p,q) locates in D 1∪D 2∪D 3∪D 4 then the population will die out. When h = 2, if (p,q) locates in D 2 ∪ D 3 ∪ D 4 then the population will die out. Similar explanations can be given to h = 3 and 4.