Dramatic population declines of the foothills yellow-legged frog, mountain yellow-legged frog, Yosemite toad and the endangered California red-legged frog have occurred in the past 10 to 15 years, but no single cause has 
(Dramatic population declines of the foothills; have occurred; T:in the past 10 to 15 years) (no single cause; has; )
Dramatic population declines of the foothills no single cause
have occurred has
T:in the past 10 to 15 years