Predator-Prey Dynamics

What happens first in predator–prey cycles: predators or prey increase?

Prey increase first → predators increase later.

What are the four steps of predator–prey cycles?

1. Prey increase

2. Predators increase (delayed)

3. Predators overconsume prey

4. Both decline → cycle repeats

Why do predators peak second?

Their reproduction depends on increased prey abundance but takes time.

What is cycle amplitude?

Size of population ups & downs.

What causes predator–prey cycles to become bigger?

• Efficient predators

• High prey growth rate

• Strong predator response

• Low prey refuge

What conditions make predator–prey cycles smaller?

• Inefficient predators

• Lots of prey refuge

• Low prey growth rate

• Low K

• Weak predation pressure

Define top-down control.

Predators regulate prey (wolves → deer).

Define bottom-up control.

Resources regulate prey, which regulate predators (grass → deer → wolves).

What happens if predator efficiency increases?

• Prey decrease

• Predator increase (briefly)

• Larger cycles

• Prey & predator peaks shift upward

What happens if prey have more hiding places?

• Prey minimum increases

• Predator numbers fall

• Cycle amplitude shrinks

Why does the lynx peak lag behind the hare peak?

Lynx reproduction responds to hare abundance with a delay.