Which of the following statements are true regarding metapopulation structures?

1. In a classical metapopulation model, all patches are small and extinction-prone.

2. Patchy metapopulations function as a single subpopulation with high dispersal rates among patches.

3. In the non-equilibrium model, recolonization rates are higher than local extinction rates.

4. Mainland-island metapopulation models assume that the mainland population never goes extinct.