Question

What realities of nature do source-sink models and landscape models include that basic metapopulation models do not include?

How would lifetime dispersal distance and neighborhood size differ for a plant whose seeds are carried by the wind and a plant whose seeds drop near the parent plant?

Why do most species have their highest densities near the center of their geographic range?

Answer 1

First Question:

The source-sink model, considers that different patches of suitable habitat are not of equal equality; source subpopulation with positive recruitment rate & sink subpopulation with negative recruitment rate. The landscape model considers differences in the quality of the suitable patches & the quality of the surrounding matrix.

Second Question:

If seeds are not dispersed then many seedlings will grow in the close vicinity of parent plants & will compete for light, space, water & nutrients. Thus a plant whose seeds are carried by the wind will have greater lifetime dispersal distance and larger neighborhood size.

Third Question:

Decreased density at the edge is result of the reduction of demographic parameters such as survival & reproduction. Some vital-rate contributions were lower in edge populations compared to central populations which may affect density at edge.