I was listening to one of my players talking about one of the PFS games he was able to play in, and he brought up an interesting point. Apparently, there is a rule that magic cannot go outside of the range of the spell. In regards to a summoned monster that is close range 25ft + 5ft/2 levels. So at level one, if I summon a dog 20 feet away, and then it moves 10ft away, does it vanish outside of the confines of short spell range?
Conjuration
Each conjuration spell belongs to one of five subschools. Conjurations transport creatures from another plane of existence to your plane (calling); create objects or effects on the spot (creation); heal (healing); bring manifestations of objects, creatures, or forms of energy to you (summoning); or transport creatures or objects over great distances (teleportation). Creatures you conjure usually—but not always—obey your commands.
A creature or object brought into being or transported to your location by a conjuration spell cannot appear inside another creature or object, nor can it appear floating in an empty space. It must arrive in an open location on a surface capable of supporting it.
The creature or object must appear within the spell's range, but it does not have to remain within the range.
Emphasis mine.
I think that should cover it.