If a druid uses Wild Shape, does he retain his Natural/Dodge/Deflection bonuses to AC? What about ability score bonuses from items (Ring, Amulet, etc) or from spells (Barkskin, Bull’s Strength)?
The natural armor will be dictated by the shape (zero if the shape doesn't give any), dodge will change based on the shape's new Dex mod but otherwise remains in tact. All magic items meld into the new form and become inactive, thus providing no armor, enhancement or deflection bonuses. Only certain magical items overcome this. Spells remain active and provide bonuses, unless the shape somehow negates the spell.
The wild shape entry answers most of these questions, but to be brief -
- Natural Armour bonus to AC is based on new form - if your normal form has natural armour, that goes away for the duration of the wild shape. You gain, however, any natural armour the animal you have turned into possesses.
- Dodge bonuses from some sources (Spells, feats, class abilities) remain. Ex or Na racial dodge bonuses, however, will generally go away. This is a grey area, and an edge case - ask your GM.
- Again, racial deflection bonuses may go away depending on type. This is a grey area. Those from spells, feats, class abilities, will stay.
- Magic Items that you are wearing are 'melded into your new form and become inactive'. Magic Items that you take off and put back on after you wild shape, since every being has 'magic item slots' for 2 rings, one necklace, one periapt, one cloak, etc, are presumably active. There's no errata about this, but by RAW, you as a bear can put on a magical necklace and get +6 to Con. It's not, though, something that you'd be doing at Combat speed, which sort of balances it out.
- Spells will generally remain active. There's some argument over what happens if you cast a spell that requires a 'person' target (like Charm Person) and then turn into a bear (not a Person anymore), does it still work? Some say that it checks for pre-reqs at casting (which is RAW), and others that it should/would check again when those pre-reqs chance (not RAW). YMMV. But things that don't specify 'a person' or 'an elf' or whatever should be fine.