Our tanks are trying to get geared for this fight, so I have compiled a list of what gear to possibly get, in order to maximize defense + stamina. Sorry in advance if some links are messed up.
First, we have the crafted NR gear..
Wildguard Breastplate: +15 Stamina, +60 Nature Resist, +14 Defense Rating
Wildguard Helm: +30 Stamina, +50 Nature Resist, +28 Defense Rating
Wildguard Leggings: +30 Stamina, +60 Nature Resist
Pendant of Withering: +18 Stamina, +30 Nature Resist
The Natural Ward: +12 Stamina, +35 Nature Resist
Next, here are the random blue or epic items with the most stamina and defense, which you can use instead of green "nature protection" armor when able.
- Sockets will be assumed to be +12 stamina sockets and added to stamina.
- No armor kits or enchants are on the items.
- Stats other than parry, hit, dodge, defense, stamina, resilience, and agility will be ignored.
- It is assumed that you will not replace any of the crafted pieces above.
I will highlight what I believe is the best in the category based on defense and stamina...
SHOULDER:
Mantle of Abrahmis: +63 Stamina, +20 Defense Rating
Warbringer Shoulderguards: +12 Agility, +58 Stamina, +14 Defense Rating, +23 Dodge Rating
Fanblade Pauldrons: +46 Stamina, +20 Defense Rating, +15 Parry Rating
BACK:
Cloak of Eternity: +36 Stamina, +23 Defense Rating
Gilded Thorium Cloak: +27 Stamina, +21 Defense Rating
Devilshark Cape: +22 Stamina, +20 Defense Rating, +18 Dodge Rating
WRIST:
Bracers of the Green Fortress: +39 Stamina, +17 Defense Rating, +10 Dodge Rating
Vambraces of Courage: +42 Stamina, +12 Defense Rating
HANDS:
Topaz-Studded Battlegrips: +64 Stamina, +26 Defense Rating
Gauntlets of the Chosen: +15 Agility, +30 Stamina, +35 Defense Rating (SCRYER ONLY)
Felsteel Gloves: +51 Stamina, +25 Defense Rating
WAIST:
Crimson Girdle of the Indomitable: +57 Stamina, +21 Defense Rating
Girdle of the Immovable: +57 Stamina, +18 Defense Rating
FEET:
Heavy Clefthoof Boots: +61 Stamina, +24 Defense Rating (I am aware they are leather)
Battlescar Boots: +49 Stamina, +20 Defense Rating, +18 Parry Rating
Boots of the Colossus: +51 Stamina, +19 Defense Rating
RING:
Band of Impenetrable Defenses: +36 Stamina, +25 Defense Rating (Random World Drop)
Crystal Band of Valor: +27 Stamina, +22 Defense Rating, +16 Hit Rating
Shermanar Great-Ring: +33 Stamina, +20 Defense Rating
Elementium Band of the Sentry: +24 Stamina, +20 Defense, +16 Dodge
Note: There are many, many rings that are extremely similar, so just go with what you think is best. I like the +hit rating on the Crystal Band of Valor.
TRINKET:
Regal Protectorate: +26 Defense Rating, Use: Increases maximum health by 900 for 15 sec. VERY NICE on use for Hydross.
Figurine - Dawnstone Crab: +32 Defense Rating, Use: Increases dodge rating by 125 for 20 sec.
Adamantine Figurine: +32 Defense Rating
Timelapse Shard: +25 Stamina, +23 Resilience (Keepers of Time EXALTED)
Argussian Compass: +36 Stamina, Use: Reduces damage from each attack by 68, up to a total of 1150 damage absorbed. Lasts 20 sec.
SHIELD:
Aldori Legacy Defender: +46 Stamina, +16 Defense Rating, +12 Hit Rating
Platinum Shield of the Valorous: +33 Stamina, +24 Defense Rating
Azure-Shield of Coldarra: +28 Stamina, +20 Defense Rating
Sorry if I made any mistakes.

Feel free to add some of your own if you want. Hopes this helps!