Walkthrough: After defeating your first Island Trial, you can return to Verdant Cavern to capture the Wild Pokemon found within, as well as obtain any items you may have missed during your Trial. As you do, you will again run into the Ultra Recon Squad. This time around, they will mention how they are curious about learning more about the aura coming from your Z-Crystal and the Totem Pokemon themselves. They will leave stating they will be further investigating the Z-Crystals.
Wild Pokemon:
Initial Pokemon (Levels 8-11): Diglett(35%), Zubat(35%), Niobat(30%)
Rustling Spots (Level 10): Yungoos
Items:
Super Potion - Southeastern Part of Cave
TM31 - On Ledge Within Cave
Super Potion - Behind Hollow Tree
X Defense - Near Hollow Tree By Northeastern Exit
TM46 - Above Pedestal (Requires Tauros)
Revive (Hidden) - In Giant Southeastern Rock
Great Ball - From Captain Ilima After Trial
Normalium Z - Defeat Trial
Energy Root - Up Cliff In Trial Site (Requires Tauros)