Hi Kirsty,
I'm the MSc student at Waikato University that Cheri mentioned, I am studying epiphytes in the context of urban restoration. This involves comparing forest and urban epiphyte populations. I am also focussing on Griselinia lucida and its water relations.
A fellow student is also looking at epiphytes but with a focus on Pittosporum cornifolium including the ecology, genetics and ecophysiology of this uncommon species.
We would be really interested in discussing your ideas. You could get in contact via the Biology office at the University of Waikato :)
Cheers,
Catherine