I'm doing a rek across south america next july/august. We'll be going to the amazon, machu picchu, iguassu falls, salt planes etc. What sort of footwear will we need. We do a lot of walking and already have a good pair of lightweightish leather boots. We're doing china first (Great wall etc) then onto OZ, NZ then south america and was thinking that maybe some summer, cavas hiking boots would do the trick for China as we can still use them in OZ and NZ (rahter than taking leather heavy duty boots).

So, do we take canvas boots/hiking shoes and use them for China, OZ, NA and S/America or will we need some harder wearing boots for SA? Any advice would be great!
Thanks