The taxation pertaining to this investment is complex and you are encouraged to read the advice letters contained in the Product Disclosure Statement.
Generally speaking though, Australian Tax residents will usually pay income tax on their income distributions (received each year) and realised capital gains (on disposal of their units).
Furthermore, it is expected that most Australian investors will qualify for a foreign tax credit for any US withholding or US income tax deducted on their behalf.
Be sure to consult an experienced accountant for specific advice. If you need a referral then the Fund’s accountants are Pitcher Partners in Melbourne. They have the skills to be able to assist, however any advice is of course at your own cost.