In addition to any other powers, authorities, duties and functions conferred or imposed upon an honorary ranger by or under this or any other Act, an honorary ranger shall have and may exercise and perform such of the powers, authorities, duties and functions as are conferred or imposed by or under this Act, the Wilderness Act 1987 or the Threatened Species Conservation Act 1995 on officers of the Service and as are specified or described in the instrument of his or her appointment, but subject to such limitations and restrictions (if any) as are specified or described therein.