Emma Macdonald – East Timor might be the newest sovereign state in the world, but for PhD graduate Nuno Oliveira the tiny country's ancient history is its most compelling feature.

Dr Oliveira graduated from the Australian National University's department of archaeology and natural history yesterday, having spent the past four years flitting between Canberra and East Timor completing his research on the origins of agriculture in the region.

Originally from Portugal, Dr Oliveira was on a scholarship paid for by the Portugese Government and last year, just after completing his final field work assignment, was offered a job as an adviser to the Secretary of State for Culture in East Timor, Virgilio Simith. The broad sweep of his role has seen him involved in writing that country's heritage management and curation policy, but also in setting up a national library, a national museum and a school of music and the arts.

His research included digging archaeological sites looking for evidence of what people have eaten in East Timor over the past 10,000 years. By showing that early inhabitants existed on root crops, fruit and nuts before the introduction of rice, Dr Oliveira's work identifies what are more sustainable crops for the future in a time of climate change.

"The archaeological record seems to suggest that rice is not really an appropriate crop for the climate of the island and other crops would be more sustainable and could be reintroduced," Dr Oliveira said. "Of course rice and corn crops have subsequently killed a lot of diversity in East Timor and this is a worldwide issue." Dr Oliveira said it was good to be back in Canberra "where life is a lot easier than in East Timor".

But he was also thrilled to be working there, in a role which was so important. "It is an amazing job, and my contract has just been extended for another year so that is great news." Dr Oliveira said there were 45 settlements pre-dating Portugese settlement in the 16th century, which had yet to be investigated.

"There is so much left to discover and so many important sites to examine, partly a result of the fact East Timor has been closed to research for the past 25 years."

But he also noted that the fledgling country "has so many things to do in terms of nation building that archaeology while important is something of a minor issue". Dr Oliveira said he felt privileged to have been able to complete his doctorate at the ANU, but it had its challenges. "I think having to write in a language that was not my first language was really hard, but I managed to get through," he said.