"I was enrolled in a business degree but two weeks before I was due to start I thought 'I don't want to do that' and switched to ecology."
He was fortunate to meet the right people who provided inspiration along the way, culminating in receiving the fellowship, Tonkin said.
"It's almost a dream come true. I was overseas for six years in various research positions. The goal was always to come home but there are very few opportunities in New Zealand you can get in academia.
"I had just got a short-term position at Canterbury and two weeks later got the interview for the fellowship.
"It will allow me to build my research programme here in New Zealand after several years overseas. Importantly, it allows me the time to tackle major environmental challenges in a way that is not necessarily possible over shorter timescales.
"The simplest way to think about it is like on television you watch tomorrow's weather forecast. I'm trying to forecast what ecosystems will look like in the future and modelling approaches to ecosystems.
"The problem is that with the rate the environment is changing, historical tools we have used aren't capable of predicting the future."
Global climate and land use changes were rapidly altering the environment for ecological systems.
The fellowship, one of 10 recently awarded to New Zealand's most talented early to mid-career researchers, provides funding of $800,000 over five years.
It will allow Tonkin to build on the work he has been doing in recent years and develop models and harvest data that is more capable of understanding the future for ecology.
Since completing his doctorate in ecology in 2014, Tonkin has conducted research as an environmental science lecturer at the Xi'an Jiaotong-Liverpool University in Suzhou, China; as a postdoctoral fellow at the Senckenberg Research Institute and Natural History Museum, based in the River Ecology and Conservation Department in Gelnhausen, Germany; and at Oregon State University in Corvallis, United States.