Leigh Campus restoration project revives native bush

Native bush once blanketed the land where the University’s Leigh Campus sits, but pests and clearance for farming reduced it to a few patches along its margins.

Marine Science Professor Andrew Jeffs recalls studying what was left of the bush for the first time as an undergraduate science student on ecology field trips, and he says the kikuyu grass that took root in place of the bush has stifled the chances of the forest regenerating in the years since.

Thanks to the efforts of staff, students and community, however, Andrew says a plan is underway to restore more native bush to the area, including its distinctive pōhutukawa-lined coast.

Last month, volunteers from Mahurangi College in Warkworth mucked in, helping plant 800 native trees cultivated through Trees for Survival, a charitable environmental education programme.
It followed previous events held this year, during which University staff, students and other volunteers planted more than 1,500 trees, and added to 700 that were planted the year prior.

Last year, pōhutukawa were planted on the coastal fringes of the campus; this year planting has been concentrated in a valley next to the Leigh Marine Laboratory. They’re adding to what’s known as the ‘legacy grove’ – an area of bush planted more than a decade ago as an alumni activity.

“Our initial goal is to try and connect the replanted valley with the coastal bush so that we have an ecological path for birds to move along the coast, and to re-establish the pōhutukawa fringe that is a real feature of the Leigh coastline,” says Andrew. 

While it may sound like a lot of trees, Andrew says they need to be planted compactly to have a chance to outgrow the kikuyu grass, and he’d ultimately like to see a much bigger vision embraced for the 60-hectare piece of land at Leigh that the University owns.

“In my time, I’ve seen some massive changes in the marine environment, and it’s being driven by climate change,” he says.

“It’s challenging, because academics like to travel and network globally, which is incredibly carbon intensive, and as a marine research institute, we run boats all the time. We have a large boat that burns a lot of diesel, so we’re all part of the problem.

“What I’d like to see is that we use that 60 hectares to offset our carbon and become the first marine lab in the world that’s carbon neutral.”

Andrew says regenerating the bush has many other positive impacts, such as reducing sediment runoff, which directly impacts water quality and clarity in the adjacent marine reserve.

Te Hāwere-a-Maki/Goat Island is also home to a sea-bird nesting colony and University staff put a huge effort into pest control to protect this from predators. However, kikuyu provides an excellent habitat for mustelids, like ferrets and stoats, who tunnel through the grass, allowing them to move across the land under cover then swim out to the island where they can decimate the colony.

“If we can replace that kikuyu with native bush, then we reduce that risk and then there’s also the potential to expand that bird colony onto the mainland, which would be really cool.”

Andrew says the planting days have also provided an opportunity to meet and talk with members of the wider community who visit the hugely popular Goat Island Marine Reserve.

“We’ve been planting along the Goat Island Walkway and there are so many people going up and down there all the time to look out over the coast.

“It’s a big resource for the public – and it’s just gorgeous.”