A walk around his truck confirms Alastair Stewart’s fears.

“I’ve put a dent in it and pushed out the taillight. I just had that fixed a week ago.”

His 1989 land cruiser was bruised and covered it in a fresh layer of mud, but that’s par for the course with his hobby.

“I enjoy four–wheel driving, there’s not two ways about it.”

Stewart has been with the Mid Canterbury Four-Wheel Drive Club for 36 years and has toured the country finding new terrain to conquer.

But he’s now begun visiting the local four-wheel drive park, which sits along the Ashburton River, and with an environmental twist that he’s proud to be involved with.

Once a week, he takes the truck for a spin along the river and empties out a circuit of animal traps made for possums, stoats and hedgehogs.

He’d just been out on his weekly check of the boxes - some mounted to trees, and others hidden on the forest floor - but only had the dent in his truck to show for it.

Usually, there’d be a few possums, mice and hedgehogs, who’d gotten too close to the bait, and he understands the importance of his predator chasing role.

“I’m farming oriented, so I understand what trapping means for the environment.”

Stewart has been trapping along the Ashburton River for four months after taking an Environment Canterbury (ECan) funded course through the Department of Conservation (DOC).

A few others in the four-wheel drive club are trap-qualified and share the workload.

“We’re volunteers, so the club gets nothing out of it,” he said.

“But as you get older, you understand how important it is for the future.”

The four-wheel drive community has had a bad rap in other parts of the country where people drive over nesting sites on rivers and tear up habitat.

Stewart said careless drivers aren’t often in a club and don’t realise the destruction they leave in their wake.

“A lot of those guys meet up on Facebook and do what they like.

“It’s not illegal to drive through the river, normally, but if you’re requested not to do it (during breeding) it’s just etiquette not to.”

He can’t change how people see the clubs, so just continues to do his small bit for local conservation.

The Ashburton River is prime real estate for New Zealand’s wildlife, with braided rivers making for great nesting, and the rapids and surrounding trees supplying food and shade.

It’s home to rare terns and river gulls, and fish that’ve evolved, like the upland longjaw galaxias.

But its abundance provides for predators, as much as our locals.

“On the river, there’s always stoats, possums and hedgehogs,” DOC community ranger Tim Exton said.

“They predate things on the ground, so the eggs and young birds in our braided rivers.”

On top of his DOC job, Exton is the predator free ranger for the South Island and runs trap training from Blenheim to Southland.

“I’d love Ashburton to become another predator free place, but it’s an educational process.”

Trainees spend two days learning how to bait, set and clear the traps under Exton’s wing.

Completing the course grants you an NZQA certification, which is an incentive for those looking for a resume boost.

There’s no age limit, but due to budget constraints, Exton asks those outside of school to apply for the course. He also knows the more who qualify can contribute to tackling challenges like Mid Canterbury’s stray cat problem.

“It’s cats gone feral,’’ he said.

“It’s kittens being dumped, it’s pets not going home.”

Exton knows that we love our cats in New Zealand, which is shown by being the highest owners of the animals per capita in the world, but he said some owners don’t consider the consequences of letting pets wander into the bush.

“What we’re asking people to do is get their cats chipped, neutered, and to keep them in at night.”

Stefan Protheroe, another volunteer trapper, said the cat issue was contentious but needs to be addressed.

“We don’t want to kill anyone’s cat, but at the same time, we want to do our job.”

Protheroe has traps under the Ashburton Hakatere bridge, near Woolworths South, that he checks during his work lunch breaks.

He catches around six pests a week, a good number of them being cats.

“I haven’t caught anything with a collar on it, or that looked remotely tame,” he said.

He said cats can kill so many birds in one night that “it’s not funny” and they’re not picky eaters and will attack eggs, chicks and adult birds alike.

Protheroe said some predator control groups had considered buying expensive traps, which could deactivate when approached by microchipped cats.

“We’re taking a big hit as protectors of the forest when we spend a heck of a lot more to buy a trap that will protect your cat.

“We’re prepared to do that, if people are chipping them.”

Protheroe, who grew up in Mid Canterbury, said trapping is his way of repaying the environment.

“I’ve done everything in that river, from boating, motoring, swimming.

“It’s sort of time for me to give back.”

He’s 39, considered a young gun amongst trappers, which paints a concerning picture for the future of volunteer conservation.

“At the course I went to, [almost] everyone else was around 60.

“Trapping’s been left up to that age group for years, and when they can’t get out, who’s there to help?”

Getting young people into trapping is a necessity to keep the good work going, he said.

ECan land management and biodiversity advisor Jess Cochrane agrees that most trappers begin the hobby later in life.

“Most of the volunteers tend to be retired, or semi-retired.

“They have the time to get into it.”

Grateful no doubt, but Cochrane, who oversees funding for the training and traps along the Ashburton River, said there’s a real need to get young people involved to continue fighting for our rare, native birds, lizards and fish.

Because with the Ashburton River under constant threat from predators, the call is clear - conservation can’t wait for retirement. Whether it’s dents in a truck or time out of a busy day, every effort counts to protect the rare wildlife that makes this place special.

And few understand that better than Alastair Stewart, who sees every scrape on his land cruiser as a small price to pay for the future of the Ashburton River’s rare and fragile wildlife.

By Claire Inkson