Over four years in the 1820s, Charles Waterton built a 9ft-high, 3-mile-long wall around the parkland and lake of Walton Hall. The fox- and poacher-proof boundary enclosed what could be the world’s first nature reserve, completed in Yorkshire 200 years ago.

Waterton, an eccentric, controversial and pioneering environmentalist, built nest boxes, special banks for sand martins and innovative bird hides, and offered local people sixpence for every hedgehog they brought into his reserve.

After completing the wall and banning hunting and shooting, he recorded 5,000 wildfowl on his lake and 123 species of birds, including ones that were widely persecuted at the time, such as herons and kestrels. Droves of hedgehogs and so-called vermin, such as weasels, were said to gambol freely like rabbits through his reserve.

Now the overlooked achievements of the innovative nature reserve and the crumbling wall that still surrounds Waterton’s former home are being remembered by WallFest, a programme of 60 community events organised by a charity created to protect the wall and remember its legacy.

The events, which take place during May around the village of Walton, West Yorkshire, and in Waterton’s former home, now a hotel, will help raise funds to repair the wall, which has collapsed in places. They include a short film supported by David Attenborough.

“We’re keen to raise the profile of the first nature reserve in the world,” said John Smith, the chair of trustees of Friends of Waterton’s Wall, a charity run by volunteers which was created after Covid when Smith and others last another century. “Waterton was a pioneering environmentalist, probably the first in this country. We also want to raise the profile of the wall itself and the need to preserve our heritage for future generations.”

The extraordinary story of Waterton’s environmentalism began after he experienced the natural wonders of the rainforests of Guyana, where he managed his father’s sugar plantations.

When he returned to his family home in rapidly industrialising West Yorkshire, he was dismayed at the polluted state of waterways, woodlands stripped of birdlife and workers looking ill.

He became famous after publishing a successful book in 1825, Wanderings in South America, about his wildlife discoveries in Guyana. At one time, he rode a caiman to subdue it after it was captured.

Unlike sportsman-naturalists of the day, Waterton abhorred shooting and got into fistfights with armed poachers, thwarting their attempts to kill birds by placing dummy birds made from metal and wood in the trees.

His nature reserve attracted 17,000 visitors a year, and Waterton provided what could be seen as the first country park in the “grotto”, offering free entry, tea and entertainments. He also invited poor neighbours to catch fish from his lake to eat.

He presciently recognised the mental health benefits of nature, bringing patients from a nearby mental health institution for days out in the parkland.

Waterton also launched one of the first known environmental legal actions, against a nearby soap works for releasing pollutants that killed trees and damaged his lake.

Despite his visionary environmentalism, Waterton is mostly remembered for his eccentricity – he was still climbing trees in his 80s, he created bizarre taxidermy, he could scratch behind his ear with his big toe and he so envied birds’ flight that he devised a flying machine, which failed.

According to Barbara Phipps, a local resident and author of a biography of Waterton, his historical portrayal as “an amusing and strange fellow”, in the words of Charles Darwin, was partly because he was a Catholic and was discriminated against, being excluded from mainstream careers in politics, law and the military.

“He was a man of many facets. I wanted to show people his character, with his flaws,” she said. “I researched him for many years and having read everything I could, I decided I rather liked him.”

John Whitaker, a curator at Wakefield council’s museums and castles and a trustee of the charity, also attributed the lack of acclaim for Waterton to his Catholicism. “He spent his life as an ‘eccentric’ Catholic, made a lot of noise and made a lot of friends and enemies. He was a marginalised aristocrat, which is a weird situation to be in. He was never in the establishment. He was massively affectionate and incredibly progressive in many ways but also hugely contradictory.”

As a young man, Waterton managed plantations in what was then British Guiana, worked by enslaved people who were owned by his father. Waterton did not inherit the plantations, nor was he compensated after the Slavery Abolition Act. His family home and estate were acquired before the plantations were purchased, according to Whitaker. “He wrote that slavery can never be defended, but the fact is, he did manage them,” he said.

“A lot of people want to talk about it [the slavery], so we are sure we do,” said Smith.

The charity has already repaired one section of the wall, which was not always well built by Waterton, who said all the money he saved from not drinking alcohol went on the construction, which cost £3m in today’s money. It estimates 65% of the wall is still standing, but in places ivy – another unfashionable species championed by Waterton – has got into the wall and is tearing it down.

“Our aim is to protect what is left,” said Whitaker. “There’s so much character in it. The sandstone has got incredible colour. But it’s like painting the Forth Bridge. If we ever get to the end of it, we will be starting again.”

Waterton died in 1865, aged 82, having survived malaria, cholera and a shipwreck off Italy. His final piece of writing in his diary noted two nightingales singing melodiously in the park. “It is particularly poignant,” wrote Whitaker, “because we don’t get nightingales nesting around here any more.”