English carnivores
HOW MEAT-EATING PLANTS ARE TAKING BACK THE BOGS
Weird and wonderful meat-eating plants are back in parts of England, thanks to an ecologist on a mission
Carnivorous plants native to Great Britain are being brought back to life in the mires of the English countryside, following a 150-year absence.
Meat-eating plants may sound like the stuff of sci-fi movies, but these organisms have as much a place in the British countryside as the common daisy. In fact, we have 13 species of carnivorous plant – belonging to the sundew, bladderwort and butterwort genera – that make their home in the boggy climes of our country.
But, while these interesting little plants are faring reasonably well in the more rugged landscapes of Scotland, Ireland and parts of Wales, in England, they’re in trouble. Over the past 150 years, intensive agriculture has wiped out virtually all (95 per cent) of their habitat, pushing them to the brink of extinction across most of the country.
Back for good?
It’s not all bad news, though. Thanks to the efforts of ecologist Joshua Styles, three species, at least, have made a comeback in the north-west, and are once again thriving in the bogs of Greater Manchester, Cheshire and parts of Lancashire too.
Styles, who set up the North West Rare Plants Initiative in 2017, has carried out 40 successful plant reintroductions to date. These include bringing back the oblong-leaved sundew (a sticky-tentacled meat-eater that nets insects much like a fly-paper trap); the equally sticky English sundew, and the nematode-slurping lesser bladderwort, all of which had gone locally extinct.
Our native carnivorous plants once thrived across Britain’s raised bogs – unique wetlands fed exclusively by rainwater and mineral salts in the air. “Unfortunately, much of this habitat has been drained and converted for agriculture or commercial peat extraction, at great loss to the plant species that depend on them,” says Styles. “But there are many reasons why we need to protect these habitats.”
The benefits of bogs
Bogland is acidic, nutrient-poor peatland. These quagmires are mostly formed by the accumulation of half-decomposed sphagnum mosses rotting below a watery surface. In the absence of oxygen, bacteria breaks down decaying matter so slowly that peat accumulates and the bog expands, sequestering more carbon from the atmosphere than it releases. These squishy homes are thus highly significant in the fight against climate change.
There’s also the medicinal potential of the carnivorous plants that live there. Since medieval times, oblong-leaved sundews have been used as a remedy for coughs and pulmonary diseases. Scientists at Colorado State University also believe that a group of allelopathic chemicals in sundews, known as naphthoquinones, has the potential to be used in chemotherapy. Meanwhile, the anther-smut fungus, which infects common butterwort, could provide a new treatment for a variety of ailments. “There is massive untapped pharmaceutical potential that has largely been unexplored,” says Styles.
Carnivorous plants have long captured our imagination. The Victorians were gripped by a sundew craze more than a century ago, and the plants became highly
desirable to own. In 1875, Charles Darwin published Insectivorous Plants to much fanfare within academic circles and the general public. He was so hooked by these curious little plants that, writing in 1860, he said he cared more about them than “the origin of all the species in the world”.
Appetite for success
Stephen Morley, ecologist and conservation officer for the Carnivorous Plant Society (CPS), says, “I’ve always been mind-blown by the fact that plants can eat animals. And personally, I quite like anything that eats insects,” he says. “But unfortunately Britain’s carnivorous plants have become increasingly isolated as their bogland habitat has disappeared.”
The CPS has been in talks with Styles about how they can help grow sundews for further reintroductions as the North West Rare Plants Initiative gathers pace. But for now, Styles is a one-man army – and his work is steadily marching on. The first of his 10 English sundews, planted covertly across the Greater Manchester bogs, have already proliferated into 43 plants. His lesser bladderworts are now thriving – he saved them from local extinction in the north-west two years after he rescued and recovered the last five surviving specimens from a tiny pond in Cheshire. At the most recent count, the population had soared to 180,000 individuals.
Nature has granted bog-dwelling plants extreme methods to find nutrients in their watery world. Like almost all other land plants, carnivorous blooms derive their energy from photosynthesis, yet being vegetarian isn’t enough. Deprived of the nitrogen and phosphorus minerals needed to generate the amino acids, DNA and cell membranes required for growth, these plants have turned to meat for sustenance. And for such an ambitious feeding strategy to be successful, they have had to spend millions of years evolving a variety of elaborate hunting mechanisms.
Arguably the most successful and alluring trap belongs to the sundews. With more than 250 species recorded worldwide, these are the most abundant of all carnivorous plants. Sundews snare their prey by means of glandular hairs laced with gluey droplets of digestive mucus. It is believed that their dewy tips give invertebrates such as dragonflies the false promise of a drink before they are bound, wrapped and consumed by a cocktail of digestive enzymes. The plants don’t call all the shots, however – they provide a key foodplant for species such as the sundew plume moth, whose young munch exclusively on sundews. Plume moth larvae are opportunistic hunters: they first slurp the sticky fluid at the plants’ tips, clearing a patch of the hairs before feeding on the remaining leaf and flower buds.
They will gladly accept a free lunch, too – pilfering the dead insects the sundews had trapped.
While sundews rely on their sticky mucus to cement their prey in place, the bladderworts – of which there are 235 species worldwide – hold the record as the fastest and perhaps greediest plants on the planet. “Bladderworts are able to alter the entire ecological landscape,” says Styles. “Their rapacious eating habits are able to impact the population numbers of other species.” In Britain, all seven species are aquatic, using sophisticated vacuum trapdoors to inhale up to 10,000 waterborne animals – including copepods, mosquito larvae, nematodes, water-living earthworms and even tadpoles – through the course of a spring and summer.
“Bladderworts’ rapacious eating habits are able to impact the populations of other species.”
Land grab
But what about the jaw-snapping Venus flytraps or the spider-eating pitcher plants of this world? Well, they too are living among us. Across the country, a strange upright plant that swallows its prey whole
has invaded the heather-rich peatbogs of Britain and Ireland. The species in question is the purple pitcher plant, originally from North America. For decades, it has been creating problems for important indigenous flora and fauna, including rare bryophytes such as the epiphytic liverworts.
“A lot of these pitcher plants were introduced in the middle of the last century, when conservation knowledge wasn’t really very strong. The problem is they’re hard as nails,” says Morley. “So, in a mild climate like Britain’s, they can produce large populations at the expense of local flora. With the small amount of wetlands we have remaining, it’s important to maintain the native wildlife.” And it’s not just the plants that are at risk – the peatlands themselves are under threat from the pitcher, too, because the sphagnum mosses – the key species responsible for peat formation – die away wherever purple pitchers take over.
As part of its climate ambitions, the Government has pledged to restore 35,000ha of peatland in England by 2025, though it is unclear if funds to tackle invasive species such as the purple pitcher will be readily available. So for now, conservationists like Styles are filling the gap. Ultimately, he hopes his work in the boggy reaches of the north-west can inspire others to think about plants in new ways.
“It goes back to this point of how people perceive plants as these static, boring green organisms. Plants just don’t grab the headlines as other wildlife does – and that’s such a shame, because ultimately plants are the foundation of all life.”
JAMES AGYEPONG-PARSONS is an environmental journalist based in London.