AS seagulls circled above and tourists watched in confusion, Duncan Holmes steered his boat through thousands of dead fish bobbing at the surface of the River Thurne in east England.
Holmes, 48, a retired engineer turned fishing instructor, was out one day in September to document the severity of a fish kill that has amplified concerns about declining biodiversity and fragmented conservation efforts in The Broads National Park.
A local fishing group estimated that hundreds of thousands of freshwater fish, mollusks and key insects died after successive high tides trapped inland by strong onshore winds – and exacerbated by a months-long drought – caused high levels of saltwater from the North Sea to surge upriver.
For Holmes – whose family has lived in the region for generations – there was “despair that you’re seeing it again and again,” he said, referring to the fish kill last year.
“I don’t know how many times I’ve seen it in my lifetime,” said Holmes, a member of The Broads Angling Services Group (BASG), a civic organisation for anglers in the area, which is Britain’s largest protected wetland and a major inland waterway.
Fish kills occur periodically in The Broads, caused by abnormally strong saltwater tides or toxic algae blooms.
However, local anglers, conservationists and officials say the kills are getting worse each time - an illustration of intensifying threats to the ecosystem due to climate change impacts, including sea level rise, as well as human activity from farming to homebuilding.
Britain is a member of the newly-signed UN Global Biodiversity Framework –which has a goal to protect 30% of the world’s land and seas by 2030, known as 30-by-30.
It also recently set its own new legally-binding environmental targets. Experts say what happens in The Broads may illustrate how effectively both of those goals will be met.
The national park, which spans Norfolk and Suffolk counties, is home to a quarter of Britain’s rarest animals and plants.
Yet Holmes described the latest fish kill as emblematic of the area’s disjointed and dysfunctional governance, which he and other local citizens said has hampered coordinated conservation efforts and risks thwarting long-term sustainability solutions.
The myriad government agencies that oversee The Broads – five separate entities deal just with different causes of floods, for example – have been hamstrung by budget cuts, slowing the collection and modelling of environmental data, according to conservationists.
In the case of the saltwater surge last September, Britain’s Environment Agency (EA) responded by manually moving thousands of fish to freshwater.
Groups such as BASG have questioned how effective this was, given that 100,000 fish died in the River Thurne alone, it estimated, and at least three other rivers were affected.
A spokesperson for the EA did not respond to a question about whether fish kills have increased in recent years but said “severe saline incursions are likely to become more frequent and of greater magnitude due to the effects of climate change”.
This is of growing concern to conservationists and officials working in The Broads, as each saltwater incursion affects entire food chains from larvae to aquatic animals and birds.
About 2,000 years ago, the eastern part of The Broads was saltwater marsh –formed in a massive estuary – which acted as a buffer between the sea and the freshwater environment.
In recent centuries, however, people have dug thousands of kilometres of drainage ditches and installed pumps to dry the land for grazing and farming. That has led the land to sink, worsening already frequent floods and saline incursions.
Matthew Philpot, area manager for The Broads Internal Drainage Board (IDB) – the agency responsible for controlling water levels on the land via the ditches –said the region is “not a landscape of nature, it’s a landscape of engineering”.
Holmes of BASG said he would like to see the channels and pumps removed to allow the area to “go back to a natural environment”.
Some officials agree.
Rick Southwood at Natural England – the government’s conservation advisory body – said that if residents in eastern parts of The Broads were willing, changing land use to allow a saltier downriver floodplain to redevelop would be beneficial for biodiversity and climate adaptation.
One obstacle, though, is that the drainage ditches are key habitats themselves, especially for invertebrates like the Norfolk hawker dragonfly, said Andrea Kelly, environment policy adviser at the Broads Authority (BA), which administers the national park.
The BA’s latest assessment of species identified for priority conservation, from 2011, showed that 52%, or more than 1,500 species, were vulnerable to any water level rise, and 63% of all species “require fully freshwater conditions” to survive.
For rare ditch-dwelling insects such as the dragonfly and the swallowtail butterfly, an influx of salty water would be fatal – but it would also be “absolutely catastrophic” for those species if ditches dried out due to drought, Kelly said.
Either scenario could massively reverse biodiversity gains, said the ecologist, much of whose work centres on rewetting some sections of lowland peat in the park that were drained over the centuries, releasing millions of tons of carbon dioxide.
Southwood – who has lived and worked in The Broads for 45 years – said he has witnessed declining biodiversity in the region and knows that the situation will worsen.
“But it’s incredibly difficult to predict over what sort of timescale.” — Reuters
