Читать книгу Rewilding - David Woodfall - Страница 15
ОглавлениеFour-spotted chaser, Whixall.
The key to landscape-scale rewilding of damaged wetlands is the restoration of the hydrological conditions necessary for their long-term self-maintenance. For 27 years, I have been lucky enough to lead Natural England/Natural Resources Wales’s rewilding of the centre of Fenn’s, Whixall, Bettisfield, Wem and Cadney Mosses Special Area of Conservation (the Marches Mosses), which straddles the English/Welsh border near Whitchurch in Shropshire, and Wrexham.
Over the last 10,000 years, a 1,000-ha rainwater-fed lowland raised bog climax community has developed there because of the amazing powers of sphagnum bog-moss. This has created cold-water-logged, nutrient-poor, acidic conditions: pickling a peat dome, 10 m higher than the current flat, drained landscape – swallowing up the wildwood and spreading over the plain of glacial outwash sand, to the limits of its enclosing moraines.
However, for the last 700 years, this huge wilderness has been drained for agriculture, peatcutting, transport systems and more recently forestry and even a scrapyard. By 1990, the centre of the moss had a peat-cutting drain every 10m and mire plants and animals had been eradicated from most of the site. Nationally, less than 4% of lowland raised mires were left in good condition by then: consequently, many raised bog plants and animals are internationally rare and raised bog is one of Europe’s most threatened habitats.
A large increase in the rate of commercial peatcutting in the late 1980s led NGOs to form the Peatlands Campaign Consortium, to save the Mosses and others like it. The campaign was driven by Shropshire Wildlife Trust’s (SWT) local volunteer Jess Clarke. North Wales Wildlife Trust staff, including myself, and SWT staff, aided by brave Nature Conservancy Council staff, particularly Mark July and Paul Day, pushed to get the government to take on the restoration of this devastated site. The realisation that there was not enough raised bog in good condition to meet Britain’s international conservation obligations, combined with the new peat-extraction company finding that the Mosses’ peat quality was inadequate to meet their site-rental costs, resulted in the Nature Conservancy acquiring the centre of the Moss in 1990.
Cowberry.
Since then, Natural England and Natural Resources Wales have been doggedly acquiring more of the bog, clearing smothering trees and bushes, damming ditches and installing storm-water control structures. SWT mirrored this on the smaller Wem Moss, at the south of the peat body. The knowledge of our local team of ex-peatcutters, particularly Bill Allmark, and Andrew and Paul Huxley, has been invaluable in understanding how to reconstruct the Mosses.
In 2016, a land-purchase opportunity led to a successful funding bid by a partnership of Natural England, NRW and SWT for the five-year, €7-million European and Heritage Lottery-funded Marches Mosses BogLIFE Project, which aims to make a step change in the rate of rewilding of the Mosses.
Importantly, the project addresses a problem affecting all British raised mires – the loss of our mire-edge ‘lagg’ (fen, carr and swamp communities), whose high-water table sustains the water table in the mire’s central expanse. Restoring the lagg involves buying marginal forests and woodland and clearing their smothering trees, buying fields, disconnecting their under-drainage, stripping their turf and reseeding with mire species. A new technique of linear cell damming or ‘bunding’ the peat then restores water levels. Lagg streams, canalised within the peat during the Enclosure Awards, to lower marginal water tables, will be moved back to the bog’s margin, so peats can be hydrologically re-united. And all without affecting our neighbours!
The project also involves adjusting dams on the central mire areas and bunding peats which haven’t got a cutting pattern to dam. The project even addresses clearing up the scrapyard and beginning to tackle the problem which is affecting most nature conservation sites nationally – high levels of aerial nitrogen pollution and, at the Moss, its consequent high coverage of purple moor-grass.
So why bother with this mammoth struggle on such a damaged peatland? In the 1980s, the main driver was biodiversity – its unusual bog wildlife, its cranberries, all three British sundew species, lesser bladderwort, white-beaked sedge, its raft spiders, large heath butterflies and moth communities, including Manchester treble-bar, silvery arches and argent and sable moth. Despite its devastation, this huge site provided corners for rare wildlife to hide in, waiting for the restoration of mire water tables. Today crucial bog-mosses have recolonised central areas and flagship species like the white-faced darter have been dragged back from the brink of extinction. Now, in spring, rare mire picture-winged species like Idioptera linnei dominate the cranefly community and the mire spider community is breaking national records. Regularly, invertebrate species, often new to either countries or counties, like micro-moth Ancyllis tineana, emerge from hiding, and the wetland bird community now is of national importance.
But today the driver for rewilding the Mosses is also restoration of the ecosystem services provided by a functioning bog – regulation of water quality and flow (particularly important with increasingly frequent flood events), re-pickling the bog’s vast carbon stores so their release doesn’t add to climate change and encouraging future carbon sequestration.
The growing pride for the restored Mosses in the local community and the increasing numbers of visitors from far afield, boosting the local economy, are a testament to the success of rewilding this quagmire and will be helped by further sensitive provision through the BogLIFE Project.
Wading through knee-high bog-moss on Clara Bog in central Ireland some years ago, brought home to me the potential resilience of bogs and their capacity to regenerate themselves after damage. The bog was acting like a giant shape-shifting amoeba: localised marginal drainage for domestic peatcutting had made the crown of the bog dome move, channelling more water and nutrients to a shrunken area, accelerating the accumulation of bog-moss and ultimately restoring the bog’s profile. Even at our devastated Marches Mosses, particularly with the challenges of climate change, the only viable option for the landscape seems to be a return to functioning raised bog. The bog is shrinking towards the lowered water table set by Enclosure Act culverts, making other land uses progressively less economically viable. Now forests fall down, marginal fields flood and pumping costs have become more expensive and cause further peat shrinkage.
Now, like at Fenn’s and Whixall, it is the time to capitalise on these devastating consequences of past drainage, to be bold, to grasp opportunities and to rewild our wetlands and regain their age-long benefits for all of us.
Curlew in flight.
