Can water landscapes – rivers, streams, lakes and ponds – be brought back from the brink?
Britain’s water landscapes have been an ailing patient for over a century, but promising recent examples show how ponds, streams and rivers can be brought back to vibrant health.
Lake covered in thick blanket of algae due to excessive nutrients in the water.
Images by the Norfolk Rivers Trust, used with permission.
Freshwaters constitute only 0.01% of the planet’s water, but provide a home to 6% of the planet’s species1. It is vital that we care for these precious habitats that provide water treatment, food and joy to humanity.
In Britain, pollution of our waterways has been happening for much longer than many people realise. As a result, some habitats are so damaged that they need active and long-term intervention to restore them back to health.
It is commonly thought that environmental degradation is a relatively recent phenomena, perhaps going back a few decades. In fact, the rise and fall of the Greco-Roman civilisations is charted by a “pollution record” with concentrations of lead, probably as a result of increased metal production, increasing measurably in ice cores taken from Greenland2.
Closer to home, the authorities in London had set up a commission to investigate what could be done about the burning of coal in the city in 1285 because of the dangerous consequences for air quality. But we now know that the release of pollutants from industrial processes such as burning coal can also pollute aquatic environments. One UCL researcher recently used dated sediment layers from London’s ponds, such as at Hampstead Heath, to demonstrate that their waters have been contaminated with potentially toxic metals for at least 150 years.
More recently, after the Second World War, increased mechanisation led to accelerated degradation and many wetlands were drained, ponds filled in and rivers straightened. Based on data available in 2013 from the Environment Agency, 75% of English waterbodies failed to reach the standard of good ecological status. In short, the degraded state of many freshwater environments is extensive and is the product of a long and complex history of abuse.
However, there is hope. A growing movement of environmental organisations and individuals, many of them rooted in support from local communities, are working hard to reverse the centuries of damage. For instance, the Wye and Usk Foundation in Wales has intervened to reverse the acidifying effects of historic acid rain, peat drainage and conifer plantations. Conifer plantations cause acidity in several ways; the pine needles of the trees release acidity when they decompose and the trees act as traps for acidic particles in the air and rain drawing the acidity towards the ground. But perhaps the greatest effect is down to the drainage ditches required to grow the trees on peat, which leads to drying and oxidation of the peat, releasing acid into the drainage channels. In a repeated theme among such projects, this work was facilitated by European Union funding and legislation.
The Wye and Usk Foundation intervened in 3 ways:
- firstly, they added neutralising lime to unnaturally acidic water sources,
- secondly, they removed conifer plantations that contribute to acidification,
- finally, they blocked drainage ditches running through peat. This final step prevented the drying of peat, a process that promotes acidity.
The result has been a return of species such as salmon, which had been driven out by the past acidity.
Olly and a colleague demolish a weir on the River Teise.
Image by Oliver van Biervliet
In another example, named the Ghost Ponds Project, ponds in agricultural land, which had been filled in during the intensification of agriculture, have been located from historic signs in the landscape, and resurrected. Incredibly, when the ponds were re-dug, the seeds of aquatic plants buried beneath the fields in these Ghost Ponds 150 years ago were found to be able to grow and thrive – scientists referred to these resurrected plants as zombies! The action movie references don’t stop there, with another scientist describing the aftermath of the first stage of pond restoration looking like “bomb craters”.
Nevertheless, the long-term benefits of this sometimes-drastic action are well evidenced. These examples illustrate an encouraging principle, which is that freshwater ecosystems have an incredible ability to recover when the causes of degradation are removed.
These success stories are not limited to rural areas. The River Wandle in South London was considered to be biologically dead in the 1960s, and was little more than an artificial conduit for contaminated effluent. However, a partnership of organisations, including the Wandle Trust and its predecessors, rose up from the community. These groups were given extra impetus by European Legislation (The Water Framework Directive), which required waterbodies to reach “good ecological status.”
This legal imperative greatly helped the community to access funds to improve the Wandle for the benefit of people and wildlife. Using increasingly sophisticated techniques, this partnership has brought the river back to a being a clear-flowing stream surrounded by diverse animal and plant communities, despite the highly urban surroundings of the river all the way from source to mouth!
The River Wandle before (left) and after (right) being restored to a more natural state.
Images by the Wandle Trust, used with permission.
To follow the medical metaphor with which this article started, the patient has started to respond to treatment, but must now be continually supported if that treatment is to be successful.
Many of the great success stories in the rehabilitation of UK freshwaters in recent years have been underpinned by European Union legislation and funding. Whether the UK’s future turns out to be inside the European Union or not, it is imperative to continue to nurture these systems, which allow the brave resurrection of life that has been seen in many streams, rivers and ponds across Britain in recent years.
References
1. Dudgeon, D. et al. Freshwater biodiversity: importance, threats, status and conservation challenges. Biol. Rev. Camb. Philos. Soc. 81, 163–82 (2006).
2. Hong, S., Candelone, J.-P., Patterson, C. C. & Boutron, C. F. Greenland Ice Evidence of Hemispheric Lead Pollution Two Millennia Ago by Greek and Roman Civilizations. Science. 265, 1841–1843 (1994).
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