Wales’ uplands have experienced dramatic changes in land-use over the past centuries. Following the last ice age, the whole of the UK was dominated by forests containing a mixture of pine and broadleaf species. The Cambrian Mountains which form the spine of Wales from Llandovery in the south to Machynlleth in the north would have eventually been dominated by species such as native oak and ash.  By 1150 it’s thought that this area, along with much of the UK had been cleared. More recently, the Cambrian Mountain’s area has been nicknamed the green desert of Wales thanks to the deforestation and transformation into grazing land. As well as this cultural shift, World War One and the massive use of timber that ensued led to the creation of the Forestry Commission which was responsible for afforestation of the country and producing more wood for future war efforts with an even greater effort in response to World War Two. Large areas of the UK, including the Welsh uplands were converted from heathlands to conifer plantations.

While conservationists have long bemoaned the monoculture plantations, forestry has remained economically important and conservation-focused forestry has come to the fore. In recent decades, much work to preserve and restore priority habitats has taken place on the public forest estate, and concepts of riparian corridors, restoration of peat and open land, and ecological connectivity have moved up the agenda. Nevertheless, the relic, monoculture plantations still remain in some places, and staff at Natural Resources Wales, the body responsible for preservation of important habitats across Wales, are tasked with transforming these areas back into havens for wildlife with huge consequential benefits to the country’s people (and balancing these against the ongoing needs for commercial timber).

Nick Young is one such conservationist working for Natural Resources Wales (NRW). As Senior Officer, Land Management: Conservation, Heritage & National Nature Reserves for the mid-Wales region (quite a mouthful), Nick oversees the conservation aspect of forestry operations which still play an important role in the business side of the organisation. Whilst NRW are busily adding ecological resilience to their forestry, bringing in mixed woodland which includes native species, planting away from waterways (to prevent acidification of the waters) and thinking carefully about where plantations should be, Nick and his team are also looking to revert some of the historical mistakes that were made. A brilliant example of which has taken place on the Afon Merin high above Devil’s Bridge in Ceredigion.

The Afon Merin, a tributary of the Rheidol which reaches the sea at Aberystwyth, is a small upland stream  in a block that was densely planted with conifers in the middle of the last century. Some of these had been cleared over time, to reopen the river corridor, but some remained dropping their needles in the water and shading the life that remains there. Whilst patchy shade is important to stream wildlife, a complete black-out does no good whatsoever. Furthermore, the combination of forestry drainage ditches and the original agricultural drainage from the farmland that preceded the forestry had broken the original ‘braided’, multi-channel course that the Merin used to follow. This had resulted in a river that, while superficially meandering across the valley bottom, was deeply incised and fixed into its current bed, and therefore subject to highs and lows of water level, and a loss of fine gravels as any rainwater rushed through the system towards the sea. The lack of fine gravels in a river means less sheltering and spawning grounds for fish and river invertebrates, and less habitat for aquatic plants. Whilst forestry operations began to thin out the plantations, Nick and his team got to work recreating the flood resilience afforded to our ancestors by native beavers.

It’s thought that the last beavers were present here in the Middle Ages, hunted to extinction for their meat, fur and their castoreum which is an anal secretion used in food and perfume! Beavers have long since been missing from the Welsh landscape. Where beavers are present, they are classed as a ‘keystone’ species because of their importance in a biodiverse ecosystem. Their dams create sheltered pools for fish and other wildlife, but they may also have huge significance to us as humans in their role in flood prevention.

Putting aside the subject of reintroducing extinct species back into habitats, Nick, the human beaver, has recreated the ‘leaky dams’ which beavers naturally engineer over a small section of the Afon Merin. He used recently felled conifers as in-stream barrages, not completely blocking the path of the water, but angled so that other woody debris from upstream would pile alongside. He started this experiment back in the March 2019 and is already seeing definite landscape improvements surrounding his efforts. The change in water flow around the obstacles has meant that the stream has begun to revert to its natural shape, with natural erosion patterns shaping a meandering river through the man-managed landscape. At periods of high rainfall, the banks overflow and the water enters relict braided river channels, creating wetland areas around the river as the high waters recede. A visit here now would see an abundance of insects and amphibians benefiting from these newly revived swampy areas and the wetlands themselves will be an increased carbon store in our global fight against climate change.

One of the ‘leaky dams’ manufactured in the waterway.

Alongside the river itself, scrub and native broadleaf trees will be encouraged, providing much needed habitats for our bird life and mammals such as the recently reintroduced pine marten as well as further reducing the speed of water flowing downstream.

Pond species, such as this water-crowfoot are colonising the wetland areas alongside the stream.

All in all, meanders and water storage outside of the river banks create valuable wildlife habitat, and may provide resilience against flooding further downstream by slowing flow and having a greater holding capacity. With the devasting flooding which recently occurred across Wales coupled with our unprecedented loss of wildlife, restoring our manipulated waterways and their natural benefits is needed now more than ever. The Merin is one small stream, but it could lead the way for better flood resilience and better wildlife habitats in the altered Welsh landscape.