A thriving habitat for wildlife at Countess Wear

Sandwiched between the River Exe to the north and the Exeter ship canal to the south and adjacent to South West Waters treatment works at Countess Wear in Exeter, lies two Sites of Special Scientific Interest (SSSI). The SSSI furthest east is a publicly accessible nature reserve looked after by Devon Wildlife Trust that is dominated by reedbed and is known as the Old Sludge Beds. The area of SSSI to the west, which is not accessible to the public because of it being within a secure area of the treatment works, has recently come under management of the South West Lakes Trust. This 4-hectare SSSI section, comprises a large pond, an area of oak dominated woodland and reedbed.

Invertebrate surveys conducted in 2016 and 2017 revealed a total of 272 invertebrate species across both of these SSSIs. Of particular interest were nine beetle and four fly species, which have Nationally Scarce status, meaning that their geographic distribution is restricted to somewhere between a minimum of 16 and maximum number of 100 hectads (a geographic area measuring 10 x 10km) across the UK. In other words both these SSSIs have recently been shown to be of considerable interest for invertebrates in the context of South West England through the SSSI project.

A total of twenty-eight bird species were recorded during 2016. These included bird including Song Thrush, Bullfinch and Reed Bunting which are all declining nationally. Reed warbler (a bird species of limited distribution within Devon) was also recorded.

At the end of last month Devon Wildlife Trust and the South West Lakes Trust worked in partnership to restore the reedbed in the area of SSSI managed by the South West Lakes Trust.  This was achieved through the coppicing and stacking of Willow that was beginning to dominate sections of the reedbed, and the cutting of a proportion of the total area of reedbed using a BCS reciprocating scythe. This was the first time this area of SSSI has received any conservation management. The coppiced willow will eventually regrow in a much denser fashion, while the cut logs were placed into habitat piles for insects. The cut reed was raked off the reedbed and then placed into large heaps. Which are known to valuable places for specialist invertebrates while the warm composting conditions encourage grass snakes to lay their eggs within them.  The creation of variation in structure between the older areas of reedbed and recently cut reedbed will create favoured areas for nest creation and feeding for birds such as reed and sedge warblers.

In the absence of this recent intervention, the reedbed would have naturally continued to accumulate reed litter, as dead stems fell over, drying the soil enough for an increasing number of trees to seed and establish. On balance allowing such natural reversion to a woodland habitat, would not the best outcome or decision for biodiversity, when considering the existence of the rich wildlife present that partly depends on the reedbed. The extent of reedbed across the UK has also reduced by approximately 45% since 1945 and therefore the preservation of such habitats is a priority.

 

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