Dulnain habitat improvements

After some surveying on the mainstem with Duncan Ferguson I was taken on a conducted tour of habitat works underway on the Dulnain and Achnahannet Burn. Starting in the Dulnain we had a look at a large field with an unfenced river frontage extending to 1400m. It is regularly used for overwintering cattle and the banks have suffered as a result.

Serious cattle trampling on the banks of the Dulnain

Serious cattle trampling on the banks of the Dulnain

Cattle need to drink a lot each day and the damage to fragile riverbanks by these heavy animals results in a lot of silt entering the river.

Thick silt deposits below damaged banks

Thick silt deposits below damaged banks

Further downstream the damage to the bank structure was obvious with riverbank alder trees undermined and roots exposed.

Several metres of riverbank have eroded away here leaving several mature alders clinging on to life

Several metres of riverbank have eroded away here leaving mature alders with exposed roots clinging on to life

The solution for this sort of damage is stock proof fencing and it was pleasing to hear that the entire riverbank will be fenced in an extension to the Achnahannet Burn works. The fencing on the burn itself is progressing very well. The fence is of high quality and a generous buffer strip implemented.

Example of fencing in the Achnahannet Burn

Example of fencing in the Achnahannet Burn, nice wide buffer strip

 

Nice buffer strip

Constructing crossing point

Watergate under construction. On straight lines they use a tractor mounted post driver but fiddly bits like this require some skillful use of the mell.

Watergate under construction. On straight lines they use a tractor mounted post driver but fiddly bits like this require some skillful swinging of the mell.

A short distance downstream an over widened bend in the burn would be a good site for monitoring changes to the burn following fencing.

Overwidened bend which should narrow quickly once fenced

Overwidened bend which should narrow quickly once fenced

Below the road the fencing is complete.

Complete fencing in lower reaches of burn

Complete fencing in lower reaches of burn

The habitat within the fenced areas should improve with more bankside cover and reduced silt input. However the impacts of damaged habitat can extend well downstream with silt  and cattle manure causing enrichment and smothering spawning gravels and sensitive species such as stoneflies and freshwater pearl mussels. In total over 6.2km of fencing is going to be erected under this project. A nice contribution to improved habitat both within the Dulnain and beyond.

There was a lot of silt and fine substrate in the bed of the burn

There was a lot of silt and fine substrate in the bed of the burn

It was clear that there was a high proportion of silt and sand in bed of the burn. The input if such material should decline after fencing. Consequently this looks like an area where some practical habitat works to loosen the gravel in preparation for spawning may be worthwhile. This sort of activity is normally done in late summer so if anyone is interested in assisting with gravel cleaning please let me know.

 

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.