Today is a two in one blog post to cover the last two days.
Firstly, the ranunculus trials. There were two main reasons for completing the surveys; firstly to see if the chemical being trialed reduces the amount of ranunculus and secondly to see how long the chemical remains in the area and what impact this might have on other life, such as the endangered freshwater pearl mussels. I headed over to meet the team from the Dee at their offices, and then we all headed over to the River Don. The site had been selected by Lorraine and Jamie from the Dee trust and they’d already been over the week before to check out its suitability and do some baseline surveys.
There were two spraying sites, one on the left side and one on the right side of the river. On each side there were three water sampling points (to monitor the distribution if the chemical and length of time in the area), one above the spraying area (control site), one at the spraying site and one below, so six sampling sites in total. Water samples were taken before the spraying, immediately after, after 5 minutes, 15 minutes, 30 minutes, 2 hours, 4 hours and 24 hours later which was done this morning. The water samples consisted of water from the surface, middle and river bed to get an average of the chemical throughout the water column.
As well as the samples, the percentage coverage of ranunculus at each of the six sites were calculated using 1m2 quadrats, as well as photos being taken for later comparison. 10 quadrats (basically a wooden square!) were laid over the area at each site and an estimate of cover given in each, giving a specific and detailed description of the ranunculus. This was done last week prior to spraying and over the next few weeks the quadrats will be repeated at each of the six sites to see if the coverage reduces and therefore if the chemical has worked. The control site, which wasn’t affected by the spraying, will be used to compare a treated area with an area that wasn’t but where natural die-back may have occurred. So it’ll be a while before we have any definitive results, but it’s great that this trial is underway and we’re moving forward. It was great working with the Dee team, I enjoyed my day and many thanks to them for having me over to help!
Now for today’s Mainstem surveys. We started at Tulchan A beat, just above the ghillies hut.
We were down on fry here, going from 114 to 44 fry, which was frustrating. The parr numbers remained the same. The next site was more encouraging; where last year we had 31 fry and 25 parr, this year we had 44 fry and 34 parr. This was below the road bridge on the A95 by Grantown. Further down, upstream of the old road bridge, we had 9 less fry than last year at 43, but improved from 24 parr to 39. At Castle Grant 1, we had an improvement in fry again, going from 24 to 27, and improving on parr from none last year to 6 this.
The Castle Grant 2 site had really good numbers of fry, with 109, but unfortunately this couldn’t match last years result of 132. The parr result had gone from 2 to 4. This site was particularly tricky to access, apologies to Kirsteen who had the water over the waders! Our final site of the day was on Castle Grant 3. The parr numbers remained exactly the same, but the fry numbers have reduced from 114 to 63. It is difficult to say at sites such as this the exact reasons for such a decline, there are a complex number of factors involved. But by gathering as much evidence as possible and completing these surveys, it means we are aware of the densities of fry and can try to understand the river environment and manage it effectively.