Ranunculus: scourge of the Spey

I suppose it was inevitable, given the low water and warm summer experienced in 2013 followed by the generally stable river levels over winter that Ranunculus would bloom in the river this year. However many of the ghillies are reporting that it is the worst it has been. The lower river appears to be suffering worse so yesterday I took the opportunity to get some photos at Delfur.

Long streamers of Ranunculus by a boat mooring point. Ranunculus is such an adaptable plant. In the Spey it can be seen growing is slower flowing glides such as this but also in fast flowing riffles ands almost still backwaters.

Long streamers of Ranunculus by a boat mooring point. Ranunculus is a very adaptable plant. In the Spey it can be seen growing is slower flowing glides such as this but also in fast flowing riffles and almost still backwaters.

Dense bed of Ranunculus at the tail of the Bridge pool

Dense bed of Ranunculus at the tail of the Bridge pool

A ghillies primary role is to ensure that theirs guests have an enjoyable visit and hopefully contact with a fish or two. There are therefore limited opportunities during the course of a long day for other issues such as riverbank management, and increasingly on the Spey weed management. Ghillies throughout the river are having a spend a lot of time hand pulling ranunculus just to keep fishing areas clear. With the weed growing so profusely this year it has become an almost impossible task.

The ranunculus often becomes established in a zone along the riverbank, making landing fish a diffucult task. These marginal areas are aslo where many fish are hooked during high water events. If we do get a summer spate this year the fishing will be even more of a challange given the profusion of ranunculus along the banks.

The ranunculus often becomes established in a zone along the riverbank, making landing fish a difficult task. These marginal areas are aslo where many fish are hooked during high water events. If we do get a summer spate this year the fishing will be even more of a challange given the profusion of weed along the margins.

Imagine trying to land a salmon through this weed bed.

Imagine trying to land a salmon through this weed bed.

The ranunculus does provide cover for juvenile fish as this heron is no doubt aware. It also provides habitat for a multitude of invertebrates but the when established it has a major influence on water movement, sediment deposition and biodiversity.

The ranunculus does provide cover for juvenile fish as this heron is no doubt aware. It also provides habitat for a multitude of invertebrates but once established it has a major influence on river flows, sediment deposition and biodiversity.

The negative impacts of ranunculus on angling have been mentioned and it is increasingly implicated in the decline of freshwater pearl mussels. In a salmon river the availability of spawning gravels is a key resource. If the ranunculus colonises spawning gravels there is a further impact of another of the species for which the Spey is designated as an SAC. Ranunculus has only been present in the Spey for around 40 years but there is a great deal of frustration at what is percieved to be a lack of action by the authorities responsible for its control.

The correlation between ranunculus abundance and nutrient inputs; be that from point sources such as sewage treatment works and septic tanks or more diffuse sources such as run-off from land, has been made during several distribution surveys. At Grantown it grows in profusion on one side of the river only; coincidently the same side as the sewage treatment works discharge point. However, in the middle river; the Knockando section for example, even this year there is relatively little ranunculus present. This part of the river is relatively distant from major effluent discharges and also benefits from the input of lower nutrient water from the River Avon. Downstream of Aberlour however the ranunculus is probably at its worst. Here there are several towns in succession with associated run-off, industry and more intensive agriculture. The River Fiddich, a naturally more productive water, also joins the Spey and it would appear that in river conditions in this area are highly highly suited for ranunculus, paricularly during low water conditions.

A report on the nutrient status of the Spey in the Aviemore to Grantown area has just been published. This report analysed water quality data collected by SEPA and others and mainly discussed impacts of freshwater pearl mussels. The levels of most nutrient were generally within the accepted thresholds for high status under the Water Framework Directive, although phosphorus gave some cause for concern. However it is possible that levels of nutrients in the lower Spey are locally, and even temporarily, much higher during low water conditions, providing ideal conditions for ranunculus to florish. A study of nutrient levels under these conditions is overdue and could be highly informative.

Ewan McIlwraith used the term “tipping point” on the recent BBC Landward programme feature on the impact of abstraction on the Spey. A very apt term. Some looking at the river now feel that point has been passed as it in places it looks more like a chalkstream than an oligotrohic (low nutrient) highland river. If the Spey is really at that point some serious work is required to a) assess its true status and b) put measures in place to turn the situation around.

There are 4 comments for this article
  1. Edward Mountain at 10:47 am

    I have resisted in making any comment on the issues of Ranunculus but feel that the issue is now so bad that I have no option.
    There is no doubt that when this weed was accidentally introduced into the river, in 1979 at Grantown, we should have been far more proactive in removing it. In the late 1980s and up until 1992 we had an effective chemical called ‘Midstream’, to control the weed. In hindsight it is a pity that the Board did not co-ordinate a spraying program to eradicate this non-native weed.
    When ‘Midstream’ was banned all efforts to control the weed were effectively stopped. As the Board member dealing with this issue I know that our attempts to deal with Ranunculus have been constantly blocked by many of the regulatory agencies including SNH and SEPA. I have the feeling the issue was just too difficult. Many distracting reasons were given at endless scoping meetings, such as the potential danger to mussels of using chemicals (odd then that they were so common when the river was designated and after we had used Midstream). How ironic is it now that mussels are suffering the most from the invasion of this weed and could soon become extinct in the Spey.
    Let me be clear I believe that Ranunculus is strangling the very life out of the river and those iconic species that inhabit it.
    At best the trials that have just started on the Don might offer some encouragement but by the time the results can benefit the Spey it might well be too late for mussels and the salmon. Nero fiddling while Rome burnt is the analogy I would use.
    So I make this plea to all those involved; Stop making excuses and let us join together and take action to defend the river before it is too late.

  2. Anthony Tinsley at 6:00 pm

    I had no idea the ranunculus was that bad at Delfur; i owe EM an apology!
    Is the nutrient problem nitrates or phosphates which latter could be scrubbed out in treatment plants?

    • Brian Shaw Author at 6:33 pm

      Not only at Delfur Anthony, it is a particularly bad year all over the upper and lower river. Still maybe a few big spates will improve things for next year.

  3. Mel McDonald at 4:32 pm

    Whilst considering this particular ‘invasive’ weed which is not a new problem and one which has been deliberated on by SEPA and SNH for years, there seems to also be a huge problem on Speyside from giant hogweed, japanese knotweed and himalayan balsam. I would go so far as to say that the Spey is reaching a tipping point for these species of plants also, risking the ecology of the Spey catchment. I doubt whether these issue will feature in the Wild Fisheries Review but if they don’t they should !

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