Mike Blackmore

Of Casters and Castors

A couple of years ago I wrote an article in the Wild Trout Trust’s annual magazine Salmo trutta, in which I keyed a few thoughts on the River Otter Beaver Trial (I still struggle with that mixed-mammal nomenclature!). In that article, amidst nonsensical ramblings about a childhood book, I expressed both concern and hope at the prospect of wild beavers returning to England. Concern that so little of our constrained, canalised and squeezed river corridors have the space for beaver dams, and hope that beavers might just force policy makers to finally give that space back to the rivers from which it was stolen.

Following the announcement that the Otter beavers (imagine the hybrids!) are here to stay, my little corner of fishy/river restoration social media immediately lit up with predictably strong and unequivocal opinions as to the correctness of the decision. You could practically hear the angry smashing of keyboards and phones as each side faced off in 280-character proclamations!  

Mike Blackmore

Many of us lucky enough to spend our working weeks designing and delivering fish habitat and passage improvements are enthusiastic and enamoured (yet, in my case, embarrassingly under-skilled) anglers. You can’t spend all day thinking about rivers and not become a bit fish obsessed! We river restoration practitioners will happily lecture anyone who’ll listen on the benefits of woody debris to river ecology, morphology, hydrology etc. but that’s a book in itself. If you aren’t already convinced of the benefits of wood in rivers, you’ll just have to trust me when I say that fish live in trees (score one for Castor fiber)!

On the other side of that coin, I demolished my first weir in my early twenties and I’m still ripping the horrible things out now. Last autumn alone my colleagues and I removed 6 and bypassed another. They are the devil’s work! So surely then, we should be up in arms at the prospect of beaver dams. Shouldn’t we?

Well, truth be told, many of us aren’t. It’s not that we’re unconcerned, quite the opposite. It’s just that many of us find the debate as to whether beavers should or shouldn’t be here a distraction, a waste of time and effort. Beavers are here! A couple of years ago I commented that at the start of the ROBT (can’t get mustelid-rodent confusion if you abbreviate it!) that “the genie was at least two-thirds out of the bottle”. Now in 2020, it’s all the way out and it’s not going back in. To muddle metaphors, nothing of value will be achieved in playing King Canute and demanding the tide turn back.

Beavers have potential to do good, they have potential to do harm. How much of each depends on where they are and what we do about it. There has been (and will continue to be) a lot of evidence thrown between the pro-beaver and anti-beaver brigades. Some of it might be good evidence but probably all of it is site and situation specific. Anyone claiming they can definitively prove that beavers will be good or bad is at best deceiving only themselves.

Jay-Carter Coles

Yes, there is plenty of evidence of fish traversing beaver dams. However, there is also evidence of the harmful impacts of even 90% passable river obstacles. Recording the number of fish that make it past a barrier doesn’t show how many tried and failed or were critically delayed in their migration. 

Yes, we know how damaging artificial impoundments are on river ecology. However, to compare concrete weirs to woody dams is to compare chalk to cheese (I’ll come to chalk later).

Yes, beavers and salmonids co-evolved and lived in harmony for thousands of years. However, with so few anadromous fish now making their inland migrations, every extra delay is potentially disastrous. Yes, in modern constrained and modified channels, dams, burrows or lodges could have a much greater impact than centuries ago. However, surely that’s just one more reason why we must give our rivers back the space they need.

The arguments are cyclical, and unlikely to win over anyone on either side. There is however, two facts which cannot be disputed: firstly that beavers are already back, and secondly that they won’t stay put.

Although privileged to work alongside some very good fisheries scientists, I am not an academic myself. Beyond a hazy environmental science BSc, my qualifications are all practical experience based. Perhaps that’s why, like many in my field, I don’t see this as a science issue. Many of us see beavers in the same way we see any potential river restoration project, something that just needs to be configured in the right way to produce the best ecological outcome. That is admittedly an over-simplification and understatement of the challenge we face, but from a pragmatist’s perspective, it’s a challenge just like any other

Mike Blackmore

Recently there has been a lot of discussion specifically around the prospect of beavers in chalk streams. Chalk streams are different to other rivers. They are low gradient, low energy, extremely biodiverse and (as many anti-restoration nimbyists will gleefully point out) are more-or-less entirely man-made. We have spent a very long time advocating the removal of weirs and sluices on the chalk streams. On these low gradient systems, the impact of impounding flow can often be much more severe than even their impact on fish passage. Moving from the near-ubiquitous practice of ‘holding-up’ water levels during the summer, to allowing the rivers to flow more naturally, has been a slow and hard-fought battle. So, it’s no small wonder that after so many years of seeing the benefits of impoundment removal, many people on the chalk are understandably concerned about beaver dams

And they may be right. Within such a heavily modified, constrained, and low-gradient system, an unexpected impoundment could have a big impact. Some parts of our larger chalk streams are back-to-back famous, and economically lucrative fisheries. A change in flow regime, fish passage or water level in one section could have significant consequences for adjoining fisheries and landowners.  The scope for the river to cut around a dam and facilitate fish passage and habitat development could be very limited on such commercially valuable ‘double-bank’ angling real estate. 

So, should the chalk streams be ring-fenced as beaver no-go areas? No. First of all, we couldn’t even if we wanted to. Whether naturally or unnaturally, legally, or illegally – beavers will arrive on the chalk streams. It’s just a matter of time. Secondly, the chalk streams are some of the most heavily managed environments in the world. If you can’t manage beavers on reaches of river with full-time workers micro-managing plant growth, you can’t do it anywhere! The question shouldn’t be should we stop them, it should be how do we manage them?  And in my opinion, the answer to that question is easily, if we are proactive now, or with difficulty if we are not.

Realistically, there is only one practical and feasible solution: we must prepare. Making a plan after beavers arrive is too late. If those worried about beavers spend all their time trying to stop them arriving, if they refuse to engage with efforts to create practical, sensible management policies, they may find their options extremely limited if their fears come true. We don’t have a great deal of data when it comes to wild beavers in modern England. We can’t get that data without mass reintroduction, by which time it would obviously be too late to use it.

Mike Blackmore

What we do have, in rapidly proliferating abundance, is geospatial data on our rivers and catchments. This is our strength; this is the greatest tool at our disposal.

We need to use new and existing catchment data to start mapping out where the greatest risks and the greatest opportunities are. We need to put plans in place so if a beaver turns up on a chalk stream tomorrow, and causes a problem, or even if it doesn’t but local stakeholders just really don’t want it there, we can say “don’t worry, we know what to do”. 

One could envisage a system whereby translocating beavers from ‘problem sites’ to ‘solution sites’ is as simple as picking up the phone. A system whereby river keepers can modify or even remove a beaver dam if it causes an issue. Practical policy that empowers landowners and river managers to manage beavers with the full (even financial) support and understanding of statutory bodies Catchment Partnerships, conservation NGOs and the public.

Whether pro-beaver or anti-beaver, nobody will win by lobbying our already de-fanged, weakened, and emaciated regulation agencies. We must do this ourselves and must do it together. River anglers are themselves a threatened, dare I say endangered breed. For so long the torchbearers of river conservation, our numbers now dwindle and our average age increases. If we are to pass the torch to a new generation of river protectors, we may well need charismatic (and probably furry) megafauna to keep the fire of public interest ablaze.

River Otter female

River Otter, tagged female

I have walked, mapped, advised on, and restored rivers all over the south of England and South Wales – especially on the chalk streams of Wessex and the Chilterns. I can state quite confidently that I believe there is a place for beavers in England and that does include some parts of our chalk streams. Without naming names, I can even think of a few chalk stream landowners who might be quite happy to have them.  However, policy and management should and must remain local, practical, and sensible. We must be cautious and protect our already beleaguered fish populations. We must strive to make space for beavers (and the benefits they can bring) where possible. 

If we act now, if we map out the best and worst places for them to be, if we can build sensible plans with the current owners and stewards of our rivers, if we can create flexible, practical management systems, if we can avoid top-down blanket policy, we absolutely can co-exist with beavers in any catchment – even on the chalk.*

Contact us for support at info@beavertrust.org and visit www.beavertrust.org for more information and to arrange a trip to the Cornwall Beaver Project.

(*This blog is written by an independent writer. Beaver Trust welcomes a breadth of opinions, and those expressed within this blog do not necessarily reflect those of the Beaver Trust.)

Mike Blackmore Wessex Rivers Trust

Mike Blackmore

Beaver Believer

Mike Blackmore has spent twelve years delivering river restoration, water quality and natural flood management projects, as well as advising on fisheries conservation/management, across Southern England and South Wales. Mike worked at Cain Bio-Engineering Ltd and The Wild Trout Trust before joining Wessex Rivers Trust as Head of Project Delivery. Follow Mike on Twitter.

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© Mike Blackmore 2020.