With Beavers still a topic oF conversation and reports that certain conservation groups are
interested to try and re introduce them perhaps to parts of Wales perhaps they might read the cautionary not supplied to me by a long time angler who in recent years has been fishing the Tay and Tummel.
Its easy for groups to try and surmise how an introduction will work out and modelling and table top predictions often come unstuck in real life.

Below is the report I received from someone with intimate experience of them and the effects they can have on the environment.
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,Based on experiences on the Tay and Tummel in Scotland. I class myself as an animal lover but a pragmatist,


1. Beavers were introduced to the Tay system both illegally and as part of "controlled" experiments.
2. They have bred like rabbits, possibly multiple litters per season, and official estimates of their numbers are gross underestimates, set against the facts experienced by ghillies, estate managers and other on the ground countryside workers. They have also spread extensively covering vast geographic areas, and seem to be impossible to contain in proscribed areas.
The Scottish Government adopted a policy of review after a few years. In reality the Tayside beaver population is now so extensive in numbers and geographic spread that containment/reduction/removal is now impossible.
3. In truly remote rural areas, such as the Knappach forest in Scotland where they were also legally re-introduced, beavers may well do some good in habitat management, flood prevention etc. However, in non-wilderness environments where modern day life is very different from that 400 years ago, the implications are very very different.
4. In the Tay system, farm owners who for generations have been ditching and managing against flooding of prime agricultural land, have found their ditches dammed by beavers, their good land flooded, and have incurred big costs in removing beaver dams repeatedly. Some farms report having to employ staff full time just to keep ditches operational.  Unlike Bavaria, there does not seem to be any formal scheme to compensate farmers/landowners for their losses/costs.
5. Bankside trees on the Tay and Tummel have been extensively felled by beavers. In Pitlochry on the Tummel, land owners and local council have incurred costs in clearing felled trees, and local angling club members have also been hard at work at their own cost clearing bankside paths. Very large trees up to 40 foot tall have been chopped by the beavers and fallen into the river, some of them to float off downstream in the next big flood to lodge against bridge pillars etc and cause flooding risk and damage.
I have a series of photo examples.

6. Beavers on Tayside have burrowed into major floodbanks, which were established to protect major conurbations such as Perth, seriously weakening them, exposing major residential areas to flood risk and requiring substantial cost to refurbish them.
7. Beavers on Tayside have hoovered up carrots and other root crops from farmers fields in large quantities and at cost to the farmers, and stored them in underground burrows, including the use of floodbanks for this purpose.
8. The Tay beaver group maintain that beavers and otters can co-habit. They do acknowledge that beavers can be aggressive to otters when they have youngsters. In my experience on Tummel, fishing late evenings I would frequently see otters from 2010 to 2014, when beavers appeared, and since then I have never seen an otter but seen beavers constantly.
9. Beavers can be very aggressive when protecting their young, and late evening fishers on Tummel were threatened regularly by beavers approaching and smacking their paddles on the water.
10. Beavers are very large creatures, one on Tay system recorded at 60 kgs !!
11. Spawning burns have been dammed by beavers, to the extent that salmon/sea trout passage is impossible. We cannot afford any loss of spawning areas or fish numbers.
12. Other burns have been dammed creating upstream flooding, and raised levels in burns that have resulted in domestic property upstream being flooded.
13. The legal rights of landowners to protect their land and to cull/kill beavers where necessary is very unclear.

For the Wye catchment, and any other parts of the country where beaver re-introduction is happening illegally or being legally considered, I believe that the risks and costs are very high, and typically underestimated, that it is impossible to contain the growth and spread of beaver population, and landowners need greater clarity on their legal rights to protect their land. Equally, local councils need clarity and support so that they are not left incurring the inevitable costs of clearing up after beavers.
Current day urbanisation and the demand for food production  is a very different picture to the vast rural wildernesses and low population levels that existed when beavers became extinct. Their reintroduction is a great romantic notion, but carries a substantial set of practical and real downsides which are not being fully considered/addressed.
Best regards,