Credit: Skip Lisle

Beavers and Technology

When one considers wildlife, biodiversity, conservation & reintroductions, a few things spring to mind. Iconic, long lost species once again roaming in or flying above the countryside where they once thrived; habitat restoration, perhaps through tree planting or natural regeneration. Controversy, of course. Perhaps the timely return of a keystone species, or an opportunity for ecotourism. But technology is not usually in that list.

However, technology can play a very important role in wildlife management. Perhaps this is not surprising considering the advances in technology we’ve seen so far this century, and their application in agriculture, which has a close relationship (positive & negative) to wildlife and biodiversity. I work in the field (pun intended) of agricultural technology and a great deal of the exciting innovations we see are focused on improving efficiencies, reducing waste and producing food better, with a sharp eye on improvements in environmental sustainability. For instance, drones help farmers & agronomists to identify, quantify and treat crop disease more efficiently, which means less time and money spent on the problem. A very useful by-product of this is reducing fungicide or herbicide use and the associated ecological damage.

Similarly, satellite imagery can help to assess cropping changes and determine the need for, and rate of application, spring fertiliser. Sensors, in particular things like cameras & moisture sensors, when combined with AI (artificial intelligence) & IoT (internet of things), can improve livestock management and crop irrigation efficiency. A few minutes of research on Google will highlight how the technology described above also has considerable application in the field of wildlife conservation.

But let’s come back to the beaver. There is one key piece of technology which can play a major, and positive, role in beaver management, whether those animals are resident or introduced. I first came across flow devices in Ben Goldfarb’s excellent book ‘Eager – the surprising, secret life of beavers and why they matter’, where the author traveled to the state of Vermont to meet Skip Lisle, the man behind one type of flow device.

Skip enjoyed fishing for trout and discovered by chance that the fish he caught from beaver ponds were generally considerably bigger than fish caught in rivers and streams where beavers weren’t present. He put this down to the increase in cover (plant life) and food (insect life) available for the fish as a result of beaver activity.

But as these beaver benefits became apparent, so did the problems they could cause – blocked culverts and flooding. Skip set out to find a non-lethal solution (partly because killing or removing beavers simply creates an opportunity for other beavers to move in, so the problem needs addressing repeatedly, at cost), and eventually came up with a technological approach, a flow device called the Beaver Deceiver. Others, such as Michael Callahan, the owner of Beaver Solutions consultancy, have developed their own types of flow devices, one of which is called the Pond Leveller, which follow a similar principle.

The basic design of this kind of device consists of weldmesh and a plastic pipe, which allows the water in the pond, behind the beaver dam, to drain continually, maintaining the pond but preventing the water level becoming unsustainably high. This then helps to manage water levels and reduce flooding – and associated damage – upstream of the dam. Or, as Michael Callahan’s Beaver Institute puts it, ‘The pipe becomes a permanent leak in the dam so the beaver pond is controlled at a safe level despite the presence of beavers.’

Goldfarb describes in detail the development of different types of flow device and their reception among state and federal wildlife (and other) agencies, which has often been negative in spite of the impressive cost-benefit ratios from using them. When conflicts (which of course do exist between beavers & humans) occur and the only way they’ve ever been addressed historically is by shooting or trapping beavers, it’s not surprising that there’s resistance to change, a reluctance to move to a ‘managed co-existence’ approach. Similarly, when low quality and unsuitable versions of these ‘flow devices’ have been installed, not properly maintained and then failed, it’s no wonder that the whole concept gets a bad press.

But things are changing, and Lisle and Callahan are adamant – and have the evidence and experience to prove it – that properly installed and managed alternative flow device technology can allow humans and beavers to co-exist successfully in the vast majority of instances.

Alex Dinsdale

© Alex Dinsdale 2020