Build back beaver

The economics of beaver ecosystem services

Ecosystem services are the various benefits that humans derive from healthy ecosystems. Within the context of our capitalist society, there is growing attention being given to the economic value of these ecosystem services, and some feel that by assigning a monetary value to them, it will make them more salient. While beavers have far more to offer than mere monetary value, thinking in such terms can potentially motivate policymakers, land managers and the wider public to support beaver restoration and management efforts.

Beavers provide their services largely round-the-clock on an ongoing basis, and for free. Costs can be incurred through their impacts and management, but such costs tend to be relatively meagre when compared to the overall benefits derived from the ecosystem services their activity yields. Impacts can also be mitigated and minimised through a proactive management strategy, with practices that promote human-beaver co-existence tending to be more cost-effective.\-g8y\-vpAd

With the recovery of beaver populations in the Northern Hemisphere from near extinction during the first half of the twentieth century, the various ecosystem services that beaver activity provides are receiving increasing attention - along with the potential costs of beaver impacts, with recent attempts being made to assign an economic value and cost to these impacts.

A paper published in 2020, titled ‘Ecosystem services provided by beavers Castor spp.’ attempted to assess the economic value of the various ecosystem services yielded by Eurasian and American beavers across the Northern Hemisphere. Ecosystem services were assigned to regulating (benefits obtained through moderation or control of ecosystem processes), provisioning (material or energy output benefits from an ecosystem), supporting (services that maintain fundamental ecosystem processes) and cultural (including recreational, tourism and spiritual benefits).

Source: Thompson et al., 2020; Ecosystem services provided by beavers Castor spp.

The researchers estimated the different types of ecosystem services provided by beavers for a hectare of land per year. Regulating services such as diminishing flood intensity was valued at $124; filtering water at $108; and capturing greenhouse gases for $75 per hectare per year (with these benefits all underpinned by the capacity of beaver eco-engineering to slow water flow). Provisioning services included groundwater aquifer recharge providing drinking water valued at $77 and the creation and maintenance of wildlife-rich habitats at $133 per hectare per year. Cultural services encompassing bird and wildlife watching and recreational potential were estimated at $167 per hectare per year. When these values are multiplied by the estimated range of beavers in the Northern Hemisphere - around 1 million hectares (and expanding) - beavers could provide a huge sum of ecosystem service benefits. This would be very hard to replicate through human means.

The study valued the ecosystem services provided by beavers at millions to hundreds of millions of dollars per year, with habitat and biodiversity provision estimated to be worth $133 million (£105 million), greenhouse gas sequestration around $75 million (£59 million) annually, non-consumptive recreation around $43 million (£34 million) and moderation of extreme events at $32 million (£25 million). The study authors concluded that “habitat and biodiversity, non-consumptive recreation, and moderation of extreme events are particularly valuable services.”

Source: Thompson et al., 2020, Ecosystem services provided by beavers Castor spp.

It should be noted that some other estimates of the total value of beaver-derived ecosystem services put the figure at much higher for a given area of land over the course of a year. Examples include an assessment of potential beaver-derived benefits in Oregon and an assessment of the economic value of beaver ecosystem services in the Escalante River Basin in Utah. In this case, it was estimated that the economic value of ponds generated by beaver activity was around $4,000 per acre per year, and that the ecosystem services of such beaver wetlands could be worth up to $138 million - $414 million per year for this river basin alone.

Populations of beavers in North America and particularly Europe are in recovery, so the valuation of the ecosystem services beavers provide across the Northern Hemisphere is only likely to be a fraction at what it could be if beaver populations were stable and at carrying capacity. Recovering beaver populations will also lead to an increased burden of costs, necessitating management, but such costs are still likely to be far exceeded by the total economic benefits derived from their activity.

Beavers boost biodiversity, a key foundation of ecosystem services

Biodiversity can be considered utterly integral to the provision of ecosystem services. Without a foundation of healthy ecosystems and biodiversity, ecosystem services will be diminished. Research has shown that beaver eco-engineering has the capacity to enhance all manner of biodiversity at landscape scale, and they can create richer wetland habitat than anything humans can hope to replicate. Recent research has also highlighted that beavers could play a role in river ‘wilding’, through their engineering activity, which is otherwise costly and labour intensive work to undertake.

Effects of beaver aquatic eco-engineering - Implications for flooding, droughts and wildfires

Beaver eco-engineering can dramatically increase the water storage capacity of the land they inhabit, while slowing the movement of overland water flow. This aspect of beaver eco-engineering has important implications for flood and drought mitigation. In areas sensitive to the effects of flooding, beaver damming can play a role in natural flood management.

The town of Winzer in Bavaria provides a notable case study. Faced with recurring flooding issues, a €1 million dam had been proposed. Beavers constructed their own dams above the town, saving it €650,000, with only modest flood prevention then needed. In Britain, beavers have been credited with mitigating flooding issues around Pickering and Sinnington in North Yorkshire (with the beavers constructing a 70 metre wide dam, considered the largest in Britain), and Finchingfield in North Essex. A ten year study of four separate beaver family territories in Devon found that these areas stored 24 million litres of water (equivalent to over 68,000 households average water usage a day), while reducing storm flows by an average of 30% during heavy rainfall periods.

Given that extreme rainfall and drought events may become more common over time in the wake of climate change, this capacity of beavers to buffer against flooding events and engineer more resilient ecosystems should not be overlooked.

This same property of beavers can also help buffer against drought, while also creating natural firebreaks in the landscape, which can help buffer against the effect of wildfires. Beaver ponds behind dams can facilitate water flow during drought conditions, and the weight of all the water at ground level trapped in these ponds behind their dams could also help facilitate aquifer recharge. Beaver dams can also help filter water, reducing levels of circulating nitrates, phosphates and sediment downstream.

One assessment of the potential economic benefits of beaver reintroduction to Portugal (one of the very few countries in Europe where beavers haven’t been reintroduced) highlighted the potential role beaver eco-engineering might play in helping buffer against wildfires (and their associated economic costs). In a future of increasing climatic uncertainty, beavers may play an important role in stabilising hydrological conditions, with the associated economic benefits this service may provide.

Beavers and wetland carbon sequestration

While beavers create rich wetland habitat that has the ability to sequester carbon in sediments, beaver wetlands can also emit methane. Further research is needed to provide more informed estimates of the influence of beavers on wetland carbon cycling to shed more light on their overall capacity to sequester carbon.

Beaver biodiversity derived cultural ecosystem services

Non-consumptive recreation encompasses ecotourism opportunities provided by beavers, and the benefits to mental health and well-being that results from having contact with nature. Local economic benefits yielded by beaver-based ecotourism have already been noted in several areas in Britain where beavers have been reintroduced, such as parts of Devon and Scotland. However, such benefits may not regionally persist once beavers become a more widespread and common feature of the wider British landscape.

A comprehensive five-year assessment of the impacts of a population of free-living beavers on the River Otter in Devon reported that the presence of beavers brought social and economic benefits to the area that far outweighed the costs associated with their negative impacts.

One study estimated that globally, protected areas in nature benefit the mental health of visitors to a value of US $6 trillion a year. However, contact with small, humble habitats can be just as important for people’s relationship with nature. There is a growing recognition that the quality of nature and the biodiversity one has contact with has important implications for the mental health benefits yielded by nature contact.

One recent study reported that areas harbouring a more diverse range of natural features (such as trees, birds, plants and waterways) were associated with stronger improvements in mental well-being when compared to spaces harbouring less natural diversity. Beaver wetlands naturally tend to exhibit these features, harbouring a complex and varied mosaic of green and blue space. An individual’s relationship with nature, sometimes encompassed by their connection to it, is an important pathway through which nature benefits mental well-being. This connection is built on a foundation of sensory awareness of nature, and more biodiverse landscapes (such as the kind beavers engineer) exhibit a richer sensorial tapestry, providing more opportunities for connection.

Costs of beaver impacts and management practices

The people who benefit from beavers economically from the ecosystem services their activity yields aren’t likely to be the same people who bear the brunt of negative beaver impacts that can incur financial costs, such as farmers and landowners. The costs and benefits of beaver presence should ideally be collectively shared, and those suffering from beaver impacts should be supported and compensated as and when necessary.

Comparisons of beaver management practices in the US (comparing traditional heavy handed approaches such as dam removal and culling) with approaches that promote coexistence (such as flow devices and culvert protectors) have found that management measures that promote coexistence tend to be far more cost-effective. An added benefit to such approaches is that they also better support the provision of ecosystem services (with associated economic benefits) that beaver presence provides.

When considering the costs that beavers may incur (such as localised flooding and crop damage), the overall cost of their negative impacts are still likely to be far outweighed by the broad benefits their associated ecosystem services yield if such impacts are mitigated as part of a proactive management strategy. One way in which those hosting beavers on their land and experiencing potential negative impacts could be supported would be through the implementation of payments for ecosystem service schemes. This would also yield a concrete way for society to benefit from the various ecosystem services that beavers provide.

Lack of government support blocks wide scale economic benefits

While there have been some tentative movements and murmurings on the subject of payments for ecosystem services from some quarters of the government, when it comes to economic support for beaver-derived ecosystem services, progress has much resembled the creature in question when out of water - slow and lumbering.

Despite the broad range of ecosystem services and associated economic benefits a well managed, free-living population of beavers in Britain could provide, the UK government in the form of DEFRA recently stated that “the reintroduction of species is not a priority for the government”. This is an incredibly short sighted and insipid attitude, bleated by a government agency that apparently seeks to improve and protect the environment, and grow a green economy. This also highlights a dramatic change in tone from DEFRA, which only a few years previously stated its support for beaver reintroduction. Reflecting on the completion of the Devon Beaver Project, it stated that the government was “committed to reintroducing formerly native species, including beavers, where there are clear environmental and socio-economic benefits.”

Without a government agency that acknowledges evidence and is more ambitious and consistent in fulfilling its stated aims, it appears that the potential economic benefits that a well managed free-living beaver population could provide will not be realised, to our great loss.