What’s an agroecosystem and what’s its value?
September 16, 2023
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Grasslands provide many ecosystem goods and services, and valuation of these services could provide more incentive to protect them. © N. Petterson
In September, the new Census of Environment for Canada released a technical paper, Ecosystem accounting in Canadian agroecosystems, which provides a framework to value ecosystem contributions, particularly contributions to the economy and human health.
Agroecosystems are ecosystems that support food production, including cropland and pasture. In the prairies, where most agroecosystems are found, agriculture can protect wildlife habitat — for example, grazing livestock can be placed on native grassland, preventing the land from being converted to other use — but it can also threaten sensitive ecosystems. Agriculture can cause the destruction of native habitat as land is used to grow crops and forage, and pesticides and fertilizers can leak into surrounding areas, changing ecosystems and harming wildlife.
According to a release in The Daily, Canada is losing agroecosystems and semi-natural pastures, possibly from industrial and urban expansion. Expanding sown pasture is likely also replacing semi-natural pastures, and these pastures are less diverse than native prairie, often failing to meet habitat requirements for many endangered prairie species. Increasing pesticide use, especially in the Central Grassland where pesticide use had the highest increase, is likely also threatening grassland habitat and wildlife such as songbirds.
The valuation of agroecosystems could help to develop incentives and policies for the protection of grasslands, although several challenges remain. Sown pasture is not always distinguished from semi-natural pasture, even though the differences for biodiversity can be enormous. Since so much natural grassland has been lost, and several species are only able to thrive in natural grassland landscapes, protecting the remaining natural landscape must be a priority.
The framework is also primarily focused on economic and human well-being, with less consideration for the benefits to biodiversity. Habitat maintenance is mentioned as a service, although measurement focuses on area of habitat. Biodiversity metrics concentrate on birds, insects and pollinators. Amphibians and reptiles, despite being acknowledged as valuable indicators of ecosystem health, are not considered in the framework.
The technical paper presents possible metrics to evaluate and quantify ecosystem services provided by agroecosystems, and could promote incentives to protect habitat and improve ecosystem health. Still, the focus is on economic benefits and human well-being. Many of the benefits that natural ecosystems bring are difficult or impossible to attach an economic gain to, and until we can appreciate ecosystems for their inherent value, protecting these landscapes will be a constant struggle against profit.
