Des Roches S., Pendleton L., Shapiro B., Palkovacs E.P. 2021. Conserving intraspecific variation for nature’s contributions to people. Nature Ecology & Evolution https://www.nature.com/articles/s41559-021-01403-5
People depend on biodiversity for the many values it provides, including food, water, shelter, medicine, and cultural inspiration. The loss of biodiversity driven by human activity places these benefits at risk. When seeking to understand the causes and consequences of biodiversity loss, Western science has focused overwhelmingly on species-level extinction. Similarly, conservation organizations such as the IUCN focus their efforts on species. As a result, the valuation of ecosystem services has typically focused on the benefits provided by species-level biodiversity.
But what about the genetic and phenotypic diversity within species (intraspecific variation)? If intraspecific variation provides important benefits to people, then biodiversity losses below the species level might be as concerning as species extinction – and perhaps even more urgent, given that the rate of intraspecific losses may exceed species extinctions.
We reviewed the published literature to ask whether intraspecific variation is declining and whether these declines threaten nature’s contributions to people (NCP). These questions were prompted by our prior meta-analysis showing that intraspecific variation plays an important role in shaping communities and ecosystems (Des Roches et al. 2018). If intraspecific variation plays a critical ecological role, then perhaps it is similarly important for NCP.
Is intraspecific variation declining? Current evidence shows that the rate of intraspecific biodiversity loss is much higher than the rate of species extinction. However, intraspecific variation is poorly characterized for most organisms, and biodiversity losses below the species level are rarely tracked. For example, just 1% of all species cataloged by the IUCN are evaluated below the species level. Thus, while there is strong evidence for an intraspecific biodiversity crisis, the rate and magnitude of intraspecific losses are still unknown for most groups of organisms.
Does declining intraspecific variation threaten NCP? Studies on a wide variety of organisms, from fish, insects, plants, and fungi, show that intraspecific variation provides critical contributions to people and that its loss threatens NCP. For example, diverse fish stocks provide more stable fisheries, and diverse plant genotypes provide more productive agro-ecosystems. These and other examples make clear that the loss of intraspecific variation threatens important aspects of NCP.
What can be done to conserve intraspecific variation and preserve NCP? We propose several immediate steps that can be taken to conserve intraspecific variation and safeguard NCP. First, we must step up efforts to document intraspecific variation and its contributions to people. These efforts should take advantage of new technologies, such as genomic tools, as well as local and Indigenous knowledge, which can offer a deep understanding of how distinct variants are used by people. Second, intraspecific variation can be directly incorporated into biodiversity assessments, such as the IPBES. Third, protecting and restoring intraspecific variation can be elevated to a major goal in conservation, with specific targets for genetic and phenotypic diversity incorporated directly into conservation plans. Current efforts to classify and preserve intraspecific variants should be dramatically expanded.
With a species extinction crisis underway and conservation budgets already strapped, a frequently asked question is whether we can afford to study and conserve intraspecific variation. However, once its value for NCP is recognized, the question becomes – can we afford to ignore it? The study of intraspecific variation and its value for NCP remains in its infancy. We will undoubtedly encounter many surprises to come. But the available evidence strongly suggests that the benefits of studying and conserving intraspecific variation will far outweigh the costs. After all, the future is uncertain and the greatest value of intraspecific variation may be in response to challenges we have yet to face.