An integrative assessment of aquatic ecosystem services based on guideline thresholds

Abstract Ecologists typically associate water quality with trophic status where oligotrophic ecosystems have excellent water quality and presumably provide more aquatic ecosystem services. However water quality is perceived differently among worldviews. Aquatic ecosystem service provisioning to the public health and agriculture sectors is determined using specific guidelines. But are these guidelines related to trophic status? Here, we developed an integrative ecosystem service framework using guideline thresholds for drinking, swimming, irrigation, suitability for livestock and aquatic wildlife in canadian rivers of varying trophic status. Drinkability was the most sensitive ecosystem service, met in 37% of cases, whereas livestock was the least, provided in 99%. Trophic status is a fair proxy for ecosystem services limited by fecal contamination as nutrients are related to human and animal populations, but not to those limited by metals. Using quantitative thresholds to assess the safe provisioning of multiple ecosystem services provides clear guidance for supporting resource management. In a nutshell Water quality is a commonly used term in management, but the metrics that determine whether a river can safely provide various aquatic ecosystem services differ among worldviews. We propose an integrative approach based on guideline thresholds to evaluate the frequency with which rivers are drinkable, swimmable, suitable for irrigation, livestock, and aquatic wildlife and compared this suitability with trophic status. Trophic status is a fair proxy for ecosystem services limited by fecal contamination, but not for those limited by metals. Using and developing more guideline thresholds provides a concrete way to assess ecosystem service provisioning that could help serve management.