Wetlands as settings for human health: The benefits and the paradox

As wetlands provide many valuable ecosystem services and are amongst the most degraded ecosystems globally, further degradation could greatly affect the well-being and health of people dependent on them. Healthy wetlands are generally associated with enhanced ecosystem services and improved outcomes for human health, and unhealthy wetlands with degraded ecosystem services and poor outcomes for human health. However, the relationships can also be paradoxical with some direct benefits for human health leading to the loss of other ecosystem services, in particular regulating and supporting services, and the enhancement of others, leading to poor outcomes for human health. This results in a health paradox whereby there is a loss of regulating and supporting services from steps to enhance human health. Examples of the health paradox include: drainage of wetlands for malaria control; conversion of a wetland into a reservoir to store water for human consumption and irrigation; and regulation of rivers for flood mitigation activities to alleviate loss of life or property. A wetland paradox also occurs when there are poor outcomes for human health as a consequence of the maintenance or enhancement of ecosystem services. Examples of the wetland paradox includes: urban wetlands protected for nature conservation can also support mosquitoes and other vectors, and expose humans to vector-borne diseases; and the maintenance of large woody debris in rivers which slows down water flows, and contributes to the trophic web and is a recreational hazard for swimming or boating. In response a framework for the conceptualisation of human and wetland relationships, including the paradoxical situations has been provided based on the concept of wetlands as settings for human health. This enables the trade-offs that have and will occur between wetland ecosystem services and human health to be addressed.