Presenter/s: Mark Beardsley
Symposium Session: 2020 - 05 Assessing biotic response to environmental change
Topics covered: beavers, community involvement, floodplain, lessons learned, monitoring, riparian, risk, and stream
Biotic processes are now recognized as key drivers of stream form and function that work in concert with hydrological and geomorphic processes, not separately from them. When we understand streams as integrated biophysical ecosystems rather than as physical habitat that simply houses plants and animals, restoration appears less like less like a physical engineering exercise and more like an organic healing process. Restoration efforts can be thought of less like construction projects and more like medical treatments. From this view, streams are like patients. They are complex organic systems that we help heal—not physical things that we design and build. We cannot simply design biotic processes or build biotic communities. Healing takes time and organic restoration requires patience. As in medicine, careful management over time (rehabilitation) is often necessary in addition to, or instead of, instant fixes (surgery).
Health, healing, and medical analogies are nothing new to the field of ecological restoration. As stream conservation and restoration practitioners, we feel the health concept should be more than a metaphor. It is a mindset and a model—a way of thinking and a practical approach to stream restoration that respects the inherent complexity of natural functioning stream ecosystems.
What does it mean for a stream to be healthy? We think it is a lot like what it means for a person or other living organism to be healthy. Medical definitions of human health are based on the ability to perform vital functions normally or properly; ability to perform valued roles; ability to deal with stress; and anatomic, physiologic, and psychological integrity. These traits apply to streams and other ecosystems in much the same way. Like organisms, streams are very complex systems (eco-systems) whose ability to perform vital functions and valuable roles, and to deal with stress (that is, to be resilient), depends on hydrological, physicochemical, and biological integrity.
The shift from an engineering/construction mindset to a medical/healing mindset opens the door to process-based restoration. It fits neatly with the four principles of process-based restoration (Beechie et al. 2010) and the five guidelines for ecologically successful river restoration (Palmer et al. 2005). In this talk, we share how the stream health model guides our assessment, diagnosis, treatment, monitoring, and evaluation of projects. Our examples come from work on small streams in the Colorado Rockies, but we think the concepts apply to all stream and river restoration efforts that seek natural and sustainable benefits.