Abstract
Watershed resilience is the ability of a watershed to maintain its characteristic system state while concurrently resisting, adapting to, and reorganizing after hydrological (for example, drought, flooding) or biogeochemical (for example, excessive nutrient) disturbances. Vulnerable waters include non-floodplain wetlands and headwater streams, abundant watershed components representing the most distal extent of the freshwater aquatic network. Vulnerable waters are hydrologically dynamic and biogeochemically reactive aquatic systems, storing, processing, and releasing water and entrained (that is, dissolved and particulate) materials along expanding and contracting aquatic networks. The hydrological and biogeochemical functions emerging from these processes affect the magnitude, frequency, timing, duration, storage, and rate of change of material and energy fluxes among watershed components and to downstream waters, thereby maintaining watershed states and imparting watershed resilience. We present here a conceptual framework for understanding how vulnerable waters confer watershed resilience. We demonstrate how individual and cumulative vulnerable-water modifications (for example, reduced extent, altered connectivity) affect watershed-scale hydrological and biogeochemical disturbance response and recovery, which decreases watershed resilience and can trigger transitions across thresholds to alternative watershed states (for example, states conducive to increased flood frequency or nutrient concentrations). We subsequently describe how resilient watersheds require spatial heterogeneity and temporal variability in hydrological and biogeochemical interactions between terrestrial systems and down-gradient waters, which necessitates attention to the conservation and restoration of vulnerable waters and their downstream connectivity gradients. To conclude, we provide actionable principles for resilient watersheds and articulate research needs to further watershed resilience science and vulnerable-water management.
| Original language | English |
|---|---|
| Pages (from-to) | 1-28 |
| Number of pages | 28 |
| Journal | Ecosystems |
| Volume | 26 |
| Issue number | 1 |
| DOIs | |
| State | Published - Feb 7 2022 |
Funding
This work was conducted as a part of the North American Analysis and Synthesis on the Connectivity of Geographically Isolated Wetlands to Downstream Waters Working Group supported by the John Wesley Powell Center for Analysis and Synthesis, funded by the US Geological Survey. We appreciate and acknowledge the effort, commitment, and contributions of Kate Schofield and Mark Bowen to the Working Group. We thank David Aldred for rendering Figures 1 and 2 and crafting Figure 8. The latter was made using MATLAB code appreciatively provided by “Infamous Heel-Filcher” (http://infamousheelfilcher.blogspot.com/2013/02/changing-viewing-angle-of-matplotlib.html ; accessed 11/2020). Peg Pelletier, John Johnston, and three anonymous reviewers provided critical feedback on earlier drafts, and their efforts improved the manuscript. This paper has been reviewed in accordance with the USEPA’s peer and administrative review policies and approved for publication. Any use of trade, firm, or other product names is for descriptive purposes only and does not imply endorsement by the US Government. Statements in this publication reflect the professional views and opinions of the authors’ and USGS and should not be construed to represent any determination or policy of the USEPA. This work was conducted as a part of the North American Analysis and Synthesis on the Connectivity of Geographically Isolated Wetlands to Downstream Waters Working Group supported by the John Wesley Powell Center for Analysis and Synthesis, funded by the US Geological Survey. We appreciate and acknowledge the effort, commitment, and contributions of Kate Schofield and Mark Bowen to the Working Group. We thank David Aldred for rendering Figures and and crafting Figure . The latter was made using MATLAB code appreciatively provided by “Infamous Heel-Filcher” ( http://infamousheelfilcher.blogspot.com/2013/02/changing-viewing-angle-of-matplotlib.html ; accessed 11/2020). Peg Pelletier, John Johnston, and three anonymous reviewers provided critical feedback on earlier drafts, and their efforts improved the manuscript.
| Funder number |
|---|
| 11/2020 |
Keywords
- ephemeral stream
- geographically isolated wetlands
- headwater stream
- intermittent river and ephemeral stream
- intermittent stream
- non-floodplain wetland
- perennial stream
- state transitions
- steady state
- thresholds
- water quality
- watershed management
