Active versus Passive Restoration of Drained Reservoirs on Elwha River Ten Years After Dam Removal
Faculty Mentor
Rebecca Brown
Presentation Type
Oral Presentation
Start Date
5-7-2024 10:20 AM
End Date
5-7-2024 10:40 AM
Location
PAT 328
Primary Discipline of Presentation
Biology
Abstract
With the increasing frequency of large dam removals, understanding the impact of restoration practices on revegetation of the drained reservoirs is crucial. The removal of two large dams on the Elwha River between 2011 and 2014 provided a unique opportunity to investigate reservoir revegetation dynamics following active restoration through seeding and planting. My objective was to determine how the effects of active restoration have changed with time. I hypothesized that over time the effects of seeding and planting would intensify. To test this, I compared native and non-native plant species richness and cover in 100 m² quadrats from seeded only, seeded and planted, and control sites sampled in 2023. My results revealed that after ten years, native species richness in actively restored plots was 54% greater and non-native species richness was 25% lower than in passively restored plots. These findings show that active restoration can help facilitate revegetation in drained reservoirs post-dam removal through the promotion of native species and inhibition of non-native species.
Recommended Citation
Trier, Michael Jacob, "Active versus Passive Restoration of Drained Reservoirs on Elwha River Ten Years After Dam Removal" (2024). 2024 Symposium. 4.
https://dc.ewu.edu/srcw_2024/op_2024/o4_2024/4
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Active versus Passive Restoration of Drained Reservoirs on Elwha River Ten Years After Dam Removal
PAT 328
With the increasing frequency of large dam removals, understanding the impact of restoration practices on revegetation of the drained reservoirs is crucial. The removal of two large dams on the Elwha River between 2011 and 2014 provided a unique opportunity to investigate reservoir revegetation dynamics following active restoration through seeding and planting. My objective was to determine how the effects of active restoration have changed with time. I hypothesized that over time the effects of seeding and planting would intensify. To test this, I compared native and non-native plant species richness and cover in 100 m² quadrats from seeded only, seeded and planted, and control sites sampled in 2023. My results revealed that after ten years, native species richness in actively restored plots was 54% greater and non-native species richness was 25% lower than in passively restored plots. These findings show that active restoration can help facilitate revegetation in drained reservoirs post-dam removal through the promotion of native species and inhibition of non-native species.
