Climate Change and Restoration on the Stillaguamish … · Annette Colombini Why are estuaries such productive ecosystems? WSU ... "Think like a mountain“ (Aldo Leopold) - Challenge

Climate Change and Restoration on the

Stillaguamish Delta: Lessons learned2006

Roger FullerWestern Washington University

2014 2015

Resilience?

Sea Level Rise Salinity

Secondary Impacts

Insects Herbivory

Marsh BiomassSeasonal Temps

Mutualism 1

Mutualism 2

Disturbance Regime Predator

Shredder

Climate Change Primary Impacts

RhizosphereBenthic diatoms, fungi, mud crabs, amphipods, N-bacteria, Fe-Sulfide bacteria, etc.(mediated by soil texture, salinity, etc.)

Bofl

Scta Tidal Marsh Boma

Scpu

PhyllosphereEpi- and endo-phytic bacteria, fungi

Hydrodynamics Summer flow, winter floods and storms, large woody debris

MacrobiotaInsects, snow geese, …

Climate Change

What we’ll talk about

1. Project Objectives2. Design process3. Outcomes 4. Ecological trends5. Lessons

The Stillaguamish Estuary

Some current estuary functionsand ecosystem services

• Food web support• Sediment sink • Water quality • Storm and flood protection• Sub-irrigation• Farmland drainage• … etc.

2012 Restoration

Restoration projects should be multi-stakeholder projects

Port Susan Bay

Skagit Bay

Project Objectives

1. Restore 150 acres of tidal wetlands, and salmon access (site scale)

2. Improve connectivity between the river and the northern estuary (estuary scale)

3. Improve flood attenuation for neighbors in the lower river valley (socio-economic)

WDOE

Low

3-square bulrush

Middle

Mixed Bulrushes3-SquareSeacoastSoft-stemRiverHard-stem

High Grasses,Sedges, Rushes

Dicots

Marsh Types

Erica Sloniker

Marsh Madness

The fuel of the estuarine food web

Annette Colombini

Why are estuaries such productive ecosystems?

WSU

Crangon alaskensis Dave Cowles, Rosario Beach Marine Lab

monkeyfacenewsCrangon franciscorum

bryanlikestofish.com

3 Spine Stickleback

Grass shrimp

Amphipod

Bay Shrimp

1/8th inch

2 inches

Steve Mlodinow

White sturgeon at low tide, PSB

Dunlin

Tavish Campbell, Vancouver Observer

Juvenile salmon

Wa DOE

Restoration Tidal marshTidal flat

Water levelsSalinitypore water

SedimentPSD, Accretion/Erosion

Estuary Ecosystemspecies composition

(plants, animals, microbiome)ecosystem services and functions

etc.

Sea level

Configuration of channels and levees

River flow regime

Climate Change

Climate Change

Storm winds

Waves

Elevation

Drivers

Feedback PathwaysControlling Factors

North and Mid-Delta Marsh Erosion

The Marsh isn’t Resilient

1964 Low Marsh Boundary

2012 Restoration Area

1964 Low Marsh Boundary

Low Marsh Boundary19642004

21 m/yr

5 m/yr

First Hypotheses:• Salinity• Sediment

pre-restoration

A. Existing conditionsA. Existing conditions

TNC dike

post-restoration

B. RestorationB. Restoration

With dike removal, area of low salinity for tidal marsh expands

Project Conceptual Design Modeling

SLR + Low Flow

Current Conditions

1m Sea Level Rise (SLR) SLR + snow geese

In what ways is the estuary vulnerable to climate change?

Note on Modeling:

“All models are wrong, but some are useful.” George Box

Ecological models GREATLY simplify complex natural processes.Models do NOT make decisions, or predictions. Don’t believe the maps.

“Marshes on the Move” – a manager’s guide to modelingSearch: NOAA marshes on the move

Flood-relief gate

2 breaches to channel

Dike removal

New dike

Restoration Project Elements

2012

150 acres

Predicted Habitat

(preliminary design)

Elevation range of the Restoration Zone

Elevations where key species are common across the estuary

Bulrushes Sedge Rush Cattails Grasses

2013 2014 2015 2016

Marsh change

Restoration Outcomes

Bore holes

Preliminary ID:Bactra sp. (Tortricidae)

2015Disturbance

2014

2015

>95% plant death by July 150 acres

Highest elevation marshClosest to river mouth

Lowest elevation marsh

Stress kills

2015 Restoration Zone (salt stress, insect attack): 70% Average decrease in biomass

2016 – no recovery below ~2.1m

Bolboschoenus maritimus~100m apart

2017 – massive expansion of non-native cattail

narrow-leaved cattail produces

phenolics

Saltiness of estuary soils

normal

2015

Record Low River Flow, April through August

Estuary Plant Height

Plants were 35% shorter and didn’t produce seeds

due to salt stress

Climate change and river flows... 2015 was a great test(record low summer river flows - projected to be the average by 2050)

(35% less fuel for the food web … imagine this as the new normal!)

Median

2015

Projected Changes in Summer Low Flow Volume

Lowest 7-day average flow in 2yr period

Low Carbon Emissions Scenario (RCP 4.5)Source: UW Climate Impacts Group

2050’s

2080’s

-35%

-45%

2013 2016

Standing water

Post-restoration Marsh plain drainage

- Slope- Lack of channels- Dense vegetation

Full drainage of marsh plain

Why did the marsh die?

Stress

Lesson – hydrology loggers and LiDAR aren’t enough to indicate marsh plain hydrology

Site elevations are all above the low tide line…so assumption is that marsh plain fully drains.

Elevation range of the Restoration Zone

Elevations where key species are common across the estuary

Bulrushes Sedge Rush Cattails Grasses

Big surprise in the restoration zone: 3-square bulrush has NOT colonized…why?

3-Square Bulrush Biomass and %Sand

3-square bulrush prefers sandier soil, the restoration zone is mostly silt/clay

but that still doesn’t explain its absence

Soil Drainage: low gas exchange, higher sulfides?

Lesson: monitoring plan didn’t include soil chemistry so we don’t know what is stressing the plants.

North Marsh erosion: insufficient sediment?

…plenty of sediment for the marshes at the moment, so no

Elevation Change (cm/yr)(from SETs)

Avg sea level rise rate over next 90 years

Historic rate of sea level rise

(Sediment Deposition)

Geese as ecosystem engineers

• excavate rhizomes• reduce bulrush stem density• remove the roots that hold the soil• disturb and loosens the soil• disrupt the diatom “glue”

Steve Mlodinow

MarshStructure

VariesSeasonally

WinterSummer

Seaside bulrush

River bulrush

Three-square bulrush

Goose disturbance interacts with winter waves

Grazed heavily

Not grazed heavilySandy soils

Characteristics of a resilient marsh

Topography – slopeSediment supply Freshwater supplyDrainage and soil particle sizePlant species (e.g. river vs. 3-square bulrush)Wave exposure

Wa DOE

Biggest restoration need: fix the delta plumbing

(levees and channels)

A few of the lessons learned

1. Summer flow - biggest direct climate change impact in estuaries (not sea level rise).

2. Climate change doesn't act alone, it interacts with the existing stress and disturbance regime in a system.

3. Resilience to stress differs spatially across the estuary…spatial position of a restoration site matters.

4. There are characteristics of resilient marsh that can be incorporated into adaptive management and restoration designs.

A few of the lessons learned

5. Consistency in project staffing from start to finish is important.

6. Slope and soil chemistry are important.

7. Starter channels were needed.

8. Include invasive plants in your monitoringplan, even if you don’t expect them. And

decide beforehand how you will respond.

9. System-scale perspective important. As are multiple reference sites.

A few bonus observations

1. "Think like a mountain“ (Aldo Leopold) - Challenge yourself to think at time scales, spatial scales, and scales of biotic interactions that you normally don't consider.

2. Use climate change concepts to build a broader base of support for restoration.

Jen Moslemi

Thanks! Roger Fuller Western Washington University

[email protected]

Acknowledgements

Colleagues: Katrina Poppe, John Rybczyk, Eric GrossmanGrad Students: Brittany Jones (UW), Chad StellernField and Data crew: Hannah LaGassey, James McArdle, Chelsea Douglas, Sarah Thomas, Abe Lloyd, Michael Heath, William Ashford, Cody Level, Adam Schnellbaecher, Christian Aguilar, Devin Debono, Andy Cortese, Alec Barber, Katy Hancock, Kaylee Guetle.

Funding: The Nature Conservancy, ESRP, NOAA