Coastal habitats are the first line of defense against sea-level rise and storms. At the same time, they are vulnerable to change, and can be pushed past tipping points and lost. A long-term, landscape-scale experiment with seagrass at Virginia Coast Reserve LTER is the first of its kind to show the role of restoration in reinstating ecosystem services, particularly ‘blue carbon’ sequestration. Fifteen years of data on recovery trajectories, thresholds, and resilience to high ocean temperatures provide novel insights that are integrated into predictive models of future change and inform management and policy.

1. Climate-resilient Coasts
How long-term research and restoration informs management
Karen McGlathery
University of Virginia
Virginia Coast Reserve LTER

2. VCR LTER:
Causes and consequences of non-linear ecosystem state change

3. Coastal Blue Carbon Systems
Challenges to incorporating blue carbon in global models:
- Estimating stocks and sequestration rates
- Understanding effects of habitat loss and recovery

4. Coastal habitats are
global hotspots
for blue carbon storage
O2
O2X X

5. Global stock estimates
led by LTER scientists
Adapted from Fourqurean et al 2012, Pan et al 2011, Pendleton et al 2012

6. LTER site contributions to
quantifying blue carbon stocks
Carbon stores in mangrove
forests 3x terrestrial forests
Jerath et al. 2016McGlathery et al. 2012
Carbon stores in seagrass
meadows 4x bare
sediments
Carbon burial rates in
Marshes exceeds forests
Drake et al. 2015

7. 31%
Fate of anthropogenic CO2 emissions
(2006-2015)
Source: CDIAC; NOAA-ESRL; Houghton et al 2012; Giglio et al 2013; Le Quéré et al 2016; Global Carbon Budget 2016
26%
91%
9%
44%
Sources = Sinks
Including blue carbon, ocean
sequestration equals forests
X32%
Blue Carbon = 25%
ocean sequestration

8. Virginia Coast Reserve: Loss and recovery

9. every 30 minutes
Rate of seagrass loss has accelerated
Waycott et al (2009)
215 studies, 126 years of data
since 1980
29% loss since 1880’s; 1.5% per year

10. Slime mold
wasting disease
VCR loss due to pandemic
wasting disease and “Great
Storm” of 1933
Cheapeake
Bay
VCR
Atlantic
Ocean

11. Reversing the state change
seeds
web.vims.edu/bio/sav/
500 acres seeded
70 million seeds
6200 acres meadow
= 25 km2

12. Reversing the state change
South BaySouth Bay0.5 – 1 acre plots
100k seeds acre-1

13. 0
100
200
300
400
500
600
700
0 2 4 6 8 10 12 14 16
Density(shootsm-2)
Meadow Age (yr)
2007 2008 2009 2010 2011 2012 2013 2014 2015 2016
0 – 15 years
Recovery is non-linear
Limited by seed
recruitment

14. Restoration reinstates soil carbon stores
Plant density drives burial rates
Greiner et al. 2013
CO2
Buried
Carbon
Particulate
Organic C
After 12 yr, burial within
range of natural systems
40% Seagrass
50% Benthic microalgae
10% Marsh

15. Data typically recorded at 32 - 64 Hz,
5 - 30 cm above benthic surface
Carbon sequestration in plant biomass
Measured by Aquatic Eddy Covariance
Peter Berg

16. 24 hours
Delgard, Berg, McGlathery
For each 24-hour period, calculate GPP and R
Carbon sequestration in plant biomass
Measured by Aquatic Eddy Covariance
10-100 m2

17. 2013 – 2014
2015
Changes in metabolism with restoration
Bare
Summer

18. 0
100
200
300
400
500
600
700
0 2 4 6 8 10 12 14 16
Density(shootsm-2)
Meadow Age (yr)
2007 2008 2009 2010 2011 2012 2013 2014 2015 2016
2014
2014
2016
How resilient are
these systems?
2015
2015
2016
2016
High temperatures cause dieback

19. 2014
2015
2016
How resilient are
these systems?
Rate of recovery
varies spatially

20. Temperature also
drives recovery
28 oC is
maximum
temperature
threshold
32%
53%
Low
recovery
High
recovery

21. High temperatures cause dieback
Jul 2014 Jul 2015
In 2105
temperatures
exceeded 28 oC
threshold 50%
of the time
Proportion
with
temperature
>28o

22. Low Tide
High Tide
High tides relieve
temperature stress
bathymetry
High flushing,
Short
residence time
Higher resilience
+

23. VCR contributions to blue carbon
• Stocks and sequestration returned within decade
• Temperature drives resilience and recovery
Long-term research critical to
• Understanding recovery and resilience of restored
ecosystems; Actionable science for management
LTER has unique capability to provide answers
• Combine long-term data with process studies to
understand mechanisms
• Long-term trends and landscape scales needed to
understand resilience
• Network of sites allows comparison to reveal generality
VCR contributions to blue carbon
• Stocks and sequestration returned within decade
• Temperature drives resilience and recovery
• Can provide guidance for management
LTER has unique capability to provide answers
• Combine long-term data with process studies to
understand mechanisms
• Long-term trends and landscape scales needed to
understand resilience
• Network of sites allows comparison to reveal generality