Commonwealth Champions VA TeCH

Transcription

1 Commonwealth Champions VA TeCH

2 Assessing Coastal Habitat Vulnerability to Local Climate Stressors within the York River Estuary CCVATCH-CBNERR Workshop December 5, 2013 Gloucester Point, Virginia

3 Chesapeake Bay National Estuarine Research Reserve Sweet Hall Marsh York River estuary Taskinas Creek Catlett Islands Microtidal estuary (range: m) Depths vary from 20 m at mouth to 6 m at West Po Moderate tidal currents (spring range: m/se can cause sediment suspension Tidal water salinity varies from fresh to polyhaline conditions Presence of 1 and 2 turbidity maximums Residence time ~ 60 days to West Point, 85 days to middle York and 100 days to York mouth Channels sediment is mud (% >80%) with shoals be sandier (% > 50%) Goodwin Islands Annual precipitation Small watershed (6900 km 2 ) moderate streamflow (~47 m 3 / no distinct fall-line Rural landuse (61% forest, 2 agricultural, 2% developed, wetlands, 8% water) Projected population (2020) 452,000

4 Climate Change: Setting the Stage Atmospheric CO2 levels to +30 ppm by to +120 ppm by 2095 UV-B radiation Air temperature Rainfall - - Past 100 yrs temperature has 0.6 C ( 1.1 F ) - Models predict 1.2 C ( 2.2 F ) by 2030 and C ( F ) by 2100 Past 100 yrs precipitation has 10% Models predict 7-24% over current rates (3-10 /yr) Seasonal changes in pattern: winter storms and drier summers Increased thunderstorms vs. slow moving fronts Frequency in high intensity, larger storms Variation in streamflow - Waves superimposed on higher SL - wave energy due to water depths - spring flow and summer flow

5 Climate Change: Setting the Stage cont. Water temperature - Warming rate on the order of 0.3 C per decade (Austin 2002) Water DIC and ph levels Sea level and water depth Saltwater intrusion Tidal range and circulation impacts - Current rate is 4.7 mm/yr ( ) with significant acceleration anticipated (0.7m by 2050; Boon 2012) - Historic rate (past 6000 yrs) was 1.4 mm/yr - Main- stem of 0.8 from (Hilton et al. 2007) ppt at West Point (conservative) - 10% in streamflow will result in 1, 4, and 7% change in lower, middle and upper main-stem Bay (Gibson and Najjar 2000) - Stratification due to spring and summer streamflow - Summer stratification due to weak summer winds

6 Framework for Developing Climate Change Adaptation Strategies Species Habitats Ecosystems 1. Identify Targets 2. Assess Vulnerability Policies 4. Implement Practices Options Institutional Monitor Review Revise 3. Identify Sensitivity Options Exposure Adaptive Capacity Adapted from: Glick et. al. 2011

7 General CBNERR Approach Acquire a fundamental understanding as to what type of changes will occur in land-margin and shallow water ecosystems Identify mechanisms, feed-backs and thresh-holds that are responsible for observed changes Move up to landscape scale and put in context of impact to ecological services provided by coastal ecosystems (Habitat is not lost it is transformed) Develop strategies to facilitate ecosystem resiliency and adaptation Why the concern this time around? (1) rate of climate change may be unprecedented. (2) organisms may be unable to adapt or migrate quickly enough (3) natural habitats are more fragmented / patchy / isolated and species may be blocked from successful migration (Markham 1996)

8 Components of NOAA Sentinel Program Observe & Monitor Spatial Analysis & Visualization Management & Decision Making Applied Research Models & Predictions Information Transfer Education & Outreach Science Service Stewardship

9 Estuarine Sentinel Site Overarching Goal: Increase our understanding of insert stressor impacts on coastal habitats, and transfer this understanding to coastal managers and communities. Small number of locations (network) selected for intensive and sustained study (highfrequency and multivariate measures) Location represents a certain, preferably large, class of ecosystems (be representative of regional ecosystem type)? Network or subset of network must encounter the stressor of interest and be responsive to that stressor? Monitoring leads to an understanding of the nature of variability and underlying forces? Detection of change or trends should be possible (heightened sensitivity to stressors and/or low background variability) Be of a size that is practical for testing adaptive management approaches Modified from Jassby 1998

10 Goodwin Island Infrastructure Map SAV Transect

11 Vulnerable Habitats at Local and Regional Scale Submerged Aquatic Vegetation (SAV) Forcing factor(s) Air temperature Sea level Storm activity Stressor(s) Light penetration Salt intrusion Water temperature Mechanical damage Seed displacement Coastal Marshes Forcing factor(s) Sea level Storm activity Marsh-Upland Ecotone Forcing factor(s) Sea level Storm activity Stressor(s) Stressor(s) Long-term inundation Salt intrusion/salt Spray Storm damage and erosion Flooding frequency Long-term inundation Salt intrusion/salt Spray Storm damage and erosion Flooding frequency

12 SAV Water Quality Assessment Water Clarity Attainment Water Clarity Non-attainment Temperature (C) Goodwin Estuarine-July 20 - August 4, Depth (m) % Relative Cumulative Frequency Clay Bank 2002 Clay Bank 2003 Goodwin mean 19-Jul Jul Jul Jul Jul Jul Jul-05 2-Aug-05 4-Aug-05 6-Aug Turbidity (NTU)

13 Marsh Surface Elevation Dynamics in Relation to Relative Sea Level Change

14 Adaptability of York River Tidal Marshes Modeled predicted threshold rates of sea level rise (Threshold from Kirwan et al. 2010) Threshold relative SLR rate (mm/yr) TF4.4 Walkerton LE4.3 Goodwin Island TF4.2 White House LE4.2 Catlett Island LE4.1 Taskinas Primary Turbidity Maximum RET4.3 West Point RET4.2 Muddy Point RET4.1 Lee Marsh Suspended sediment concentration (mg/l)

15 Historical Analysis of Tree Line Change

16 Ecotone Transplant Pilot Studies Pinus taeda (1 yr-old seedlings); Goodwin Island: Transect 1 Marsh reference: m NAVD88, WT: 0.05 m, Salt: 16.5 % Seedling survival Ecotone edge m NAVD88 WT: 0.33 m Salt: 8.1 WT: 0.29 m Salt: m m NAVD88 WT: 0.20 m Salt: Years since planted +40 m m NAVD88

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