Tidal Wetlands & Climate Change

Transcription

1 Tidal Wetlands & Climate Change Tom Parker (SF State) John Callaway (Univ SF) Lisa Schile (UCB); Ellen Herbert (Indiana U); Evyan Borgnis (USF, SFSU) Jessica Vandenberg (SFSU) Vance Vredenburg (SF State)

2 Data comes from these wetlands

3 What do we know?

4 Observed Species Diversity Increases as Salinity Decreases China Camp Petaluma River Coon Rush Ranch Browns Island Sand Mound Slough Freshwater-Oligo/MesoBrackish Individuals Brackish-Salt Marsh

5 Average Number of Species per Plot (20mx 50m) B B B A A 8 A CC PRM CI RR BRI SMS Site

6 Productivity (g m -2 ) Productivity in strongly reduced by salinity China Camp High salinity Petaluma River Coon Rush Ranch Browns Sand Mound Freshwater

7 Biomass (g/m 3 ) Biomass (g/m 2 ) Belowground biomass is also quite high High Low 0 High Low Petaluma River Marsh Browns Island

8 Inundation reduces productivity when interacting with salinity. Productivity in well-drained and poorly-drained sites Plant height in well-drained and poorly-drained sites Schile et al. Wetlands in press

9 What aspects of climate change will impact SF Bay-Delta tidal wetlands?

10 Climate change and tidal wetlands Increased CO 2 Increased temperatures during growing season Increased rate of sea level rise Increased salinity in brackish and freshwater tidal areas Decreased freshwater flows in summer and fall Salinity stress increases due to summer evapotranspiration

11 What are we sure about? Increasing salinity strongly influences composition, and reduces diversity and productivity Inundation reduces diversity and productivity

12 Can tidal wetlands keep up with sea level rise? Relative Wetland surface elevation

13 Processes contributing to elevation decline Subsidence & compaction Relative Wetland surface elevation Sea Level Rise

14 Processes contributing to elevation increase Sediment supply Relative Wetland surface elevation Plant organic matter

15 Processes that promote accretion Gains Sediment supply Losses Suspended sediment Erosion Gains Plant organic matter Losses Species composition Below ground productivity Above ground productivity Macrodetritivores Microbial decomposition

16 Gains Sediment supply Losses Suspended sediment Erosion Feldsparmarker horizons SET- Sediment Erosion Tables

17 Gains Plant organic matter Losses Species composition Below ground productivity Above ground productivity Macrodetritivores Microbial decomposition

18 Is sediment supply sufficient?

19 Short-term Sediment Accretion Rates using feldspar markers: MID-MARSH LOCATIONS North Bay rates based on one year of data 3.3 mm/yr 4.9 mm/yr 3.1 mm/yr 2.2 mm/yr 3.4 mm/yr South Bay rates based on six years of data 3.9 mm/yr 5.9 mm/yr

20 Island Ponds Pond A21 Breached March 2006

21 Sediment pins

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25 High rates of sedimentation-colonization in the 3 rd year Photos Cris Benton

26 Carl s Marsh at 8 years post-restoration

27 Suspended sediment currently is sufficient; other researcher s estimate it will not keep up with higher rates of sea level rise, especially in some areas of the Bay. Organic matter additions? Very high productivity and high belowground biomass: Decomposition?

28 Freshwater Typha latifolia Saline Current data indicate 5-10% lasting to the end of the second Schoenoplectus year. Differences acutus among species and wetlands decrease. Sarcocornia pacifica

29 Long-term Sediment Accretion Rates ( 137 Cs and 210 Pb dating-) 1-3 mm/yr 1-3 mm/yr These values incorporate sediment, organic matter and compaction 5 mm/yr* Data from Callaway et al. (unpublished) *data or *Patrick from and Patrick Lehune and (1990) DeLaune (1990) 4 mm/yr* 3-4 mm/yr 3-6 mm/yr 42 mm/yr*

30 Gaps in our knowledge CO 2 Temperature Impact on plant physiology and interactions

31 Impacts of CO 2 Plant resource, especially for C3 plants Shown to stimulate root growth in 2 experiments (Maryland, Louisiana)

32 Direct effects-temperature Influence on photosynthesis/respiration balance of dominant plants rate photosynthesis respiration temperature

33 Direct effects-temperature Influence on photosynthesis/respiration balance of dominant plants Increase in ANPP rate Decrease in ANPP Mortality temperature

34 Interactions among all these processes?