Tidal Marshes and Mercury Concerns Using biosentinel species to monitor, identify sources and guide

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Tidal Marshes and Mercury ConcernsUsing
biosentinel species to monitor, identify sources
and guide restoration

• Presentation to RMP TRC
• 17 September 2007

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Habitat-specific Biosentinels

• Mercury cycling varies at the scale of habitats
• Match up spatial scale of mercury cycling
  patterns and mercury monitoring
• Managers and restoration designers can act on the
  scale of habitats

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Habitat-based Hg Monitoring

• Each sentinel species is specific to one habitat
• Year-round residents
• Small home range
• Abundant
• Important role in food web

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• Wide-ranging, subembayment scale
• Consume fish from a variety of habitats (open
  Bay, Bay margin, sloughs, ponds)

high
Habitat Specificity
Double-crested Cormorant
low
small
large
Spatial Scale

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• Small regional scale
• Eat from a few habitats (pond, slough, Bay margin)

high
Forsters Tern
Habitat Specificity
low
small
large
Spatial Scale

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Saltmarsh Song Sparrow

• Small local scale (lt1 ha)
• Eat from one habitat (marsh plain)

high
Habitat Specificity
low
small
large
Spatial Scale
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high
Habitat Specificity
low
.
small
large
Spatial Scale
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Longjaw Mudsucker
high
Mississippi Silversides
Habitat Specificity
Striped Bass
low
.
small
large
Spatial Scale
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Habitat-specific Biosentinels

• Mercury cycling varies at the scale of habitats
• Match-up spatial scale of mercury cycling
  patterns and mercury monitoring
• Managers and restoration designers can act on the
  scale of habitats

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Habitat-specific Sentinel Species
Grenier 2004
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Research from Eastern NA

• Biodiversity Research Institute, D. Evers and O.
  Lane (unpubl. data)
• Data from 4 rivers (MA, VA, ME) where invertivore
  blood Hg levels exceed those of associated
  piscivores. 
• E.g., Red-winged blackbirds higher than
  kingfishers
• Tidal marsh sparrows from east coast follow the
  same patterns of invertivores being higher than
  piscivores (kingfishers, cormorants, and osprey)

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South Bay Salt Pond Restoration
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Comparisons within a Species
Salt Pond
Tidal Marsh
after
before
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Wetland Characteristics Compare among Marshes
Petaluma

• Saltmarsh song sparrow
• Year-round resident
• Marsh plain food web
• September 2006
• Mercury in blood (ww)

Alviso Guadalupe
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Bird Blood Higher than Fish Tissue Relative to
Trophic Level

• Sparrow (median 0.31 ug/g ww, n 37) 6x small
  fish mean (RMP 2005 data), despite both being
  secondary consumers
• Yellowthroat (median 0.42 ug/g ww, n 4)
  striped bass (RMP 2003 data)
• Wren (0.82 ug/g ww, n 1) leopard shark median
  (RMP 2003 data)

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Research from Eastern NA

• Biodiversity Research Institute, D. Evers and O.
  Lane (unpubl. data)
• Data from 4 rivers (MA, VA, ME) where invertivore
  blood Hg levels exceed those of associated
  piscivores. 
• E.g., Red-winged blackbirds higher than
  kingfishers
• Tidal marsh sparrows from east coast follow the
  same patterns of invertivores being higher than
  piscivores (kingfishers, cormorants, and osprey)

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Mercury Varied by Species
Marsh Plain aerial insect and spider food chain
Marsh Plain more epibenthic food chain
(transient)
South Bay data
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Higher Hg in North Bay Marshes
Song Sparrow
0.96 ppm threshold for concern
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Mississippi Silverside

• Highest concentrations in South Bay fish

Data from Darell Slotton and Ben Greenfield
Unpublished data provided by Darell Slotton
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Higher Variability in North Bay
Song Sparrow
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H1 ? Elevation leads to ? Mercury
Higher, older marshes, with more variable
elevation
Lower, newer, subsided marshes
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Elevation

• Proxy for
• Frequency of wetting/drying
• Tide/Groundwater
• Amount of organic matter (peat)
• Marsh age

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Restoration OptionsCompare Marsh to Pond

• Bar height is Hg concentration
• Longjaw mudsucker
• Territorial, resident goby
• September 2006
• Size limits applied
• Whole body
• ppm (ug/g ww)

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Tidal Marsh Channel and Pond hadSimilar Fish Hg
Length controlled Small sample size (low power)
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Management OptionsCompare Management Regimes
Brine Flies
Summer 2006
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Early spring
7
5
8
Later in Summer
8
5/7
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Management OptionsCompare Management Regimes
Brine Flies
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Bill Deformities PCBs?

• 7 of sparrows had bill deformities
• Linked to dioxin-like PCBs in literature
• Alviso Slough and Coyote Creek
• Working on a proposal

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Acknowledgements

• Thanks to the following funding sources
• Santa Clara Valley Water District
• State Coastal Commission
• San Francisco Foundation Bay Fund
• Regional Monitoring Program for Water Quality
• Thanks to the Don Edwards SF Bay National
  Wildlife Refuge

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Scott Haefner