u.s. department of the interior u.s. geological survey effects of restoration on avian populations...
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U.S. Department of the InteriorU.S. Geological Survey
Effects of restoration on avian populations in the Napa Sonoma Marshes Wildlife Area: density changes from 2000-2010
L. Arriana Brand, Lacy Smith, Joel Shinn, Isa Woo, Tanya Graham, and John Takekawa
Acknowledgements
USGS Western Ecological Research Center
USGS Priority Ecosystem Studies, SF Bay Program
Ducks Unlimited – Renee Spenst, Steve Carroll, Austin Payne, Russell Lowgren, Ron Galindo, Fritz Reid
Wildlife Conservation Board - Bonnie Turner, Tony Chappelle
State Coastal Conservancy – Amy Hutzel, Nadine Hitchcock, Betsy Wilson
SF Bay Joint Venture - Beth Huning, Christina Sloop
California Department of Fish and Game – Karen Taylor, Tom Huffman, Mike Sipes, Larry Wyckoff, Stacy Martinelli
GAIA Consulting, Inc. - Susanne von Rosenberg
Cargill – Butch Paredes
Critical region for migratory birds
Central challenge: How to maintain waterbird populations given conversion to tidal marsh?
Western Waterfowl Migration Routes
• Pacific flyway - 20% of North American waterfowl in the Central Valley & SF Bay
• Western Hemispheric Shorebird Reserve Network
Napa Sonoma Marshes Timeline
1994 NSMWA
purchased by DFG
1995Breach of Pond 2A
Aug 2002“Midnight”
breach Pond 3
Mar 2003NPS
purchased by DFG
Apr 2004NSMWA
Project EIR
Feb 2006NPS
Draft EIR
Fall 2006Breach
Ponds 3, 4, and 5
Oct 2008Breach
Pond 9/10
Sept 2009Breach Wash Pond
Aug 2010Breach
Crystallizers
Restoration Phases
I: Managed Ponds 1, 1A, 2II: Breached Ponds 3, 4, 5III: Breached Ponds NPSIV: Managed Ponds 6-8
Largest salt pond conversion to tidal wetlands in the SF Bay(~1500 ha)
Questions
Do breached ponds support similar avian densities to managed ponds?
How have avian densities changed over time in breached vs. managed ponds?
What factors may be influencing these patterns?
Methods
Data collection Monthly counts at HT Counts at LT 2008-2010 WQ sampling
Data analysis Aggregate to pond scale Generalized LS regression for clustered data with
pond random effect Monthly sequence as time series variable
Avian Guilds
Drawing adapted from Warnock 2004
Avian guilds by season
Wad
ing B
irds
Terns
Eared
Gre
be
Fish E
ating
Bird
sGull
s
Med
ium S
hore
birds
Diving
Duc
k
Dabbli
ng D
uck
Small
Sho
rebir
ds0
0.51
1.52
2.53
3.54
SummerFallWinterSpring
De
ns
ity
(b
ird
s/h
a)
North Bay Ponds 2000-2010
Salinity changes over time
Winter
20002001
20022003
20042005
20062007
20082009
20100
70
140
210
280
Breached: NPSBreached: 3, 4, 5Managed: 6-8Managed: 1, 1A, 2
Year
Salin
ity
Dabbling Duck trends
20002001
20022003
20042005
20062007
20082009
20100
0.5
1
1.5
2
Managed: 6-8
Managed: 1, 1A, 2
Year
Avg.
Den
sity
(bird
s / h
a)
Winter
Dabbling Duck trends
20002001
20022003
20042005
20062007
20082009
20100
0.5
1
1.5
2
Breached: NPS
Breached:3, 4, 5
Managed: 6-8
Managed: 1, 1A, 2
Year
Avg.
Den
sity
(bird
s / h
a)
Winter
Diving Duck trends
20002001
20022003
20042005
20062007
20082009
20100
0.8
1.6
2.4
3.2
Managed: 6-8
Managed: 1, 1A, 2
Year
Avg.
Den
sity
(bird
s / h
a)
Winter
Diving Duck trends
20002001
20022003
20042005
20062007
20082009
20100
0.8
1.6
2.4
3.2
Breached: NPSBreached: 3, 4, 5Managed: 6-8Managed: 1, 1A, 2
Year
Avg.
Den
sity
(bird
s / h
a)
Winter
Medium shorebirds trends
20002001
20022003
20042005
20062007
20082009
20100
0.6
1.2
1.8
2.4
Managed: 6-8
Managed: 1, 1A, 2
Year
Avg.
Den
sity
(bird
s / h
a)
Winter
Medium shorebirds trends
20002001
20022003
20042005
20062007
20082009
20100
0.6
1.2
1.8
2.4
Breached: NPSBreached: 3, 4, 5Managed: 6-8Managed: 1, 1A, 2
Year
Avg.
Den
sity
(bird
s / h
a)
Winter
Small shorebird trends
20002001
20022003
20042005
20062007
20082009
20100
1.2
2.4
3.6
4.8
Managed: 6-8
Managed: 1, 1A, 2
Year
Avg.
Den
sity
(bird
s / h
a)
Winter
Small shorebird trends
20002001
20022003
20042005
20062007
20082009
20100
1.2
2.4
3.6
4.8
Breached: NPSBreached: 3, 4, 5Managed: 6-8Managed: 1, 1A, 2
Year
Avg.
Den
sity
(bird
s / h
a)
Winter
Use of breached ponds 3, 4, 5 at low versus high tide
High Tide
Low Tide
High Tide
Low Tide
High Tide
Low Tide
Small shorebirds
Medium shorebirds
Dabbling Ducks
0
0.5
1
1.5
2
Foraging
Den
sity
(bir
ds /
ha)
2008-2010 winter
Use of breached ponds 3, 4, 5 at low versus high tide
High Tide
Low Tide
High Tide
Low Tide
High Tide
Low Tide
Small shorebirds
Medium shorebirds
Dabbling Ducks
0
0.5
1
1.5
2
RoostingForaging
Den
sity
(bir
ds /
ha)
2008-2010 winter
Vegetation changes in breached ponds 3, 4 and 5
Percent of ponds with elevations sufficient to support Spartina foliosa
Pond 3: 19.3%Pond 4: 12.6%Pond 5: 25.3%
Dynamic avian response to pond changes over time
19992000
20012002
20032004
20052006
20072008
20092010
0
2
4
6
8
10
12
14
16
18
20
2A534
Winter Small shorebirds
Conclusions
Birds respond quickly to changes in water level and/or salinity
Once ponds accrete enough sediment, vegetation establishment may be rapid
Initial bird response is not necessarily indicative of long-term population changes
Newly breached ponds create temporary mudflats that are desynchronized with Bay mudflats and extend shorebird foraging time
Marsh conversion may replace mudflats, reducing foraging value
Future studies
Need to quantify what factors influence bird density patterns in order to best manage reduced salt pond habitat for birds: Water depth Water quality Inundation time Tidal lags Vegetation growth Prey resources Proximity to islands and levees Landscape context
Drainage development over time
Conclusions
Production ponds contain lower densities compared with ducks in Alviso and shorebirds in Eden Landing
Density trends vary by pond complex
Dabbling ducks, med. and small shorebirds densities have increased in restoration ponds
11© Peter LaTourrette
Goal: Mixture of habitats
… diverse mosaic of habitats and species…
Managed pond
salt pan
slough
tidal marsh
mud flat
upland
Small shorebird trends
20002001
20022003
20042005
20062007
20082009
20100
1.2
2.4
3.6
4.8
Breached: NPSBreached: 3, 4, 5Managed: 6-8Managed: 1, 1A, 2
Year
Avg.
Den
sity
(bird
s / h
a)
Winter