U.S. Department of the Interior U.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
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U.S. Department of the Interior U.S. Geological Survey Effects of restoration on avian populations in the Napa Sonoma Marshes Wildlife Area: density changes.
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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
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