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 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 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 1995 Breach of Pond 2A Aug 2002 “Midnight” breach Pond 3 Mar 2003 NPS purchased by DFG Apr 2004 NSMWA Project EIR Feb 2006 NPS Draft EIR Fall 2006 Breach Ponds 3, 4, and 5 Oct 2008 Breach Pond 9/10 Sept 2009 Breach Wash Pond Aug 2010 Breach Crystallizers

Restoration Phases I: Managed Ponds 1, 1A, 2 II: Breached Ponds 3, 4, 5 III: Breached Ponds NPS IV: 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  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 North Bay Ponds

Salinity changes over time Winter

Dabbling Duck trends Winter

Dabbling Duck trends Winter

Diving Duck trends Winter

Diving Duck trends Winter

Medium shorebirds trends Winter

Medium shorebirds trends Winter

Small shorebird trends Winter

Small shorebird trends Winter

Use of breached ponds 3, 4, 5 at low versus high tide winter

Use of breached ponds 3, 4, 5 at low versus high tide 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 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

1 1 © Peter LaTourrette Goal: Mixture of habitats … diverse mosaic of habitats and species… Ma nag ed pon d salt pan slo ugh tidal mars h mu d flat upl and

Small shorebird trends Winter