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The Impact of Drought on Waterbirds and Their Wetland Habitats in California’s Central Valley

Impacts of Drought on Waterbird Wetland Habitats, Bioenergetics, and Movements in the Central Valley of California
Principal Investigator
Joseph Fleskes

Dates

Start Date
2015-09-15
End Date
2017-12-31
Release Date
2015

Summary

California’s Central Valley is a nexus for water resources in the state, draining the Sacramento and San Joaquin River watersheds. Urban centers, agricultural operations, and the environment all compete for limited water, and demand is expected to only increase as the population grows and agriculture intensifies. At the same time, the water supply is projected to decrease as temperatures rise, precipitation patterns change, and the frequency of extreme droughts increases. The Central Valley also provides critical wetland habitats to migratory waterbirds, and wetland managers require information on how to best use water resources to support wildlife objectives, particularly during drought. This project seeks to evaluate how drought [...]

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SW-2015-16_CentralValley_CA_Waterfowl_BobWick_BLM.jpg
“Waterfowl in California's Central Valley - Credit: Bob Wick, BLM”
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Purpose

Wetland managers in the Central Valley of California require information regarding the amount and location of existing wetland habitat to make decisions on how to best use water resources to support multiple wildlife objectives, particularly during drought. Scientists from the USGS-Western Ecological Research Center, Point Blue Conservation Science, and the US Fish and Wildlife Service are partnering to learn how the flooded wetland, often agricultural, habitats used by waterfowl and shorebirds change through the year. During extreme drought conditions, the ability to provide sufficient water for wildlife often depends on the timing of water deliveries and decisions whether to fallow croplands. Waterfowl and shorebirds may be particularly affected by these decisions since they typically rest and feed in flooded habitats. Poor habitats resulting from improper water deliveries could reduce waterfowl hunting opportunities and body condition. Point Blue will develop near real-time tracking of waterbird habitats and the USGS will connect this with near real-time tracking of waterfowl throughout the valley to learn which habitats the birds use and why. This will teach us how wetlands can be managed to provide the best possible habitat for waterbirds even during extreme drought.

Project Extension

parts
typeTechnical Summary
valueWetland managers in the Central Valley (San Joaquin and Sacramento River Basins) require information regarding the extent and timing of existing wetland habitat to make decisions on how to best allocate limited water resources to wildlife habitats, particularly during drought. Remote sensing data are a powerful tool to help delineate available wetland habitat to assess progress towards conservation objectives within a management year and to measure the effect of drought, as well as other drivers, on wetland availability. New and ongoing research is quantifying how the spatio-temporal patterns of wetland habitat availability in the Central Valley (San Joaquin River and Sacramento River Basins; Point Blue and NDVI, USFWS). Understanding these habitat dynamics, particularly during drought, will improve the precision of the bioenergetics models in the Central Valley; TRUEMET (Central Valley Joint Venture 2006) and SWAMP (Miller et al. 2014). But knowing where food resources are may not be completely sufficient if bird behavior influences bird distribution and make food resources differentially “available”. Decision processes made by individual waterfowl may also have synergistic effects with particular habitat dynamic patterns (e.g., spatial density dependence). We propose a two phase project to better understand the impact of drought on waterbirds and increase the utility of dynamic habitat mapping projects by integrating with concurrently collected near real-time waterfowl movement data to inform parameter space in landscape (TRUEMET) and agent-based (SWAMP) bioenergetics models. In Phase I, we will (1) conduct model analysis to identify how drought influences available wetland habitat types and the duration and extent of flooding, (2) evaluate changes in waterbird food energy supplies using TRUEMET with parameters derived from the classified wetland data developed above to assess impact of changing wetland availability as the result of drought on meeting waterfowl and shorebird conservation objectives, and (3) implement the tested classification algorithms to calculate wetland and energy availability at different scales from automated classifications of Landsat 8 satellite data as an ongoing assessment of drought, water management decisions, and subsequent impacts on wetlands and waterbird habitat. In Phase II, we will use kernel and change‐point utilization distributions (CPUDs [Overton 2014]) heuristic and statistical (e.g, logistic regression) analysis methods to link bird movement data combined with habitat data to develop the necessary movement metrics that will inform agent-based (SWAMP) and landscape (TRUEMET) bioenergetics models to assess impacts of drought conditions. Decision on optimal allocation and management of water resources must consider multiple wildlife objectives, including but not limited to habitat objectives for waterfowl, shorebirds, and other waterbirds. Additional information on responsiveness of waterfowl and shorebirds to water allocation and management decisions will help evaluate the effectiveness of water management practices intended to provide adequate wetland habitat for waterbirds. Products developed as part of this work will include Normalized Difference Vegetation Index data layers for the entire Central Valley for April through 2000 – 2011; classification heuristic for delineating wetland types (irrigated seasonal, non-irrigated, semi-permanent) based on inundation frequency and NDVI indices to represent irrigation; model and analysis quantifying the effect of drought on wetland composition, as well as water inundation frequency and duration in the Central Valley; evaluation of the effect of drought on food availability for waterfowl and shorebirds by integrating modeled wetland type, water abundance and irrigation information with the TRUMET bioenergetics model; application of the classification heuristic to track wetland type and extent over time using Landsat 8 data; integration of Landsat 8 wetland tracking with movement data on ducks marked with satellite transmitters to develop parameters for SWAMP model . Information developed as part of this project will be made available via a webpage. Key partners to facilitate this work include Ducks Unlimited, USGS, U.S. Fish and Wildlife Service I&M and U.S. Fish and Wildlife Service Refuges. Stakeholders envisioned to benefit from the information derived in this study include the U.S. Fish and Wildlife Service, California Department of Fish and Wildlife State Wildlife Areas, Grasslands Water District, Central Valley Joint Venture, The Nature Conservancy, Audubon California, Ducks Unlimited, and the California Landscape Conservation Cooperative.
projectStatusCompleted

Waterfowl in California's Central Valley - Credit: Bob Wick, BLM
Waterfowl in California's Central Valley - Credit: Bob Wick, BLM

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  • National and Regional Climate Adaptation Science Centers
  • Southwest CASC
  • USGS Western Ecological Research Center

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RegistrationUUID NCCWSC 64bd7810-f6a9-473d-9211-5d16ee2458c5
StampID NCCWSC SW15-ME0534

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