Conservation Objectives for Wintering and Breeding Waterbirds in California’s Central Valley

Birds associated with wetlands have declined historically across North America from extensive habitat loss and degradation. Among the regions most affected is California’s Central Valley, where over 90% of the wetland base has been lost. Still, this region remains of continental importance to waterbirds. On-the-ground conservation efforts for all bird groups are the focus of the Central Valley Joint Venture, guided by a periodically updated implementation plan. To track progress toward goal attainment, that plan sets time-bound, quantitative conservation goals. Lacking robust data on the size and trends of populations of most species of waterbirds in the Central Valley, we set conservation goals for this group by selecting 10 focal species. These species are of heightened conservation concern or are otherwise representative of the habitat needs of Central Valley waterbirds. Given the great loss of historical habitat, we assumed focal species populations have declined by ≥ 50%. Hence, we defined population objectives for most focal species as increasing their current populations by 10% over 10 years and doubling them in 100 years. The corresponding habitat objectives are to increase wetlands or enhance suitable crops for waterbirds in proportion to the population objectives. These include an increase over 10 years of 7,948 ha (19,641 acres) of winter seasonal wetlands, 921 ha (2,276 acres) each of semi-permanent and summer seasonal wetlands, and 573 ha (1,416 acres) of strategically placed riparian forest. Agricultural needs include additional winter flooding of 15,160 ha (37,461 acres) of rice and 2,137 ha (5,281 acres) of corn. We distributed the habitat objectives across five planning regions, in some cases favoring proportionally larger increases in those regions with the greatest need. To maximize success, however, conservationists must take into account the specific needs of individual waterbird species, as a one-size-fits-all approach will not support the highest diversity of waterbirds

Conservation Objectives for Wintering and Breeding Waterbirds in California’s Central Valley

Birds associated with wetlands have declined historically across North America from extensive habitat loss and degradation. Among the regions most affected is California’s Central Valley, where over 90% of the wetland base has been lost. Still, this region remains of continental importance to waterbirds. On-the-ground conservation efforts for all bird groups are the focus of the Central Valley Joint Venture, guided by a periodically updated implementation plan. To track progress toward goal attainment, that plan sets time-bound, quantitative conservation goals. Lacking robust data on the size and trends of populations of most species of waterbirds in the Central Valley, we set conservation goals for this group by selecting 10 focal species. These species are of heightened conservation concern or are otherwise representative of the habitat needs of Central Valley waterbirds. Given the great loss of historical habitat, we assumed focal species populations have declined by ≥ 50%. Hence, we defined population objectives for most focal species as increasing their current populations by 10% over 10 years and doubling them in 100 years. The corresponding habitat objectives are to increase wetlands or enhance suitable crops for waterbirds in proportion to the population objectives. These include an increase over 10 years of 7,948 ha (19,641 acres) of winter seasonal wetlands, 921 ha (2,276 acres) each of semi-permanent and summer seasonal wetlands, and 573 ha (1,416 acres) of strategically placed riparian forest. Agricultural needs include additional winter flooding of 15,160 ha (37,461 acres) of rice and 2,137 ha (5,281 acres) of corn. We distributed the habitat objectives across five planning regions, in some cases favoring proportionally larger increases in those regions with the greatest need. To maximize success, however, conservationists must take into account the specific needs of individual waterbird species, as a one-size-fits-all approach will not support the highest diversity of waterbirds

Population and Habitat Objectives for Avian Conservation in California’s Central Valley Grassland–Oak Savannah Ecosystems

In California’s Central Valley, grassland and oak savannah ecosystems provide multiple economic and social benefits, ecosystem services, and vital bird habitat. There is a growing interest in protecting, restoring, and managing these ecosystems, and the Central Valley Joint Venture (CVJV) provides leadership in the formulation of conservation goals and objectives. We defined a long-term goal of protecting, restoring, and managing Central Valley grassland and oak savannah ecosystems so that they are capable of supporting genetically robust, self-sustaining, and resilient wildlife populations. To measure progress toward this goal, we selected a suite of 12 landbird focal species that primarily breed in grasslands and oak savannahs as indicators of the state of these ecosystems on the Central Valley floor (primary focus area) and in the Central Valley’s surrounding foothills (secondary focus area). Using data on current densities and habitat extent, we estimated that at least three of the focal species populations in the primary focus area and at least two of the focal species populations in the secondary focus area are currently small (<10,000 individuals) and may be vulnerable to extirpation. Furthermore, at least two species appear to have steeply declining population trends. We defined long-term (100-year) population objectives for each focal species that we expect to meet the goal of genetically robust, self-sustaining, and resilient populations. We then estimated corresponding short-term (10-year) habitat objectives of 4,183 ha of additional grassland and 3,433 ha of additional oak savannah that will be required to make progress toward the long-term objectives. We expect that habitat restoration and enhancement efforts aimed at reaching these long-term conservation objectives will result in improvements to the function of Central Valley grassland and oak savannah ecosystems

Population and Habitat Objectives for Avian Conservation in California’s Central Valley Grassland–Oak Savannah Ecosystems

http://escholarship.org/uc/item/0dn9f9b4In California’s Central Valley, grassland and oak savannah ecosystems provide multiple economic and social benefits, ecosystem services, and vital bird habitat. There is a growing interest in protecting, restoring, and managing these ecosystems, and the Central Valley Joint Venture (CVJV) provides leadership in the formulation of conservation goals and objectives. We defined a long-term goal of protecting, restoring, and managing Central Valley grassland and oak savannah ecosystems so that they are capable of supporting genetically robust, self-sustaining, and resilient wildlife populations. To measure progress toward this goal, we selected a suite of 12 landbird focal species that primarily breed in grasslands and oak savannahs as indicators of the state of these ecosystems on the Central Valley floor (primary focus area) and in the Central Valley’s surrounding foothills (secondary focus area). Using data on current densities and habitat extent, we estimated that at least three of the focal species populations in the primary focus area and at least two of the focal species populations in the secondary focus area are currently small (&lt;10,000 individuals) and may be vulnerable to extirpation. Furthermore, at least two species appear to have steeply declining population trends. We defined long-term (100-year) population objectives for each focal species that we expect to meet the goal of genetically robust, self-sustaining, and resilient populations. We then estimated corresponding short-term (10-year) habitat objectives of 4,183 ha of additional grassland and 3,433 ha of additional oak savannah that will be required to make progress toward the long-term objectives. We expect that habitat restoration and enhancement efforts aimed at reaching these long-term conservation objectives will result in improvements to the function of Central Valley grassland and oak savannah ecosystems.</p

Population and Habitat Objectives for Avian Conservation in California’s Central Valley Grassland–Oak Savannah Ecosystems

In California’s Central Valley, grassland and oak savannah ecosystems provide multiple economic and social benefits, ecosystem services, and vital bird habitat. There is a growing interest in protecting, restoring, and managing these ecosystems, and the Central Valley Joint Venture (CVJV) provides leadership in the formulation of conservation goals and objectives. We defined a long-term goal of protecting, restoring, and managing Central Valley grassland and oak savannah ecosystems so that they are capable of supporting genetically robust, self-sustaining, and resilient wildlife populations. To measure progress toward this goal, we selected a suite of 12 landbird focal species that primarily breed in grasslands and oak savannahs as indicators of the state of these ecosystems on the Central Valley floor (primary focus area) and in the Central Valley’s surrounding foothills (secondary focus area). Using data on current densities and habitat extent, we estimated that at least three of the focal species populations in the primary focus area and at least two of the focal species populations in the secondary focus area are currently small (&lt;10,000 individuals) and may be vulnerable to extirpation. Furthermore, at least two species appear to have steeply declining population trends. We defined long-term (100-year) population objectives for each focal species that we expect to meet the goal of genetically robust, self-sustaining, and resilient populations. We then estimated corresponding short-term (10-year) habitat objectives of 4,183 ha of additional grassland and 3,433 ha of additional oak savannah that will be required to make progress toward the long-term objectives. We expect that habitat restoration and enhancement efforts aimed at reaching these long-term conservation objectives will result in improvements to the function of Central Valley grassland and oak savannah ecosystems

Population and Habitat Objectives for Breeding Shorebirds in California’s Central Valley

The Central Valley of California provides important breeding habitat to numerous species of wetland-dependent birds, despite the loss of over 90% of naturally occurring wetlands. A majority of shorebirds breeding in this region rely on shallow-flooded habitat adjacent to sparsely vegetated uplands as provided by rice (Oryza sativa), managed wetlands, and other habitats. We estimated the current extent of potential breeding shorebird habitat provided by rice and managed permanent and semi-permanent wetlands in each of four major planning regions of the Central Valley, and estimated the average breeding densities and current population sizes of two species of shorebirds: the Black-Necked Stilt (Himantopus mexicanus) and American Avocet (Recurvirostra americana). Using a population status framework based on principles of conservation biology, we estimated that stilt populations are small (&lt;10,000 individuals) or very small (&lt;1,000 individuals) in three of the four planning regions, and avocet populations are small or very small in all four planning regions. We then used the framework to define long-term (100-year) population objectives for stilts, avocets, and a third species, Killdeer (Charadrius vociferous), designed to meet our long-term conservation goal of supporting self-sustaining, genetically robust, and resilient populations of breeding shorebirds in the Central Valley. We also estimated the long-term species’ density and wetland habitat objectives necessary to achieve the population objectives for all three species. The corresponding short-term (10-year) conservation objectives are to restore semi-permanent wetlands to provide an additional 11,537 ha (28,508 ac) of habitat for breeding shorebirds (by planning region: 2,842 ha in Sacramento, 2,897 ha in Yolo–Delta, 2,943 ha in San Joaquin, and 2,855 ha in Tulare), and to enhance existing habitat to support density objectives. Our approach provides a transparent, repeatable process for defining science-based conservation objectives for breeding shorebirds and their habitats in the Central Valley, which can help unite stakeholders around common goals and motivate conservation actions

Population and Habitat Objectives for Breeding Shorebirds in California’s Central Valley

The Central Valley of California provides important breeding habitat to numerous species of wetland-dependent birds, despite the loss of over 90% of naturally occurring wetlands. A majority of shorebirds breeding in this region rely on shallow-flooded habitat adjacent to sparsely vegetated uplands as provided by rice (Oryza sativa), managed wetlands, and other habitats. We estimated the current extent of potential breeding shorebird habitat provided by rice and managed permanent and semi-permanent wetlands in each of four major planning regions of the Central Valley, and estimated the average breeding densities and current population sizes of two species of shorebirds: the Black-Necked Stilt (Himantopus mexicanus) and American Avocet (Recurvirostra americana). Using a population status framework based on principles of conservation biology, we estimated that stilt populations are small (&lt;10,000 individuals) or very small (&lt;1,000 individuals) in three of the four planning regions, and avocet populations are small or very small in all four planning regions. We then used the framework to define long-term (100-year) population objectives for stilts, avocets, and a third species, Killdeer (Charadrius vociferous), designed to meet our long-term conservation goal of supporting self-sustaining, genetically robust, and resilient populations of breeding shorebirds in the Central Valley. We also estimated the long-term species’ density and wetland habitat objectives necessary to achieve the population objectives for all three species. The corresponding short-term (10-year) conservation objectives are to restore semi-permanent wetlands to provide an additional 11,537 ha (28,508 ac) of habitat for breeding shorebirds (by planning region: 2,842 ha in Sacramento, 2,897 ha in Yolo–Delta, 2,943 ha in San Joaquin, and 2,855 ha in Tulare), and to enhance existing habitat to support density objectives. Our approach provides a transparent, repeatable process for defining science-based conservation objectives for breeding shorebirds and their habitats in the Central Valley, which can help unite stakeholders around common goals and motivate conservation actions

Appendix A. Model-selection results for the effects of age and year on juvenile survival.

Model-selection results for the effects of age and year on juvenile survival