Strum K.M.,Audubon California |
Dybala K.E.,Point Blue Conservation Science |
Iglecia M.N.,Manomet PlymouthMA |
David Shuford W.,Point Blue Conservation Science
San Francisco Estuary and Watershed Science | Year: 2017
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 (< 10,000 individuals) or very small (< 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 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.
Dybala K.E.,Point Blue Conservation Science |
Reiter M.E.,Point Blue Conservation Science |
Hickey C.M.,Point Blue Conservation Science |
David Shuford W.,Point Blue Conservation Science |
And 2 more authors.
San Francisco Estuary and Watershed Science | Year: 2017
An extensive network of managed wetlands and flooded agriculture provides habitat for migrating and wintering shorebirds in California's Central Valley. Yet with over 90% of historical wetlands in the region lost, Central Valley shorebird populations are likely diminished and limited by available habitat. To identify the timing and magnitude of any habitat limitations during the non-breeding season, we developed a bioenergetics model that examined whether currently available shorebird foraging habitat is sufficient to meet the daily energy requirements of the shorebird community, at either the baseline population size surveyed from 1992 to 1995 or double this size, which we defined as our long-term (100-year) population objectives. Using recent estimates of the extent of managed wetlands and flooded agriculture, satellite imagery of surface water, energy content of benthic invertebrates, and shorebird metabolic rates, we estimated that shorebir foraging habitat in the Central Valley is currently limited during the fall. If the population sizes were doubled, we estimated substantial energy shortfalls in the fall (late July-September) and spring (mid-March-April) totaling 4.02 billion kJ (95% CI: 2.23-5.83) and 7.79 billion kJ (2.00-14.14), respectively. We then estimated long-term habitat objectives as the minimum additional shorebird foraging habitat required to eliminate these energy shortfalls; the corresponding short-term (10-year) habitat objective are to maintain an additional 2,160 ha (5,337 ac) of shallow (<10 cm) open water area in the fall and 4,692 ha (11,594 ac) in the spring. Because the Central Valley is one of the most important regions in the Pacific Flyway for migrating and wintering shorebirds, we expect that achieving these habitat objectives will benefit shorebirds well beyond the Central Valley. Our bioenergetics approach provides a transparent, repeatable process for identifying the timing and magnitude of habitat limitations as well as the most efficient strategies for achieving conservation objectives.
David Shuford W.,Point Blue Conservation Science |
Hertel M.,Audubon California
San Francisco Estuary and Watershed Science | Year: 2017
Populations of many species of birds are declining worldwide from habitat loss and degradation and the effects of contamination, disease, and alien species. Effects have been great in California's Central Valley from the loss of over 90% of its historical wetland and riparian habitats. Conservation initiatives at various geographic scales have ranged from protecting and restoring habitats or ecosystems for broad suites of species to ones identifying individual declining and vulnerable taxa and spurring actions to halt or reverse their population declines. In taking the first approach, the Central Valley Joint Venture initially focused on restoring habitats and populations of wintering and breeding waterfowl but currently promotes the conservation of all birds. This joint venture is setting population and habitat objectives for seven taxonomic or habitat bird groups, but to date little attention has been paid to at-risk species of particular conservation concern. We identified 38 at-risk species, subspecies, or distinct populations of birds that warrant heightened conservation efforts in the Central Valley. At-risk birds are unevenly distributed among subregions and habitat types in this valley, but most face the primary threat of habitat loss and degradation. The treatment of at-risk species varies greatly among the seven bird groups considered by the joint venture, and, overall, conservation objectives are not addressed specifically for 50% of the region's at-risk taxa, though some surely benefit from objectives set for other groups. To adequately treat at-risk species, we recommend a framework for setting conservation objectives that evaluates assumptions about limiting factors, considers objectives already set for threatened and endangered species, assesses whether objectives set for other groups or focal species meet the needs of at-risk species lacking such objectives, establishes objectives for at-risk species for habitats or seasons not currently considered, and highlights information gaps to be filled to effectively set new or refined objectives.
News Article | May 3, 2017
“It’s going to be kind of noisy — and very smelly,” Laura Anhalt warns, laughing, as we enter our first building at the primary wastewater treatment plant in Modesto, California. She’s right: The funk of processed sewage hits quickly. Inside, a conveyor rake scrapes crumbling, sodden paper up out of a vat of water. Nearby, a large metal mouth swallows the paper pieces and feeds them through a compactor that extrudes a solid hunk of waste nearly as wide around as a human torso. Separating out the solids — unappetizing as it smells — is the first step in cleaning the water that Modesto residents wash down their sinks and flush down their toilets every day. This process happens at thousands of similar plants all around the world. But Modesto’s sewage treatment will soon be part of a novel project: Starting as early as December, the city will sell its highly treated wastewater to struggling nearby farmers. When it’s up and running, Modesto’s experiment should be California’s largest wastewater-to-agriculture reuse project, and it will mark the first time recycled water flows through a federal canal. In the past several years, California’s drought has cut back water supplies for many growers, forcing them to fallow fields. Though much of California has been deluged with precipitation this year, scientists warn that the wet weather won’t last. Climate change is expected to make the state’s dry-and-drenched extremes even more drastic. To maintain the state’s agricultural might, farmers will need new water sources that won’t dry up in the next drought. The North Valley Regional Recycled Water Program, as the project is known, will serve an area in the Central Valley, California’s most productive agricultural region. Its planners hope it will serve as a model for other drought-stricken regions of an environmentally friendly way to get water to farmers. Some environmental advocates hope so, too. The project has won the support of conservation groups like Audubon California and Ducks Unlimited because it will also provide water for the state’s wildlife refuges. But getting the project off the ground hasn’t been easy. Nearby water suppliers criticized and challenged the proposal to reroute water, fearing it might affect their own supplies. Documents obtained via a Freedom of Information Act request show that the water district pushing the plan had to delicately negotiate compromises to coax the project forward, in some cases offering other districts a cut of their water. In California, it seems, the best way to solve disagreements over water is with more water. The city of Modesto has two wastewater treatment plants, called Sutter and Jennings, about eight miles apart. Anhalt, or as she quippily labels herself, “the dirty water gal,” has managed both for nine years. She has a cat tattoo on her left calf and a quick laugh. She’s lived in California her whole life, apart from a stopover in another drought-stricken locale, Australia. After a visit to Sutter, where the first round of water treatment takes place, Anhalt drives me to Jennings in her red Lexus, a cat air freshener dangling from the rearview mirror. We pass row after row of spindly young trees that will eventually produce lucrative walnut and almond crops — if farmers have enough water to keep them alive. Many of the orchards display signs with the words “Worth Your Fight” and an image of a water droplet. “Ah, water!” Anhalt exclaims when I ask about them. She says they’re part of a campaign to defend farmers’ water supplies in the Central Valley. Modesto’s two plants pump out nearly 15 million treated gallons a day. The initial processing at Sutter strips out solids. Then the city pumps the water to Jennings, where further treatment breaks down organic matter and any remaining solids with digesting protozoa “bugs.” Last, the water is zapped with UV lights to disinfect it. Jennings is a vast complex that stretches over 5,000 acres, 1,000 of which are oxidation ponds extending nearly as far as the eye can see. The ponds look more like a nature preserve than a sewage treatment facility, attracting birds and birders. Anhalt tours us around a number of structures at Jennings — sometimes testing doors to see if they’re unlocked, because she forgot her keys. She easily rattles off descriptions of the complicated processes at work. For her, this is second nature. She’s been working in wastewater for 23 years. At an aromatic tank of “mixed liquor,” which contains raw wastewater and microorganisms that break down its contents, she seems pleased to be the overseer of such an enormous, complicated system. “Good stuff. It looks pretty,” Anhalt says, nodding at the brown liquid rippling with bubbles. “Not too foamy.” Later we visit what she frames as the pièce de résistance: “You just have to see the blowers.” As we wend our way through another building, a muted buzzing sound slowly builds to a deep whooshing. These machines aerate the membrane tanks to encourage processing. “I’m so excited,” she smiles. “I love the blowers.” After treatment is done, Modesto uses the water to irrigate city-owned land and sends any left over into the San Joaquin River to flow to users downstream. By the end of the year, that should change. A refurbished pump station at Jennings will send most of the wastewater into a new $100 million, six-mile pipeline. That will feed into the Delta-Mendota irrigation canal, which ferries water to farmers as part of the Central Valley Project, a federal system that manages and doles out water in the area. Ultimately, Modesto’s wastewater will reach farms about 20 miles away in the northwestern San Joaquin Valley, where growers on 45,000 acres of farmland in the Del Puerto Water District have struggled to water their crops since the drought began. By 2045, when all phases of the project are complete, these farmers should be receiving nearly 60,000 acre-feet per year from the North Valley project — enough to fill roughly 30,000 Olympic-sized swimming pools. Anthea Hansen, head of the Del Puerto Water District, is the one who pulled the entire project together. She’s been working nonstop for the past seven years to bring more water to farmers there. After the drought started in late 2011, and restrictions set aside more water for wildlife, allocations from the Central Valley Project to water districts in the San Joaquin Valley plummeted. The Del Puerto Water District received zero percent of its contracted supply in 2014 and 2015, and just 5 percent last year. In 2017, already a historically wet year, it will receive its full allotment, but Hansen expects that to drop as soon as next year. Because the district hasn’t been able to rely on water from the Central Valley Project, for the past several years Hansen has had to negotiate water purchases within California’s tricky water-rights system. The district has been buying excess surface supply when it’s available, and has also purchased groundwater from other districts at high prices. “We’ve survived on supplemental water, and about one quarter of our irrigated acreage is fallowed,” Hansen says. The water from the North Valley project will make an enormous difference to the farmers in her area. “It pretty much changes the course of the future for our district,” she says. Daniel Bays is one of those farmers. His grandfather moved to the area in 1957, and the family now grows apricots, walnuts, lima beans, tomatoes, and melons at Bays Ranch in Westley. His farm has struggled to get by with the minimal supply. He’s also used groundwater, but it’s often salty and can cause land to sink if pumped to excess. “It’s expensive, poor quality, and there’s no guarantee you’ll be able to get it when you need it,” he tells me. Water from the North Valley project will still be expensive — potentially two or three times the price of Central Valley Project water — and it will only meet about a third of the water district’s need. But it will at least be reliable and high quality, something farmers haven’t been able to count on in recent years. Bays points out that this new water source is not going to dry up, because Modesto will keep producing wastewater: “People are flushing their toilets every day and taking showers,” he says. Above his desk at Turlock City Hall, Garner Reynolds has taped a photo printed out on computer paper. It shows two men in jeans standing in a field, menacingly wielding shovels at each other. The caption reads: “Discussing water rights, a Western pastime.” Turlock is also involved in the North Valley project, as is another nearby city, Ceres. Turlock is building its own 7.5-mile pipeline, at a cost of $20 million to $30 million, to transport wastewater from its primary treatment plant, as well as some wastewater from Ceres, over to Jennings. It should be complete in December 2018. Reynolds, Turlock’s regulatory affairs manager, sports a goatee and a bright aqua dress shirt. Like most of the people I spoke with about the North Valley project, he said it would be a win-win for Del Puerto growers and the participating cities, which will get paid for their recycled water. “It works for everybody,” he says. But reaching that point took a lot of effort. Negotiating water rights and diversions is notoriously arduous in California. The North Valley deal involves the three cities, the Del Puerto Water District, Stanislaus County, and the U.S. Bureau of Reclamation. Still more parties had to be mollified along the way. Westlands Water District, the biggest in the country and among the most powerful, argued that Modesto’s diversion of water away from the San Joaquin River would cut into its supply. The district also worried that the recycled water might lower water quality in the Delta-Mendota Canal, which delivers water to Westlands through the Central Valley Project. The oldest water district in the state, Turlock Irrigation District (a body separate from the city), also raised concerns. Emails obtained through a FOIA request show that in March of 2015, a lawyer representing the district sent comments to Modesto and the Bureau of Reclamation, claiming the environmental impact report for the project was inadequate and did not properly assess how it would affect groundwater. These kinds of quibbles can delay projects for months or years while water districts and agencies negotiate a solution. It fell to Hansen to break through many of these logjams and keep the project moving forward, the emails show. She repeatedly emphasized the urgency of the situation, knowing how much the farmers in her district needed water. “Sooner is better,” she wrote in an April 2016 note to the Bureau of Reclamation project lead, pushing to get paperwork completed. “I’m like a cat on a hot tin roof right now.” To quiet the complaints from nearby water districts, Modesto agreed not to use any water from the Turlock Irrigation District or the Turlock Subbasin to irrigate its ranchlands. And the Del Puerto Water District brokered a deal to deliver 500 acre-feet per year to Westlands after the North Valley project kicks off. Even though the lengthy bargaining process has been tiresome, Hansen says it’s worth it for a project that will sustain a way of life in an area where most growers are small family farmers. “We figure out how to work through the complicated system in California to get the water moved from point A to point B,” she says. “It’s very difficult, it’s fraught with heavy levels of environmental documentation and a lot of cost to make it work, but it helps us to survive.” “There’s a lot of things with California’s plumbing that I wish were different,” she adds. But if all goes according to plan, at least no growers will be brandishing shovels at one another.
Schuetz J.,Audubon California
PLoS ONE | Year: 2011
Collection and analysis of demographic data play a critical role in monitoring and management of endangered taxa. I analyzed long-term clutch size and fledgling productivity data for California least tern (Sternula antillarum browni), a federally endangered subspecies that has recently become a candidate for down-listing. While the breeding population grew from approximately 1,253 to 7,241 pairs (578%) during the study period (1988-2009) both clutch size and fledgling productivity declined. Clutch size decreased by approximately 0.27 eggs (14%) from 1990-2004 then showed a moderate increase of 0.11 eggs from 2004-2009. Estimates of fledgling productivity showed a similar pattern of decline and moderate increase even after controlling for clutch size. Sea surface temperature anomalies, an index of El Niño-Southern Oscillation activity, did not influence clutch size but were associated with fledgling productivity through a non-linear relationship. Both clutch size and fledgling productivity increased with latitude, potentially indicating a gradient of life-history trade-offs. Random site effects explained little of the overall variation in clutch size (3%) or fledgling productivity (<1%) suggesting that site characteristics beyond those associated with latitude had little bearing on either measure of reproduction. Despite intensive monitoring and management, causes of variation in key demographic parameters remain poorly understood. Long-term declines in clutch size and fledgling productivity may reflect: 1) reduced food availability, 2) increased density-dependent competition, and/or 3) age-dependent reproduction coupled with a shifting population age-structure. Until the mechanisms shaping demographic parameters and population change are better understood, the success of past management and the probability of ongoing recovery will remain difficult to characterize. © 2011 Justin Schuetz.
White M.D.,Tejon Ranch Conservancy |
Pandolrno E.R.,5530 Delrose Court |
Jones A.,Audubon California
Western Birds | Year: 2011
The Purple Martin (Progne subis), a species of significant conservation concern in California, once nested widely in oak, sycamore, and coniferous woodlands throughout the state. Currently, the Tehachapi Mountains of southern California are the only area where significant numbers of Purple Martins are known to still nest in oaks. We surveyed for the Purple Martin and other cavity-nesting birds on a portion of Tejon Ranch in the Tehachapi Mountains during summer 2010. We found 23 nesting pairs of Purple Martins, all using cavities in large Valley Oaks (Quercus lobata) at or near the tops of ridges in open savanna settings. The Acorn Woodpecker (Melanerpes formicivorus) was the most abundant other cavity nester in the area and likely creates the cavities used by Purple Martins. The European Starling (Sturnus vulgaris), considered a serious competitor of the Purple Martin for nest sites in most of the Purple Martin's range, was rarely encountered near these nest sites.
Use of occupancy models to evaluate expert knowledge-based species-habitat relationships [Utilisation de modèles de présence pour évaluer les relations espèceshabitat fondées sur les connaissances dexperts]
Iglecia M.N.,Audubon California |
Collazo J.A.,U.S. Geological Survey |
McKerrow A.J.,U.S. Geological Survey
Avian Conservation and Ecology | Year: 2012
Expert knowledge-based species-habitat relationships are used extensively to guide conservation planning, particularly when data are scarce. Purported relationships describe the initial state of knowledge, but are rarely tested. We assessed support in the data for suitability rankings of vegetation types based on expert knowledge for three terrestrial avian species in the South Atlantic Coastal Plain of the United States. Experts used published studies, natural history, survey data, and field experience to rank vegetation types as optimal, suitable, and marginal. We used single-season occupancy models, coupled with land cover and Breeding Bird Survey data, to examine the hypothesis that patterns of occupancy conformed to species-habitat suitability rankings purported by experts. Purported habitat suitability was validated for two of three species. As predicted for the Eastern Wood-Pewee (Contopus virens) and Brown-headed Nuthatch (Sitta pusilla), occupancy was strongly influenced by vegetation types classified as "optimal habitat" by the species suitability rankings for nuthatches and wood-pewees. Contrary to predictions, Red-headed Woodpecker (Melanerpes erythrocephalus) models that included vegetation types as covariates received similar support by the data as models without vegetation types. For all three species, occupancy was also related to sampling latitude. Our results suggest that covariates representing other habitat requirements might be necessary to model occurrence of generalist species like the woodpecker. The modeling approach described herein provides a means to test expert knowledge-based species-habitat relationships, and hence, help guide conservation planning. © 2012 by the author(s).
Weinstein A.,Audubon California |
Levalley R.,Mad River Biologists |
Doster R.H.,U.S. Fish and Wildlife Service |
Distler T.,Audubon California |
Krieger K.,Audubon California
Marine Ornithology | Year: 2014
Black Oystercatcher Haematopus bachmani is considered vulnerable to decline owing to small global population size, low reproductive success and complete dependence on rocky intertidal shorelines that are impacted by human use and rising sea levels. In response to poor baseline knowledge of the population of the species in California, during 2011 we undertook the first targeted survey measuring distribution and abundance. For the mainland, we used a standardized protocol developed specifically for detecting Black Oystercatchers during the early breeding season, when pair fidelity to breeding territories is highest and movement is lowest. For the Channel Islands, government biologists used a standardized seabird monitoring protocol adapted to detect Black Oystercatchers. For the Farallones, data are taken from the literature. On the mainland, 164 observers participated in the survey in 12 of the state's 15 coastal counties. Observers surveyed approximately 9% of the mainland California coast, equalling approximately 18% of the state's mainland suitable habitat, defined below. A total of 1 160 Black Oystercatchers were detected in this subset of habitat, more than the previous estimate for the entire state (<1 000 individuals). Average density of individuals in mainland surveyed areas was 3.14 birds/km; 135 nests were positively identified, and average nest density was 0.4 nests/km surveyed. On the Northern Channel Islands, approximately 20% the total coastline (66 km), and 20% of the suitable habitat (58 km) of San Miguel, Santa Rosa, Santa Cruz, Anacapa and Santa Barbara islands was surveyed. A total of 176 adult or sub-adult Black Oystercatchers were detected. Average density of individuals in surveyed areas was 2.7 individuals/km, comparable to mainland densities. In areas thoroughly surveyed, observers found densities of nesting territories comparable with those in Alaska and British Columbia, considered the core of the species' range. Based on observed densities in surveyed areas, and including estimates from the literature and more recent observations of a population of 60 at the Farallones, we conservatively estimate a total mainland and Farallones population between 3 971 and 5 213 and a Northern Channel Islands population between 779 and 854, for a total statewide population between 4 749 and 6 067. Our results indicate that California is a critical rather than peripheral part of the Black Oystercatcher range. This result, plus ongoing threats, emphasizes the need to monitor Black Oystercatcher population trends and to identify and protect the most important habitats for Black Oystercatchers in California. The Black Oystercatcher appears highly amenable to citizen science monitoring, particularly at smaller spatial scales, owing to its life history characteristics and charismatic appeal to the public.
PubMed | Audubon California
Type: Journal Article | Journal: PloS one | Year: 2011
Collection and analysis of demographic data play a critical role in monitoring and management of endangered taxa. I analyzed long-term clutch size and fledgling productivity data for California least tern (Sternula antillarum browni), a federally endangered subspecies that has recently become a candidate for down-listing. While the breeding population grew from approximately 1,253 to 7,241 pairs (578%) during the study period (1988-2009) both clutch size and fledgling productivity declined. Clutch size decreased by approximately 0.27 eggs (14%) from 1990-2004 then showed a moderate increase of 0.11 eggs from 2004-2009. Estimates of fledgling productivity showed a similar pattern of decline and moderate increase even after controlling for clutch size. Sea surface temperature anomalies, an index of El Nio-Southern Oscillation activity, did not influence clutch size but were associated with fledgling productivity through a non-linear relationship. Both clutch size and fledgling productivity increased with latitude, potentially indicating a gradient of life-history trade-offs. Random site effects explained little of the overall variation in clutch size (3%) or fledgling productivity (<1%) suggesting that site characteristics beyond those associated with latitude had little bearing on either measure of reproduction. Despite intensive monitoring and management, causes of variation in key demographic parameters remain poorly understood. Long-term declines in clutch size and fledgling productivity may reflect: 1) reduced food availability, 2) increased density-dependent competition, and/or 3) age-dependent reproduction coupled with a shifting population age-structure. Until the mechanisms shaping demographic parameters and population change are better understood, the success of past management and the probability of ongoing recovery will remain difficult to characterize.