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Hall LA, Wang IJ, Escalona M, Beraut E, Sacco S, Sahasrabudhe R, Nguyen O, Toffelmier E, Shaffer HB, Beissinger SR. Reference genome of the Virginia rail, Rallus limicola. J Hered 2023; 114:428-435. [PMID: 37105531 PMCID: PMC10287147 DOI: 10.1093/jhered/esad026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 04/27/2023] [Indexed: 04/29/2023] Open
Abstract
The Virginia rail, Rallus limicola, is a member of the family Rallidae, which also includes many other species of secretive and poorly studied wetland birds. It is recognized as a single species throughout its broad distribution in North America where it is exploited as a game bird, often with generous harvest limits, despite a lack of systematic population surveys and evidence of declines in many areas due to wetland loss and degradation. To help advance understanding of the phylogeography, biology, and ecology of this elusive species, we report the first reference genome assembly for the Virginia rail, produced as part of the California Conservation Genomics Project (CCGP). We produced a de novo genome assembly using Pacific Biosciences HiFi long reads and Hi-C chromatin-proximity sequencing technology with an estimated sequencing error rate of 0.191%. The assembly consists of 1,102 scaffolds spanning 1.39 Gb, with a contig N50 of 11.0 Mb, scaffold N50 of 25.3 Mb, largest contig of 45 Mb, and largest scaffold of 128.4 Mb. It has a high BUSCO completeness score of 96.9% and represents the first genome assembly available for the genus Rallus. This genome assembly will help resolve questions about the complex evolutionary history of rails and evaluate the potential of rails for adaptive evolution in the face of growing threats from climate change and habitat loss and fragmentation. It will also provide a valuable resource for rail conservation efforts by quantifying Virginia rail vagility, population connectivity, and effective population sizes.
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Affiliation(s)
- Laurie A Hall
- Department of Environmental Science, Policy & Management, University of California, Berkeley, Berkeley, CA 94720, United States
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA 94720, United States
| | - Ian J Wang
- Department of Environmental Science, Policy & Management, University of California, Berkeley, Berkeley, CA 94720, United States
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA 94720, United States
| | - Merly Escalona
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA 95064, United States
| | - Eric Beraut
- Department of Ecology & Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, United States
| | - Samuel Sacco
- Department of Ecology & Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, United States
| | - Ruta Sahasrabudhe
- DNA Technologies and Expression Analysis Core Laboratory, Genome Center, University of California, Davis, Davis, CA 95616, United States
| | - Oanh Nguyen
- DNA Technologies and Expression Analysis Core Laboratory, Genome Center, University of California, Davis, Davis, CA 95616, United States
| | - Erin Toffelmier
- Department of Ecology & Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, United States
- La Kretz Center for California Conservation Science, Institute of the Environment & Sustainability, University of California, Los Angeles, Los Angeles, CA 90095, United States
| | - H Bradley Shaffer
- Department of Ecology & Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, United States
- La Kretz Center for California Conservation Science, Institute of the Environment & Sustainability, University of California, Los Angeles, Los Angeles, CA 90095, United States
| | - Steven R Beissinger
- Department of Environmental Science, Policy & Management, University of California, Berkeley, Berkeley, CA 94720, United States
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA 94720, United States
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Hall LA, Wang IJ, Escalona M, Beraut E, Sacco S, Sahasrabudhe R, Nguyen O, Toffelmier E, Shaffer HB, Beissinger SR. Reference genome of the black rail, Laterallus jamaicensis. J Hered 2023; 114:436-443. [PMID: 37119047 PMCID: PMC10287143 DOI: 10.1093/jhered/esad025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 04/27/2023] [Indexed: 04/30/2023] Open
Abstract
The black rail, Laterallus jamaicensis, is one of the most secretive and poorly understood birds in the Americas. Two of its five subspecies breed in North America: the Eastern black rail (L. j. jamaicensis), found primarily in the southern and mid-Atlantic states, and the California black rail (L. j. coturniculus), inhabiting California and Arizona, are recognized across the highly disjunct distribution. Population declines, due primarily to wetland loss and degradation, have resulted in conservation status listings for both subspecies. To help advance understanding of the phylogeography, biology, and ecology of this elusive species, we report the first reference genome assembly for the black rail, produced as part of the California Conservation Genomics Project (CCGP). We produced a de novo genome assembly using Pacific Biosciences HiFi long reads and Hi-C chromatin-proximity sequencing technology with an estimated sequencing error rate of 0.182%. The assembly consists of 964 scaffolds spanning 1.39 Gb, with a contig N50 of 7.4 Mb, scaffold N50 of 21.4 Mb, largest contig of 44.8 Mb, and largest scaffold of 101.2 Mb. The assembly has a high BUSCO completeness score of 96.8% and represents the first genome assembly available for the genus Laterallus. This genome assembly can help resolve questions about the complex evolutionary history of rails, assess black rail vagility and population connectivity, estimate effective population sizes, and evaluate the potential of rails for adaptive evolution in the face of growing threats from climate change, habitat loss and fragmentation, and disease.
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Affiliation(s)
- Laurie A Hall
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, United States
- Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, United States
| | - Ian J Wang
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, United States
- Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, United States
| | - Merly Escalona
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA 95064, United States
| | - Eric Beraut
- Department of Ecology and Evolutionary Biology, University of Califin JHornia, Santa Cruz, CA 95064, United States
| | - Samuel Sacco
- Department of Ecology and Evolutionary Biology, University of Califin JHornia, Santa Cruz, CA 95064, United States
| | - Ruta Sahasrabudhe
- DNA Technologies and Expression Analysis Core Laboratory, Genome Center, University of California, Davis, CA 95616, United States
| | - Oanh Nguyen
- DNA Technologies and Expression Analysis Core Laboratory, Genome Center, University of California, Davis, CA 95616, United States
| | - Erin Toffelmier
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, United States
- La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, University of California, Los Angeles, CA 90095, United States
| | - H Bradley Shaffer
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, United States
- La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, University of California, Los Angeles, CA 90095, United States
| | - Steven R Beissinger
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, United States
- Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, United States
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Beissinger SR, Peterson SM, Hall LA, Van Schmidt N, Tecklin J, Risk BB, Richmond OM, Kovach TJ, Kilpatrick AM. Stability of patch-turnover relationships under equilibrium and nonequilibrium metapopulation dynamics driven by biogeography. Ecol Lett 2022; 25:2372-2383. [PMID: 36209497 PMCID: PMC9828715 DOI: 10.1111/ele.14111] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 06/27/2022] [Accepted: 07/31/2022] [Indexed: 01/12/2023]
Abstract
Two controversial tenets of metapopulation biology are whether patch quality and the surrounding matrix are more important to turnover (colonisation and extinction) than biogeography (patch area and isolation) and whether factors governing turnover during equilibrium also dominate nonequilibrium dynamics. We tested both tenets using 18 years of surveys for two secretive wetland birds, black and Virginia rails, during (1) a period of equilibrium with stable occupancy and (2) after drought and arrival of West Nile Virus (WNV), which resulted in WNV infections in rails, increased extinction and decreased colonisation probabilities modified by WNV, nonequilibrium dynamics for both species and occupancy decline for black rails. Area (primarily) and isolation (secondarily) drove turnover during both stable and unstable metapopulation dynamics, greatly exceeding the effects of patch quality and matrix conditions. Moreover, slopes between turnover and patch characteristics changed little between equilibrium and nonequilibrium, confirming the overriding influences of biogeographic factors on turnover.
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Affiliation(s)
- Steven R. Beissinger
- Department of Environmental Science, Policy & ManagementUniversity of CaliforniaBerkeleyCaliforniaUSA,Museum of Vertebrate ZoologyUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Sean M. Peterson
- Department of Environmental Science, Policy & ManagementUniversity of CaliforniaBerkeleyCaliforniaUSA,Department of Environmental BiologyState University of New York College of Environmental Science and ForestryNew YorkUSA
| | - Laurie A. Hall
- Department of Environmental Science, Policy & ManagementUniversity of CaliforniaBerkeleyCaliforniaUSA,Museum of Vertebrate ZoologyUniversity of CaliforniaBerkeleyCaliforniaUSA,U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field StationCaliforniaUSA
| | - Nathan Van Schmidt
- Department of Environmental Science, Policy & ManagementUniversity of CaliforniaBerkeleyCaliforniaUSA,US Geological Survey, Fort Collins Science CenterFort CollinsColoradoUSA
| | - Jerry Tecklin
- Sierra Foothills Research and Extension CenterBrowns ValleyCaliforniaUSA,21170 Shields Camp RoadNevada CityCaliforniaUSA
| | - Benjamin B. Risk
- Department of Environmental Science, Policy & ManagementUniversity of CaliforniaBerkeleyCaliforniaUSA,Department of Biostatistics and BioinformaticsEmory UniversityAtlantaGeorgiaUSA
| | - Orien M. Richmond
- Department of Environmental Science, Policy & ManagementUniversity of CaliforniaBerkeleyCaliforniaUSA,Rocky Mountain Arsenal National Wildlife RefugeCommerce CityColoradoUSA
| | - Tony J. Kovach
- Department of Ecology and Evolutionary BiologyUniversity of CaliforniaSanta CruzCaliforniaUSA,California Department of Public Health/Vector Borne Disease SectionCaliforniaUSA
| | - A. Marm Kilpatrick
- Department of Ecology and Evolutionary BiologyUniversity of CaliforniaSanta CruzCaliforniaUSA
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Zink RM, Klicka LB. The taxonomic basis of subspecies listed as threatened and endangered under the endangered species act. FRONTIERS IN CONSERVATION SCIENCE 2022. [DOI: 10.3389/fcosc.2022.971280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
More than 170 subspecies are listed as threatened or endangered under the US Endangered Species Act. Most of these subspecies were described decades ago on the basis of geographical variation in morphology using relatively primitive taxonomic methods. The US Fish and Wildlife Service defaults to subspecies descriptions by taxonomists working with specific groups of organisms, but there is no single definition of subspecies across plants and animals. Valid tests today usually entail molecular analyses of variation within and among populations, although there is no reason that behavioral, ecological or molecular characters could not be used, and include tests for significant differences between samples of the putative endangered subspecies and its nearest geographic relatives. We evaluated data gathered since subspecies listed under the ESA were described finding about one-third are valid (distinct evolutionary taxa), one-third are not, and one-third have not been tested. Therefore, it should not be assumed that because a subspecies occurs in a checklist, it is taxonomically valid. If the US Fish and Wildlife Service intends to continue listing subspecies, we suggest that they convene taxonomic experts representing various groups of organisms to provide a minimal set of criteria for a subspecies to be listed under the ESA.
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Evolutionary History of the Galápagos Rail Revealed by Ancient Mitogenomes and Modern Samples. DIVERSITY 2020. [DOI: 10.3390/d12110425] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The biotas of the Galápagos Islands are one of the best studied island systems and have provided a broad model for insular species’ origins and evolution. Nevertheless, some locally endemic taxa, such as the Galápagos Rail Laterallus spilonota, remain poorly characterized. Owing to its elusive behavior, cryptic plumage, and restricted distribution, the Galápagos Rail is one of the least studied endemic vertebrates of the Galapagos Islands. To date, there is no genetic data for this species, leaving its origins, relationships to other taxa, and levels of genetic diversity uncharacterized. This lack of information is critical given the adverse fate of island rail species around the world in the recent past. Here, we examine the genetics of Galápagos Rails using a combination of mitogenome de novo assembly with multilocus nuclear and mitochondrial sequencing from both modern and historical samples. We show that the Galápagos Rail is part of the “American black rail clade”, sister to the Black Rail L. jamaicensis, with a colonization of Galápagos dated to 1.2 million years ago. A separate analysis of one nuclear and two mitochondrial markers in the larger population samples demonstrates a shallow population structure across the islands, possibly due to elevated island connectivity. Additionally, birds from the island Pinta possessed the lowest levels of genetic diversity, possibly reflecting past population bottlenecks associated with overgrazing of their habitat by invasive goats. The modern and historical data presented here highlight the low genetic diversity in this endemic rail species and provide useful information to guide conservation efforts.
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Affiliation(s)
- Eamon J. Harrity
- Idaho Cooperative Fish and Wildlife Research Unit, Department of Fish & Wildlife SciencesUniversity of Idaho 875 Perimeter Drive, Mail Stop 1141 Moscow ID 83844 USA
| | - Courtney J. Conway
- U.S. Geological Survey, Idaho Cooperative Fish and Wildlife Research Unit, Department of Fish & Wildlife SciencesUniversity of Idaho 875 Perimeter Drive, Mail Stop 1141 Moscow ID 83844 USA
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Hall LA, Van Schmidt ND, Beissinger SR. Validating dispersal distances inferred from autoregressive occupancy models with genetic parentage assignments. J Anim Ecol 2018; 87:691-702. [DOI: 10.1111/1365-2656.12811] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 01/19/2018] [Indexed: 11/27/2022]
Affiliation(s)
- Laurie A. Hall
- Department of Environmental Science, Policy and Management Museum of Vertebrate Zoology University of California Berkeley CA USA
| | - Nathan D. Van Schmidt
- Department of Environmental Science, Policy and Management Museum of Vertebrate Zoology University of California Berkeley CA USA
| | - Steven R. Beissinger
- Department of Environmental Science, Policy and Management Museum of Vertebrate Zoology University of California Berkeley CA USA
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Small-scale genetic structure in an endangered wetland specialist: possible effects of landscape change and population recovery. CONSERV GENET 2017. [DOI: 10.1007/s10592-017-1020-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Hall LA, Beissinger SR. Inferring the timing of long-distance dispersal between Rail metapopulations using genetic and isotopic assignments. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2017; 27:208-218. [PMID: 28052492 DOI: 10.1002/eap.1432] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 07/22/2016] [Accepted: 08/02/2016] [Indexed: 06/06/2023]
Abstract
The stochastic and infrequent nature of long-distance dispersal often makes it difficult to detect. We quantified the frequency, distance, and timing of long-distance dispersal in a nonmigratory, secretive wetland bird, the California Black Rail (Laterallus jamaicensis coturniculus), between an inland and a coastal metapopulation separated by greater than 100 km. Using 15 microsatellites in conjunction with stable carbon, nitrogen, and sulfur isotopes, we classified Rails as residents of their capture population, recent migrants that dispersed to their capture population less than one year before capture, established migrants that dispersed to their capture population more than one year before capture, and seasonal migrants that dispersed away from their capture population to forage, but returned the next season. Most Rails (195 of 204, or 95.6%) were classified as residents, but we detected two established migrants that had moved >100 km more than a year before capture. Seven Rails appeared to be seasonal migrants, but comparisons of feather isotope values with isotope values from wetland soils indicated that the isotope values in the feathers of these Rails likely resulted from natural environmental variation (e.g., source element effects) rather than long-distance dispersal of individuals. Thus, these seven Rails were most likely misassigned by isotopic population assignments due to small-scale variation in the isoscape. Using genetic data in conjunction with isotopic data allowed us to not only infer the timing of long-distance dispersal events, but to successfully track long-distance movements of nonmigratory Rails between metapopulations even when environmental variation of isotopes occurred across small spatial scales.
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Affiliation(s)
- Laurie A Hall
- Department of Environmental Science, Policy and Management, Museum of Vertebrate Zoology, University of California, 130 Mulford Hall #3114, Berkeley, California, 94720, USA
| | - Steven R Beissinger
- Department of Environmental Science, Policy and Management, Museum of Vertebrate Zoology, University of California, 130 Mulford Hall #3114, Berkeley, California, 94720, USA
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Wood DA, Bui TVD, Overton CT, Vandergast AG, Casazza ML, Hull JM, Takekawa JY. A century of landscape disturbance and urbanization of the San Francisco Bay region affects the present-day genetic diversity of the California Ridgway’s rail (Rallus obsoletus obsoletus). CONSERV GENET 2016. [DOI: 10.1007/s10592-016-0888-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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de Camargo C, Gibbs HL, Costa MC, Del-Rio G, Silveira LF, Wasko AP, Francisco MR. Marshes as "Mountain Tops": Genetic Analyses of the Critically Endangered São Paulo Marsh Antwren (Aves: Thamnophilidae). PLoS One 2015; 10:e0140145. [PMID: 26447791 PMCID: PMC4598188 DOI: 10.1371/journal.pone.0140145] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 09/21/2015] [Indexed: 12/03/2022] Open
Abstract
Small populations of endangered species can be impacted by genetic processes such as drift and inbreeding that reduce population viability. As such, conservation genetic analyses that assess population levels of genetic variation and levels of gene flow can provide important information for managing threatened species. The São Paulo Marsh Antwren (Formicivora paludicola) is a recently-described and critically endangered bird from São Paulo State (Brazil) whose total estimated population is around 250-300 individuals, distributed in only 15 isolated marshes around São Paulo metropolitan region. We used microsatellite DNA markers to estimate the population genetic characteristics of the three largest remaining populations of this species all within 60 km of each other. We detected a high and significant genetic structure between all populations (overall FST = 0.103) which is comparable to the highest levels of differentiation ever documented for birds, (e.g., endangered birds found in isolated populations on the tops of African mountains), but also evidence for first-generation immigrants, likely from small local unsampled populations. Effective population sizes were small (between 28.8-99.9 individuals) yet there are high levels of genetic variability within populations and no evidence for inbreeding. Conservation implications of this work are that the high levels of genetic structure suggests that translocations between populations need to be carefully considered in light of possible local adaptation and that remaining populations of these birds should be managed as conservation units that contain both main populations studied here but also small outlying populations which may be a source of immigrants.
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Affiliation(s)
- Crisley de Camargo
- Departamento de Genética, Instituto de Biociências, Universidade Estadual Paulista “Júlio de Mesquita Filho”, Distrito de Rubião Júnior, s/n, CEP 18618–970, Botucatu, São Paulo, Brazil
| | - H. Lisle Gibbs
- Department of Evolution, Ecology and Organismal Biology, Ohio State University, Columbus, Ohio 43210–1293, United States of America
| | - Mariellen C. Costa
- Departamento de Ciências Ambientais, Universidade Federal de São Carlos, Campus de Sorocaba, Rod. João Leme dos Santos, km 110, CEP 18052–780, Sorocaba, São Paulo, Brazil
| | - Glaucia Del-Rio
- Museum of Natural Science, Louisiana State University, Baton Rouge, Louisiana 70803, United States of America
| | - Luís F. Silveira
- Seção de Aves, Museu de Zoologia da Universidade de São Paulo, Caixa Postal 42494, CEP 04218–970, São Paulo, São Paulo, Brazil
| | - Adriane P. Wasko
- Departamento de Genética, Instituto de Biociências, Universidade Estadual Paulista “Júlio de Mesquita Filho”, Distrito de Rubião Júnior, s/n, CEP 18618–970, Botucatu, São Paulo, Brazil
| | - Mercival R. Francisco
- Departamento de Ciências Ambientais, Universidade Federal de São Carlos, Campus de Sorocaba, Rod. João Leme dos Santos, km 110, CEP 18052–780, Sorocaba, São Paulo, Brazil
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Richmond OMW, Tecklin J, Beissinger SR. Impact of cattle grazing on the occupancy of a cryptic, threatened rail. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2012; 22:1655-1664. [PMID: 22908720 DOI: 10.1890/11-1021.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Impacts of livestock grazing in arid and semiarid environments are often concentrated in and around wetlands where animals congregate for water, cooler temperatures, and green forage. We assessed the impacts of winter-spring (November-May) cattle grazing on marsh vegetation cover and occupancy of a highly secretive marsh bird that relies on dense vegetation cover, the California Black Rail (Laterallus jamaicensis coturniculus), in the northern Sierra Nevada foothills of California, U.S.A. Using detection-nondetection data collected during repeated call playback surveys at grazed vs. ungrazed marshes and a "random changes in occupancy" parameterization of a multi-season occupancy model, we examined relationships between occupancy and habitat covariates, while accounting for imperfect detection. Marsh vegetation cover was significantly lower at grazed marshes than at ungrazed marshes during the grazing season in 2007 but not in 2008. Winter-spring grazing had little effect on Black Rail occupancy at irrigated marshes. However, at nonirrigated marshes fed by natural springs and streams, grazed sites had lower occupancy than ungrazed sites. Black Rail occupancy was positively associated with marsh area, irrigation as a water source, and summer vegetation cover, and negatively associated with marsh isolation. Residual dry matter (RDM), a commonly used metric of grazing intensity, was significantly associated with summer marsh vegetation cover at grazed sites but not spring cover. Direct monitoring of marsh vegetation cover, particularly at natural spring- or stream-fed marshes, is recommended to prevent negative impacts to rails from overgrazing.
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Affiliation(s)
- Orien M W Richmond
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California 94720, USA.
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