Joshua I. Brown, Philip Lavretsky, G. Cumming, J. Peters
ABSTRACT Secondary contact and hybridization between recently diverged taxa have been increasing due to anthropogenic changes to the environment. Determining whether secondary contact leads to gene flow between species is important for understanding both the evolutionary consequences of such events (i.e. genetic swamping, speciation reversal, hybrid speciation) and for establishing proper conservation measures. Mallards (Anas platyrhynchos), which natively have a Holarctic distribution, have been introduced nearly worldwide due to game-farm and domestic pet releases. Their expanding range has resulted in secondary contact and increased incidences of hybridization with many closely related Mallard-like ducks that comprise the Mallard complex. Here, we assay molecular diversity for 19 nuclear introns and the mitochondrial DNA for wild Mallards (n = 50) across their Holarctic range and Yellow-billed Ducks (n = 30–75; Anas undulata) from southern Africa to determine population genetic structure and test for evidence of Mallard introgression into Yellow-billed Ducks. While we found limited support for contemporary gene flow across nuclear markers, we provide evidence from mitochondrial DNA that best supports ancient gene flow between Yellow-billed Ducks and Mallards. Yellow-billed Ducks best fit a single population at nuclear markers but show some location-specific mtDNA structure that suggests recent founder or bottleneck events. Although we find that introgression from Mallards into Yellow-billed Duck is limited, Yellow-billed Duck populations should be monitored to determine if expanding feral Mallard populations in southern Africa are increasing introgression.
{"title":"Strong population structure and limited gene flow between Yellow-billed Ducks and Mallards in southern Africa","authors":"Joshua I. Brown, Philip Lavretsky, G. Cumming, J. Peters","doi":"10.1093/condor/duz042","DOIUrl":"https://doi.org/10.1093/condor/duz042","url":null,"abstract":"ABSTRACT Secondary contact and hybridization between recently diverged taxa have been increasing due to anthropogenic changes to the environment. Determining whether secondary contact leads to gene flow between species is important for understanding both the evolutionary consequences of such events (i.e. genetic swamping, speciation reversal, hybrid speciation) and for establishing proper conservation measures. Mallards (Anas platyrhynchos), which natively have a Holarctic distribution, have been introduced nearly worldwide due to game-farm and domestic pet releases. Their expanding range has resulted in secondary contact and increased incidences of hybridization with many closely related Mallard-like ducks that comprise the Mallard complex. Here, we assay molecular diversity for 19 nuclear introns and the mitochondrial DNA for wild Mallards (n = 50) across their Holarctic range and Yellow-billed Ducks (n = 30–75; Anas undulata) from southern Africa to determine population genetic structure and test for evidence of Mallard introgression into Yellow-billed Ducks. While we found limited support for contemporary gene flow across nuclear markers, we provide evidence from mitochondrial DNA that best supports ancient gene flow between Yellow-billed Ducks and Mallards. Yellow-billed Ducks best fit a single population at nuclear markers but show some location-specific mtDNA structure that suggests recent founder or bottleneck events. Although we find that introgression from Mallards into Yellow-billed Duck is limited, Yellow-billed Duck populations should be monitored to determine if expanding feral Mallard populations in southern Africa are increasing introgression.","PeriodicalId":50624,"journal":{"name":"Condor","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2019-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duz042","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45756163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT We simulated bird surveys using recorded bird songs to assess factors affecting detection probability in grassland bird point counts. We used mixed effects logistic regression models to estimate effects of those factors and to estimate and visualize the variation in the area around the observer where birds can be perceived (the perception area). We simulated surveys with 8,926 binary opportunities for detection in Minnesota grasslands in 2011 and 2012. Species, distance to the observer, wind speed and direction, observer, and density of vegetation all affected detection of recorded bird songs. Species had a strong effect; the size of the predicted perception area around the observer differed by an order of magnitude among species. Wind also had a strong effect on detection. As wind speed increased, probability of detection downwind of the observer was reduced and the perception area around the observer became smaller and more asymmetrical. The effective distance at which an observer is more likely to detect a bird than not detect it may differ among species and angles to the wind, even within the same survey. Eight of 10 species had low probability of misidentification (≤0.03), but Grasshopper Sparrow (Ammodramus savannarum) and LeConte's Sparrow (Ammospiza leconteii) were frequently misidentified (probability = 0.09–0.24 among observers), contributing to a low rate of correct detection for those species. We recommend collecting point-count data within distance bands so that data can be analyzed based on the effective radius for each species and standardizing surveys across wind conditions to reduce variation in detection probability.
{"title":"Factors affecting detection probability, effective area surveyed, and species misidentification in grassland bird point counts","authors":"Elizabeth A. Rigby, Douglas H. Johnson","doi":"10.1093/condor/duz030","DOIUrl":"https://doi.org/10.1093/condor/duz030","url":null,"abstract":"ABSTRACT We simulated bird surveys using recorded bird songs to assess factors affecting detection probability in grassland bird point counts. We used mixed effects logistic regression models to estimate effects of those factors and to estimate and visualize the variation in the area around the observer where birds can be perceived (the perception area). We simulated surveys with 8,926 binary opportunities for detection in Minnesota grasslands in 2011 and 2012. Species, distance to the observer, wind speed and direction, observer, and density of vegetation all affected detection of recorded bird songs. Species had a strong effect; the size of the predicted perception area around the observer differed by an order of magnitude among species. Wind also had a strong effect on detection. As wind speed increased, probability of detection downwind of the observer was reduced and the perception area around the observer became smaller and more asymmetrical. The effective distance at which an observer is more likely to detect a bird than not detect it may differ among species and angles to the wind, even within the same survey. Eight of 10 species had low probability of misidentification (≤0.03), but Grasshopper Sparrow (Ammodramus savannarum) and LeConte's Sparrow (Ammospiza leconteii) were frequently misidentified (probability = 0.09–0.24 among observers), contributing to a low rate of correct detection for those species. We recommend collecting point-count data within distance bands so that data can be analyzed based on the effective radius for each species and standardizing surveys across wind conditions to reduce variation in detection probability.","PeriodicalId":50624,"journal":{"name":"Condor","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2019-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duz030","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49285082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Unconventional shale gas development is a rapidly expanding driver of forest loss and fragmentation in the central Appalachian region. We evaluated the relationship between breeding passerine abundances and distance from shale gas development at a long-term (2008–2017) study site in northern West Virginia, USA. We examined responses of 27 species within 3 habitat guilds: forest interior, early successional, and synanthropic. More than half of the species evaluated showed sensitivity to distance from unconventional shale gas infrastructure (e.g., well pads, access roads, pipelines). Five forest interior species occurred in greater abundances farther from shale gas development, whereas 3 forest interior gap specialists increased in abundance closer to shale gas. Early successional and synanthropic species, including the nest-parasitic Brown-headed Cowbird (Molothrus ater), generally occurred in greater abundances closer to shale gas infrastructure. We used interpolated distributions of 4 focal species to assess their spatial response to unconventional shale gas development over time. Our results indicate that breeding passerine distributions and community composition are changing with forest disturbance driven by unconventional shale gas energy development.
{"title":"Proximity to unconventional shale gas infrastructure alters breeding bird abundance and distribution","authors":"L. Farwell, P. Wood, Donald J. Brown, J. Sheehan","doi":"10.1093/condor/duz020","DOIUrl":"https://doi.org/10.1093/condor/duz020","url":null,"abstract":"ABSTRACT Unconventional shale gas development is a rapidly expanding driver of forest loss and fragmentation in the central Appalachian region. We evaluated the relationship between breeding passerine abundances and distance from shale gas development at a long-term (2008–2017) study site in northern West Virginia, USA. We examined responses of 27 species within 3 habitat guilds: forest interior, early successional, and synanthropic. More than half of the species evaluated showed sensitivity to distance from unconventional shale gas infrastructure (e.g., well pads, access roads, pipelines). Five forest interior species occurred in greater abundances farther from shale gas development, whereas 3 forest interior gap specialists increased in abundance closer to shale gas. Early successional and synanthropic species, including the nest-parasitic Brown-headed Cowbird (Molothrus ater), generally occurred in greater abundances closer to shale gas infrastructure. We used interpolated distributions of 4 focal species to assess their spatial response to unconventional shale gas development over time. Our results indicate that breeding passerine distributions and community composition are changing with forest disturbance driven by unconventional shale gas energy development.","PeriodicalId":50624,"journal":{"name":"Condor","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2019-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duz020","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46307676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Exotic grasses such as bermudagrass (Cynodon dactylon) and tall fescue (Schedonorus arundinaceus) are widely established across the southeastern United States as livestock forage, but their structure and management can limit avian reproductive success. Native warm-season grasses (NWSG) are promoted as sustainable forage alternatives. To examine nesting suitability for tall structure specialists such as Dickcissels (Spiza americana) we established an operational-scale study in northeastern Mississippi, USA, with 4 treatments along a gradient of beef production intensity. Treatments included grazed exotic forages, 2 grazed NWSG treatments including Indiangrass (Sorghastrum nutans) monoculture and NWSG polyculture of Indiangrass, little bluestem (Schizachyrium scoparium), and big bluestem (Andropogon gerardii), and an ungrazed NWSG polyculture treatment. We monitored 208 Dickcissel nests in 2011 and 2012 to evaluate effects of treatment, vegetation structure, fire ants (Solenopsis spp.), and arthropod prey biomass on nest-site selection and nest survival. Survival rates varied among treatments and increased with pasture-scale visual obstruction reading (VOR), being lowest among grazed exotic grass, intermediate in grazed NWSG, and highest in ungrazed NWSG. Although Dickcissels selected nest sites with greater VOR, we found little support for effects of nest-site vegetation on survival. However, nest survival was lower for nests in shrubs that also occurred in pastures with greater shrub cover, and selection for shrubs declined as pasture-scale VOR increased, suggesting a functional response in selection. We found little support for food availability influencing nest survival. These results suggest NWSG pastures increase Dickcissel nest success through greater pasture-scale VOR by reducing Dickcissel selection of shrubs for nest sites, and possibly by reducing predator efficiency. Incorporating NWSG into beef production systems while maintaining availability of tall vegetation could benefit Dickcissels and other tall structure specialists.
{"title":"Pasture-scale vegetation predicts Dickcissel nest-site selection and success in native and exotic grass pastures","authors":"A. Monroe, L. Burger, J. Martin","doi":"10.1093/condor/duz027","DOIUrl":"https://doi.org/10.1093/condor/duz027","url":null,"abstract":"ABSTRACT Exotic grasses such as bermudagrass (Cynodon dactylon) and tall fescue (Schedonorus arundinaceus) are widely established across the southeastern United States as livestock forage, but their structure and management can limit avian reproductive success. Native warm-season grasses (NWSG) are promoted as sustainable forage alternatives. To examine nesting suitability for tall structure specialists such as Dickcissels (Spiza americana) we established an operational-scale study in northeastern Mississippi, USA, with 4 treatments along a gradient of beef production intensity. Treatments included grazed exotic forages, 2 grazed NWSG treatments including Indiangrass (Sorghastrum nutans) monoculture and NWSG polyculture of Indiangrass, little bluestem (Schizachyrium scoparium), and big bluestem (Andropogon gerardii), and an ungrazed NWSG polyculture treatment. We monitored 208 Dickcissel nests in 2011 and 2012 to evaluate effects of treatment, vegetation structure, fire ants (Solenopsis spp.), and arthropod prey biomass on nest-site selection and nest survival. Survival rates varied among treatments and increased with pasture-scale visual obstruction reading (VOR), being lowest among grazed exotic grass, intermediate in grazed NWSG, and highest in ungrazed NWSG. Although Dickcissels selected nest sites with greater VOR, we found little support for effects of nest-site vegetation on survival. However, nest survival was lower for nests in shrubs that also occurred in pastures with greater shrub cover, and selection for shrubs declined as pasture-scale VOR increased, suggesting a functional response in selection. We found little support for food availability influencing nest survival. These results suggest NWSG pastures increase Dickcissel nest success through greater pasture-scale VOR by reducing Dickcissel selection of shrubs for nest sites, and possibly by reducing predator efficiency. Incorporating NWSG into beef production systems while maintaining availability of tall vegetation could benefit Dickcissels and other tall structure specialists.","PeriodicalId":50624,"journal":{"name":"Condor","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2019-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duz027","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45891114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Urban Ornithology: 150 years of Birds in New York City","authors":"R. Veit","doi":"10.1093/condor/duz041","DOIUrl":"https://doi.org/10.1093/condor/duz041","url":null,"abstract":"","PeriodicalId":50624,"journal":{"name":"Condor","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2019-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duz041","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47504471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nicolas J. Rawlence, M. Rayner, T. G. Lovegrove, D. Stoddart, M. Vermeulen, L. Easton, A. Tennyson, R. Scofield, M. Kennedy, H. Spencer, J. Waters
ABSTRACT Genetic data are increasingly being used to prioritize species conservation in a fiscally constrained age of seemingly boundless conservation crises. Such data can also reveal previously cryptic biodiversity requiring further revision of conservation management guidelines. Using a combination of mitochondrial (control region) and nuclear (beta fibrinogen intron 7) DNA, and morphology, we reveal that the endemic New Zealand Spotted Shag (Phalacrocorax punctatus) complex exhibits phylogenetic structure that is decoupled from previously recorded qualitative morphological variation. Crucially, the most genetically distinct populations within P. punctatus are from northern New Zealand; recent surveys show that these populations, which house important genetic diversity within Spotted Shags, are in danger of being extirpated. In contrast, we find the previously phenotypically differentiated nominate (P. punctatus punctatus) and Blue (P. punctatus oliveri) Shag subspecies show no genetic and morphological separation, and are of least conservation concern.
{"title":"Archival DNA reveals cryptic biodiversity within the Spotted Shag (Phalacrocorax punctatus) from New Zealand","authors":"Nicolas J. Rawlence, M. Rayner, T. G. Lovegrove, D. Stoddart, M. Vermeulen, L. Easton, A. Tennyson, R. Scofield, M. Kennedy, H. Spencer, J. Waters","doi":"10.1093/condor/duz029","DOIUrl":"https://doi.org/10.1093/condor/duz029","url":null,"abstract":"ABSTRACT Genetic data are increasingly being used to prioritize species conservation in a fiscally constrained age of seemingly boundless conservation crises. Such data can also reveal previously cryptic biodiversity requiring further revision of conservation management guidelines. Using a combination of mitochondrial (control region) and nuclear (beta fibrinogen intron 7) DNA, and morphology, we reveal that the endemic New Zealand Spotted Shag (Phalacrocorax punctatus) complex exhibits phylogenetic structure that is decoupled from previously recorded qualitative morphological variation. Crucially, the most genetically distinct populations within P. punctatus are from northern New Zealand; recent surveys show that these populations, which house important genetic diversity within Spotted Shags, are in danger of being extirpated. In contrast, we find the previously phenotypically differentiated nominate (P. punctatus punctatus) and Blue (P. punctatus oliveri) Shag subspecies show no genetic and morphological separation, and are of least conservation concern.","PeriodicalId":50624,"journal":{"name":"Condor","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2019-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duz029","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47053556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Birds of the Central Carolinas","authors":"Jeremy Hyman","doi":"10.1093/condor/duz022","DOIUrl":"https://doi.org/10.1093/condor/duz022","url":null,"abstract":"","PeriodicalId":50624,"journal":{"name":"Condor","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2019-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duz022","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45039653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Popović, D. P. Toews, Carson C. Keever, C. T. St. Clair, Blake A Barbaree, G. Fernández, James Rourke
ABSTRACT Information on how migratory populations are genetically structured during the overwintering season of the annual cycle can improve our understanding of the strength of migratory connectivity and help identify populations as units for management. Here, we use a genotype-by-sequencing approach to investigate whether population genetic structure exists among overwintering aggregations of the Pacific Dunlin subspecies (Calidris alpina pacifica) sampled at 2 spatial scales (within and among overwintering sites) in the eastern Pacific Flyway. Genome-wide analyses of 874 single nucleotide polymorphisms across 80 sampled individuals revealed no evidence for genetic differentiation among aggregations overwintering at 3 locations within the Fraser River Estuary (FRE) of British Columbia. Similarly, comparisons of aggregations in the FRE and those overwintering in southern sites in California and Mexico indicated no genetic segregation between northern and southern overwintering areas. These results suggest that Pacific Dunlin within the FRE, Sacramento Valley (California), and Guerrero Negro (Mexico) are genetically homogeneous, with no evident genetic structure between sampled sites or regions across the overwintering range. Despite no evidence for differentiation among aggregations, we identified a significant effect of geographical distance between sites on the distribution of individual genotypes in a redundancy analysis. A small proportion of the total genotypic variance (R2 = 0.036, P = 0.011) was explained by the combined effect of latitude and longitude, suggesting weak genomic patterns of isolation-by-distance that are consistent with chain-like migratory connectivity between breeding and overwintering areas. Our study represents the first genome-scale investigation of population structure for a Dunlin subspecies and provides essential baseline estimates of genomic diversity and differentiation within the Pacific Dunlin.
{"title":"Genotyping-by-sequencing reveals genomic homogeneity among overwintering Pacific Dunlin (Calidris alpina pacifica) aggregations along the Pacific coast of North America","authors":"I. Popović, D. P. Toews, Carson C. Keever, C. T. St. Clair, Blake A Barbaree, G. Fernández, James Rourke","doi":"10.1093/condor/duz036","DOIUrl":"https://doi.org/10.1093/condor/duz036","url":null,"abstract":"ABSTRACT Information on how migratory populations are genetically structured during the overwintering season of the annual cycle can improve our understanding of the strength of migratory connectivity and help identify populations as units for management. Here, we use a genotype-by-sequencing approach to investigate whether population genetic structure exists among overwintering aggregations of the Pacific Dunlin subspecies (Calidris alpina pacifica) sampled at 2 spatial scales (within and among overwintering sites) in the eastern Pacific Flyway. Genome-wide analyses of 874 single nucleotide polymorphisms across 80 sampled individuals revealed no evidence for genetic differentiation among aggregations overwintering at 3 locations within the Fraser River Estuary (FRE) of British Columbia. Similarly, comparisons of aggregations in the FRE and those overwintering in southern sites in California and Mexico indicated no genetic segregation between northern and southern overwintering areas. These results suggest that Pacific Dunlin within the FRE, Sacramento Valley (California), and Guerrero Negro (Mexico) are genetically homogeneous, with no evident genetic structure between sampled sites or regions across the overwintering range. Despite no evidence for differentiation among aggregations, we identified a significant effect of geographical distance between sites on the distribution of individual genotypes in a redundancy analysis. A small proportion of the total genotypic variance (R2 = 0.036, P = 0.011) was explained by the combined effect of latitude and longitude, suggesting weak genomic patterns of isolation-by-distance that are consistent with chain-like migratory connectivity between breeding and overwintering areas. Our study represents the first genome-scale investigation of population structure for a Dunlin subspecies and provides essential baseline estimates of genomic diversity and differentiation within the Pacific Dunlin.","PeriodicalId":50624,"journal":{"name":"Condor","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2019-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duz036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46421958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anna O. Mangan, Tara Chestnut, J. Vogeler, Ian K. Breckheimer, W. M. King, Keith E. Bagnall, Katie M. Dugger
ABSTRACT Protected lands like national parks are important refuges for threatened and endangered species as environmental pressures on wildlife and their habitats increase. The Northern Spotted Owl (Strix occidentalis caurina), a species designated as threatened under the Endangered Species Act, occurs on public lands throughout the western United States including Mount Rainier National Park (MRNP), Washington. With virtually no history of timber harvest or large forest disturbance within MRNP boundaries since the park's creation in 1899, MRNP provides an ideal place to evaluate potential impacts of climate change and invasive Barred Owls (Strix varia) on the Northern Spotted Owl. We used a multi-state, multi-season occupancy model to investigate how Northern Spotted Owl occupancy dynamics and breeding propensity are related to the presence of Barred Owls, local and regional weather, and habitat characteristics at MRNP from 1997 to 2016. Historical occupancy of Northern Spotted Owl breeding territories in MRNP has declined by 50% in the last 20 yr, and territory occupancy by breeding Northern Spotted Owls also decreased, reaching a low of 25% in 2016. Occupancy rates were higher on territories with steeper terrain and breeding rates were lower when Barred Owls were detected within historical territories. Our results also indicated that breeding propensity was higher when early nesting season temperatures during March and April were higher. In addition, the ability to detect breeding Northern Spotted Owls decreased when Barred Owls were present in the territory. Habitat variables from LiDAR were not correlated with Northern Spotted Owl occupancy dynamics, likely reflecting the dominance of old-growth forest in this protected park. This study illustrates the strong relationship between Barred Owls and Northern Spotted Owl demographics and breeding site selection in a landscape where habitat loss by timber harvest and fire has not occurred.
摘要随着野生动物及其栖息地面临的环境压力的增加，国家公园等保护区是受威胁和濒危物种的重要避难所。北方斑点猫头鹰（Strix occidentalis caurina）是《濒危物种法》规定的受威胁物种，分布在美国西部的公共土地上，包括华盛顿的雷尼尔山国家公园（MRNP）。自1899年公园创建以来，MRNP边界内几乎没有木材采伐或大规模森林干扰的历史，MRNP为评估气候变化和入侵的Barred Owls（Strix varia）对北方斑点猫头鹰的潜在影响提供了一个理想的场所。从1997年到2016年，我们使用了一个多州、多季节的入住模型来调查北方斑点猫头鹰的入住动态和繁殖倾向与Barred Owls的存在、当地和区域天气以及MRNP的栖息地特征之间的关系。在过去20年中，MRNP中北方斑点猫头鹰繁殖区的历史占有率下降了50%，北方斑点猫头鹰的繁殖区占有率也有所下降，2016年达到25%的低点。在地势较陡的地区，入住率较高，而在历史地区发现Barred Owls时，繁殖率较低。我们的研究结果还表明，当三月和四月的早期筑巢季节温度较高时，繁殖倾向更高。此外，当北斑猫头鹰出现在该地区时，发现繁殖中的北斑猫头鹰的能力下降。来自激光雷达的栖息地变量与北方斑点猫头鹰的占用动态无关，这可能反映了该保护公园中古老森林的主导地位。这项研究表明，在没有发生因木材采伐和火灾而导致栖息地丧失的景观中，Barred Owls和Northern Spotted Owl的人口统计和繁殖地点选择之间存在着密切的关系。
{"title":"Barred Owls reduce occupancy and breeding propensity of Northern Spotted Owl in a Washington old-growth forest","authors":"Anna O. Mangan, Tara Chestnut, J. Vogeler, Ian K. Breckheimer, W. M. King, Keith E. Bagnall, Katie M. Dugger","doi":"10.1093/condor/duz031","DOIUrl":"https://doi.org/10.1093/condor/duz031","url":null,"abstract":"ABSTRACT Protected lands like national parks are important refuges for threatened and endangered species as environmental pressures on wildlife and their habitats increase. The Northern Spotted Owl (Strix occidentalis caurina), a species designated as threatened under the Endangered Species Act, occurs on public lands throughout the western United States including Mount Rainier National Park (MRNP), Washington. With virtually no history of timber harvest or large forest disturbance within MRNP boundaries since the park's creation in 1899, MRNP provides an ideal place to evaluate potential impacts of climate change and invasive Barred Owls (Strix varia) on the Northern Spotted Owl. We used a multi-state, multi-season occupancy model to investigate how Northern Spotted Owl occupancy dynamics and breeding propensity are related to the presence of Barred Owls, local and regional weather, and habitat characteristics at MRNP from 1997 to 2016. Historical occupancy of Northern Spotted Owl breeding territories in MRNP has declined by 50% in the last 20 yr, and territory occupancy by breeding Northern Spotted Owls also decreased, reaching a low of 25% in 2016. Occupancy rates were higher on territories with steeper terrain and breeding rates were lower when Barred Owls were detected within historical territories. Our results also indicated that breeding propensity was higher when early nesting season temperatures during March and April were higher. In addition, the ability to detect breeding Northern Spotted Owls decreased when Barred Owls were present in the territory. Habitat variables from LiDAR were not correlated with Northern Spotted Owl occupancy dynamics, likely reflecting the dominance of old-growth forest in this protected park. This study illustrates the strong relationship between Barred Owls and Northern Spotted Owl demographics and breeding site selection in a landscape where habitat loss by timber harvest and fire has not occurred.","PeriodicalId":50624,"journal":{"name":"Condor","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2019-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duz031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44083268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chelsea E. Weithman, Samantha G. Robinson, K. Hunt, Jon Altman, Henrietta A. Bellman, Audrey Derose‐Wilson, Katie M. Walker, J. Fraser, S. Karpanty, D. Catlin
ABSTRACT Species listed under the U.S. Endangered Species Act are required to meet stated recovery goals for delisting. These goals often are developed early in the species' conservation history and may need to be updated or refined as new information becomes available. The Atlantic Coast Piping Plover (Charadrius melodus), which was listed more than 30 yr ago, has not met recovery goals through much of its range. Initial recovery goals included maintaining a reproductive output of 1.5 fledged chicks per pair for 5 yr. This goal was based on modelling that assumed equal survival rates for adults throughout the range, but recent studies suggest that demographic rates may vary with latitude. To investigate latitudinal variation, we developed demographic and population growth estimates for 2 breeding populations of Piping Plovers on the U.S. Atlantic Coast on Fire Island, New York (40.7°N), and on the Outer Banks of North Carolina (35.3°N) in 2013–2017. Breeding success (nest success and pre-fledge chick survival) varied annually but was lower in North Carolina than New York. Average adult true survival in New York ( = 0.73, SE = 0.04) was similar to average survival in North Carolina ( = 0.69, SE = 0.07). Annual post-fledging survival for both sites, however, was variable and often higher than had been previously reported for Atlantic Coast Piping Plovers (0.43–0.66 for New York; 0.31 and 1.0 for North Carolina). While the estimated reproductive output needed for a stationary population for both sites was similar (1.10 chicks per pair for New York, 95% CI: 0.83–1.41; 1.08 for North Carolina, 95% CI: 0.67–1.59), only the New York population achieved or exceeded these values during our study. Our findings suggest that understanding annual and latitudinal demographic variability would be helpful in refining recovery goals.
{"title":"Growth of two Atlantic Coast Piping Plover populations","authors":"Chelsea E. Weithman, Samantha G. Robinson, K. Hunt, Jon Altman, Henrietta A. Bellman, Audrey Derose‐Wilson, Katie M. Walker, J. Fraser, S. Karpanty, D. Catlin","doi":"10.1093/condor/duz037","DOIUrl":"https://doi.org/10.1093/condor/duz037","url":null,"abstract":"ABSTRACT Species listed under the U.S. Endangered Species Act are required to meet stated recovery goals for delisting. These goals often are developed early in the species' conservation history and may need to be updated or refined as new information becomes available. The Atlantic Coast Piping Plover (Charadrius melodus), which was listed more than 30 yr ago, has not met recovery goals through much of its range. Initial recovery goals included maintaining a reproductive output of 1.5 fledged chicks per pair for 5 yr. This goal was based on modelling that assumed equal survival rates for adults throughout the range, but recent studies suggest that demographic rates may vary with latitude. To investigate latitudinal variation, we developed demographic and population growth estimates for 2 breeding populations of Piping Plovers on the U.S. Atlantic Coast on Fire Island, New York (40.7°N), and on the Outer Banks of North Carolina (35.3°N) in 2013–2017. Breeding success (nest success and pre-fledge chick survival) varied annually but was lower in North Carolina than New York. Average adult true survival in New York ( = 0.73, SE = 0.04) was similar to average survival in North Carolina ( = 0.69, SE = 0.07). Annual post-fledging survival for both sites, however, was variable and often higher than had been previously reported for Atlantic Coast Piping Plovers (0.43–0.66 for New York; 0.31 and 1.0 for North Carolina). While the estimated reproductive output needed for a stationary population for both sites was similar (1.10 chicks per pair for New York, 95% CI: 0.83–1.41; 1.08 for North Carolina, 95% CI: 0.67–1.59), only the New York population achieved or exceeded these values during our study. Our findings suggest that understanding annual and latitudinal demographic variability would be helpful in refining recovery goals.","PeriodicalId":50624,"journal":{"name":"Condor","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2019-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duz037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47035841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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