scholarly journals A wood-warbler produced through both interspecific and intergeneric hybridization

2018 ◽  
Vol 14 (11) ◽  
pp. 20180557 ◽  
Author(s):  
David P. L. Toews ◽  
Henry M. Streby ◽  
Lowell Burket ◽  
Scott A. Taylor
Keyword(s):  
Intergeneric Hybridization ◽  
Population Declines ◽  
Morphometric Traits ◽  
Early Generation ◽  
Phenotypic Differences ◽  
Vermivora Chrysoptera ◽  
Hybridization Event ◽  
Wood Warblers ◽  
Declining Populations ◽  
Female Hybrid

Hybridization between divergent taxa can provide insight into the breakdown of characters used in mate choice, as well as reproductive compatibility across deep evolutionary timescales. Hybridization can also occur more frequently in declining populations, as there is a smaller pool of conspecific mates from which to choose. Here, we report an unusual combination of factors that has resulted in a rare, three-species hybridization event among two genera of warblers, one of which is experiencing significant population declines. We use bioacoustic, morphometric and genetic data, to demonstrate that an early generation female hybrid between a golden-winged warbler ( Vermivora chrysoptera ) and a blue-winged warbler ( V. cyanoptera ) went on to mate and successfully reproduce with a chestnut-sided warbler ( Setophaga pensylvanica ) . We studied the product of this event—a putative chrysoptera × cyanoptera × pensylvanica hybrid—and show that this male offspring sang songs like S. pensylvanica , but had morphometric traits similar to Vermivora warblers. The hybrid's maternal parent had V. chrysoptera mitochondrial DNA and , with six plumage-associated loci, we predicted the maternal parent's phenotype to show that it was likely an early generation Vermivora hybrid . That this hybridization event occurred within a population of Vermivora warblers in significant decline suggests that females may be making the best of a bad situation, and that wood-warblers in general have remained genetically compatible long after they evolved major phenotypic differences.

scholarly journals Theoretical justification of the possibility of selection perspective individuals in variety populations of self-pollinators on the example of soybean

2021 ◽  
Vol 186 (2) ◽  
pp. 31-40
Author(s):  
V.M. Lukomets ◽  
◽  
S.V. Zelentsov ◽  
E.V. Moshnenko ◽  
◽  
...  
Keyword(s):  
F1 Hybrids ◽  
Individual Selection ◽  
Breeding Methods ◽  
Morphometric Traits ◽  
Phenotypic Differences ◽  
Soybean Cultivars ◽  
Oil Crops ◽  
Experimental Base ◽  
Modified Formula ◽  
Selection Of

Breeding practice shows that soybean cultivars developed by synthetic breeding methods are submitted for the state variety testing in the F10–F11 generation. But the newly bred cultivars are not completely homozygous. The studies were related to the determination of the frequencies of formation of atypical and suitable for selection promising individuals in soybean cultivars developed by synthetic breeding methods. The studies were carried out in 2019–2020 at the central experimental base of V.S. Pustovoit All-Russian Research Institute of Oil Crops, Krasnodar. In the experiments, we used cultivars of our own breeding: Selena, Puma, Vita, Irbis, Bars, Barguzin and Sayana with a total age of 11–15 years from the year F1 hybrids were obtained. To confirm the practical possibility of isolating individuals differing from the phenotypic varietal norm in varietal populations, a complete examination of the crops of all studied soybean cultivars was carried out. In the fields of all cultivars, individuals were identified that differed from the varietal norm phenotypically. Mostly, the isolated individuals were distinguished by an increased plant height, a more powerful habit, an increased number of beans per plant, and resistance to lodging. The facts of the detection of atypical individuals with improved morphological traits in soybean cultivars of different ages confirm the possibility of individual selection of plants in varietal populations based on morphometric traits. The statistical dynamics of a decrease in heterozygous individuals in increasing generations in a hybrid self-pollinating population in terms of the number of paired genes, by which the parental forms can hypothetically differ, were calculated using the modified formula of S. Borojević (1984). It was found that the frequency of formation of phenotypically different individuals in varietal populations of soybeans depends on the total age of the cultivar. The frequency of the formation of morphologically different individuals decreases with an increase in the number of generations of the cultivar. Individual selection of individuals with positive phenotypic differences from the varietal norm can be recommended as an additional source of promising and practically homozygous starting material for accelerated analytical breeding of soybean.

Survival and cause-specific mortality of translocated female mule deer in southern New Mexico, USA

2018 ◽  
Vol 45 (4) ◽  
pp. 325 ◽  
Author(s):  
James W. Cain III ◽  
Jana B. Ashling ◽  
Stewart G. Liley
Keyword(s):  
New Mexico ◽  
San Francisco ◽  
Urban Areas ◽  
Mule Deer ◽  
Survival Rates ◽  
Management Tool ◽  
Population Declines ◽  
Short Period ◽  
Specific Mortality ◽  
Declining Populations

Context Many mule deer (Odocoileus hemionus) populations in New Mexico have failed to recover from previous population declines, while some populations near urban areas have increased, resulting in more frequent human–wildlife conflicts. Translocations were used in an effort to simultaneously reduce an urban mule deer population and augment two low-density populations in south-western New Mexico, USA. Aims Because of insufficient monitoring, the efficacy of many ungulate translocations is unknown. Our goal was to monitor cause-specific mortality and 1 year post-release survival of mule deer translocated during 2013 and 2014. We compared survival rates of mule deer released with a hard- versus soft-release during the 2014 translocation. Methods . We translocated 218 mule deer in 2013 and 2014 into the Peloncillo Mountains (PM) and San Francisco River Valley (SFRV); 106 adult female mule deer were fitted with telemetry collars to determine cause-specific mortality and estimate survival 1 year post-release. All deer were hard-released in 2013. In 2014, translocated mule deer were either held in a soft-release pen (0.81 ha) for approximately 3 weeks or hard-released into their new environment. We used a Kaplan–Meier approach to estimate survival of translocated mule deer at each release area and to compare survival of mule deer translocated using each release method (i.e. hard- versus soft-release). Key results In 2013–14, survival of hard-released deer in the PM was 0.627 (s.e. = 0.09), compared with 0.327 (s.e. = 0.10) in the SFRV. In 2014–15, survival of hard–released deer in the PM was 0.727 (s.e. = 0.13) and survival of soft-released deer was 0.786 (s.e. = 0.11). In the SFRV, survival of hard- and soft-released deer was 0.656 (s.e. = 0.14) and 0.50 (s.e. = 0.16), respectively. Causes of mortality were predation (51%), potential disease (9%; blue tongue or epizootic haemorrhagic disease), accident (5%), poaching (5%) and unknown (20%). Conclusions Translocations can be an effective management tool to augment populations of mule deer while reducing overabundant urban populations. Soft-released mule deer did not have higher survival than hard-released mule deer, although the length and conditions of the acclimation period were limited in our study. Implications Overabundant mule deer populations in urban areas may serve as sources of animals to bolster declining populations. Soft-release pens of smaller size and short period of acclimation did not influence survival.

An experimental study of declining populations

2005 ◽  
Vol 32 (6) ◽  
pp. 481 ◽  
Author(s):  
Jim Hone ◽  
the late Graeme Caughley ◽  
David Grice
Keyword(s):  
Experimental Study ◽  
Population Decline ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Second Phase ◽  
Population Declines ◽  
Negative Effects ◽  
Instantaneous Rate ◽  
Rate Of Increase ◽  
Declining Populations

Wildlife population declines have been attributed to predation, habitat change, and other agents of decline. An experimental study applied predation (at three levels) and habitat (at two levels) treatments over two years and measured the patterns of decline of populations of a medium-sized mammal (European rabbits). A model of population dynamics and effects of the treatments predicted negative effects of both treatments and an interaction of the treatments. All populations declined during the study including the experimental controls. During the first seven months (first phase of the study) the rate of decline, as estimated by the observed monthly instantaneous rate of increase (r), was more negative (P < 0.05) with increasing predation levels but there was no effect (P > 0.05) of habitat manipulation on r. There were no significant effects of treatments on rabbit abundance, or density, during the first phase of the study. During the second phase of the study, of 12 months’ duration, there were no significant (P > 0.05) effects of treatments on rabbit abundance, density, or r. There were no significant (P > 0.05) interactions of treatments on any response variable during either phase of the study. The interaction predicted by the theoretical model was not supported. Estimated abundance at the end of the study was not related (P > 0.05) to initial abundance (correlation = 0.023). The implications of the results are that such experimental studies can be used to evaluate theoretical models, though such studies may require a larger number of treatment replicates, and treatments at more extreme levels, to more clearly detect the effects of agents of population decline and their interactions.

scholarly journals Ultrasonic Acoustic Surveys of State Endangered Northern Flying Squirrels in the Pocono Mountains, Pennsylvania

2020 ◽  
Vol 11 (2) ◽  
pp. 644-653
Author(s):  
Corinne A. Diggins ◽  
L. Michelle Gilley ◽  
Gregory G. Turner ◽  
W. Mark Ford
Keyword(s):  
New York ◽  
Probability Of Detection ◽  
Population Declines ◽  
Glaucomys Volans ◽  
Detection Rates ◽  
Flying Squirrel ◽  
Flying Squirrels ◽  
Declining Populations ◽  
Acoustic Surveys ◽  
Study Sites

Abstract Surveying for flying squirrels by using traditional techniques produces extremely low detection rates compared with ultrasonic acoustics. Within Pennsylvania, the northern flying squirrel subspecies Glaucomys sabrinus macrotis is state listed as endangered due to habitat loss and parasite-mediated competition by and hybridization with the southern flying squirrel Glaucomys volans. This subspecies is isolated from adjacent populations in West Virginia and New York and has experienced drastic population declines. The discovery and characterization of ultrasonic vocalizations of G. s. macrotis and G. volans, as well as successful field surveys with ultrasonic acoustic detectors in the southern Appalachian Mountains, highlight the potential use of this technique for determining the presence of G. s. macrotis. To confirm the feasibility of using this technique on declining populations of G. s. macrotis sympatric with G. volans, we conducted 108 nights of passive ultrasonic acoustic surveys for G. s. macrotis at six survey sites by using two detectors per survey site (N = 12 detectors) in June 2017. We considered sites high quality (“high”) or low quality (“low”) based on the number of physical capture records during the past 2 decades and the dominance of boreo-montane conifer tree species in the overstory. We detected G. s. macrotis at four study sites and G. volans at all six study sites. We found higher average probability of detection for G. s. macrotis in high vs. low sites (0.28 ± 0.06 [mean ± SE] and 0.09 ± 0.07, respectively), whereas probability of detection was similar for G. volans between high and low sites (0.13 ± 0.05 and 0.17 ± 0.05, respectively). We also found G. s. macrotis had lower latency of detection at high vs. low sites (2.7 ± 0.8 and 7.83 ± 1.5 nights, respectively) but G. volans did not vary in latency of detection between sites (5 ± 1.6 and 3.8 ± 1.5 nights, respectively). Our study shows acoustics can be successfully used to efficiently survey G. s. macrotis in Pennsylvania, where populations are small and monitoring these populations more effectively is critical to determining changes in persistence due to climate- and disease-induced factors.

scholarly journals Reciprocal Introgression Between Golden-Winged Warblers (Vermivora Chrysoptera) and Blue-Winged Warblers (V. Pinus) in Eastern North America

The Auk ◽  
2004 ◽  
Vol 121 (4) ◽  
pp. 1019-1030
Author(s):  
Leo H. Shapiro ◽  
Ronald A. Canterbury ◽  
Dollie M. Stover ◽  
Robert C. Fleischer
Keyword(s):  
North America ◽  
West Virginia ◽  
Molecular Genetic ◽  
Molecular Genetic Analysis ◽  
Small Samples ◽  
Eastern North America ◽  
Population Declines ◽  
Neotropical Migrant ◽  
Vermivora Chrysoptera ◽  
The Many

Abstract Golden-winged Warblers (Vermivora chrysoptera) and Blue-winged Warblers (V. pinus) are small, brightly colored Neotropical migrant birds that breed in eastern North America. Wherever the two species occur together, they hybridize to a limited degree, producing distinctive hybrid phenotypes. In recent decades, chrysoptera has experienced dramatic population declines across much of its range. Those declines have often been correlated with establishment and increase of pinus in the same areas, but it remains uncertain what, if any, role pinus has played in driving the decline of chrysoptera. In a first attempt at molecular genetic analysis of chrysoptera-pinus population dynamics, Gill (1997) reported cryptic, completely asymmetric, and possibly very rapid introgression of pinus mitochondrial DNA (mtDNA) into chrysoptera, causing what he termed “local cytonuclear extinction” of chrysoptera. As Gill (1997) noted, however, those results were based on relatively small samples from a single area in Pennsylvania. To begin to investigate the generality of Gill’s findings and to establish a baseline for long-term genetic and ecological studies, we intensively sampled one new study area (in southern West Virginia) and also sampled more broadly across two other areas (in Michigan and Ohio) that have experienced pinus invasions and chrysoptera declines. In southern West Virginia, introgression of mtDNA appeared to be roughly symmetrical: 15% (11 of 72) of pinus phenotypes possessed chrysoptera mtDNA, and 12% (17 of 137) of chrysoptera phenotypes possessed pinus mtDNA. Results from much smaller samples from Michigan and Ohio also failed to show any evidence of asymmetric mitochondrial introgression. The results we report here, based on mtDNA and plumage phenotype information for 337 birds representing much of the range of the two species, indicate that previous genetic results and inferences from Pennsylvania may not be broadly applicable to the many areas of contact between chrysoptera and pinus in eastern North America.

scholarly journals Comparison of Patterns of Genetic Variation and Demographic History in the Greater Sage-Grouse (Centrocercus urophasianus): Relevance for Conservation

2014 ◽  
Vol 7 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Robert M. Zink
Keyword(s):  
Genetic Variation ◽  
Spatial Scales ◽  
Demographic History ◽  
Local Population ◽  
Centrocercus Urophasianus ◽  
Columbia Basin ◽  
Population Declines ◽  
Microsatellite Data ◽  
Sage Grouse ◽  
Declining Populations

The greater sage-grouse (Centrocercus urophasianus) was once widespread in western North America but its range has contracted by an uncertain degree owing to anthropogenic and natural causes. Concern over population declines has led to its proposed listing as threatened under the U.S. Endangered Species Act. Detailed genetic and demographic analyses of this species throughout its range are available but heretofore have not been compared. Reduced genetic variability is often taken as a proxy for declining populations, but rarely are there quantitative population estimates with which to compare. I compared published mitochondrial DNA (mtDNA) control region sequences, microsatellite allele frequencies at seven loci, and estimates of numbers of males per lek, number of active leks, percent decline in the best population models, and the probability (P) of Ne < 50 in 30 years and P(Ne < 500) in 100 years, at two spatial scales, 45 local population samples and 16 larger aggregates of samples. When excluding the populations from the Columbia Basin, which show little genetic diversity and are statistical outliers, there were no consistent relationships between estimates of genetic variation and demographic trends across the remainder of the range at either spatial scale. A measure of inbreeding derived from microsatellite data was also not related to population trends. Thus, despite habitat reduction and range fragmentation, the greater sage-grouse does not exhibit expected genetic signatures of declining populations. Possibly, the mtDNA and microsatellite data are insufficiently sensitive to detect population declines that have occurred over the span of a half century. Alternatively, only when populations are reduced to the levels seen in the Columbia Basin will genetic effects be seen, suggesting that the bulk of the range of the greater sage-grouse is not currently in genetic peril.

scholarly journals What threatens Brazilian endangered species and how they are Red-Listed

2019 ◽  
Author(s):  
Enrico Bernard ◽  
Fernanda Silva de Barros ◽  
Vitória Edna Fernandes Felix ◽  
Thomas E. Lacher
Keyword(s):  
Endangered Species ◽  
Population Declines ◽  
Rural Settlements ◽  
Terrestrial Vertebrates ◽  
Declining Populations ◽  
In The Wild ◽  
Population Sizes ◽  
Near Future ◽  
Brazilian Biodiversity

AbstractBrazil is a continental-sized megadiverse country with high rates of habitat loss and degradation. Part of the Brazilian biodiversity – including endemic species – is recognized as threatened. By following the IUCN standards, we review the classification of all the 1172 endangered species in Brazil, analyzing differences among categories and groups. Based on a subsample of all 464 terrestrial vertebrates we identified 1036 records of threats affecting them. Criterion B was the most used (56% overall; 70% for CR species; 75% for EN), mainly related to reductions in their habitat area, extent and/or quality due to deforestation. Data on population declines (criterion A), number of reproductive individuals (criterion C), and population sizes (criterion D) are available for only a small fraction of the Brazilian fauna. Criterion E (probability of extinction in the wild) was used for only one species. Birds and mammals had the highest diversity of used criteria, while marine fish the lowest (90% related to declining populations). Two out of three of the 464 vertebrate species analyzed were negatively impacted by agribusiness. Other major threats are hunting, urban sprawl, rural settlements, and the construction of hydroelectric dams. Birds and mammals experience more co-occurrence of threats. Some threats are clearly underestimated in Brazil: climate change was indicated for only 2% species analyzed, but included no birds or amphibians. The main threats identified are linked to the patterns of economic development in Brazil and the current political and economic context points to a worrisome conservation scenario in the near future.

scholarly journals Influence of Season and Frequency of Fire on Henslow's Sparrows (Ammodramus Henslowii) Wintering on Gulf Coast Pitcher Plant Bogs

The Auk ◽  
2003 ◽  
Vol 120 (1) ◽  
pp. 96-106 ◽  
Author(s):  
James W. Tucker ◽  
W. Douglas Robinson
Keyword(s):  
Gulf Coast ◽  
Longleaf Pine ◽  
Pinus Palustris ◽  
Growing Season ◽  
Breeding Habitat ◽  
Population Declines ◽  
Pitcher Plant ◽  
Blackwater River ◽  
Ammodramus Henslowii ◽  
Declining Populations

Abstract Henslow's Sparrow (Ammodramus henslowii) is a grassland bird that has suffered drastic population declines for over 30 years. Declining populations can be largely attributed to loss of breeding habitat, but loss of wintering habitat associated with longleaf pine (Pinus palustris) communities, especially pitcher plant (Sarracenia spp.) bogs, along the Gulf Coast also may be a contributing factor. Fire is critical for restoration and conservation of remaining longleaf pine communities, but the influence of fire on wintering Henslow's Sparrows has not been evaluated. We examined the influence of season and frequency (time since burning) of fire on use of pitcher plant bogs by Henslow's Sparrows wintering in the Conecuh National Forest, Alabama, and Blackwater River State Forest, Florida, during winters of 1999–2000 and 2000–2001. Density of Henslow's Sparrows was greatest on bogs the first winter after burning. Although significant effects for season of burning were not found, bogs burned during winter typically hosted Henslow's Sparrows for only one winter, whereas bogs burned during the growing season hosted sparrows for at least three winters. Growing-season fires may be more beneficial than dormant-season fires and will prevent forced abandonment of bogs burned during winter. Frequency of seed stalks of grasses and density of forbs were the most influential vegetation parameters affecting occurrence of Henslow's Sparrows at pitcher plant bogs. Henslow's Sparrows were found on bogs as small as 0.06 ha, but were found on bogs >0.25 ha more frequently than on smaller bogs. We conclude that burning pitcher plant bogs on an annual or biennial basis during the growing season will maximize the benefits to both wintering Henslow's Sparrows and the host of other organisms associated with those unique communities.

scholarly journals The state of breeding birds in Greece: trends, threats, and implications for conservation

2020 ◽  
pp. 1-15
Author(s):  
DIMITRIOS VAVYLIS ◽  
ANASTASIOS BOUNAS ◽  
GEORGIOS KARRIS ◽  
KOSTAS A. TRIANTIS
Keyword(s):  
Population Change ◽  
Conservation Status ◽  
Global Scale ◽  
Iucn Red List ◽  
Red List ◽  
Breeding Birds ◽  
Ecosystem Functions ◽  
Population Declines ◽  
Population Size Estimates ◽  
Declining Populations

Summary Birds are suffering from steep population declines on a global scale and they are one of the few taxonomic groups for which these declines are well documented by long-term monitoring data. This study provides a synthesis of the status of the breeding birds of Greece. To this aim, we retrieved population size estimates from six sources spanning 22 years (1992–2014) and calculated species’ trends in Greece. Using the IUCN Red List assessments for each species we assessed whether ecological traits including habitat and diet preferences were associated with species’ trends and conservation status in Europe and determined major threats affecting birds in Greece. Moreover, we assessed the importance of Important Bird & Biodiversity Areas (IBAs) in terms of declining trigger species. Results showed that almost one fifth of the breeding birds in Greece have declining populations. Raptors were found to be the most threatened group of birds whereas the highest declines by dietary group were observed in scavengers, with 60% of species showing a decreasing trend. The most common threats were those that cause habitat alteration and degradation as well as more direct effects such as poisoning. Our results suggest that restoration of habitat and ecosystem functions along with the management of protected areas and improvement of legislation should be the main conservation actions undertaken and pinpointed the IBAs where they should be prioritized for implementation. Finally, further research, especially on specific drivers of population change, along with further examination of current and past population trends, will increase the power and accuracy of future regional Red List assessments especially concerning the breeding species for which the country bears the greatest responsibility.

A potential model system for studying the genetics of domestication: behavioral variation among wild and domesticated strains of zebra danio (Danio rerio)

2005 ◽  
Vol 62 (9) ◽  
pp. 2046-2054 ◽  
Author(s):  
Barrie D Robison ◽  
William Rowland
Keyword(s):  
Growth Rate ◽  
Danio Rerio ◽  
Laboratory Strain ◽  
Model System ◽  
Population Declines ◽  
Behavioral Differences ◽  
Large Space ◽  
Genetic Changes ◽  
Phenotypic Differences ◽  
Domestication Process

The process of domestication in fish is fundamentally important to conservation efforts because of the extensive use of hatcheries to mitigate population declines. Research into the genetic changes associated with the domestication process in many endangered species is impeded by a lack of genomic tools, long generation times, and large space requirements. The study of the genetics of fish domestication could therefore benefit from the introduction of a model system. In this paper, we document behavioral and growth rate differences observed between a domesticated laboratory strain of zebra danio (Danio rerio) and a strain newly introduced into the laboratory from its native habitat in India. Domesticated zebra danio showed a higher degree of surface orientation, a reduced startle response, and higher growth rate compared with wild zebra danio. Wild–domesticated interstrain hybrids were intermediate in phenotype for all traits. When strains were reared together, most interstrain behavioral differences were maintained, indicating a genetic basis underlying the interstrain phenotypic variation. Phenotypic differences observed in this study are consistent with the effects of domestication in other fish species, indicating that the zebra danio can be used as a model system for studying the genetics of the domestication process in fish.

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