Pub Date : 2023-01-17DOI: 10.2179/0008-7475.87.2.211
A. Krings, H. Cabell
ABSTRACT The development and assessment of Piedmont upland grassland restoration efforts is hampered in part by continued challenges in identifying immature individuals of three associated pines, Pinus echinata, P. taeda, and P. virginiana, the penultimate of which is thought alien to the system. To help fill this gap, we studied three quantitative and 25 qualitative characters in 174, 2- to 5-year-old saplings in managed stands in Durham County (North Carolina) and 169 herbarium specimens of mature individuals from 94 Piedmont counties from Georgia to Virginia. Although mean short-shoot needle and fascicle sheath lengths differed significantly between lifestage classes of the three species (F8,335=185, p<0.0001 and F8,335=173.5, p<0.0001, respectively), there was substantial range overlap, likely contributing to diagnostic confusion in the field when existing keys are applied. For example, needle length ranges of all lifestage classes of all species overlapped with those of mature P. echinata and 2-year-old P. virginiana. In addition, at the apex of the previous season's growth, 2-year-old saplings of P. echinata and P. virginiana exhibited needles either predominantly or in higher percentages of threes, than the contrasting described preponderance of pairs for mature individuals. Of the 25 qualitative characters evaluated, we found (1) absence of decurrency glaucescence distinguishes 2- to 5-year-old saplings of P. taeda from P. echinata and P. virginiana, and (2) absence of stomatal plugs distinguishes P. virginiana from the others. A diagnostic key to saplings is provided.
{"title":"Distinguishing Saplings of Pines of Piedmont Upland Grassland Systems","authors":"A. Krings, H. Cabell","doi":"10.2179/0008-7475.87.2.211","DOIUrl":"https://doi.org/10.2179/0008-7475.87.2.211","url":null,"abstract":"ABSTRACT The development and assessment of Piedmont upland grassland restoration efforts is hampered in part by continued challenges in identifying immature individuals of three associated pines, Pinus echinata, P. taeda, and P. virginiana, the penultimate of which is thought alien to the system. To help fill this gap, we studied three quantitative and 25 qualitative characters in 174, 2- to 5-year-old saplings in managed stands in Durham County (North Carolina) and 169 herbarium specimens of mature individuals from 94 Piedmont counties from Georgia to Virginia. Although mean short-shoot needle and fascicle sheath lengths differed significantly between lifestage classes of the three species (F8,335=185, p<0.0001 and F8,335=173.5, p<0.0001, respectively), there was substantial range overlap, likely contributing to diagnostic confusion in the field when existing keys are applied. For example, needle length ranges of all lifestage classes of all species overlapped with those of mature P. echinata and 2-year-old P. virginiana. In addition, at the apex of the previous season's growth, 2-year-old saplings of P. echinata and P. virginiana exhibited needles either predominantly or in higher percentages of threes, than the contrasting described preponderance of pairs for mature individuals. Of the 25 qualitative characters evaluated, we found (1) absence of decurrency glaucescence distinguishes 2- to 5-year-old saplings of P. taeda from P. echinata and P. virginiana, and (2) absence of stomatal plugs distinguishes P. virginiana from the others. A diagnostic key to saplings is provided.","PeriodicalId":50984,"journal":{"name":"Castanea","volume":"87 1","pages":"211 - 223"},"PeriodicalIF":0.4,"publicationDate":"2023-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45193121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-17DOI: 10.2179/0008-7475.87.2.224
Phillip D. Lowe, J. R. Carter
ABSTRACT A novel flatsedge from karst ponds in southwestern Georgia, Cyperus excurrens, is described, and the results of principal component analysis are presented in support of the recognition of this new species. A technical description, dichotomous key, comparative photographs of spikelets and achenes, distribution maps, habitat data, and specimen citations are included. The status of the related taxon, Cyperus strigosus var. stenolepis, is also evaluated.
{"title":"Cyperus excurrens (Cyperaceae), a New Species from Karst Ponds in Southern Georgia, U.S.A.","authors":"Phillip D. Lowe, J. R. Carter","doi":"10.2179/0008-7475.87.2.224","DOIUrl":"https://doi.org/10.2179/0008-7475.87.2.224","url":null,"abstract":"ABSTRACT A novel flatsedge from karst ponds in southwestern Georgia, Cyperus excurrens, is described, and the results of principal component analysis are presented in support of the recognition of this new species. A technical description, dichotomous key, comparative photographs of spikelets and achenes, distribution maps, habitat data, and specimen citations are included. The status of the related taxon, Cyperus strigosus var. stenolepis, is also evaluated.","PeriodicalId":50984,"journal":{"name":"Castanea","volume":"87 1","pages":"224 - 243"},"PeriodicalIF":0.4,"publicationDate":"2023-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47423242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-15DOI: 10.2179/0008-7475.87.1.147
E. Moore, C. Siniscalchi, J. Mandel, Nicole M. Fama, Brandon T. Sinn, Craig F. Barrett
The Richard and Minnie Windler Award recognizes the authors of the best systematics and ecology papers published in Castanea during the previous year. For 2020, authors of two articles were selected as winners: Erika R. Moore, Carolina M. Siniscalchi, and Jennifer R. Mandel for their article, “Reevaluating genetic diversity and structure of Helianthus verticillatus (Asteraceae) after the discovery of new populations” (Castanea 86[2]:196–213), and Nicole M. Fama, Brandon T. Sinn, and Craig F. Barrett for their article, “Integrating genetics, morphology, and host specificity in conservation studies of a vulnerable, selfing, mycoheterotrophic orchid.” (Castanea 86[1]:1–21). The whorled sunflower (Helianthus verticillatus Small) is a federally listed endangered plant known from six disjunct populations occurring in Alabama, Georgia, Mississippi, Tennessee, and Virginia. Employing microsatellite data to explore genetic structuring and diversity of these populations, Moore and her colleagues discovered that though differentiated, these populations had high allelic diversity. The most recently discovered populations in Mississippi and Virginia had experienced genetic bottlenecks. Because the whorled sunflower is self-incompatible, such bottlenecks may have led to increased reliance on asexual reproduction in these populations. Nevertheless, these populations are genetically distinct, and harbor alleles important to the diversity of the species as a whole. Given the small size and unique genetic constitution of each population, species conservation necessitates protecting as many of these populations as possible.
{"title":"2022 Richard and Minnie Windler Award Recipients","authors":"E. Moore, C. Siniscalchi, J. Mandel, Nicole M. Fama, Brandon T. Sinn, Craig F. Barrett","doi":"10.2179/0008-7475.87.1.147","DOIUrl":"https://doi.org/10.2179/0008-7475.87.1.147","url":null,"abstract":"The Richard and Minnie Windler Award recognizes the authors of the best systematics and ecology papers published in Castanea during the previous year. For 2020, authors of two articles were selected as winners: Erika R. Moore, Carolina M. Siniscalchi, and Jennifer R. Mandel for their article, “Reevaluating genetic diversity and structure of Helianthus verticillatus (Asteraceae) after the discovery of new populations” (Castanea 86[2]:196–213), and Nicole M. Fama, Brandon T. Sinn, and Craig F. Barrett for their article, “Integrating genetics, morphology, and host specificity in conservation studies of a vulnerable, selfing, mycoheterotrophic orchid.” (Castanea 86[1]:1–21). The whorled sunflower (Helianthus verticillatus Small) is a federally listed endangered plant known from six disjunct populations occurring in Alabama, Georgia, Mississippi, Tennessee, and Virginia. Employing microsatellite data to explore genetic structuring and diversity of these populations, Moore and her colleagues discovered that though differentiated, these populations had high allelic diversity. The most recently discovered populations in Mississippi and Virginia had experienced genetic bottlenecks. Because the whorled sunflower is self-incompatible, such bottlenecks may have led to increased reliance on asexual reproduction in these populations. Nevertheless, these populations are genetically distinct, and harbor alleles important to the diversity of the species as a whole. Given the small size and unique genetic constitution of each population, species conservation necessitates protecting as many of these populations as possible.","PeriodicalId":50984,"journal":{"name":"Castanea","volume":"87 1","pages":"147 - 148"},"PeriodicalIF":0.4,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49313617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-15DOI: 10.2179/0008-7475.87.1.121
Claire M. Ciafré, L. Estes
ABSTRACT Dichanthelium wrightianum, a species of panic grass whose North American range is exclusive to the Coastal Plain, is reported from Tennessee for the first time. A single population of this species was discovered in a wet grassland remnant in the Eastern Highland Rim physiographic region alongside many other species disjunct from the Coastal Plain. Another Coastal Plain Dichanthelium, D. roanokense, was found at a second wet grassland nearby. While D. roanokense was previously reported for Tennessee, it has not been recently documented or confirmed to be extant within the state and its current status should be reviewed. The ecology and conservation of Tennessee populations of both species are discussed.
{"title":"Two Coastal Plain Dichanthelium (Poaceae: Paniceae) Disjunct in Tennessee Grasslands and Their Conservation","authors":"Claire M. Ciafré, L. Estes","doi":"10.2179/0008-7475.87.1.121","DOIUrl":"https://doi.org/10.2179/0008-7475.87.1.121","url":null,"abstract":"ABSTRACT Dichanthelium wrightianum, a species of panic grass whose North American range is exclusive to the Coastal Plain, is reported from Tennessee for the first time. A single population of this species was discovered in a wet grassland remnant in the Eastern Highland Rim physiographic region alongside many other species disjunct from the Coastal Plain. Another Coastal Plain Dichanthelium, D. roanokense, was found at a second wet grassland nearby. While D. roanokense was previously reported for Tennessee, it has not been recently documented or confirmed to be extant within the state and its current status should be reviewed. The ecology and conservation of Tennessee populations of both species are discussed.","PeriodicalId":50984,"journal":{"name":"Castanea","volume":"87 1","pages":"121 - 128"},"PeriodicalIF":0.4,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42764680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-15DOI: 10.2179/0008-7475.87.1.81
Katherine E. Culatta, A. Krings, Lilian P. Matallana-Ramirez, R. Whetten
ABSTRACT Nuphar sagittifolia (Nymphaeaceae), Cape Fear spatterdock, is an aquatic macrophyte endemic to the Atlantic Coastal Plain and of conservation concern in North Carolina, South Carolina, and Virginia in the United States. The existence of populations of unclear taxonomic identity has precluded assessment of the number of populations, distribution, and conservation needs of N. sagittifolia. The circumscription of the species was re-assessed using morphological and genetic analyses. Approximately 30 individuals from each of 21 populations of Nuphar across the N. sagittifolia range were included in genetic and morphological analyses, along with the type populations for three taxa. Genetic diversity was assessed by genotyping individuals across 26 SNP loci identified for this study, and morphological variation was assessed through measurement of 31 leaf, flower, and fruit characters. STRUCTURE analysis identified three genetic groups with corresponding morphological differences in the N. sagittifolia range: N. sagittifolia, N. advena subsp. advena, and a third group in the Chowan-Roanoke River drainage that requires further study. A revised key based on Classification and Regression Tree (CART) and Bayesian analyses identifies N. sagittifolia based on a leaf sinus-to-leaf length ratio <0.22, leaves not emergent, and leaf length-to-width ratio usually greater than 2.4. Genetic analyses within the N. sagittifolia group as indicated by the revised key indicated relatively low clonality, low gene flow, and low allelic differentiation among populations. Observed heterozygosity was higher than expected heterozygosity in all populations, an observation consistent with a combination of limited clonal reproduction and sexual reproduction resulting in long-lived genets.
{"title":"Clarifying Taxonomic Boundaries in Nuphar sagittifolia (Nymphaeaceae): Insights from Morphology and Population Genetic Diversity","authors":"Katherine E. Culatta, A. Krings, Lilian P. Matallana-Ramirez, R. Whetten","doi":"10.2179/0008-7475.87.1.81","DOIUrl":"https://doi.org/10.2179/0008-7475.87.1.81","url":null,"abstract":"ABSTRACT Nuphar sagittifolia (Nymphaeaceae), Cape Fear spatterdock, is an aquatic macrophyte endemic to the Atlantic Coastal Plain and of conservation concern in North Carolina, South Carolina, and Virginia in the United States. The existence of populations of unclear taxonomic identity has precluded assessment of the number of populations, distribution, and conservation needs of N. sagittifolia. The circumscription of the species was re-assessed using morphological and genetic analyses. Approximately 30 individuals from each of 21 populations of Nuphar across the N. sagittifolia range were included in genetic and morphological analyses, along with the type populations for three taxa. Genetic diversity was assessed by genotyping individuals across 26 SNP loci identified for this study, and morphological variation was assessed through measurement of 31 leaf, flower, and fruit characters. STRUCTURE analysis identified three genetic groups with corresponding morphological differences in the N. sagittifolia range: N. sagittifolia, N. advena subsp. advena, and a third group in the Chowan-Roanoke River drainage that requires further study. A revised key based on Classification and Regression Tree (CART) and Bayesian analyses identifies N. sagittifolia based on a leaf sinus-to-leaf length ratio <0.22, leaves not emergent, and leaf length-to-width ratio usually greater than 2.4. Genetic analyses within the N. sagittifolia group as indicated by the revised key indicated relatively low clonality, low gene flow, and low allelic differentiation among populations. Observed heterozygosity was higher than expected heterozygosity in all populations, an observation consistent with a combination of limited clonal reproduction and sexual reproduction resulting in long-lived genets.","PeriodicalId":50984,"journal":{"name":"Castanea","volume":"87 1","pages":"81 - 104"},"PeriodicalIF":0.4,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44287788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-15DOI: 10.2179/0008-7475.87.1.1
A. Hessl, Andrew M. Liebhold, M. L. Leef
ABSTRACT During biological invasions, the initial arrival and establishment of invading populations often go unnoticed for many years yet information on early invasion dynamics is key to understanding and managing invasions. We used the presence of ring discoloration, “rotholz”, in tree cores to date historical Adelges piceae outbreaks and reconstruct its invasion history in 14 Abies balsamea subsp. phanerolepis stands in West Virginia. In 2018, we collected and cross-dated tree ring samples from 676 cores. We measured ring width increments and recorded the presence of rotholz in each annually dated ring. Rotholz was present in tree cores sampled from each of the 14 study sites, with the first rotholz occurrence in 1952 and widespread evidence of rotholz as early as the 1980s. Time series of rotholz frequencies indicate two synchronized waves of elevated rotholz frequencies that were observed at most sites from 1998 to 2003 and again from 2006 to 2013, coincident with observed outbreaks. Unlike patterns of growth suppression found among trees affected by defoliating insects, we observed a significant and positive relationship between rotholz frequency and standardized growth increment. This relationship is consistent with earlier observations of abnormal growth among trees infested by A. piceae. Our samples of rotholz frequencies suggests that rotholz may be a better indicator of past outbreaks of A. piceae than growth. The presence of A. piceae and its role in hastening decline of these rare relic tree populations would lend support to increased attention for the search for A. piceae biological control agents to limit damage by this insect.
{"title":"Dendrochronological Reconstruction of the Historical Invasion of Balsam Woolly Adelgid, Adelges piceae, Feeding on Canaan Fir, Abies balsamea subsp. phanerolepis in the Central Appalachian Mountains","authors":"A. Hessl, Andrew M. Liebhold, M. L. Leef","doi":"10.2179/0008-7475.87.1.1","DOIUrl":"https://doi.org/10.2179/0008-7475.87.1.1","url":null,"abstract":"ABSTRACT During biological invasions, the initial arrival and establishment of invading populations often go unnoticed for many years yet information on early invasion dynamics is key to understanding and managing invasions. We used the presence of ring discoloration, “rotholz”, in tree cores to date historical Adelges piceae outbreaks and reconstruct its invasion history in 14 Abies balsamea subsp. phanerolepis stands in West Virginia. In 2018, we collected and cross-dated tree ring samples from 676 cores. We measured ring width increments and recorded the presence of rotholz in each annually dated ring. Rotholz was present in tree cores sampled from each of the 14 study sites, with the first rotholz occurrence in 1952 and widespread evidence of rotholz as early as the 1980s. Time series of rotholz frequencies indicate two synchronized waves of elevated rotholz frequencies that were observed at most sites from 1998 to 2003 and again from 2006 to 2013, coincident with observed outbreaks. Unlike patterns of growth suppression found among trees affected by defoliating insects, we observed a significant and positive relationship between rotholz frequency and standardized growth increment. This relationship is consistent with earlier observations of abnormal growth among trees infested by A. piceae. Our samples of rotholz frequencies suggests that rotholz may be a better indicator of past outbreaks of A. piceae than growth. The presence of A. piceae and its role in hastening decline of these rare relic tree populations would lend support to increased attention for the search for A. piceae biological control agents to limit damage by this insect.","PeriodicalId":50984,"journal":{"name":"Castanea","volume":"87 1","pages":"1 - 11"},"PeriodicalIF":0.4,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42428522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-15DOI: 10.2179/0008-7475.87.1.39
Katharine Putney, Mavis Wolf, Chase M. Mason, Shu-Mei Chang
ABSTRACT Sexual dimorphism in plant growth and/or reproductive responses to the surrounding environment has been documented in some plant species. In gynodioecious plants, it is especially important to understand whether females and hermaphrodites differ in their response to environmental stressors, as the fitness of females relative to hermaphrodites determines the extent to which these separate sexes are maintained in natural populations. Soil nutrient availability is of particular importance given the different nutrient requirements of male and female sexual functions in plants. Here, we evaluated and compared the growth of females and hermaphrodites of Geranium maculatum in response to varying levels of nutrients. Using a greenhouse experiment, we manipulated the overall nutrient, nitrogen, and phosphorus levels in the soil and measured growth, allocation, and leaf quality responses in both females and hermaphrodites. We found that the sexes responded similarly in their growth and allocation responses to nutrient availability, despite evidence that female leaf chlorophyll content may have increased more than that of hermaphrodites across soil nitrogen levels. Our findings demonstrate that while hermaphrodites may differ from females in terms of their physiological response to varying nutrient levels, these slight physiological differences do not translate into meaningful growth differences.
{"title":"The Effects of Varying Nutrient Availability on Females and Hermaphrodites of the Gynodioecious Geranium maculatum","authors":"Katharine Putney, Mavis Wolf, Chase M. Mason, Shu-Mei Chang","doi":"10.2179/0008-7475.87.1.39","DOIUrl":"https://doi.org/10.2179/0008-7475.87.1.39","url":null,"abstract":"ABSTRACT Sexual dimorphism in plant growth and/or reproductive responses to the surrounding environment has been documented in some plant species. In gynodioecious plants, it is especially important to understand whether females and hermaphrodites differ in their response to environmental stressors, as the fitness of females relative to hermaphrodites determines the extent to which these separate sexes are maintained in natural populations. Soil nutrient availability is of particular importance given the different nutrient requirements of male and female sexual functions in plants. Here, we evaluated and compared the growth of females and hermaphrodites of Geranium maculatum in response to varying levels of nutrients. Using a greenhouse experiment, we manipulated the overall nutrient, nitrogen, and phosphorus levels in the soil and measured growth, allocation, and leaf quality responses in both females and hermaphrodites. We found that the sexes responded similarly in their growth and allocation responses to nutrient availability, despite evidence that female leaf chlorophyll content may have increased more than that of hermaphrodites across soil nitrogen levels. Our findings demonstrate that while hermaphrodites may differ from females in terms of their physiological response to varying nutrient levels, these slight physiological differences do not translate into meaningful growth differences.","PeriodicalId":50984,"journal":{"name":"Castanea","volume":"87 1","pages":"39 - 53"},"PeriodicalIF":0.4,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46713255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-15DOI: 10.2179/0008-7475.87.1.149
Kate Mathews, Chris Randle, Zack Murell, Conley K Mcmullen, W. Zomlefer
{"title":"2022 Elizabeth Ann Bartholomew Award Ronald W. Lance","authors":"Kate Mathews, Chris Randle, Zack Murell, Conley K Mcmullen, W. Zomlefer","doi":"10.2179/0008-7475.87.1.149","DOIUrl":"https://doi.org/10.2179/0008-7475.87.1.149","url":null,"abstract":"","PeriodicalId":50984,"journal":{"name":"Castanea","volume":"87 1","pages":"149 - 150"},"PeriodicalIF":0.4,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45209581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-15DOI: 10.2179/0008-7475.87.1.129
Mahboubeh Hosseinalizadeh Nobarinezhad, L. Wallace
ABSTRACT Chamaecrista fasciculata is a widely distributed, phenotypically variable species in the eastern U.S. Whereas studies have demonstrated genetic structure and local adaptation in northern areas of its distribution, there has been no comparison of genetic variability among populations at the southern extent where phenotypic variation is more complex. We characterized genetic variation at 14 microsatellite loci for populations in Mississippi and Alabama and compared this to variation in a phenotypic trait, leaf pubescence. Geographic distance, climatic variables, and elevation were evaluated as factors to explain the observed patterns of genetic diversity. A significant amount of variation (19%) resided among populations, but most variation (68%) was among individuals. Assignment of individuals into genetic groups suggests two primary clusters, but these groups are not concordant with known geographical or ecological breaks, nor phenotypic variants. Genetic structure at a regional scale can be characterized as isolation by distance, while environmental factors may play a secondary role in limiting gene flow at local scales. Mean population FST is strongly associated with allelic diversity and heterozygosity, suggesting that genetic drift influences population variation. Despite the presence of genetic and phenotypic variation in southern populations of C. fasciculata, the lack of concordant patterns between these types of variation indicate that they are not driven by the same factors. This study demonstrates how local factors differentially influence the maintenance of intraspecific variation and suggest the southern distributional range is an active area of evolution for C. fasciculata.
{"title":"Determinants of Population Genetic Structure in Chamaecrista fasciculata (Michx.) Greene (Fabaceae) in the Southeastern United States","authors":"Mahboubeh Hosseinalizadeh Nobarinezhad, L. Wallace","doi":"10.2179/0008-7475.87.1.129","DOIUrl":"https://doi.org/10.2179/0008-7475.87.1.129","url":null,"abstract":"ABSTRACT Chamaecrista fasciculata is a widely distributed, phenotypically variable species in the eastern U.S. Whereas studies have demonstrated genetic structure and local adaptation in northern areas of its distribution, there has been no comparison of genetic variability among populations at the southern extent where phenotypic variation is more complex. We characterized genetic variation at 14 microsatellite loci for populations in Mississippi and Alabama and compared this to variation in a phenotypic trait, leaf pubescence. Geographic distance, climatic variables, and elevation were evaluated as factors to explain the observed patterns of genetic diversity. A significant amount of variation (19%) resided among populations, but most variation (68%) was among individuals. Assignment of individuals into genetic groups suggests two primary clusters, but these groups are not concordant with known geographical or ecological breaks, nor phenotypic variants. Genetic structure at a regional scale can be characterized as isolation by distance, while environmental factors may play a secondary role in limiting gene flow at local scales. Mean population FST is strongly associated with allelic diversity and heterozygosity, suggesting that genetic drift influences population variation. Despite the presence of genetic and phenotypic variation in southern populations of C. fasciculata, the lack of concordant patterns between these types of variation indicate that they are not driven by the same factors. This study demonstrates how local factors differentially influence the maintenance of intraspecific variation and suggest the southern distributional range is an active area of evolution for C. fasciculata.","PeriodicalId":50984,"journal":{"name":"Castanea","volume":"87 1","pages":"129 - 146"},"PeriodicalIF":0.4,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44289265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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