Natural Hybridization And Taxonomy In The Genus Typha

Author : Sara Jean Pieper
Publisher :
ISBN 13 :
Total Pages : 432 pages
Book Rating : 4.:/5 (132 download)

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Download or read book Hybridization Dynamics in Cattails (Typha Spp.,) in North Eastern North America: Niche Segregation, Pollen Dispersal, Mating Patterns, and the Importance of Local-scale Processes written by Sara Jean Pieper and published by . This book was released on 2019 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interspecific hybridization is an important evolutionary process which can contribute to the invasiveness of species complexes. In this dissertation I used the hybridizing species complex of cattails (Typhaspp., Typhaceae) to explore some of the processes that could contribute to hybridization rates. Cattails in northeastern North America comprise the native T. latifolia, the non-native T. angustifolia, and their fertile hybrid, T. U+00d7 glauca. First, I examined whether these taxa segregate by water depth as habitat segregation may be associated with lower incidence of hybridization. I found that these taxa occupy similar water depths and therefore that habitat segregation by water depth does not promote mating isolationamong these taxa. I then compared pollen dispersal patterns between progenitor species as pollen dispersal can also influence rates of hybrid formation. Each progenitor exhibits localized pollen dispersal, and the maternal parent of first generation hybrids captures more conspecific than heterospecific pollen; both of which should lead to reduced hybrid formation. I then conducted controlled crosses using all three Typhataxa to quantify hybrid fertility and to parameterize a fertility model to predict howmating compatibilities should affect the composition of cattail stands. I found that highly asymmetric formation of hybrids and backcrosses and reduced hybrid fertility should favour the maintenance of T. latifoliaunder certain conditions. Finally, I used a population genetics approach to characterize genetic diversity and structure of Typhain northeastern North America to determine the extent to which broad-scale processes such as gene flow influence site-level processes. I concluded that hybrids are most often created within sites or introduced in small numbers rather than exhibiting broad-scale dispersal. This suggests that local processes are more important drivers of hybrid success than landscape-scale processes which would be expected to limit the spread of the hybrid. Though my findings indicate some barriers to hybridization in these Typha taxa, hybrid cattail dominates much of northeastern North America. My results therefore show that incomplete barriers tohybridization may not be sufficient to prevent the continued dominance of hybrids and that active management of invasive hybrids may be required to limit their spread. KEYWORDSHybridization;niche segregation;pollen dispersal;genetic structure;fertility model;invasive species; Typha.