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Population growth and genetic diversity dynamics of modeled conservation methodologies for threatened plant species

Kashimshetty, Yamini
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1468512768

Abstract Details

2016, PhD, University of Cincinnati, Arts and Sciences: Biological Sciences.
Tropical and temperate plant species in forests around the world are threatened by human-induced land-use changes which produce various outcomes such as increased spread of invasive species, habitat fragmentation, and alterations of community structure among others. These factors can lower population sizes and genetic diversity levels of native plant species, making the risk of extinction imminent. Methodologies to mitigate such effects can involve introducing endangered plant species back to their native habitats either via in situ management of exploited species, or ex situ conservation. To study such species conservation, highly-replicated predictive computer modeling can be an inexpensive tool to suggest those scenarios that can better maintain viable population sizes and genetic diversity levels over the long term, since field studies are less feasible given the limited time and resources available. I used a species-specific, spatially-explicit, individual-based computer program (NEWGARDEN) capable of modeling and monitoring plant population growth and genetic diversity patterns in simulated stands over time to comparatively model various restoration methodologies for different threatened tree species. Specifically, I examined: 1) effective reintroduction geometries of the American chestnut; 2) sustainable spatial deforestation patterns for long-lived canopy tree species in tropical lowland rain forests (TLRFs); and 3) seed collection strategies capable of maximizing the harvest of genetic variation from rare TLRF tree species for use in developing ex situ rescue populations. These species conservation methodologies were tested under differing offspring and pollen dispersal distances, as this life-history trait can affect the spatial distribution of allelic diversity in populations. Results indicate that for reintroductions of the American chestnut, planting and stewarding a limited number of individuals at least 100m in from the preserve border (for a preserve sized 500m x 500m) were adequate in maximizing retention of founder genetic diversity, while planting at least 300m in best promoted population growth, especially under more distant offspring and pollen dispersal. With regards to sustainable deforestation practices for fragmented long-lived TLRF canopy tree species, alterations to their gene dispersal kernels following fragmentation effectuated larger variations in population recovery and genetic diversity retention than did alterations in spatial deforestation patterns. More distant offspring and pollen dispersal improved population recovery and allelic diversity retention in such situations, suggesting manual manipulations of propagules as a practical restoration measure. For the ex situ genetic conservation of rare TLRF trees, strategies that promoted the harvest of genetic diversity from the source population included: collecting fewer seeds from a larger sample of trees from peripheral subdivided sampling regions of the population, using a random pattern of collection compared to a nearest-neighbor methodology, and collecting from species with more distant gene dispersal. Collectively, these results demonstrate how gene dispersal attributes of target species can have interactive effects with various spatial aspects of plant conservation methodologies in determining the overall success of such efforts. Conservation project planning for threatened plant species would benefit from greater availability of accurate information regarding life-history characteristics of target species combined with predictive computer simulation modeling methods using tools such as NEWGARDEN.
Steven Rogstad, Ph.D. (Committee Chair)
Theresa Culley, Ph.D. (Committee Member)
Stephen Matter, Ph.D. (Committee Member)
Eric Maurer, Ph.D. (Committee Member)
Stephan Pelikan, Ph.D. (Committee Member)
176 p.
Botany
plant conservation; tropical deforestation; conservation genetics; plant gene dispersal; forest fragmentation; ex situ conservation

Recommended Citations

Citations

  • Kashimshetty, Y. (2016). Population growth and genetic diversity dynamics of modeled conservation methodologies for threatened plant species [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1468512768

    APA Style (7th edition)

  • Kashimshetty, Yamini. Population growth and genetic diversity dynamics of modeled conservation methodologies for threatened plant species. 2016. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1468512768.

    MLA Style (8th edition)

  • Kashimshetty, Yamini. "Population growth and genetic diversity dynamics of modeled conservation methodologies for threatened plant species." Doctoral dissertation, University of Cincinnati, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1468512768

    Chicago Manual of Style (17th edition)

ucin1468512768
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© 2016, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.