Date of Graduation

12-2018

Document Type

Thesis

Degree Name

Master of Science in Biology (MS)

Degree Level

Graduate

Department

Biological Sciences

Advisor/Mentor

Steven L. Stephenson

Committee Member

Frederick L. Paillet

Second Committee Member

Johnnie L. Gentry

Keywords

Arkansas, Castanea, Castanea Ozarkensis, Castanea Pumila, Ecology, Morphology

Abstract

Around the turn of the twentieth-century, the chestnut blight fungus (Cryphonectria parasitica) was accidentally introduced into North America. This strong pathogen, which specializes on trees of the genus Castanea, spread rapidly and within half a century had nearly extirpated North America’s Castanea natives from their ranges. During this catastrophe, the American chestnut (Castanea dentata) garnered much of the scientific attention, pushing the other Castanea natives – the chinquapins – to the wayside. More than a century following the spread of the blight, little research into the ecology of North America’s chinquapins had been performed, leaving these trees significantly underrepresented. The ranges of the two native geographical varieties of chinquapin (C. pumila var. pumila and C. pumila var. ozarkensis) converge along a gradient that bisects the state of Arkansas. The objectives of this project were to (1) assess the distribution and status of C. pumila populations throughout Arkansas, (2) to describe and compare the ecology of each variety, and (3) to quantify and compare the vegetative morphologies of the two varieties. The results indicate that C. pumila populations throughout Arkansas persisted, but remained highly suppressed by the blight in both growth form and reproduction. Castanea pumila var. pumila tended to occur at lower elevations and sub-mesic sites in the Coastal Plain, whereas C. pumila var. ozarkensis tended to occur at higher elevations and steeper slopes on sub-xeric to xeric sites of the Ozark Plateau and Ouachita Mountains. In a multivariate morphometric analysis of vegetation, mature leaves of C. pumila var. ozarkensis tended to be significantly larger than those of C. pumila var. pumila, yet specimens of both varieties from Arkansas were significantly larger than C. pumila var. pumila specimens from other states. Despite leaf size differences, no significant difference was observed in leaf shape. Additionally, no significant difference in foliar vestiture was observed between varieties.

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