The UTC Graduate School is pleased to announce that Thomas Wiegand will present Master's research titled, Increased Phenotypic Plasticity Linked to Broader Geographic Range Size in Sunflower (Helianthus) Species on 07/05/2023 at 2:00 pm - 4:00 pm in Holt 229. Everyone is invited to attend. 

Environmental Science

Chair: Dr. Jennifer Boyd

Co-Chair: Dr. Hope Klug

Abstract:
Human activity worsens global biodiversity loss, particularly for vulnerable rare species. Plant species can respond to environmental changes via adaptation and/or acclimation or migration, yet limited genetic diversity and fitness in rare species can hinder these processes. Changes in light availability from human activities impact the growth and fitness of broadleaf species like sunflowers (Helianthus spp.). In a garden experiment, we compared the phenotypic plasticity of five Helianthus species representing different geographic ranges. Locally restricted H. longifolius and H. verticillatus showed less plasticity in growth and allocation traits than widespread H. angustifolius and H. maximiliani. Rare species with narrower ranges also displayed less population-level plasticity compared to common species. Geographically restricted rare species may struggle to acclimate to changes in light availability caused by human activities, which could increase extinction vulnerability. Conservation efforts should target limiting invasive and woody species to mitigate reduced light availability in their native habitats.