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Abstract Detail


Mitchell, Nora [1], Carlson, Jane [2], Holsinger, Kent [3].

The effects of climate on a microscale: testing for functional consequences in a Protea hybrid zone.

Plant functional traits covary with of environmental factors at the global and biome scales at among- and within-clade levels. But establishing the “function” of these traits requires direct measures of fitness, physiological performance, or stress tolerance. Hybrid zones provide an unusual opportunity to relate trait differences to functional differences, both because they provide a broad range of phenotypic values within a very small geographic area and because segregation in F2 and backcross progeny produces individuals with unusual combinations of traits. We use a natural, cryptic hybrid zone between two Protea species, P. punctata and P. venusta, in South Africa to examine local-scale relationships among traits, function, and environment. We use field-collected trait and environment data to relate traits and environment in a natural setting with individual functional response to water stress in a greenhouse experiment. We collected data on functional traits and fecundity on 150 plants in a single hybrid zone along a steep elevational gradient. We also recorded hourly temperature and humidity data at ten points across the zone in addition to collecting soil samples for nutrient analysis at these points. To understand trait-microclimate relationships, we used Bayesian linear modeling to relate traits to position in the hybrid zone and microenvironment data. To corroborate findings from the field data, we grew 450+ individuals derived from Protea seed collected from the hybrid zone in greenhouses. We imposed a drought stress through a drydown experiment on half of the plants after a period of establishment. We measured plant growth and stomatal conductance before and during the drydown, and we measured plant health, functional traits, and root/shoot biomass after. Our results show that different morphological species types respond to the microenvironment in different ways, providing further evidence that global patterns break down at finer geographic and taxonomic scales. We find a complicated relationship between maternal and offspring traits in a controlled setting, suggesting a role for ontogenetic or plastic responses in regulating these traits.

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1 - University Of Connecticut, Ecology & Evolutionary Biology, 75 North Eagleville Rd, U-3043, Storrs, CT, 06269, USA
2 - Nicholls State University, P.O. Box 2021, Thibodaux, CT, 70310, USA
3 - University Of Connecticut, Department Of Ecology & Evolutionary Biology, 75 N. Eagleville Road, U-3043, STORRS, CT, 06269-3043, USA

functional trait

Presentation Type: Oral Paper
Session: 14, Ecology Section: Plant Functional Traits and Responses
Location: 201/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 2:15 PM
Number: 14002
Abstract ID:163
Candidate for Awards:Ecological Section Best Graduate Student Paper

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