Persistent Link:
http://hdl.handle.net/10150/195710
Title:
The Physiology of Exploitation Competition
Author:
Eilts, J. Alexander
Issue Date:
2007
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Water is a critical resource for which plants compete in many terrestrial communities. In arid communities where water most limits plant growth, rainfall events occur in discrete, pulsed events. These pulses of water create highly variable soil moisture availabilities. Plant species respond differently to variation in soil water availabilities throughout a season and between years. How species vary in their responses to a range of water availabilities is thought to influence community and ecosystem properties. Many previously proposed hypotheses are not suitable to explain rapidly fluctuating resource availabilities or numerous input events throughout the growing season. This dissertation uses variation in water availability as a model resource to examine how species characteristics influence the process of exploitation competition within plant communities.Experiments were conducted to examine variation in growing season, exploitation competition between several pairs of co-occurring species in the Sonoran desert. Three separate studies evaluated several components of community dynamics thought to be influenced by exploitation competition. Spatial attributes of exploitation competition were assessed by measuring the performance of a deep-rooted species across the boundary of a natural expansion of a shallowly rooted species. Then, neighborhood composition was varied for species of similar growth-form to address the affects of species characteristics to shifts in abundances under field conditions. Lastly, species from the neighborhood composition study were placed under controlled, manipulated water availabilities to measure their fundamental operational conditions.Performances of plant species in all experiments were assessed using a combination of physiological and vegetative measurements, capturing the responses of the plants to both the dynamic growth conditions during the growing season, and integrated measures of plant performance post growth season. A shared preference was found for all species, where the performance of all species was greatest when water was most available in the soil profile. This work suggests the mechanism within a functional type by which plants coexist at various abundances is in part due to the variation in responses to temporal resource gradients. The variation in availability of resources and the species composition within the community should be considered in studies of competition between plant species.
Type:
text; Electronic Dissertation
Keywords:
Ecology & Evolutionary Biology
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Ecology & Evolutionary Biology; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Huxman, Travis E,
Committee Chair:
Huxman, Travis E,

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleThe Physiology of Exploitation Competitionen_US
dc.creatorEilts, J. Alexanderen_US
dc.contributor.authorEilts, J. Alexanderen_US
dc.date.issued2007en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractWater is a critical resource for which plants compete in many terrestrial communities. In arid communities where water most limits plant growth, rainfall events occur in discrete, pulsed events. These pulses of water create highly variable soil moisture availabilities. Plant species respond differently to variation in soil water availabilities throughout a season and between years. How species vary in their responses to a range of water availabilities is thought to influence community and ecosystem properties. Many previously proposed hypotheses are not suitable to explain rapidly fluctuating resource availabilities or numerous input events throughout the growing season. This dissertation uses variation in water availability as a model resource to examine how species characteristics influence the process of exploitation competition within plant communities.Experiments were conducted to examine variation in growing season, exploitation competition between several pairs of co-occurring species in the Sonoran desert. Three separate studies evaluated several components of community dynamics thought to be influenced by exploitation competition. Spatial attributes of exploitation competition were assessed by measuring the performance of a deep-rooted species across the boundary of a natural expansion of a shallowly rooted species. Then, neighborhood composition was varied for species of similar growth-form to address the affects of species characteristics to shifts in abundances under field conditions. Lastly, species from the neighborhood composition study were placed under controlled, manipulated water availabilities to measure their fundamental operational conditions.Performances of plant species in all experiments were assessed using a combination of physiological and vegetative measurements, capturing the responses of the plants to both the dynamic growth conditions during the growing season, and integrated measures of plant performance post growth season. A shared preference was found for all species, where the performance of all species was greatest when water was most available in the soil profile. This work suggests the mechanism within a functional type by which plants coexist at various abundances is in part due to the variation in responses to temporal resource gradients. The variation in availability of resources and the species composition within the community should be considered in studies of competition between plant species.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectEcology & Evolutionary Biologyen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineEcology & Evolutionary Biologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorHuxman, Travis E,en_US
dc.contributor.chairHuxman, Travis E,en_US
dc.contributor.committeememberRobichaux, Robert H.en_US
dc.contributor.committeememberRosenzweig, Micahel L.en_US
dc.identifier.proquest2506en_US
dc.identifier.oclc659748413en_US
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