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dc.contributor.advisorSchaap, Marcel G.en
dc.contributor.authorPearlstein, Susanna Leeen
dc.creatorPearlstein, Susanna Leeen
dc.date.accessioned2016-01-22T20:41:05Zen
dc.date.available2016-01-22T20:41:05Zen
dc.date.issued2015en
dc.identifier.urihttp://hdl.handle.net/10150/594631en
dc.description.abstractThe Dolores River in Utah and the Virgin River in Nevada are ecosystems under pressure from increased groundwater withdrawal due to growing human populations, climate change and introduced species such as Tamarix spp. (tamarisk). Tamarisk is reputed to take excessive water from its environment. Controlling tamarisk is of concern in the western United States where plants grow quickly in already fragile and diminishing riparian areas. For this reason, biologic control beetles Chrysomelidae: Diorhabda carinulata were released to weaken the tamarisk population, thus reducing its water use. The studies for this dissertation were conducted between 2010 and 2011. We quantified tamarisk water use over multiple cycles of annual defoliation using sap flow measurements, leaf area index (LAI), well data, allometry and satellite imagery from EOS-1 Moderate Resolution Imaging Spectrometer (MODIS) sensor. Study objectives for the Virgin River were to measure evapotranspiration (ET) before beetles ever arrived and to examine the effects on tamarisk ET in the year after beetle arrival. This site showed plant ET from sap flow averaged about 4.3 mm m⁻² leaf day⁻¹ in 2010. In 2011, ET from sap flow averaged 6.4 mm m⁻² leaf area day⁻¹ pre beetle arrival, but dropped to 3-4 mm m⁻² leaf area day⁻¹ after beetle arrival. Stand level ET measured by MODIS was 2.2 mm d⁻¹ in 2010 and approximately 1.5 mm day⁻¹ when beetle arrival was measured in 2011. Significant visual change was apparent as the trees senesced. Results showed the first year of beetle arrival resulted in reduced ET but did not result in significant water savings. We also compared the reaction of the newly defoliated (in 2011) Virgin River site to the long-term defoliated (since 2007) Dolores River site to explore if all beetle invasions were created equal. This paper views the two sites as fairly extreme examples of tamarisk stand reaction to the beetle. While no mortality was reported at the Dolores River site, the site is much older, less photosynthetically active and covers far less ground when compared to the younger tamarisk monoculture on the Virgin River. Pre-beetle arrival Normalized Difference Vegetation Index (NDVI) values were higher on the Virgin River than on the Dolores River. Beetle arrival at each site was captured with Landsat NDVI and a reduced NDVI signal (13% drop in NDVI at Dolores River, 5% drop at Virgin River) was seen after beetle arrival.
dc.language.isoen_USen
dc.publisherThe University of Arizona.en
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
dc.subjectsap flowen
dc.subjectTamarisken
dc.subjectVirgin Riveren
dc.subjectSoil, Water & Environmental Scienceen
dc.subjectDolores Riveren
dc.titleMethods for Measuring Tamarisk (Tamarix spp.) Water Use on Two Sub-Watersheds in The Western United States as Impacted by The Tamarisk Leaf Beetle (Diorhabda spp.)en_US
dc.typetexten
dc.typeElectronic Dissertationen
thesis.degree.grantorUniversity of Arizonaen
thesis.degree.leveldoctoralen
dc.contributor.committeememberSchaap, Marcel G.en
dc.contributor.committeememberCrimmins, Michaelen
dc.contributor.committeememberLeavitt, Stevenen
dc.contributor.committeememberRasmussen, Craigen
dc.description.releaseRelease 06-Oct-2017en
thesis.degree.disciplineGraduate Collegeen
thesis.degree.disciplineSoil, Water & Environmental Scienceen
thesis.degree.namePh.D.en
refterms.dateFOA2017-10-06T00:00:00Z
html.description.abstractThe Dolores River in Utah and the Virgin River in Nevada are ecosystems under pressure from increased groundwater withdrawal due to growing human populations, climate change and introduced species such as Tamarix spp. (tamarisk). Tamarisk is reputed to take excessive water from its environment. Controlling tamarisk is of concern in the western United States where plants grow quickly in already fragile and diminishing riparian areas. For this reason, biologic control beetles Chrysomelidae: Diorhabda carinulata were released to weaken the tamarisk population, thus reducing its water use. The studies for this dissertation were conducted between 2010 and 2011. We quantified tamarisk water use over multiple cycles of annual defoliation using sap flow measurements, leaf area index (LAI), well data, allometry and satellite imagery from EOS-1 Moderate Resolution Imaging Spectrometer (MODIS) sensor. Study objectives for the Virgin River were to measure evapotranspiration (ET) before beetles ever arrived and to examine the effects on tamarisk ET in the year after beetle arrival. This site showed plant ET from sap flow averaged about 4.3 mm m⁻² leaf day⁻¹ in 2010. In 2011, ET from sap flow averaged 6.4 mm m⁻² leaf area day⁻¹ pre beetle arrival, but dropped to 3-4 mm m⁻² leaf area day⁻¹ after beetle arrival. Stand level ET measured by MODIS was 2.2 mm d⁻¹ in 2010 and approximately 1.5 mm day⁻¹ when beetle arrival was measured in 2011. Significant visual change was apparent as the trees senesced. Results showed the first year of beetle arrival resulted in reduced ET but did not result in significant water savings. We also compared the reaction of the newly defoliated (in 2011) Virgin River site to the long-term defoliated (since 2007) Dolores River site to explore if all beetle invasions were created equal. This paper views the two sites as fairly extreme examples of tamarisk stand reaction to the beetle. While no mortality was reported at the Dolores River site, the site is much older, less photosynthetically active and covers far less ground when compared to the younger tamarisk monoculture on the Virgin River. Pre-beetle arrival Normalized Difference Vegetation Index (NDVI) values were higher on the Virgin River than on the Dolores River. Beetle arrival at each site was captured with Landsat NDVI and a reduced NDVI signal (13% drop in NDVI at Dolores River, 5% drop at Virgin River) was seen after beetle arrival.


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