Influence of a Population Irruption by Roosevelt Elk on a Vegetation Index

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dc.contributor.advisorWeckerly, Floyd W.
dc.contributor.authorStarns, Heath D.
dc.contributor.committeeMemberGreen, M. Clay
dc.contributor.committeeMemberSimpson, Thomas R.
dc.date.accessioned2014-04-15T20:53:58Z
dc.date.available2014-04-15T20:53:58Z
dc.date.issued2014-05
dc.description.abstractUnderstanding the factors that influence population growth is central to the study of any species. Large herbivores can influence their food supplies through herbivory. Over 23 years just before and throughout an irruption by a Roosevelt elk population I assessed temporal and spatial patterns of the Normalized Difference Vegetation Index (NDVI). My objectives were to determine if elk herbivory was associated with NDVI and whether the plant community foraged by the irruptive population was tolerant or resistant to elk grazing. Using Landsat 5 Thematic Mapper imagery, I obtained estimates of NDVI for three areas of Redwood National and State Parks, each inhabited by distinct populations of Roosevelt elk. Each population exhibited a different pattern of growth through the time series of the study. One population underwent the irruptive growth pattern while the other two populations did not. Using piece wise regression, I detected temporal changes in NDVI for the area used by the irruptive population that suggested a decline in forage biomass during the end of the dry season but I detected no decline in NDVI at the peak of the growing season. My findings suggest that the area used by the irruptive elk population may have undergone changes in plant community composition favoring plants that were resistant to elk grazing.
dc.description.departmentBiology
dc.formatText
dc.format.extent44 pages
dc.format.medium1 file (.pdf)
dc.identifier.citationStarns, H. D. (2014). <i>Influence of a population irruption by Roosevelt elk on a vegetation index</i> (Unpublished thesis). Texas State University, San Marcos, Texas.
dc.identifier.urihttps://hdl.handle.net/10877/4969
dc.language.isoen
dc.subjectIrruption
dc.subjectNDVI
dc.subjectHerbivory
dc.subject.lcshRoosevelt elk--Habitat--California--Redwood National and State Parksen_US
dc.subject.lcshElk--Habitat--California--Redwood National and State Parksen_US
dc.subject.lcshVegetation dynamics--California--Redwood National and State Parksen_US
dc.subject.lcshVegetation mapping--California--Redwood National and State Parksen_US
dc.titleInfluence of a Population Irruption by Roosevelt Elk on a Vegetation Index
dc.typeThesis
thesis.degree.departmentBiology
thesis.degree.disciplineWildlife Ecology
thesis.degree.grantorTexas State University
thesis.degree.levelMasters
thesis.degree.nameMaster of Science

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