Influence of Agricultural Land Use on Allochthonous Input and Leaf Breakdown in Southern Appalachian Streams

dc.contributor.authorHagen, Elizabeth M.en
dc.contributor.committeechairWebster, Jackson R.en
dc.contributor.committeememberJones, Robert H.en
dc.contributor.committeememberBenfield, Ernest F.en
dc.contributor.departmentBiologyen
dc.date.accessioned2011-08-06T16:01:28Zen
dc.date.adate2004-05-07en
dc.date.available2011-08-06T16:01:28Zen
dc.date.issued2004-04-22en
dc.date.rdate2004-05-07en
dc.date.sdate2004-05-04en
dc.description.abstractStreams and terrestrial ecosystems are linked through allochthonous organic matter inputs from streamside vegetation. This allochthonous material makes up the energy base for forested aquatic food webs. Therefore, removal of riparian vegetation associated with agricultural land use affects stream ecosystem structure and function. The objectives of this study were to measure and compare allochthonous input and leaf breakdown rates along a gradient of agricultural land use in southern Appalachian streams. Study streams were placed into the following land use categories: forest and light, moderate, and heavy agriculture. Several physical, chemical, and biological parameters also were measured including discharge, temperature, nutrient concentrations, macroinvertebrate abundance and density, periphyton biomass, and chlorophyll a concentration. In forested, light agricultural, and moderate agricultural streams, the quantity and quality of allochthonous input were not significantly different. However, the timing and composition of allochthonous materials were related to land use. Chlorophyll a and periphyton biomass did not vary among land use types. Leaf breakdown rates were significantly faster in light and moderate agricultural streams in comparison to forested and heavy agricultural streams. Slow breakdown rates in forested streams resulted from low nutrient concentration and cool stream temperature. The scarcity of shredding macroinvertebrates and sedimentation probably limited leaf breakdown in heavy agricultural streams. Though limited riparian vegetation along agricultural streams resulted in an energy supply equivalent to forested streams, agricultural land use may still have long term impacts on stream structure including nutrient concentrations, temperature, macroinvertebrate community, and sedimentation thus affecting stream ecosystem function.en
dc.description.degreeMaster of Scienceen
dc.format.mediumETDen
dc.identifier.otheretd-05042004-140626en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05042004-140626en
dc.identifier.urihttp://hdl.handle.net/10919/9897en
dc.publisherVirginia Techen
dc.relation.haspartHagen.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectleaf breakdownen
dc.subjectagricultureen
dc.subjectleaf litter inputen
dc.subjectland useen
dc.subjectorganic matter dynamicsen
dc.subjectstream structure and functionen
dc.titleInfluence of Agricultural Land Use on Allochthonous Input and Leaf Breakdown in Southern Appalachian Streamsen
dc.typeThesisen
thesis.degree.disciplineBiologyen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen
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