{"id":{"repo_id":"sdstate","oai_identifier":"oai:openprairie.sdstate.edu:etd-1150"},"canonical_url":"https://search.dev.ndltd.org/etd/sdstate/oai:openprairie.sdstate.edu:etd-1150","repository":{"repo_id":"sdstate","name":"South Dakota State University","base_url":"https://openprairie.sdstate.edu/do/oai/"},"display":{"title":"Effects of Introduced Muskrat Populations on Emergent Vegetation in South Dakota Wetland","abstract":"Muskrats (Ondatra zibethicus) and fluctuations of water level are the main forces controlling wetland vegetation cover and composition on a long term basis. IN the absence of artificial water control structures, properly managed muskrat populations are the most natural, long term means of regulating wetland vegetation. Reduction of prairie wetlands has the potential to influence muskrat dispersal patterns and consequently, to reduce the beneficial influences of muskrats on wetland habitats. The objective of this study was to evaluate the changes in seasonal wetlands emergent vegetation cover resulting from experimental manipulation of muskrat populations. Changes in cover of emergent vegetation due to muskrat introductions were difficult to interpret because of major fluctuations in water levels and muskrat populations. During 1986, high precipitation levels influenced emergent vegetation by increasing wetland mean water depth and inundating emergent vegetation. Any reduction of emergent vegetation cover created by manipulation of muskrat population could not be discerned from the effects of flooding. During 1987, extremely low precipitation reduced water levels and increased mean vegetation cover of treatment wetlands between the spring and fall period. Variations in water levels between years also influence muskrat populations, which further complicated the interpretation of the experimental effects. During both years, muskrat densities fluctuated during the experimental period due to dispersal of muskrats into and out of treatment wetlands during the experimental period. There were no significant differences (p>0.05) in emergent vegetation cover between treatments, years, or seasons, the interaction between seasons and treatments was not significant (p>0.05) indicating there was no seasonal change in emergent vegetation cover due to muskrat population manipulation. There was a highly significant interaction between year and seasonal effects (p<0.01), indicating the annual differences in water fluctuations were the controlling factor influencing seasonal changes in wetland vegetation. Indices of muskrat densities varied between treatments and years, and there was a treatment by year interaction (p<0.01), reflecting differences in water levels and public trapping pressure between years. Management implications and future research recommendations are discussed.","abstract_html":"Muskrats (Ondatra zibethicus) and fluctuations of water level are the main forces controlling wetland vegetation cover and composition on a long term basis. IN the absence of artificial water control structures, properly managed muskrat populations are the most natural, long term means of regulating wetland vegetation. Reduction of prairie wetlands has the potential to influence muskrat dispersal patterns and consequently, to reduce the beneficial influences of muskrats on wetland habitats. The objective of this study was to evaluate the changes in seasonal wetlands emergent vegetation cover resulting from experimental manipulation of muskrat populations. Changes in cover of emergent vegetation due to muskrat introductions were difficult to interpret because of major fluctuations in water levels and muskrat populations. During 1986, high precipitation levels influenced emergent vegetation by increasing wetland mean water depth and inundating emergent vegetation. Any reduction of emergent vegetation cover created by manipulation of muskrat population could not be discerned from the effects of flooding. During 1987, extremely low precipitation reduced water levels and increased mean vegetation cover of treatment wetlands between the spring and fall period. Variations in water levels between years also influence muskrat populations, which further complicated the interpretation of the experimental effects. During both years, muskrat densities fluctuated during the experimental period due to dispersal of muskrats into and out of treatment wetlands during the experimental period. There were no significant differences (p&gt;0.05) in emergent vegetation cover between treatments, years, or seasons, the interaction between seasons and treatments was not significant (p&gt;0.05) indicating there was no seasonal change in emergent vegetation cover due to muskrat population manipulation. There was a highly significant interaction between year and seasonal effects (p&lt;0.01), indicating the annual differences in water fluctuations were the controlling factor influencing seasonal changes in wetland vegetation. Indices of muskrat densities varied between treatments and years, and there was a treatment by year interaction (p&lt;0.01), reflecting differences in water levels and public trapping pressure between years. Management implications and future research recommendations are discussed.","abstract_has_math":false,"creators":["Kjellsen, Michael Lynn"],"institution":null,"degree_name":"Master of Science (MS)","degree_level":"Thesis - University Access Only","degree_discipline":"Wildlife and Fisheries Science","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1989,"date_issued":"1989-01-01T08:00:00Z","date_published":"1989-01-01T08:00:00Z","updated_at":"2026-07-24T04:27:36Z","subjects":["Natural Resources and Conservation"],"languages":["en"],"rights":["<p>No Copyright - Non-Commercial Use Only<br /><a href=\"http://rightsstatements.org/vocab/InC-EDU/1.0/\">http://rightsstatements.org/vocab/NoC-NC/1.0/</a></p>"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://openprairie.sdstate.edu/etd/150","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Kjellsen, Michael Lynn"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"thesis:degree_discipline","label":"Discipline","values":["Wildlife and Fisheries Science"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis - University Access Only"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science (MS)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Natural Resources and Conservation"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["<p>No Copyright - Non-Commercial Use Only<br /><a href=\"http://rightsstatements.org/vocab/InC-EDU/1.0/\">http://rightsstatements.org/vocab/NoC-NC/1.0/</a></p>"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://openprairie.sdstate.edu/etd/150"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Muskrats (Ondatra zibethicus) and fluctuations of water level are the main forces controlling wetland vegetation cover and composition on a long term basis. IN the absence of artificial water control structures, properly managed muskrat populations are the most natural, long term means of regulating wetland vegetation. Reduction of prairie wetlands has the potential to influence muskrat dispersal patterns and consequently, to reduce the beneficial influences of muskrats on wetland habitats. The objective of this study was to evaluate the changes in seasonal wetlands emergent vegetation cover resulting from experimental manipulation of muskrat populations. Changes in cover of emergent vegetation due to muskrat introductions were difficult to interpret because of major fluctuations in water levels and muskrat populations. During 1986, high precipitation levels influenced emergent vegetation by increasing wetland mean water depth and inundating emergent vegetation. Any reduction of emergent vegetation cover created by manipulation of muskrat population could not be discerned from the effects of flooding. During 1987, extremely low precipitation reduced water levels and increased mean vegetation cover of treatment wetlands between the spring and fall period. Variations in water levels between years also influence muskrat populations, which further complicated the interpretation of the experimental effects. During both years, muskrat densities fluctuated during the experimental period due to dispersal of muskrats into and out of treatment wetlands during the experimental period. There were no significant differences (p>0.05) in emergent vegetation cover between treatments, years, or seasons, the interaction between seasons and treatments was not significant (p>0.05) indicating there was no seasonal change in emergent vegetation cover due to muskrat population manipulation. There was a highly significant interaction between year and seasonal effects (p<0.01), indicating the annual differences in water fluctuations were the controlling factor influencing seasonal changes in wetland vegetation. Indices of muskrat densities varied between treatments and years, and there was a treatment by year interaction (p<0.01), reflecting differences in water levels and public trapping pressure between years. Management implications and future research recommendations are discussed."]},{"key":"dc:title","label":"Title","values":["Effects of Introduced Muskrat Populations on Emergent Vegetation in South Dakota Wetland"]}]}],"canonical_facts":{"dc:creator":["Kjellsen, Michael Lynn"],"dc:description.abstract":["Muskrats (Ondatra zibethicus) and fluctuations of water level are the main forces controlling wetland vegetation cover and composition on a long term basis. IN the absence of artificial water control structures, properly managed muskrat populations are the most natural, long term means of regulating wetland vegetation. Reduction of prairie wetlands has the potential to influence muskrat dispersal patterns and consequently, to reduce the beneficial influences of muskrats on wetland habitats. The objective of this study was to evaluate the changes in seasonal wetlands emergent vegetation cover resulting from experimental manipulation of muskrat populations. Changes in cover of emergent vegetation due to muskrat introductions were difficult to interpret because of major fluctuations in water levels and muskrat populations. During 1986, high precipitation levels influenced emergent vegetation by increasing wetland mean water depth and inundating emergent vegetation. Any reduction of emergent vegetation cover created by manipulation of muskrat population could not be discerned from the effects of flooding. During 1987, extremely low precipitation reduced water levels and increased mean vegetation cover of treatment wetlands between the spring and fall period. Variations in water levels between years also influence muskrat populations, which further complicated the interpretation of the experimental effects. During both years, muskrat densities fluctuated during the experimental period due to dispersal of muskrats into and out of treatment wetlands during the experimental period. There were no significant differences (p>0.05) in emergent vegetation cover between treatments, years, or seasons, the interaction between seasons and treatments was not significant (p>0.05) indicating there was no seasonal change in emergent vegetation cover due to muskrat population manipulation. There was a highly significant interaction between year and seasonal effects (p<0.01), indicating the annual differences in water fluctuations were the controlling factor influencing seasonal changes in wetland vegetation. Indices of muskrat densities varied between treatments and years, and there was a treatment by year interaction (p<0.01), reflecting differences in water levels and public trapping pressure between years. Management implications and future research recommendations are discussed."],"dc:identifier":["https://openprairie.sdstate.edu/etd/150"],"dc:language":["en"],"dc:rights":["<p>No Copyright - Non-Commercial Use Only<br /><a href=\"http://rightsstatements.org/vocab/InC-EDU/1.0/\">http://rightsstatements.org/vocab/NoC-NC/1.0/</a></p>"],"dc:subject":["Natural Resources and Conservation"],"dc:title":["Effects of Introduced Muskrat Populations on Emergent Vegetation in South Dakota Wetland"],"thesis:degree_discipline":["Wildlife and Fisheries Science"],"thesis:degree_level":["Thesis - University Access Only"],"thesis:degree_name":["Master of Science (MS)"]},"updated_at":"2026-07-24T04:27:36Z"}