Lonicera maackii (Amur Honeysuckle) is an invasive woody plant species that is present across the United States. Previous studies have assessed the biotic effects of honeysuckle, as well as abiotic effects such as changes in soil chemistry, ground level light, and forest floor temperature. Although directs effects of L. maackii on native terrestrial plant communities are well studied, little is known about its indirect effects, especially in aquatic ecosystems. Based on limited prior studies, I predicted addition of L. maackii leaves to aquatic systems would increase mortality of a top amphibian predator due to the release of phenolic compounds that inhibit respiration. A mesocosm experiment was developed to characterize the cascading effects of increased top predator (Ambystoma maculatum) mortality on larval salamander growth, macroinvertebrate densities, zooplankton densities, leaf litter mass loss, chlorophyll a abundance, biofilm growth, and availability of soluble nutrients. Of the 20 mesocosms that contained larval A. maculatum, only 11 produced metamorphs, and only one mesocosm with leaf litter from L. maackii produced metamorphs. All 10 mesocosms containing A. maculatum larvae and native leaf litter produced metamorphs. A total of 117 metamorphs were retrieved from all mesocosms, and only three of those 117 were retrieved from mesocosms with leaf litter from L. maackii. Salamander survival and growth rates (mm/day) were significantly lower in mesocosms with L. maackii than in mesocosms with native leaf litter alone. Mesocosms with L. maackii leaf litter also contained substantially more mosquito larvae, suggesting reduced water quality. There was no indication that apex predator mortality in L. maackii mesocosms altered aquatic ecosystem functions. However, increased mass loss occurred in leaf packs containing L. maackii compared to leaf packs containing native leaf litter removed from the same mesocosm, which was not caused by greater invertebrate densities within L. maackii packs. I also found there to be an oily sheen on the water surface of mesocosms containing L. maackii leaf litter, which could hinder gill-breathing by amphibians. Relatively high invertebrate densities and diversity may have served as a buffer for lower trophic levels, such that they were not affected when A. maculatum individuals were eliminated from mesocosms due to exposure to L. maackii phenolic compounds. The results of this study will help complete the overall picture of the possible consequences of biological invasion.
","abstract_html":"<p>Lonicera maackii (Amur Honeysuckle) is an invasive woody plant species that is present across the United States. Previous studies have assessed the biotic effects of honeysuckle, as well as abiotic effects such as changes in soil chemistry, ground level light, and forest floor temperature. Although directs effects of L. maackii on native terrestrial plant communities are well studied, little is known about its indirect effects, especially in aquatic ecosystems. Based on limited prior studies, I predicted addition of L. maackii leaves to aquatic systems would increase mortality of a top amphibian predator due to the release of phenolic compounds that inhibit respiration. A mesocosm experiment was developed to characterize the cascading effects of increased top predator (Ambystoma maculatum) mortality on larval salamander growth, macroinvertebrate densities, zooplankton densities, leaf litter mass loss, chlorophyll a abundance, biofilm growth, and availability of soluble nutrients. Of the 20 mesocosms that contained larval A. maculatum, only 11 produced metamorphs, and only one mesocosm with leaf litter from L. maackii produced metamorphs. All 10 mesocosms containing A. maculatum larvae and native leaf litter produced metamorphs. A total of 117 metamorphs were retrieved from all mesocosms, and only three of those 117 were retrieved from mesocosms with leaf litter from L. maackii. Salamander survival and growth rates (mm/day) were significantly lower in mesocosms with L. maackii than in mesocosms with native leaf litter alone. Mesocosms with L. maackii leaf litter also contained substantially more mosquito larvae, suggesting reduced water quality. There was no indication that apex predator mortality in L. maackii mesocosms altered aquatic ecosystem functions. However, increased mass loss occurred in leaf packs containing L. maackii compared to leaf packs containing native leaf litter removed from the same mesocosm, which was not caused by greater invertebrate densities within L. maackii packs. I also found there to be an oily sheen on the water surface of mesocosms containing L. maackii leaf litter, which could hinder gill-breathing by amphibians. Relatively high invertebrate densities and diversity may have served as a buffer for lower trophic levels, such that they were not affected when A. maculatum individuals were eliminated from mesocosms due to exposure to L. maackii phenolic compounds. The results of this study will help complete the overall picture of the possible consequences of biological invasion. </p>","abstract_has_math":false,"creators":["Berta, Josey Lee-Anne"],"institution":"Eastern Kentucky University","degree_name":"Master of Science (MS)","degree_level":"Master's","degree_discipline":"Biological Sciences","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019-01-01T08:00:00Z","date_published":"2019-01-01T08:00:00Z","updated_at":"2026-07-24T02:15:47Z","subjects":["Ambystoma Maculatum","Apex Predator","Ephemeral Pond","Invasive Plant","Lonicera maackii","Trophic Cascade","Terrestrial and Aquatic Ecology"],"languages":[],"rights":["Copyright 2019 Josey Lee-Anne Berta"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://encompass.eku.edu/etd/590","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Berta, Josey Lee-Anne"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:publisher","label":"Institution","values":["Encompass Digital Archive, Eastern Kentucky University"]},{"key":"dc:type","label":"Dc Type","values":["Master Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Biological Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Master's"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science (MS)"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Eastern Kentucky University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Ambystoma Maculatum","Apex Predator","Ephemeral Pond","Invasive Plant","Lonicera maackii","Trophic Cascade","Terrestrial and Aquatic Ecology"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2019 Josey Lee-Anne Berta"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://encompass.eku.edu/etd/590"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Lonicera maackii (Amur Honeysuckle) is an invasive woody plant species that is present across the United States. Previous studies have assessed the biotic effects of honeysuckle, as well as abiotic effects such as changes in soil chemistry, ground level light, and forest floor temperature. Although directs effects of L. maackii on native terrestrial plant communities are well studied, little is known about its indirect effects, especially in aquatic ecosystems. Based on limited prior studies, I predicted addition of L. maackii leaves to aquatic systems would increase mortality of a top amphibian predator due to the release of phenolic compounds that inhibit respiration. A mesocosm experiment was developed to characterize the cascading effects of increased top predator (Ambystoma maculatum) mortality on larval salamander growth, macroinvertebrate densities, zooplankton densities, leaf litter mass loss, chlorophyll a abundance, biofilm growth, and availability of soluble nutrients. Of the 20 mesocosms that contained larval A. maculatum, only 11 produced metamorphs, and only one mesocosm with leaf litter from L. maackii produced metamorphs. All 10 mesocosms containing A. maculatum larvae and native leaf litter produced metamorphs. A total of 117 metamorphs were retrieved from all mesocosms, and only three of those 117 were retrieved from mesocosms with leaf litter from L. maackii. Salamander survival and growth rates (mm/day) were significantly lower in mesocosms with L. maackii than in mesocosms with native leaf litter alone. Mesocosms with L. maackii leaf litter also contained substantially more mosquito larvae, suggesting reduced water quality. There was no indication that apex predator mortality in L. maackii mesocosms altered aquatic ecosystem functions. However, increased mass loss occurred in leaf packs containing L. maackii compared to leaf packs containing native leaf litter removed from the same mesocosm, which was not caused by greater invertebrate densities within L. maackii packs. I also found there to be an oily sheen on the water surface of mesocosms containing L. maackii leaf litter, which could hinder gill-breathing by amphibians. Relatively high invertebrate densities and diversity may have served as a buffer for lower trophic levels, such that they were not affected when A. maculatum individuals were eliminated from mesocosms due to exposure to L. maackii phenolic compounds. The results of this study will help complete the overall picture of the possible consequences of biological invasion.
"]},{"key":"dc:format","label":"Dc Format","values":["application/PDF"]},{"key":"dc:source","label":"Dc Source","values":["Encompass Digital Archive: Online Theses and Dissertations"]},{"key":"dc:title","label":"Title","values":["Ecosystem Functional Consequences of Top Predator Mortality Due to the Invasive Shrub, Lonicera maackii"]}]}],"canonical_facts":{"dc:creator":["Berta, Josey Lee-Anne"],"dc:description.abstract":["Lonicera maackii (Amur Honeysuckle) is an invasive woody plant species that is present across the United States. Previous studies have assessed the biotic effects of honeysuckle, as well as abiotic effects such as changes in soil chemistry, ground level light, and forest floor temperature. Although directs effects of L. maackii on native terrestrial plant communities are well studied, little is known about its indirect effects, especially in aquatic ecosystems. Based on limited prior studies, I predicted addition of L. maackii leaves to aquatic systems would increase mortality of a top amphibian predator due to the release of phenolic compounds that inhibit respiration. A mesocosm experiment was developed to characterize the cascading effects of increased top predator (Ambystoma maculatum) mortality on larval salamander growth, macroinvertebrate densities, zooplankton densities, leaf litter mass loss, chlorophyll a abundance, biofilm growth, and availability of soluble nutrients. Of the 20 mesocosms that contained larval A. maculatum, only 11 produced metamorphs, and only one mesocosm with leaf litter from L. maackii produced metamorphs. All 10 mesocosms containing A. maculatum larvae and native leaf litter produced metamorphs. A total of 117 metamorphs were retrieved from all mesocosms, and only three of those 117 were retrieved from mesocosms with leaf litter from L. maackii. Salamander survival and growth rates (mm/day) were significantly lower in mesocosms with L. maackii than in mesocosms with native leaf litter alone. Mesocosms with L. maackii leaf litter also contained substantially more mosquito larvae, suggesting reduced water quality. There was no indication that apex predator mortality in L. maackii mesocosms altered aquatic ecosystem functions. However, increased mass loss occurred in leaf packs containing L. maackii compared to leaf packs containing native leaf litter removed from the same mesocosm, which was not caused by greater invertebrate densities within L. maackii packs. I also found there to be an oily sheen on the water surface of mesocosms containing L. maackii leaf litter, which could hinder gill-breathing by amphibians. Relatively high invertebrate densities and diversity may have served as a buffer for lower trophic levels, such that they were not affected when A. maculatum individuals were eliminated from mesocosms due to exposure to L. maackii phenolic compounds. The results of this study will help complete the overall picture of the possible consequences of biological invasion.
"],"dc:format":["application/PDF"],"dc:identifier":["https://encompass.eku.edu/etd/590"],"dc:publisher":["Encompass Digital Archive, Eastern Kentucky University"],"dc:rights":["Copyright 2019 Josey Lee-Anne Berta"],"dc:source":["Encompass Digital Archive: Online Theses and Dissertations"],"dc:subject":["Ambystoma Maculatum","Apex Predator","Ephemeral Pond","Invasive Plant","Lonicera maackii","Trophic Cascade","Terrestrial and Aquatic Ecology"],"dc:title":["Ecosystem Functional Consequences of Top Predator Mortality Due to the Invasive Shrub, Lonicera maackii"],"dc:type":["Master Thesis"],"thesis:degree_discipline":["Biological Sciences"],"thesis:degree_level":["Master's"],"thesis:degree_name":["Master of Science (MS)"],"thesis:institution_name":["Eastern Kentucky University"]},"updated_at":"2026-07-24T02:15:47Z"}