{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/137294"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/137294","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Impacts of Invasive Asian Jumping Worms on Soil Properties in Turfgrass Systems and their effects on Plant Nutrient Acquisition and Physiological Responses in Greenhouse Experiments","abstract":"This thesis examines the ecological impact of invasive Asian jumping worms (Amynthas spp.) in turfgrass systems and controlled greenhouse conditions. In the field, we evaluated jumping worm presence using environmental DNA (eDNA) and assessed associated changes in microarthropod abundance, microbial enzyme activity, soil chemical and physical properties, and turf condition. The study was conducted at four residential sites in southwest Virginia, each with garden bed infestations and adjacent turfgrass lawns. Sampling occurred in May and September 2024. At each site, four fixed transects were established, beginning one meter inside the garden bed and extending ten meters into the lawn. Soil and turf data were collected from one-square-meter quadrats placed at three locations along each transect: within the garden (\"Bed\"), at the turf edge (\"Turf Near\"), and six meters further into the lawn (\"Turf Far\"), resulting in 48 quadrats across all sites. Jumping worms were most frequently detected in turf quadrats adjacent to garden beds, confirming our hypothesis of turf as a zone of invasion. Microarthropod communities, particularly Collembola, exhibited a pronounced early-season increase in jumping worm-invaded areas followed by a late-season collapse. This shift coincided with changes in microbial enzyme activity: chitin-degrading NAG increased after arthropod decline, while nitrogen-releasing LAP decreased most in jumping worm-infested garden soils. Soil structure was primarily affected in garden beds, specifically, large aggregates (>2 mm) increased in jumping worm-infested beds, while mid-sized aggregates (0.25–2 mm) decreased. Soil nutrients remained largely stable, though phosphorus and organic matter showed seasonally dependent shifts linked to jumping worm presence. Firth logistic regression identified organic matter as a significant predictor of jumping worm detection, though this relationship reversed over time, likely reflecting resource exhaustion or outward migration into turf. Turfgrass condition appeared visually unaffected. Collectively, these findings indicate that while aboveground vegetation may appear intact, significant biological restructuring is underway below ground. In a complementary greenhouse experiment, we tested whether invasive jumping worms alter soil conditions in ways that influence bean physiology. We collected jumping worm-free topsoil from a local farm and divided it evenly into two 151 liter bins. Both bins received identical amendments of coconut coir and compost. One bin was inoculated with 80 live jumping worms; the other remained jumping worm-free. These bins were kept moist and left undisturbed for 12 weeks to allow soil conditioning. No fertilizers were added. After this period, we used each soil type to fill ten 3.8-liter nursery pots (n = 20 total), with no jumping worms transferred into the pots. Provider bush beans (Phaseolus vulgaris) were sown directly into each pot, and plants were grown under uniform greenhouse conditions. We repeated this process in a second planting round using the same bins after six months of soil conditioning to test for cumulative jumping worm effects. Across both rounds, we measured developmental stage (BBCH), chlorophyll content (SPAD), stomatal conductance, biomass, tissue nutrients, and soil chemistry. While planting round was the main driver of BBCH and SPAD, jumping worm-conditioned soils in Round 2 consistently showed slightly elevated values, suggesting compounding effects over time. Stomatal conductance declined sharply in jumping worm-free pots between rounds but remained stable in jumping worm-conditioned soils, possibly reflecting moisture or nutrient buffering. Notably, jumping worm-treated plants produced greater fresh biomass but lower nitrogen content, resulting in elevated C:N ratios. This pattern may reflect a mild dilution effect, where increased growth and water content are associated with slightly lower nutrient concentrations in vegetative tissues. However, carbon and nitrogen concentrations in bean pods remained consistent across treatments, suggesting that plants prioritized allocation of limited resources to reproductive tissues despite reduced shoot nitrogen content. Soil chemistry shifts, especially in calcium, magnesium, potassium, and organic matter, were consistent with accelerated nutrient turnover in jumping worm-conditioned soils.","abstract_html":"This thesis examines the ecological impact of invasive Asian jumping worms (Amynthas spp.) in turfgrass systems and controlled greenhouse conditions. In the field, we evaluated jumping worm presence using environmental DNA (eDNA) and assessed associated changes in microarthropod abundance, microbial enzyme activity, soil chemical and physical properties, and turf condition. The study was conducted at four residential sites in southwest Virginia, each with garden bed infestations and adjacent turfgrass lawns. Sampling occurred in May and September 2024. At each site, four fixed transects were established, beginning one meter inside the garden bed and extending ten meters into the lawn. Soil and turf data were collected from one-square-meter quadrats placed at three locations along each transect: within the garden ("Bed"), at the turf edge ("Turf Near"), and six meters further into the lawn ("Turf Far"), resulting in 48 quadrats across all sites. Jumping worms were most frequently detected in turf quadrats adjacent to garden beds, confirming our hypothesis of turf as a zone of invasion. Microarthropod communities, particularly Collembola, exhibited a pronounced early-season increase in jumping worm-invaded areas followed by a late-season collapse. This shift coincided with changes in microbial enzyme activity: chitin-degrading NAG increased after arthropod decline, while nitrogen-releasing LAP decreased most in jumping worm-infested garden soils. Soil structure was primarily affected in garden beds, specifically, large aggregates (>2 mm) increased in jumping worm-infested beds, while mid-sized aggregates (0.25–2 mm) decreased. Soil nutrients remained largely stable, though phosphorus and organic matter showed seasonally dependent shifts linked to jumping worm presence. Firth logistic regression identified organic matter as a significant predictor of jumping worm detection, though this relationship reversed over time, likely reflecting resource exhaustion or outward migration into turf. Turfgrass condition appeared visually unaffected. Collectively, these findings indicate that while aboveground vegetation may appear intact, significant biological restructuring is underway below ground. In a complementary greenhouse experiment, we tested whether invasive jumping worms alter soil conditions in ways that influence bean physiology. We collected jumping worm-free topsoil from a local farm and divided it evenly into two 151 liter bins. Both bins received identical amendments of coconut coir and compost. One bin was inoculated with 80 live jumping worms; the other remained jumping worm-free. These bins were kept moist and left undisturbed for 12 weeks to allow soil conditioning. No fertilizers were added. After this period, we used each soil type to fill ten 3.8-liter nursery pots (n = 20 total), with no jumping worms transferred into the pots. Provider bush beans (Phaseolus vulgaris) were sown directly into each pot, and plants were grown under uniform greenhouse conditions. We repeated this process in a second planting round using the same bins after six months of soil conditioning to test for cumulative jumping worm effects. Across both rounds, we measured developmental stage (BBCH), chlorophyll content (SPAD), stomatal conductance, biomass, tissue nutrients, and soil chemistry. While planting round was the main driver of BBCH and SPAD, jumping worm-conditioned soils in Round 2 consistently showed slightly elevated values, suggesting compounding effects over time. Stomatal conductance declined sharply in jumping worm-free pots between rounds but remained stable in jumping worm-conditioned soils, possibly reflecting moisture or nutrient buffering. Notably, jumping worm-treated plants produced greater fresh biomass but lower nitrogen content, resulting in elevated C:N ratios. This pattern may reflect a mild dilution effect, where increased growth and water content are associated with slightly lower nutrient concentrations in vegetative tissues. However, carbon and nitrogen concentrations in bean pods remained consistent across treatments, suggesting that plants prioritized allocation of limited resources to reproductive tissues despite reduced shoot nitrogen content. Soil chemistry shifts, especially in calcium, magnesium, potassium, and organic matter, were consistent with accelerated nutrient turnover in jumping worm-conditioned soils.","abstract_has_math":false,"creators":["Thompson, Jordan Catherine"],"institution":"Virginia Tech","degree_name":"Master of Science in Life Sciences","degree_level":"masters","degree_discipline":"Entomology","degree_department":"Entomology","school":null,"contributors":[],"advisors":[],"committee_chairs":["Kuhar, Thomas P.","Del Pozo-Valdivia, Alejandro"],"committee_members":["Jernigan, Ashley"],"year":2025,"date_issued":"2025-08-11","date_published":"2025-08-11","updated_at":"2026-07-22T22:19:33Z","subjects":["Asian jumping worms","invasive earthworms","soil ecology","turfgrass ecology","eDNA"],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:44471"],"render_values":[{"text":"vt_gsexam:44471","href":null,"code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/10919/137294","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Kuhar, Thomas P.","Del Pozo-Valdivia, Alejandro"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Jernigan, Ashley"]},{"key":"dc:contributor.department","label":"Department","values":["Entomology"]},{"key":"dc:creator","label":"Author","values":["Thompson, Jordan Catherine"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-08-12T08:00:16Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2025-08-12T08:00:16Z"]},{"key":"dc:date.issued","label":"Date","values":["2025-08-11"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Entomology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science in Life Sciences"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Asian jumping worms","invasive earthworms","soil ecology","turfgrass ecology","eDNA"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:44471"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10919/137294"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This thesis examines the ecological impact of invasive Asian jumping worms (Amynthas spp.) in turfgrass systems and controlled greenhouse conditions. In the field, we evaluated jumping worm presence using environmental DNA (eDNA) and assessed associated changes in microarthropod abundance, microbial enzyme activity, soil chemical and physical properties, and turf condition. The study was conducted at four residential sites in southwest Virginia, each with garden bed infestations and adjacent turfgrass lawns. Sampling occurred in May and September 2024. At each site, four fixed transects were established, beginning one meter inside the garden bed and extending ten meters into the lawn. Soil and turf data were collected from one-square-meter quadrats placed at three locations along each transect: within the garden (\"Bed\"), at the turf edge (\"Turf Near\"), and six meters further into the lawn (\"Turf Far\"), resulting in 48 quadrats across all sites. Jumping worms were most frequently detected in turf quadrats adjacent to garden beds, confirming our hypothesis of turf as a zone of invasion. Microarthropod communities, particularly Collembola, exhibited a pronounced early-season increase in jumping worm-invaded areas followed by a late-season collapse. This shift coincided with changes in microbial enzyme activity: chitin-degrading NAG increased after arthropod decline, while nitrogen-releasing LAP decreased most in jumping worm-infested garden soils. Soil structure was primarily affected in garden beds, specifically, large aggregates (>2 mm) increased in jumping worm-infested beds, while mid-sized aggregates (0.25–2 mm) decreased. Soil nutrients remained largely stable, though phosphorus and organic matter showed seasonally dependent shifts linked to jumping worm presence. Firth logistic regression identified organic matter as a significant predictor of jumping worm detection, though this relationship reversed over time, likely reflecting resource exhaustion or outward migration into turf. Turfgrass condition appeared visually unaffected. Collectively, these findings indicate that while aboveground vegetation may appear intact, significant biological restructuring is underway below ground. In a complementary greenhouse experiment, we tested whether invasive jumping worms alter soil conditions in ways that influence bean physiology. We collected jumping worm-free topsoil from a local farm and divided it evenly into two 151 liter bins. Both bins received identical amendments of coconut coir and compost. One bin was inoculated with 80 live jumping worms; the other remained jumping worm-free. These bins were kept moist and left undisturbed for 12 weeks to allow soil conditioning. No fertilizers were added. After this period, we used each soil type to fill ten 3.8-liter nursery pots (n = 20 total), with no jumping worms transferred into the pots. Provider bush beans (Phaseolus vulgaris) were sown directly into each pot, and plants were grown under uniform greenhouse conditions. We repeated this process in a second planting round using the same bins after six months of soil conditioning to test for cumulative jumping worm effects. Across both rounds, we measured developmental stage (BBCH), chlorophyll content (SPAD), stomatal conductance, biomass, tissue nutrients, and soil chemistry. While planting round was the main driver of BBCH and SPAD, jumping worm-conditioned soils in Round 2 consistently showed slightly elevated values, suggesting compounding effects over time. Stomatal conductance declined sharply in jumping worm-free pots between rounds but remained stable in jumping worm-conditioned soils, possibly reflecting moisture or nutrient buffering. Notably, jumping worm-treated plants produced greater fresh biomass but lower nitrogen content, resulting in elevated C:N ratios. This pattern may reflect a mild dilution effect, where increased growth and water content are associated with slightly lower nutrient concentrations in vegetative tissues. However, carbon and nitrogen concentrations in bean pods remained consistent across treatments, suggesting that plants prioritized allocation of limited resources to reproductive tissues despite reduced shoot nitrogen content. Soil chemistry shifts, especially in calcium, magnesium, potassium, and organic matter, were consistent with accelerated nutrient turnover in jumping worm-conditioned soils."]},{"key":"dc:description.abstractgeneral","label":"General Abstract","values":["This research looked at how invasive Asian jumping worms are affecting soil life and plant health in turfgrass lawns and greenhouse experiments. In the field, we studied where jumping worms were spreading using environmental DNA testing and measured their effects on soil insects, microbial activity, soil structure, and turf condition. We found that jumping worms often spread from garden beds into nearby turf, making those areas especially vulnerable. In those spots, soil arthropods like springtails, first increased in abundance early in the season, then suffered a population decline later. This matched changes in microbial activity: one key enzyme related to breaking down chitin increased after insect numbers dropped, while another enzyme tied to nitrogen release declined in jumping worm-heavy soils. These patterns suggest that jumping worms are disrupting the normal balance of the underground soil food web. We also observed changes in soil structure within garden beds, while most nutrients remained stable. Phosphorus declined over time in jumping worm-free soils but remained stable when the wroms were present, suggesting a potential buffering or sustained input effect linked to worm activity. Organic matter generally increased across sites over time, but its relationship with jumping worm presence changed from spring to fall. In spring, high organic matter was associated with jumping worm presence, while by fall, lower organic matter predicted worm presence. This may reflect jumping worm-driven resource depletion or movement from garden beds into turf. Aboveground, turf still appeared healthy overall, though subtle signs of early impact such as increased bare ground and weed presence were more common in invaded areas. In the greenhouse, we tested how jumping worms affect the growth of bean plants. We measured plant development, leaf color, water use, biomass, nutrient levels, and soil nutrients. Beans grown in jumping worm-treated soil showed slightly faster development and greener leaves over time. Interestingly, plants in jumping worm-treated soil had more fresh weight but lower nitrogen levels, suggesting they grew quickly but with reduced nutrient density in vegetative tissues. However, the bean pods themselves maintained comparable nitrogen and carbon concentrations to those in control soils, indicating that reproductive tissues remained nutritionally intact despite changes elsewhere in the plant. Soil tests supported the idea that jumping worm activity accelerates nutrient cycling and organic matter turnover."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science in Life Sciences"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:title","label":"Title","values":["Impacts of Invasive Asian Jumping Worms on Soil Properties in Turfgrass Systems and their effects on Plant Nutrient Acquisition and Physiological Responses in Greenhouse Experiments"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Kuhar, Thomas P.","Del Pozo-Valdivia, Alejandro"],"dc:contributor.committeemember":["Jernigan, Ashley"],"dc:contributor.department":["Entomology"],"dc:creator":["Thompson, Jordan Catherine"],"dc:date.accessioned":["2025-08-12T08:00:16Z"],"dc:date.available":["2025-08-12T08:00:16Z"],"dc:date.issued":["2025-08-11"],"dc:description.abstract":["This thesis examines the ecological impact of invasive Asian jumping worms (Amynthas spp.) in turfgrass systems and controlled greenhouse conditions. In the field, we evaluated jumping worm presence using environmental DNA (eDNA) and assessed associated changes in microarthropod abundance, microbial enzyme activity, soil chemical and physical properties, and turf condition. The study was conducted at four residential sites in southwest Virginia, each with garden bed infestations and adjacent turfgrass lawns. Sampling occurred in May and September 2024. At each site, four fixed transects were established, beginning one meter inside the garden bed and extending ten meters into the lawn. Soil and turf data were collected from one-square-meter quadrats placed at three locations along each transect: within the garden (\"Bed\"), at the turf edge (\"Turf Near\"), and six meters further into the lawn (\"Turf Far\"), resulting in 48 quadrats across all sites. Jumping worms were most frequently detected in turf quadrats adjacent to garden beds, confirming our hypothesis of turf as a zone of invasion. Microarthropod communities, particularly Collembola, exhibited a pronounced early-season increase in jumping worm-invaded areas followed by a late-season collapse. This shift coincided with changes in microbial enzyme activity: chitin-degrading NAG increased after arthropod decline, while nitrogen-releasing LAP decreased most in jumping worm-infested garden soils. Soil structure was primarily affected in garden beds, specifically, large aggregates (>2 mm) increased in jumping worm-infested beds, while mid-sized aggregates (0.25–2 mm) decreased. Soil nutrients remained largely stable, though phosphorus and organic matter showed seasonally dependent shifts linked to jumping worm presence. Firth logistic regression identified organic matter as a significant predictor of jumping worm detection, though this relationship reversed over time, likely reflecting resource exhaustion or outward migration into turf. Turfgrass condition appeared visually unaffected. Collectively, these findings indicate that while aboveground vegetation may appear intact, significant biological restructuring is underway below ground. In a complementary greenhouse experiment, we tested whether invasive jumping worms alter soil conditions in ways that influence bean physiology. We collected jumping worm-free topsoil from a local farm and divided it evenly into two 151 liter bins. Both bins received identical amendments of coconut coir and compost. One bin was inoculated with 80 live jumping worms; the other remained jumping worm-free. These bins were kept moist and left undisturbed for 12 weeks to allow soil conditioning. No fertilizers were added. After this period, we used each soil type to fill ten 3.8-liter nursery pots (n = 20 total), with no jumping worms transferred into the pots. Provider bush beans (Phaseolus vulgaris) were sown directly into each pot, and plants were grown under uniform greenhouse conditions. We repeated this process in a second planting round using the same bins after six months of soil conditioning to test for cumulative jumping worm effects. Across both rounds, we measured developmental stage (BBCH), chlorophyll content (SPAD), stomatal conductance, biomass, tissue nutrients, and soil chemistry. While planting round was the main driver of BBCH and SPAD, jumping worm-conditioned soils in Round 2 consistently showed slightly elevated values, suggesting compounding effects over time. Stomatal conductance declined sharply in jumping worm-free pots between rounds but remained stable in jumping worm-conditioned soils, possibly reflecting moisture or nutrient buffering. Notably, jumping worm-treated plants produced greater fresh biomass but lower nitrogen content, resulting in elevated C:N ratios. This pattern may reflect a mild dilution effect, where increased growth and water content are associated with slightly lower nutrient concentrations in vegetative tissues. However, carbon and nitrogen concentrations in bean pods remained consistent across treatments, suggesting that plants prioritized allocation of limited resources to reproductive tissues despite reduced shoot nitrogen content. Soil chemistry shifts, especially in calcium, magnesium, potassium, and organic matter, were consistent with accelerated nutrient turnover in jumping worm-conditioned soils."],"dc:description.abstractgeneral":["This research looked at how invasive Asian jumping worms are affecting soil life and plant health in turfgrass lawns and greenhouse experiments. In the field, we studied where jumping worms were spreading using environmental DNA testing and measured their effects on soil insects, microbial activity, soil structure, and turf condition. We found that jumping worms often spread from garden beds into nearby turf, making those areas especially vulnerable. In those spots, soil arthropods like springtails, first increased in abundance early in the season, then suffered a population decline later. This matched changes in microbial activity: one key enzyme related to breaking down chitin increased after insect numbers dropped, while another enzyme tied to nitrogen release declined in jumping worm-heavy soils. These patterns suggest that jumping worms are disrupting the normal balance of the underground soil food web. We also observed changes in soil structure within garden beds, while most nutrients remained stable. Phosphorus declined over time in jumping worm-free soils but remained stable when the wroms were present, suggesting a potential buffering or sustained input effect linked to worm activity. Organic matter generally increased across sites over time, but its relationship with jumping worm presence changed from spring to fall. In spring, high organic matter was associated with jumping worm presence, while by fall, lower organic matter predicted worm presence. This may reflect jumping worm-driven resource depletion or movement from garden beds into turf. Aboveground, turf still appeared healthy overall, though subtle signs of early impact such as increased bare ground and weed presence were more common in invaded areas. In the greenhouse, we tested how jumping worms affect the growth of bean plants. We measured plant development, leaf color, water use, biomass, nutrient levels, and soil nutrients. Beans grown in jumping worm-treated soil showed slightly faster development and greener leaves over time. Interestingly, plants in jumping worm-treated soil had more fresh weight but lower nitrogen levels, suggesting they grew quickly but with reduced nutrient density in vegetative tissues. However, the bean pods themselves maintained comparable nitrogen and carbon concentrations to those in control soils, indicating that reproductive tissues remained nutritionally intact despite changes elsewhere in the plant. Soil tests supported the idea that jumping worm activity accelerates nutrient cycling and organic matter turnover."],"dc:description.degree":["Master of Science in Life Sciences"],"dc:format.medium":["ETD"],"dc:identifier.other":["vt_gsexam:44471"],"dc:identifier.uri":["https://hdl.handle.net/10919/137294"],"dc:language.iso":["en"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Asian jumping worms","invasive earthworms","soil ecology","turfgrass ecology","eDNA"],"dc:title":["Impacts of Invasive Asian Jumping Worms on Soil Properties in Turfgrass Systems and their effects on Plant Nutrient Acquisition and Physiological Responses in Greenhouse Experiments"],"dc:type":["Thesis"],"thesis:degree_discipline":["Entomology"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science in Life Sciences"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:19:33Z"}