Mon, Aug 15, 2022: 5:00 PM-6:30 PM
ESA Exhibit Hall
Background/Question/MethodsTrees alter soil biogeochemistry through inputs of leaves, roots, and reproductive tissues. These alterations to the soil influence communities of soil organisms, including bacteria, fungi, insects, and other invertebrates. Soil organisms also drive carbon and nutrient cycling in the soil by immobilizing, transforming, and mineralizing them. Because different plant species create inputs that vary in quantity and quality, they may shape soil communities both directly via litter and indirectly by a shared influence on soil properties. In this study, we used 18 tree monoculture plots at the Morton Arboretum (Lisle, IL USA) to evaluate the effects of tree traits and soil properties on soil invertebrate communities. Trees in these monocultures vary in leaf habit and mycorrhizal association with all combinations well represented. In June and July 2021, we used weekly cover board surveys to assess soil macroinvertebrate community composition. We also assessed ammonium, nitrate, and phosphate availability with anion and cation resin strips on a biweekly basis and quantified extractable organic carbon and microbial biomass concentrations and nitrogen mineralization rates once in June and once in July.
Results/ConclusionsWe identified 20 orders among the 36,147 soil invertebrates surveyed. Communities were dominated by Isopoda (69% of all invertebrates) and Hymenoptera (17% of all invertebrates). Araneae, Opiliones, and Orthoptera were also abundant. No effects of leaf habit or mycorrhizal type were noted for soil phosphorus availability and soil carbon availability. On the other hand, evergreen plots and AM plots had greater ammonium and nitrate availability and faster nitrogen mineralization rates (P < 0.01). Extractable organic carbon concentrations were greater in July and microbial biomass was greater in June (P < 0.001) though other variables did not vary over time (P ≥ 0.06). Variation in the macroinvertebrate community was significantly related to tree traits and soil properties (39% of variation explained). The largest effect was leaf habit, which was correlated with the nitrogen mineralization rate. Isopoda, in particular, was most abundant in evergreen plots, though the community composition of Isopoda at the genera level varied with tree traits and soil properties (57% of variation explained). Our results confirm that trees can both directly and indirectly shape soil invertebrate communities. Primarily, tree leaf habits were observed to affect variability among soil macroinvertebrate communities via soil nitrogen availability.
Results/ConclusionsWe identified 20 orders among the 36,147 soil invertebrates surveyed. Communities were dominated by Isopoda (69% of all invertebrates) and Hymenoptera (17% of all invertebrates). Araneae, Opiliones, and Orthoptera were also abundant. No effects of leaf habit or mycorrhizal type were noted for soil phosphorus availability and soil carbon availability. On the other hand, evergreen plots and AM plots had greater ammonium and nitrate availability and faster nitrogen mineralization rates (P < 0.01). Extractable organic carbon concentrations were greater in July and microbial biomass was greater in June (P < 0.001) though other variables did not vary over time (P ≥ 0.06). Variation in the macroinvertebrate community was significantly related to tree traits and soil properties (39% of variation explained). The largest effect was leaf habit, which was correlated with the nitrogen mineralization rate. Isopoda, in particular, was most abundant in evergreen plots, though the community composition of Isopoda at the genera level varied with tree traits and soil properties (57% of variation explained). Our results confirm that trees can both directly and indirectly shape soil invertebrate communities. Primarily, tree leaf habits were observed to affect variability among soil macroinvertebrate communities via soil nitrogen availability.