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Wills BD, Kim TN, Fox AF, Gratton C, Landis DA. Reducing Native Ant Abundance Decreases Predation Rates in Midwestern Grasslands. ENVIRONMENTAL ENTOMOLOGY 2019; 48:1360-1368. [PMID: 31713603 PMCID: PMC6894410 DOI: 10.1093/ee/nvz127] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Indexed: 06/10/2023]
Abstract
Diverse and robust predator communities are important for effective prey suppression in natural and managed communities. Ants are ubiquitous components of terrestrial systems but their contributions to natural prey suppression is relatively understudied in temperate regions. Growing evidence suggests that ants can play a significant role in the removal of insect prey within grasslands, but their impact is difficult to separate from that of nonant predators. To test how ants may contribute to prey suppression in grasslands, we used poison baits (with physical exclosures) to selectively reduce the ant population in common garden settings, then tracked ant and nonant ground predator abundance and diversity, and removal of sentinel egg prey for 7 wk. We found that poison baits reduced ant abundance without a significant negative impact on abundance of nonant ground predators, and that a reduction in ant abundance decreased the proportion of sentinel prey eggs removed. Even a modest decrease (~20%) in abundance of several ant species, including the numerically dominant Lasius neoniger Emery (Hymenoptera: Formicidae), significantly reduced sentinel prey removal rates. Our results suggest that ants disproportionately contribute to ground-based predation of arthropod prey in grasslands. Changes in the amount of grasslands on the landscape and its management may have important implications for ant prevalence and natural prey suppression services in agricultural landscapes.
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Affiliation(s)
- B D Wills
- Department of Entomology and DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI
| | - T N Kim
- Department of Entomology and DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI
| | - A F Fox
- Department of Entomology and DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI
| | - C Gratton
- Department of Entomology and DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI
| | - D A Landis
- Department of Entomology and DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI
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Kim T, Bartel S, Gratton C. Grassland harvesting alters ant community trophic structure: An isotopic study in tallgrass prairies. Ecol Evol 2019; 9:9815-9826. [PMID: 31534696 PMCID: PMC6745673 DOI: 10.1002/ece3.5523] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 05/20/2019] [Accepted: 07/01/2019] [Indexed: 11/11/2022] Open
Abstract
Disturbances have long been recognized as important forces for structuring natural communities but their effects on trophic structure are not well understood, particularly in terrestrial systems. This is in part because quantifying trophic linkages is a challenge, especially for small organisms with cryptic feeding behaviors such as insects, and often relies on conducting labor-intensive feeding trials or extensive observations in the field. In this study, we used stable isotopes of carbon and nitrogen to examine how disturbance (annual biomass harvesting) in tallgrass prairies affected the trophic position, trophic range, and niche space of ants, a widespread grassland consumer. We hypothesized that biomass harvest would remove important food and nesting resources of insects thus affecting ant feeding relationships and trophic structure. We found shifts in the feeding relationships inferred by isotopic signatures with harvest. In particular, these shifts suggest that ants within harvest sites utilized resources at lower trophic levels (possibly plant-based resources or herbivores), expanded trophic breadth, and occupied different niche spaces. Shifts in resource use following harvest could be due to harvest-mediated changes in both the plant and arthropod communities that might affect the strength of competition or alter plant nitrogen availability. Because shifts in resource use alter the flow of nutrients across the food web, disturbance effects on ants could have ecosystem-level consequences through nutrient cycling.
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Affiliation(s)
- Tania Kim
- Great Lakes Bioenergy Research CenterUniversity of Wisconsin MadisonMadisonWIUSA
| | - Savannah Bartel
- Department of Integrative BiologyUniversity of Wisconsin MadisonMadisonWIUSA
| | - Claudio Gratton
- Great Lakes Bioenergy Research CenterUniversity of Wisconsin MadisonMadisonWIUSA
- Department of EntomologyUniversity of Wisconsin MadisonMadisonWIUSA
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Spiesman BJ, Bennett A, Isaacs R, Gratton C. Harvesting effects on wild bee communities in bioenergy grasslands depend on nesting guild. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2019; 29:e01828. [PMID: 30412332 DOI: 10.1002/eap.1828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/05/2018] [Indexed: 06/08/2023]
Abstract
Conversion of annual crops to native perennial grasslands for bioenergy production may help conserve wild bees by enhancing nest and food resources. However, bee response to the disturbance of biomass harvesting may depend on their nesting location, thus their vulnerability to nest destruction, and the response of the forb community on which they forage. Moreover, because bees have long foraging ranges, effects of local harvesting may depend on the amount of natural habitat in the surrounding landscape. We performed a large-scale one- and two-year experiment in Michigan and Wisconsin, USA, respectively, to examine how grassland harvesting, landscape context, and study year affect the forb community, above- and belowground-nesting bee species richness, community composition, trap nest emergence, and visitation rate. In Wisconsin, harvesting increased forb richness, cover, and evenness compared to unharvested control sites. Harvesting negatively affected aboveground-nesting bee richness and emergence from trap nests, possibly because of nest destruction during the previous harvest. By contrast, harvesting positively affected belowground-nesting bee richness, possibly because of the greater food resource availability and reduced thatch allowing greater access to nesting sites in the soil. Harvesting also affected bee community composition, reflecting the increase in belowground-nesting species at harvested sites. Despite harvesting effects on forb and bee communities, there was no effect on flower visitation rate, indicating little effect on pollination function. We did not find a harvest by landscape context interaction, which, in combination with the negative harvesting effect on trap nest emergence, suggests that harvesting can affect local population growth rather than simply affecting forager aggregation in different resource environments. For bees, there was no harvest by study year interaction, indicating a consistent response over a short timescale. Similarly, in Michigan, belowground-nesting species also responded positively to harvesting, which was more pronounced in sandier soils that are preferred for nesting. However, other components of the Michigan bee and forb communities were not significantly affected by biomass harvesting. Overall, our study demonstrates that harvesting grasslands can positively affect the ~80% of bee species that nest belowground by enhancing nest and/or forage resources, but that conserving aboveground nesters may require leaving some area unharvested.
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Affiliation(s)
- Brian J Spiesman
- Department of Entomology, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
- Department of Entomology, Kansas State University, Manhattan, Kansas, 66506, USA
| | - Ashley Bennett
- Department of Entomology, Michigan State University, East Lansing, Michigan, 48824, USA
- Department of Extension Plant Sciences, New Mexico State University, Los Lunas, New Mexico, 87031, USA
| | - Rufus Isaacs
- Department of Entomology, Michigan State University, East Lansing, Michigan, 48824, USA
- Ecology, Evolutionary Biology, and Behavior Program, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Claudio Gratton
- Department of Entomology, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
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Kim TN, Bartel S, Wills BD, Landis DA, Gratton C. Disturbance differentially affects alpha and beta diversity of ants in tallgrass prairies. Ecosphere 2018. [DOI: 10.1002/ecs2.2399] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Tania N. Kim
- Great Lakes Bioenergy Research Center University of Wisconsin Madison Madison Wisconsin 53726 USA
| | - Savannah Bartel
- Great Lakes Bioenergy Research Center University of Wisconsin Madison Madison Wisconsin 53726 USA
| | - Bill D. Wills
- Center for Integrated Plant Systems Lab Michigan State University East Lansing Michigan 48824 USA
| | - Douglas A. Landis
- Center for Integrated Plant Systems Lab Michigan State University East Lansing Michigan 48824 USA
| | - Claudio Gratton
- Great Lakes Bioenergy Research Center University of Wisconsin Madison Madison Wisconsin 53726 USA
- Department of Entomology University of Wisconsin Madison Madison Wisconsin 53706 USA
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