| Abstract Detail
Ecology Wu, Yingtong [1], Ricklefs, Robert [2]. Herbivory, seed predators, or soil microbes: What determines species range limits in oaks (Quercus)? Why a species is present at certain locations but absent from others is a key issue in ecology and biogeography. While ecologists have recognized the importance of abiotic factors in constraining species’ ranges, we know little about the role of natural enemies in shaping species distributions, especially through antagonistic interactions with soil microbes, seed predators, and herbivores. In this study, we investigated whether these antagonistic interactions constrain range limits of oaks (Quercus sp.) in eastern North America. We used a greenhouse soil inoculum experiment to investigate the impact of beyond-range soil microbes in general, or beyond-range soil microbes associated only with the sister species, on host species ranges. To test the effects of seed predation, we conducted a seed-predator exclosure experiment with acorns of beyond-range and home-range sister species planted within and beyond exclosure cages. We also performed a field survey to compare seed predation rates at the range edge vs. the range interior. To test the effects of herbivores, we transplanted seedlings of beyond-range and home-range sister species in the field and compared their survival within and beyond the herbivore exclosure. Soil microbes from sister species decreased the survival and aboveground biomass of seedlings of the beyond-range species, while beyond-range soil microbes in general did not affect their survival or growth, indicating microbe-mediated apparent competition between sister species. In the seed-predator exclosure and the herbivore exclosure experiments, seed predation and herbivory were equally strong for both the home-range and beyond-range oak species. In the field survey, we found that seed predation rates were similar at range edge and range interior. Our results indicate that apparent competition through soil microbes partially explain the range limits of studied oak species. This study showcased the importance of testing multiple hypotheses within the same system to fully understand how biotic interactions restrict species ranges. Considering belowground soil-plant interactions is essential to making accurate predictions of plant range shifts, and to the conservation of range-restricted species that are sensitive to novel pathogens.
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1 - University Of Missouri-St. Louis, Biology Department, R223 Research Building, 1 University Blvd, St. Louis, MO, 63121, United States
2 - University Of Missouri-St. Louis, Biology Department, R223 Research Building, 1 University Blvd, St. Louis, MO, 63121, USA
Keywords:
species distribution models
Quercus
oaks
seed predation
abiotic stress
soil microbes
soil pathogens.
Presentation Type: Oral Paper
Session: ECO9, Ecology: Species Ranges and Distributions
Location: /
Date: Friday, July 23rd, 2021
Time: 3:30 PM(EDT)
Number: ECO9003
Abstract ID:211
Candidate for Awards:Ecological Section Best Graduate Student Paper |
