Publication Date
11-4-2025
Document Type
Article
Organizational Units
College of Natural Science and Mathematics, Biological Sciences
Keywords
Anthropogenic disturbance, Cheatgrass, Competition, Invasive species, Light pollution, Urban ecosystem
Abstract
Artificial light at night (ALAN) is an important global disturbance that affects community dynamics, but how it affects species interactions, such as competition, is not well understood and needs investigation. In plant communities, some exotic-invasive plant species seem to be facilitated by ALAN, which may alter competitive outcomes with native plant communities and promote invasion. Despite these intriguing results, whether ALAN affects competitive outcomes between native and invasive species is understudied. Here we tested how ALAN affects competitive outcomes between two native prairie grasses and two grasses that are exotic-invasive in North America. We planted each native species with a range of densities of each exotic species, thereby creating a competition gradient for the native species. We grew these competition treatments under ambient or ALAN light treatments to test if ALAN altered competitive outcomes between native and exotic grasses. We found that ALAN-stimulated growth was significantly greater for our exotic grasses than for the native grasses as predicted, and this enhanced their competitive impact on native species as seen in decreases in native carbon:nitrogen ratios. Our experiment provides support for the hypothesis that the stimulating effect of ALAN on exotic plant growth can increase the competitive ability of exotic grasses and thus the negative effect of these invasive species on native plants.
Copyright Date
11-4-2025
Copyright Statement / License for Reuse

This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Rights Holder
Shannon M. Murphy, Kylee Grenis, and Anna A. Sher
Provenance
Received from Elsevier
File Format
application/pdf
Language
English (eng)
Extent
9 pgs
File Size
3.50 MB
Publication Statement
Copyright is held by the Authors. User is responsible for all copyright compliance. This article was originally published as
Murphy, S. M., Grenis, K., & Sher, A. A. (2025). Artificial Light at Night Can Worsen Competitive Outcomes Between Native and Invasive Grasses. Biological Conservation, 313. https://doi.org/10.1016/j.biocon.2025.111586
Publication Title
Biological Conservation
Volume
313
First Page
111586
ISSN
0006-3207
Recommended Citation
Murphy, Shannon M.; Grenis, Kylee; and Sher, Anna A., "Artificial Light at Night Can Worsen Competitive Outcomes Between Native and Invasive Grasses" (2025). Biological Sciences: Faculty Scholarship. 71.
https://digitalcommons.du.edu/biological_sciences_faculty/71
https://doi.org/10.1016/j.biocon.2025.111586
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