Effects of Warming on Growth and Leaf Colonization by Litter Mat-Forming Fungi in a Wet Tropical Forest in Puerto Rico

Authors

• Ari E. Puentes, University of Tennessee, Knoxville
• D. Jean Lodge, University of Georgia
• Deyaneira A. Ortiz-Iglesias, USDA Forest Service
• Tatiana Barreto-Vélez, USDA Forest Service
• Laura C. Rubio-Lebrón, USDA Forest Service
• Hieu Chu, Macalester College
• Christine S. O'Connell, Chapman UniversityFollow
• Sasha C. Reed, U.S. Geological Survey
• Tana E. Wood, USDA Forest Service

Document Type

Article

Publication Date

5-24-2026

Abstract

Wet tropical forests are experiencing rising temperatures and increased frequency and intensity of extreme climatic events, such as cyclones, which can increase rates of soil erosion and surface runoff. Fungal litter mats, formed by agaric decomposer fungi, play a crucial role in stabilizing slopes, preventing erosion, and aiding nutrient cycling; however, little is known about how warming affects litter mat growth and function. We investigated two litter mat-forming fungi, Gymnopus johnstonii and Marasmius aff. crinis-equi, in warmed (+4°C above ambient) and control plots in the Luquillo Experimental Forest, Puerto Rico. Growth and time-to-leaf colonization were monitored over 6 weeks in spring (both species) and summer (G. johnstonii only). We hypothesized that warming would inhibit fungal mat growth and slow leaf colonization, particularly for G. johnstonii since it is drought sensitive. As expected, warming significantly reduced relative growth rates (RGR) in spring, though M. aff. crinis-equi showed slightly higher RGR than G. johnstonii. Leaf colonization was also delayed by 22% in warmed plots, with M. aff. crinis-equi colonizing leaves 4.3 times faster than G. johnstonii. There were significant seasonal differences in response to warming for G. johnstonii, with warming increasing RGR during the consistently wetter summer sampling period. Overall, warming led to significant inhibition of leaf colonization when conditions were dry, whereas there was a trend toward increased colonization in warm and wet conditions. Our findings suggest that warming, combined with drier conditions, is likely to suppress drought-sensitive fungal mat growth, reducing their ability to prevent nutrient and soil loss via erosion.

Comments

This article was originally published in Biotropica, volume 58, issue 3, in 2026. https://doi.org/10.1111/btp.70201

Recommended Citation

Puentes, A. E., D. J.Lodge, D. A.Ortiz-Iglesias, et al. 2026. “Effects of Warming on Growth and Leaf Colonization by Litter Mat-Forming Fungi in a Wet Tropical Forest in Puerto Rico.” Biotropica 58, no. 3: e70201. https://doi.org/10.1111/btp.70201

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This work is licensed under a Creative Commons Attribution 4.0 License.