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Top-down effects of a terrestrial frog on forest nutrient dynamics
Karen H Beard1, Kristiina A Vogt2, Andrew Kulmatiski3
1School of Forestry and Environmental Studies, Yale University, New Haven, CT, 06511, USA. karen.beard@usu.edu.
Oecologia
|May 4, 2017
Summary
Terrestrial frogs significantly impact nutrient cycling by converting insects into plant-available forms. Their waste products and population turnover alter nutrient concentrations in subtropical forests.
Area of Science:
- Ecology
- Nutrient Cycling
- Terrestrial Ecosystems
Background:
- Top-down predator effects on prey are well-documented.
- Few studies link vertebrate predator impacts to terrestrial nutrient cycling.
Purpose of the Study:
- To investigate the impact of the terrestrial frog Eleutherodactylus coqui (coquí) on nutrient concentrations and fluxes.
- To determine if coquí presence influences nutrient dynamics in a subtropical wet forest.
Main Methods:
- A manipulative experiment using 1 m³ enclosures over 4 months.
- Exclusion of coquís at natural densities from experimental plots.
- Measurement of nutrient chemistry in leaf wash, foliage, and decomposing leaf litter.
Main Results:
- Coquí exclusion significantly decreased elemental concentrations in leaf wash (e.g., 83% for dissolved organic C, 71% for NH₄⁺).
- Exclusion reduced nutrient availability in leaf litter (12% for K, 14% for P) and increased C:N ratios by 13%.
- No significant effect on the foliar chemistry of transplanted plants was observed.
Conclusions:
- Coquís exert a significant influence on forest nutrient dynamics, primarily through waste products and population turnover.
- Frogs facilitate nutrient cycling by converting insect biomass into more readily available forms for microbes and plants.
- The role of higher trophic levels in nutrient cycling warrants further consideration.
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