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Simulated elephant foraging alters tree root exudation rates: Species-specific responses and implications for belowground carbon dynamics in tropical forests
| First Author: |
Khatri, Pratibha |
| Abstract: |
Societal Impact Statement Asian elephants play crucial roles in ecosystem functioning, and their interactions with plants influence above- and belowground carbon cycling. We tested whether their mechanically destructive foraging triggers short-term, stress-induced shifts in tree root exudation, an underappreciated pathway linking herbivory to belowground carbon processes. We found that elephant herbivory can increase root exudation (i.e., carbon release to soils), which shapes soil microbial activity and nutrient cycling. Recognizing this pathway clarifies elephants' indirect role in belowground carbon dynamics and strengthens the case for conserving ecologically functional populations to support resilient soils and ecosystems, with practical relevance for restoration and nature-based climate solutions.Summary Asian elephants (Elephas maximus) have uniquely destructive foraging habits, damaging large numbers of saplings of fast-growing, early-successional trees. We hypothesized that elephant foraging might increase root carbon exudation rates as a stress response, potentially altering belowground carbon dynamics in tropical forests. We aimed to evaluate (1) how varying herbivory intensities affect root exudation rates; (2) how these effects vary among tree species and over time; and (3) how root exudation rates correlate with root traits and soil properties. We simulated elephant herbivory on saplings of three early-successional tree species commonly consumed by elephants, applying three levels of damage: control (no damage), mild (10% aboveground biomass removal), and severe (50% removal). We then quantified root exudation rates in situ at 24, 48, 72, and 96 h post-damage. The three tree species differed in their basal root exudation rates and displayed species-specific responses to herbivory. Macaranga indica doubled its exudation rate after mild damage but showed no response to severe herbivory; Ficus hispida exhibited elevated exudation rates following severe herbivory but not after mild herbivory; and Bauhinia variegata did not respond to either level. Exudation rates also correlated with root traits and soil properties, supporting a traits-environment-disturbance framework. We identified a previously underappreciated pathway by which large browsing herbivores-particularly elephants-influence belowground biogeochemical processes and soil organic carbon pools in tropical forests through short-term, species-specific shifts in root carbon exudation. These findings have implications for conservation, restoration, and nature-based solutions-via elephant-compatible forest mosaics, targeted species screening, and soil-function monitoring. |
| Contact the author: |
Campos-Arceiz, A |
| Page Number: |
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| Issue: |
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| Subject: |
Biodiversity Conservation; Plant Sciences; Ecology |
| Impact Factor: |
3.6 |
| Authors units: |
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| PubYear: |
2025 |
| Volume: |
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| Publication Name: |
PLANTS PEOPLE PLANET |
| The full text link: |
10.1002/ppp3.70152 |
| ISSN: |
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| Download: |
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