# Unveiling the Dietary Selection of Lowland Tapirs (Tapirus terrestris) in a Tropical Rainforest

## TL;DR

Lowland tapirs in a tropical rainforest have a generalist diet, consuming a wide variety of plant species and contributing to plant diversity.

## Contribution

This study provides new insights into the dietary ecology of lowland tapirs using DNA metabarcoding and functional trait analysis in a tropical rainforest.

## Key findings

- Lowland tapirs consumed 61 plant species from diverse families, showing broad dietary tolerance.
- Tapir diets differ from surrounding vegetation, indicating selective feeding across their home range.
- Tapirs consume plants with both 'fast' and 'slow' leaf economic spectrum traits, suggesting generalist feeding behavior.

## Abstract

Large terrestrial herbivores play crucial roles in shaping ecosystem structure and function through their foraging activities. Still, the dietary ecology of elusive tropical species remains poorly understood. We investigated the diet composition of lowland tapirs (
Tapirus terrestris
), the largest terrestrial herbivore in the Neotropics, using DNA metabarcoding of fecal samples from 31 latrines in Carlos Botelho State Park, Brazil. We characterized local plant communities through vegetation plots and analyzed five leaf economic spectrum (LES) traits from both consumed and surrounding vegetation to assess selective feeding patterns. Lowland tapirs consumed 61 plant species from 69 genera and 46 families, predominantly those from the Melastomataceae, Asteraceae, and Myrtaceae families. Beta‐diversity analysis revealed high compositional turnover among latrines, with a high dissimilarity index, indicating that the samples being compared are distinct in species composition. The plant composition in tapir diets differed significantly from that of the surrounding vegetation, suggesting that this species forages on distinct plant species across its extensive home range rather than consuming locally abundant species. Finally, the functional trait analysis revealed no significant differences between the dietary species and the surrounding vegetation in LES traits. Tapirs consumed plants that spanned both “fast” (high specific leaf area and high nitrogen content) and “slow” (high leaf dry matter content and thick leaves) strategies, indicating a broad dietary tolerance rather than trait‐based selectivity. This suggests that tapirs can adapt to diverse plant textures and nutritional profiles, browsing on leaves ranging from tough to softer and more digestible. Our findings demonstrate that lowland tapirs exhibit generalist feeding strategies, which promote high plant species turnover, potentially contributing to the maintenance of tropical forest diversity, as observed in the Atlantic forest. Given the critical threats facing this endangered megafauna, understanding their generalist diet is essential for developing effective conservation strategies.

Large terrestrial herbivores, such as lowland tapirs (Tapirus terrestris) present many dietary ecological roles in their habitat. In this article, we investigated the diet of lowland tapirs in a tropical rainforest combining different techniques such as DNA metabarcoding, fieldwork, and plant functional traits. Our results suggests that this large herbivore is a generalist feeder, consuming 61 plant species, enhancing diversity turnover within latrines, and not consuming the immediate surrounding vegetation. We also found that this species consume plants with both ends of the leaf economic spectrum traits. We discuss the importance of tapirs for the plant biodiversity and conservation of this endangered animal.