# Intraspecific Variations in Ecomorphological Functional Traits of Montane Stream-Dwelling Frogs Were Driven by Their Microhabitat Conditions

## TL;DR

This study shows how frogs in mountain streams adapt their body shapes to different habitats, highlighting the need to protect diverse stream environments for amphibian survival.

## Contribution

The study reveals intraspecific morphological adaptations in frogs driven by microhabitat conditions in montane streams.

## Key findings

- High-elevation frogs had larger bodies and shorter legs, possibly to conserve heat.
- Amphibian traits like body mass and limb proportions were linked to microhabitat variables like air humidity and flow rate.
- Sex and seasonal effects also influenced morphological variations in the studied species.

## Abstract

Protecting wildlife requires understanding how animals adapt to their surroundings, yet amphibians in montane streams remain understudied. This research studied three amphibian species in Tianping Mountain, China, to explore how their physical traits, such as body size, leg length, and head shape, respond to varying habitat conditions. By comparing individuals from high- and low-elevation sites, we found that those living in colder, higher-altitude areas developed larger bodies and shorter legs, adaptations that may aid in conserving heat. One species also exhibited broader heads, which could enhance prey capture in fast-flowing streams. These morphological changes highlight the amphibians’ ability to adjust to specific environmental pressures. Our findings underscore the importance of maintaining diverse habitats (e.g., streams with varying water depths and flow rates) to support amphibian populations. Since amphibians serve as indicators of environmental health, protecting their habitats contributes to the well-being of entire ecosystems, including human communities. This study offers practical guidance for conservation efforts, emphasizing the need to preserve habitat heterogeneity to ensure amphibian resilience in the face of climate change and human disturbance.

Understanding how habitat conditions drive morphological adaptations in animals is critical in ecology, yet amphibian studies remain limited. This study investigated intraspecific variation in ecomorphological traits of three montane stream-dwelling frogs (Quasipaa boulengeri, Amolops sinensis, and Odorrana margaratae) across elevation gradients in Tianping Mountain, China. Using morphological measurements and environmental variables collected from ten transects, we analyzed functional traits related to feeding and locomotion and assessed their associations with microhabitat variables. Significant trait differences between low- and high-elevation groups were detected only in Q. boulengeri, with high-elevation individuals exhibiting greater body mass and shorter hindlimbs. Redundancy analysis demonstrated that microhabitat variables, particularly air humidity, flow rate, and rock coverage, were linked to trait variations. For example, air humidity and flow rate significantly influenced Q. boulengeri’s body and limb proportions, while flow rate affected A. sinensis’s snout and limb morphology. In addition, sex and seasonal effects were also associated with trait variations. These results underscore amphibians’ phenotypic plasticity in response to the environment and highlight the role of microhabitat complexity in shaping traits. By linking habitat heterogeneity to eco-morphology, this study advocates for conservation strategies that preserve varied stream environments to support amphibian resilience amid environmental changes.