Amphibian community structure along elevation gradients in eastern Nepal Himalaya

Janak R Khatiwada,Youhua Chen,Jianping Jiang,David C Cannatella,Bin Wang,Tian Zhao,Feng Xie

doi:10.1186/s12898-019-0234-z

Abstract

BackgroundSpecies richness and composition pattern of amphibians along elevation gradients in eastern Nepal Himalaya are rarely investigated. This is a first ever study in the Himalayan elevation gradient, the world’s highest mountain range and are highly sensitive to the effects of recent global changes. The aim of the present study was to assess amphibian community structure along elevation gradients and identify the potential drivers that regulate community structures. Amphibian assemblages were sampled within 3 months in both 2014 and 2015 (from May to July) using nocturnal time constrained and acoustic aids visual encounter surveys. In total, 79 transects between 78 and 4200 m asl were sampled within 2 years field work. A combination of polynomial regression, generalized linear models, hierarchical partitioning and canonical correspondence analysis were used to determine the effects of elevation and environmental variables on species richness, abundance, and composition of amphibian communities.ResultsSpecies richness and abundance declined linearly with increasing elevation, which did not support the Mid-Domain Model. Among all the environmental variables, elevation, surface area and humidity were the best predictors of species richness, abundance and composition of amphibians. The majority of amphibian species had narrow elevation ranges. There was no significant correlation between species range size and elevation gradients. However, body size significantly increased along elevation gradients, indicating that Bergmann’s rule is valid for amphibians in eastern Nepal Himalaya.ConclusionsThis study indicates that eastern Nepal Himalaya is a hotspot in amphibian diversity, and it should be served as a baseline for management and conservation activities.

Highlights

Species richness and composition pattern of amphibians along elevation gradients in eastern Nepal Himalaya are rarely investigated
Understanding how community patterns change along elevation gradients have been a central topic in modern ecology, biogeography, and conservation [1]
The present study examined amphibian community structure along elevation gradients in eastern Nepal Himalaya

Summary

Introduction

Species richness and composition pattern of amphibians along elevation gradients in eastern Nepal Himalaya are rarely investigated. This is a first ever study in the Himalayan elevation gradient, the world’s highest mountain range and are highly sensitive to the effects of recent global changes. Understanding how community patterns (e.g., species richness, abundance, distribution range size, and body size variation) change along elevation gradients have been a central topic in modern ecology, biogeography, and conservation [1]. Species with small distribution range will be more at risk as their entire range can be more easy to be affected by threatening factors [15] These species usually have small population, which may induce inbreeding and demographic stochasticity, and further enhance extinction risk in the long run [16]. A hump shape relationship between species richness and elevation gradients can be detected (i.e., mid-domain effect [25])

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Discussion

Conclusion