# Multifaceted Biodiversity Patterns and Influencing Factors of Lucanus Stag Beetles (Coleoptera, Lucanidae) in China

## TL;DR

This study explores how different types of biodiversity in stag beetles across China are shaped by climate and geography, highlighting the importance of mountain regions for conservation.

## Contribution

The study introduces a multidimensional framework integrating taxonomic, phylogenetic, and functional diversity patterns in stag beetles.

## Key findings

- Maximum species richness and phylogenetic diversity occur in southwest mountain ranges, influenced by annual temperature range.
- Functional diversity indicators are mainly driven by precipitation, with distinct patterns in the southeast and southwest regions.
- Mountain ecosystems consistently act as biodiversity arks, showing strong environmental filtering effects.

## Abstract

As keystone decomposers in forest ecosystems, stag beetles occupy unique ecological niches within forest carbon and nitrogen cycles. While previous studies have predominantly focused on taxonomic inventories of this group, we present a multidimensional assessment integrating taxonomic, phylogenetic, and functional diversity patterns across the model genus Lucanus of stag beetles in China. Using random forest analyses, we identify key environmental factors influencing these biodiversity dimensions—contemporary climate factors, habitat heterogeneity, and paleoclimatic fluctuations. Our results show that maximum species richness and phylogenetic diversity (Faith's PD) emerge in southwest mountain ranges (Hengduan and Gaoligong Mountains), primarily regulated by annual temperature range constrictions. This region also retains older lineages and shows phylogenetic dispersion, while South China and Taiwan exhibit more recent differentiation and phylogenetic aggregation, primarily influenced by precipitation and temperature anomalies. Functional richness and functional dispersion are higher in the southeastern region, whereas the southwest displays greater functional evenness and functional divergence, reflecting stronger environmental filtering. Functional diversity indicators are mainly driven by precipitation. These multidimensional diversity patterns exhibit geographical decoupling, with mountain ecosystems consistently serving as biodiversity arks. Our findings establish an integrative framework for insect conservation in Asian forest ecosystems, emphasizing the need for topography‐sensitive management strategies.

As keystone indicators of forest integrity, stag beetles (genus Lucanus) in China reveal novel multidimensional patterns integrating taxonomic, phylogenetic, and functional diversity. Our integrative framework elucidates the interactive effects of contemporary environmental gradients and historical climatic oscillations on these biodiversity dimensions, advancing evolutionary‐informed conservation strategies for forest arthropods.