Elevational Distribution of Ants Across Seasons in a Subtropical Rainforest of Eastern Australia

Abstract

<p>Elevational gradients are widely studied to understand environmental variability and species distribution. Ants play vital roles in ecosystems and are frequently included in elevational biogeography studies. Despite their ecological importance and well-documented elevational patterns, little is known about their temporal variability across elevations. We surveyed ground and arboreal ants in austral summer, autumn, spring, and winter in a subtropical rainforest of Lamington National Park, Queensland, Australia. Given their physiological and microhabitat differences, ground and arboreal ants may exhibit distinct spatiotemporal patterns. Using litter extraction for ground ants and bark spraying for arboreal ants, we collected 14,916 individuals from 124 species. Species richness and abundance were lowest in austral winter, particularly for arboreal ants. Both richness and abundance declined with elevation, and this pattern remained consistent across seasons. While seasonal and elevational differences significantly influenced species composition, seasonal variation did not cause major shifts in the elevational distribution of ground or arboreal ants. A total of 43 species were identified as indicators of specific elevations, with species such as Notoncus capitatus and Colobostruma biconvexa being specialists of low elevations, and undescribed Monomorium and Discothyrea species being specialists of high elevations. In contrast, only two species were identified as seasonal indicators, which were undescribed Tapinoma and Anonychomyrma species, specialists of the warm season. Our findings suggest that ants reduce activity in winter but maintain stable elevational distributions regardless of season or microhabitat use, making their distributions a reliable indicator of their climatic niches.</p>