Microbial communities are highly diverse, yet the mechanisms underlying microbial community assembly are not well understood. In 1967, Daniel Janzen hypothesized that low climatic variability along elevational gradients results in greater limitations to animal migration and plant dispersal for tropical taxa compared to temperate taxa.
In a study published in Ecography, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) and their collaborators tried to examine whether Janzen's mountain passes hypothesis applies to microorganisms, which would suggest that both dispersal limitation and environmental selection drive microbial β-diversity patterns.
The researchers investigated changes in microbial community dissimilarities, distributional range sizes and ecological processes along elevational gradients in three montane ecosystems representing a climatic variability gradient.
They used soil bacteria and fungi across three climatic gradients of tropical, subtropical and subalpine climates to explore the pattern, drivers, mechanisms and responses of mountain soil microbial diversity to climate change.
They found that climate (climate overlap and differences between elevations), degree of climate variability and spatial distance played dominant roles in the microbial beta diversity pattern and species distribution range size along the elevation gradient.
They further found that mountainous areas with low climate variability and overlap had higher beta diversity and endemism, smaller species distribution ranges and steeper distance decay trends. But all mountain microbiomes showed consistent climate-driven niches and dispersal limitation processes, which indicated that the dispersal ability of mountain microbes was limited and strongly constrained by climatic conditions, so that microbial diversity faced severe challenges under the background of climate change.
"Our study showed that the Janzen mountain hypothesis also applied to the community assembly process of microbial communities. It proved that climate-dependent dispersal limitation played an important role in mountain soil microbiome, ” said YANG Jie of XTBG.
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Contact
YANG Jie Ph.D Principal Investigator
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
E-mail: yangjie@xtbg.org.cn
First published: 26 December 2023
