Older Lineages of Oribatid Mites in Mountain Ranges Have Broader Geographic Ranges and Exhibit More Generalistic Traits

Understanding ecological and evolutionary mechanisms that drive biodiversity patterns is important for comprehending biodiversity. Despite being critically important to the functioning of ecosystems, the mechanisms driving belowground biodiversity are little understood. We investigated the radiation and trait diversity of soil oribatid mites from two mountain ranges, that is, the Alps in Austria and Changbai Mountain in China, at similar latitude in the temperate zone differing in formation processes (orogenesis) and exposed to different climates. We collected and sequenced soil oribatid mites from forests at 950-1700 m at each mountain and embedded them into the chronogram of species from temperate Eurasia. We investigated the phylogenetic age of oribatid mites and compared the node age of species with the mountain uplift time of the Alps and Changbai Mountain. We then inspected trophic variation, geographical range size, and reproductive mode, and identified traits that promote oribatid mite survival and evolution in montane forest ecosystems. We found that oribatid mites on Changbai Mountain are phylogenetically older than species in the Alps. All species on Changbai Mountain evolved long before the uplift of Changbai Mountain, but some species in the Alps evolved after the orogenesis of the Alps. On Changbai Mountain, more species possess broader trophic variation, have larger geographical range sizes, and more often reproduce via parthenogenesis compared to species from the Alps. Species on Changbai Mountain survived the mountain uplift or colonized the mountain thereafter, supporting the view that generalistic traits promote survival and evolution in phylogenetically old soil animal species. Collectively, our findings highlight that combining species traits and phylogeny allow deeper insight into the evolutionary forces shaping soil biodiversity in montane ecosystems.