Geographic patterns and ecological correlates of the mean genus age of liverworts in regional floras across China

摘要

Aim: Mean lineage age is an important metric of evolutionary history and community structure of biological assemblages. Many studies have investigated geographic patterns and ecological drivers of mean lineage age in plant assemblages but all previous studies focused on vascular plants. Similar studies for bryophytes, a lineage of the oldest land plants, are lacking. Here, we fill this critical knowledge gap by investigating geographic patterns and ecological correlates of the mean genus age (MGA) of liverworts, a major lineage of bryophytes, in regional floras across China. @@@ Location: China. Taxon: Liverworts (hepatics, Division Marchantiophyta of bryophytes). @@@ Methods: MGA and its standardized effect size (MGA(ses)) of liverworts in each of the 28 province-level regions across China were related to 12 explanatory variables representing geography, contemporary climate and historical climate change, using correlation and regression analyses, and a variation partitioning approach. @@@ Results: We found that (1) MGA and MGA(ses) of liverworts were correlated negatively with latitude and elevational range, and positively with mean annual temperature, and annual precipitation in the regions across China, (2) MGA and MGA(ses) of liverworts were more strongly affected by temperature-related variables than by precipitation-related variables, and (3) MGA and MGA(ses) of liverworts were more strongly affected by climate extremes than by climate seasonality. Main @@@ Conclusions: The relationships of mean lineage age with climatic condition in one of the oldest lineages of land plants (i.e. liverworts) are consistent with those in angiosperms, a relatively young lineage of land plants. Our study is the first to show that geographic and ecological distributions of the oldest land plants are generally consistent with the pattern frequently observed in angiosperms that biological assemblages in colder and drier climates have, on average, younger lineage ages.

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