Drivers of large‐scale geographical variation in sexual systems of woody plants

Abstract

Aim: Sexual systems strongly influence angiosperm evolution and play important roles in community assembly and species responses to climate change. However, geographical variation in proportions of different sexual systems (dioecy, monoecy and hermaphroditism) in response to changes in climate, life-history traits and evolutionary age remains poorly understood. Here, we map the geographical variation in proportions of different sexual systems and hypothesize that the prevalence of hermaphrodites increases with aridity owing to their advantages in colonizing harsh environments, whereas dioecy is most successful in humid regions with tall-canopy vegetation and old floras. Location: China. Time period: Current. Major taxa studied: Woody angiosperms. Methods: Using data on sexual systems and distributions of 10,449 woody species in China, we estimated the proportions of different sexual systems in local floras (50 km × 50 km grid cells). Spatial linear models, phylogenetic general linear models and structural equation models were used to compare the relative influences of climate, plant height and evolutionary age on geographical variation in proportions of different sexual systems. Results: We found contrasting geographical patterns in the proportions of different sexual systems. The proportions of dioecy and monoecy increased with plant height | 547 WANG et Al.

Spatial Patterns and Drivers of Angiosperm Sexual Systems in China Differ Between Woody and Herbaceous Species

“…The differences in the effects of climate on proportions of sexual systems between woody and herbaceous growth forms may be partly due to the coevolution of sexual systems with growth forms (Renner and Ricklefs, 1995;Vamosi et al, 2003;Case and Barrett, 2004). Moreover, our results further corroborate previous findings that climate may have influenced the spatial pattern of sexual systems via its effect on the composition of plant growth forms (Wang et al, 2020). We also found that the sexual system composition of woody species was more closely associated with contemporary climate than that of herbaceous species, which is consistent with previous studies at broad scales (Oberle et al, 2009;Wang et al, 2009).…”

“…The proportion of hermaphroditic species for all species combined was high in areas with high AI or MTCQ, consistent with Wang et al (2020). The proportion of dioecious species among all species combined (e.g.…”

“…Because different sexual systems are associated with variation of plant growth form, there are large-differences in the distributions of plant sexual systems between contrasting woody and herbaceous species. Compared with Wang et al (2020) , we advanced our understanding of the spatial distribution of plant sexual systems and the determinants underlying these patterns, especially between growth forms. Growth form significantly differed the relationships between geographic patterns in the proportions of all three sexual systems with different biotic and abiotic factors.…”

“…Previous studies have shown that the geographical distributions of angiosperm sexual systems may ultimately reflect coevolution with vegetative traits that are tied closely to sexual systems (i.e. growth form, Vamosi et al, 2003;Moeller et al, 2017;Wang et al, 2020). Nonetheless, the determinants of geographical patterns of sexual systems remain controversial.…”

“…Grid cells without data are shown in white. The patterns in the proportions of sexual systems for woody species were updated fromWang et al, 2020.…”