Life history characteristics and climate correlates of monoecious plant species in central southern Australia

Context Monoecy is a sexual system observed in slightly more than 7.0% of flowering plant species where individuals produce distinct male and female flowers on the same plant. Understanding the life history and climate conditions associated with monoecious species may reveal the survival advantages and opportunities for conservation for this rare reproductive system. Aim To identify monoecious species in central southern Australia, determine their life history and climate associations and map their proportional species richness by Interim Biogeographical Regionalisation of Australia (IBRA) subregions. Methods Monoecious species and life history trait data were identified from online Flora of South Australia (eFlora), the Flora of Australia or relevant peer-reviewed research. Proportions of monoecy were determined for 66 contiguous IBRA subregions in semi-arid south-east Australia using Australasian Virtual Herbarium collection records, as well as subregion climate averages using Terrestrial Ecology Research Network raster data. Generalised linear mixed-models were applied to determine associations between proportion of monoecious and climate. Key results Non-woody growth forms and abiotic pollination were associated with monoecy, as well as extremes of daily temperature and higher number of sun hours. Conclusions The occurrence of monoecy between subregions indicates that this reproductive system may confer greater survival advantages than dioecy in desert habitats where resources and reproductive assurance are limited. Implications With these new data, monoecious plants can be studied and conserved in the systems where they are most prevalent and may have fitness advantages compared to other plant sexual systems.