The geno-geo-climate nexus: contributions of geographic and ecological factors in shaping the genomic divergence of two closely related threatened rainforest species of Fontainea Heckel (Euphorbiaceae)

Context Processes that shape genomic and ecological divergence can reveal important evolutionary dynamics to inform the conservation of threatened species. Fontainea is a genus of rainforest shrubs and small trees including critically endangered and threatened species restricted to narrow, but complex geographic and ecological regions. Several species of Fontainea are subject to spatially explicit conditions and experience limited intra-specific gene flow, likely generating genetic differentiation and local adaptation. Objectives Here, we explored the genetic and ecological mechanisms underlying patterns of diversification in two, closely related threatened Fontainea species. Our aim was to compare spatial patterns of genetic variation between the vulnerable Fontainea australis (Southern Fontainea) and critically endangered F. oraria (Coastal Fontainea), endemic to the heterogeneous subtropical region of central, eastern Australia, where large-scale clearing has severely reduced rainforest habitat to a fraction (