With climate change impacting trees worldwide, enhancing adaptation capacity has become an important goal of provenance translocation strategies for forestry, ecological renovation, and biodiversity conservation. Given that not every species can be studied in detail, it is important to understand the extent to which climate adaptation patterns can be generalised across species, in terms of the selective agents and traits involved. We here compare patterns of genetic-based population (co)variation in leaf economic and hydraulic traits, climate–trait associations, and genomic differentiation of two widespread tree species (Eucalyptus pauciflora and E. ovata). We studied 2-year-old trees growing in a common-garden trial established with progeny from populations of both species, pair-sampled from 22 localities across their overlapping native distribution in Tasmania, Australia. Despite originating from the same climatic gradients, the species differed in their levels of population variance and trait covariance, patterns of population variation within each species were uncorrelated, and the species had different climate–trait associations. Further, the pattern of genomic differentiation among populations was uncorrelated between species, and population differentiation in leaf traits was mostly uncorrelated with genomic differentiation. We discuss hypotheses to explain this decoupling of patterns and propose that the choice of seed provenances for climate-based plantings needs to account for multiple dimensions of climate change unless species-specific information is available.

Habitat loss and fragmentation are critical threats to biodiversity. Consequent decreases in population size and connectivity can impact genetic diversity and, thus, future adaptability and resilience to environmental change. Understanding landscape patterns of genetic diversity, including patterns of adaptive variation, can assist in developing conservation strategies that maximise population persistence and adaptability in the face of environmental change. Using a reduced-representation genomic approach, we investigated genetic diversity, structure, and adaptive variation across an aridity gradient in the woodland forb Arthropodium fimbriatum. Moderate levels of genetic diversity (HS = 0.14–0.23) were found in all 13 sampled provenances. Inbreeding varied among provenances (FIS = 0.08–0.42) but was not associated with estimated population size. Four genetic clusters were identified, including one highly differentiated cluster. Higher pairwise FST (0.23–0.42) between the three provenances of this cluster and the remaining 10 provenances (pairwise FST between 10 provenances 0.02–0.32) suggested two highly divergent lineages or potentially a cryptic species. After excluding the three highly differentiated populations, outlier and genotype-environment association analysis identified 275 putatively adaptive loci suggesting genomic signatures of climate adaptation in A. fimbriatum is primarily associated with changes in aridity. Combined, these results suggest that all provenances have conservation value, contributing to the maintenance of genetic diversity and adaptive variation in this species. The uncovering of a potential cryptic taxon highlights the power of genomics approaches in conservation genetics and the importance of understanding the role of landscape variation shaping genetic variation to effectively define conservation management units in an era of rapid biodiversity decline.