Landscape adaptations of forests
Comparative analysis can provide broader patterns for forest management, where concurrent genetic and spatial patterns of local adaptation within co-occurring tree species provides strong evidence for environmental fitness and evolution (Bragg et al., 2015). Our analysis here identified SNPs associated with both temperature and precipitation in jarrah; while a similar study on a co-occurring species, marri (Corymbia calophylla ), found SNPs associated with temperature to explain more deviance than precipitation (Ahrens et al., 2019a), thereby suggesting that temperature is a stronger driver of local adaptation for marri. It is interesting that there were similarities in functional genes associated with several adaptive variants between jarrah and marri (e.g., ABC transporters and CBL gene families). Comparison of SNPs across both species identified a set of 26 SNPs that were also found to be associated with at least one of the five variables analysed (Table S3). Most of these shared SNPs are associated with either TMAX (16) or PWQ (12) in jarrah; while for marri, the majority of the shared SNPs are associated with TMAX (24), which is consistent with adaptation to both temperature and precipitation in jarrah and with temperature in marri. This comparison adds weight to our finding that the hypothesis of precipitation as a more important driver than temperature in jarrah is not supported
as our evidence indicates that both temperature and precipitation are important climate factors for adaptation in jarrah.