Conclusion and prospects
Known patterns of morphological variations coupled with new results of
genetic diversity and structure obtained during the present study
revealed a long history of geographic isolation and local adaptation inE. coccineum in South American temperate forests. Here, we
observed a strong genetic structure in E. coccineum in part
linked to local adaptation, especially to differential access to water
during the driest months. These results support previous studies that
have reported the existence of distinct ecotypes along the species
natural distribution (Souto and Premoli, 2007). The identification and
quantification of the environmental variables structuring population
genetic variation could inform management decisions for conservation,
restoration or reforestation purposes (Gugger et al., 2017). For
example, knowledge about the association between genotype and
environment is important for selecting proper seed when tree populations
are locally adapted (Aitken and Whitlock, 2013) as is the case ofE. coccineum. However, as the environment changes, nonlocal seed
sources may be considered for restoration or reforestation purpose based
on their match to the novel environment. Therefore, seed transfer
guidelines can benefit from knowledge on factors structuring the
landscape of genetic variation. Many conservation efforts rely on
delineating distinct populations for management but often ignore the
continuous nature of landscape variation and its potential relationship
with local adaptation or other processes that lead to
genotype–environment associations (Frankham, 2010; Rodríguez-Quilón et
al., 2016). Concerning land management decisions, the present results
advocate for seed transfer guidelines that should be restricted within
each ecological zone (Dudley et al., 2017). The strong genetic structure
also offers an opportunity to further explore local adaptation among
groups and exploit these for agroforestry.