The importance of quantitative trait differentiation in restoration: landscape heterogeneity and functional traits inform seed transfer guidelines

Abstract

For widely distributed species, understanding the scale over which genetic variation correlates to landscape structure and composition is critical. Particularly within the context of restoration, the evolution of genetic differences may impact success if seeds are maladapted to the restoration environment. In this study, we used Geum triflorum to quantify the scale over which genetic differences for quantitative traits important to adaptation have evolved, comparing the proportion of variance attributed to broad regional- and local population-level effects. Geum triflorum is a widely distributed species spanning a range of environments, including alvar and prairie habitats, which have extreme regional differences in soil-moisture availability. Alvar habitats are regions of thin soil over limestone that experience substantial seasonal variation in water availability, from flooding to desiccation annually. This contrasts with prairie habitats, whose deeper soils mitigate irregular flood–desiccation cycles. Using a common garden experiment, we evaluated 15 traits broadly grouped into three trait classes: resource allocation, stomatal characteristics, and leaf morphological traits for individuals sourced from prairie and alvar environments. We quantified the proportion of trait variance explained by regional- and population-scale effects and compared the proportion of regional- and population-trait variances explained across trait classes. Significant regional differentiation was observed for the majority of quantitative traits; however, population-scale effects were equal or greater than regional effects, suggesting that important genetic differences may have evolved across the finer population scale. Stomatal and resource allocation trait classes exhibited substantial regional differentiation relative to morphological traits, which may indicate increased strength of selection for stomatal and resource allocation traits relative to morphological traits. These patterns point towards the value in considering the scale over which genetic differences may have evolved for widely distributed species and identify different functional trait classes that may be valuable in establishing seed transfer guidelines.

Testing for evolutionary change in restoration: a genomic comparison betweenex situ, native and commercial seed sources ofHelianthus maximiliani

“…Varying genomic composition of commercial seed sources relative to wild, contemporary populations suggest further study is required to evaluate whether genomic differences correspond to functional differences that impact restoration success. Common garden studies have shown that seed transfer across environments can impact plant traits and performance (Bucharova et al 2017, Giencke et al 2018, Johnson et al 2004, Lesica & Allendorf 1999, Yoko et al 2020). Consequently, the genomic differences we observe here warrant additional study of H. maximiliani seed sources linking genomic differences to traits important to adaptation and persistence in restored environments.…”

Spatiotemporal seed transfer zones as an efficient restoration strategy in response to climate change

“…This approach is not often practical, since in the frame of germplasm collecting, extensive genetic characterization may lead to redundancy (Jaramillo and Baena 2000, Parra‐Quijano 2011), and resources for this task are a limiting factor (Vogel et al 2005). However, validation of the delineated STZs in terms of genetic differentiation is essential (Massatti et al 2020, Yoko et al 2020) especially in the context of climate change. Here we present provisional spatiotemporal STZs as a first step in seed transfer guidance for restoration purposes of Argentinian rangelands in response to climate change.…”

The relevance of pedigrees in the conservation genomics era.

“…For example, a recent study in hihi (Notiomystis cincta ) used pedigree-based heritability to reveal low evolutionary potential in this threatened bird (de Villemereuil et al, 2019a). In addition to heritability, known family groups or distinct populations have also been essential to understanding GxE interactions, especially in plant species (Bisbing et al, 2020;Yoko, Volk, Dochtermann, & Hamilton, 2020). Empirical estimates of relatedness can be used instead of pedigrees, and may overcome pedigree pitfalls while providing realised estimates of genome-sharing (Hill & Weir, 2011;Hill & Weir 2012;Speed & Balding, 2015).…”