Assessment of population genetics and climatic variability can refine climate‐informed seed transfer guidelines

Abstract

Restoration guidelines increasingly recognize the importance of genetic attributes in translocating native plant materials (NPMs). However, when species-specific genetic information is unavailable, seed transfer guidelines use climate-informed seed transfer zones (CSTZs) as an approximation. While CSTZs may improve how NPMs are developed and/or matched to restoration sites, they overlook genetic factors that can diminish restoration success and/or deteriorate natural patterns of genetic diversity and environmental factors that may introduce unexpected variation. Here, we analyze molecular data and geographic patterns of environmental variability across the western United States and demonstrate how they can refine CSTZs. Using genetic data available for 13 relevant plant species, we found that the probability of mixing genetically differentiated individuals (i.e. from different evolutionary lineages, or populations) was approximately 8% when considering locations separated by 50 km and reached nearly 80% by 500 km, which are distances relevant to ecoregionally constrained CSTZs. Furthermore, climate analyses revealed that geographically proximate locations are likely to maintain environmental similarity, regardless of CSTZ or ecoregion assignment. These results suggest constraining CSTZ-informed seed transfer decisions by distance may mitigate the opportunity for negative genetic outcomes. Furthermore, environmental variability and/or specificity of NPMs (depending upon the restoration strategy) should be achieved by sourcing NPMs from geographically proximate locations to avoid introducing excessive genetic differentiation. Our results highlight the utility of combining molecular genetic data with other genetic inferences (i.e. of adaptation) to determine how best to transfer seed across restoration species' ranges and develop new restoration materials.

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

“…Regardless of the method used for STZ development, for most of the species used in restoration projects, the results are often a best guess, given the lack of a true understanding of adaptive variation (Broadhurst et al 2008). Although some studies relating adaptive genetic variation to geographical and climatic variables have been performed (Hamann et al 2011, St. Clair et al 2013, Massatti et al 2020), the genetic characterization of each population of every species used for restoration, though a valuable conservation task, is often logistically and economically unfeasible (McKay et al 2005). 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).…”

“…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.…”

Származási régiók növényföldrajzi felülvizsgálata honos fajok magjainak restaurációs célú felhasználására

“…Az ökológiai restauráció közérdek, ezért térbeli kiterjedését és a beavatkozások intenzitását növelni szükséges (Aronson & Alexander 2013). Ezen célok csak a honos fajok szaporítóanyagának, elsősorban magjainak nagyobb mértékű felhasználásával érhetők el (Massatti et al 2020, Pedrini & Dixon 2020. A "restaurációs fajkínálat", vagyis a piacon hozzáférhető fajok magkészlete a restaurációs projektek kritikus pontját jelenthetik (Ladouceur et al 2018).…”

Implications of genetic heterogeneity for plant translocation during ecological restoration

“…Models based on climate (Bower et al., 2014; Crow et al., 2018) or genetic data (Krauss & Koch, 2004), or a combination of both (Massatti et al., 2020) may be useful for establishing seed transfer guidelines without the financial or time investment required by a transplant experiment. For example, the average distance at which significant genetic differentiation is found may be used to guide seed transfer of species (Krauss & He, 2006).…”