Genecology ofHolodiscus discolor(Rosaceae) in the Pacific Northwest, U.S.A.

Abstract

An important goal for land managers is the incorporation of appropriate (e.g., locally adapted and genetically diverse) plant materials in restoration and revegetation activities. To identify these materials, researchers need to characterize the variability in essential traits in natural populations and determine how they are related to environmental conditions. This common garden study was implemented to characterize the variability in growth and phenological traits relative to climatic and geographic variables of 39 Holodiscus discolor (Pursh) Maxim. accessions from locations throughout the Pacific Northwest, U.S.A. Principal component analysis of 12 growth and phenological traits explained 48.2% of the observed variability in the first principal component (PC-1). With multiple regressions, PC-1 was compared to environmental values at each source location. Regression analysis identified a four-variable model containing elevation, minimum January temperature, maximum October temperature, and February precipitation that explained 86% of the variability in PC-1 (r 2 ¼ 0.86, p < 0.0001). Spatial analysis using this regression model identified patterns of genetic diversity within the Pacific Northwest that can help guide germplasm selection (i.e., seed collections) for restoration and revegetation activities.

Climate drives adaptive genetic responses associated with survival in big sagebrush (Artemisia tridentata)

“…Our results support previous research that also indicated the adaptive importance of minimum temperatures (Bower et al., ; Erickson, Mandel, & Sorensen, ; Horning et al., ; Johnson, Sorensen, Bradley St Clair, & Cronn, ; Richardson et al., ; St. Clair et al., ). Although A. tridentata is generally thought of as being cold tolerant, winterkill has been documented in natural populations (Walser et al., ) and common gardens of seedlings at relatively warm sites (Brabec et al., ).…”

“…Our results support previous research that also indicated the adaptive importance of minimum temperatures (Bower et al, 2014;Erickson, Mandel, & Sorensen, 2004;Horning et al, 2010;Johnson, Sorensen, Bradley St Clair, & Cronn, 2004;Richardson et al, 2014;St. Clair et al, 2013).…”

“…Responses to the environment can then be used to create geographically delineated seed zones to help ensure that seed can be transferred among areas of similar climate, increasing odds of appropriately adapted vegetation and successful restoration (Bower, St. Clair, & Erickson, ). Recent genecology studies have found that winter minimum temperatures are a primary agent of genetic variation in conifers (Rehfeldt, ; Rehfeldt & Jaquish, ; Rehfeldt, Jaquish, Sáenz‐Romero, et al., ), native grasses (R. C. Johnson et al., ; St. Clair, Kilkenny, Johnson, Shaw, & Weaver, ), and shrubs (Horning, McGovern, Darris, Mandel, & Johnson, ; Richardson et al., ). However, sufficient information on climatic adaptations is lacking in the majority of native grasses, forbs, and shrubs used for restoration purposes.…”

“…Recent genecology studies have found that winter minimum temperatures are a primary agent of genetic variation in conifers (Rehfeldt, 2004;Rehfeldt & Jaquish, 2010;, native grasses (R. C. Johnson et al, 2012;St. Clair, Kilkenny, Johnson, Shaw, & Weaver, 2013), and shrubs (Horning, McGovern, Darris, Mandel, & Johnson, 2010;Richardson et al, 2014). However, sufficient information on climatic adaptations is lacking in the majority of native grasses, forbs, and shrubs used for restoration purposes.…”

Adaptive responses reveal contemporary and future ecotypes in a desert shrub

“…Minimum temperatures have been shown to be an important factor in the adaptive genetic variation of other grass, shrub, and tree species (St Clair et al 2005, Horning et al 2010, Johnson et al 2012. Our data suggest that the accumulation of minimum degree-days ,08C is a principal factor in blackbrush adaptive genetic variation.…”