Location: Forage and Range Research
Title: Ecological adaptation of Shepherdia rotundifolia to conditions in its native range Authors
Submitted to: Western North American Naturalist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 6, 2013
Publication Date: June 1, 2014
Citation: Sriladda, C., Kjelgren, R., Kratsch, H., Larson, S.R., Monaco, T.A. 2014. Ecological adaptation of Shepherdia rotundifolia to conditions in its native range. Western North American Naturalist. 74:79-91. Technical Abstract: Water conservation using drought tolerant species is increasingly important for many urbanized areas due to limited water supplies. The Colorado Plateau endemic shrub Shepherdia rotundifolia Parry is a potential candidate for use in sustainable urban low-water landscapes (LWL) for its aesthetic and drought tolerant qualities. However, it is difficult to establish in irrigated urban landscape conditions. A better understanding of environmental and genetic constraints in its native habitat may facilitate its use. The goal of this study was to investigate variability in environmental conditions, morphology, and genetics among six populations of S. rotundifolia along an elevation gradient (range: 1,200 m to 2,500 m). Existing 30-yr precipitation and air temperature data from nearby weather stations, and intra-annual air temperature recorded in the field represented weather conditions at each site. We analyzed site-specific soils for analysis of structure, pH, salinity, organic matter (OM), and macronutrients. Relative light intensity (RLI) was analyzed using hemispherical canopy images. Leaf samples were used for measurements of leaf area and specific leaf area (SLA), for scanning electron microscopic imaging of trichome structure and leaf thickness, and for Amplified Fragment Length Polymorphism (AFLP) genetic variation among populations. Distinct AFLP banding patterns among high- and low-elevation populations suggested differences due to isolation-by-distance. Precipitation, air temperature, RLI, and soil properties varied widely among populations. Differences among leaf area, SLA, and leaf trichome structure suggest population-level adaptations consistent with environmental differences. SLA was correlated with RLI, OM, and potassium (K). Relatively high native K levels and positive correlation of K with SLA suggest that K may be a limiting factor in urban landscape soils. Selection of plants adapted to environmental conditions similar to those present in an urban landscape may enhance its successful use in this setting. Genetic variation suggests potential for cultivar selection.