DOI: 10.5061/dryad.12g6t
title: Data from: Invasive Bromus tectorum alters natural selection in arid systems

description: While much research has documented the impact of invaders on native
 communities and ecosystem services, there has been less work quantifying
 how invasion affects the genetic composition of native populations. That
 is, when invaders dominate a community, can they shift selection regimes
 and impact the evolutionary trajectory of native populations? The invasion
 of the annual grass Bromus tectorum in the Intermountain West provides an
 opportunity to quantify the effects of invasion on natural selection in
 wild populations. The shift from a perennial-dominated native community to
 one dominated by a highly competitive annual species alters the timing and
 intensity of competitive pressure, which has the potential to strongly
 shift selection regimes for native plants. To quantify traits under
 selection in contrasting environments, we planted seeds of two native
 perennial grasses, Elymus multisetus and Poa secunda, into three invaded,
 invaded but weeded and relatively uninvaded sagebrush systems. We
 quantified phenotypic traits of seedlings from separate maternal plants,
 describing differences in phenotypes among individuals. We then asked
 which traits were associated with survival and plant size in adjacent
 invaded and uninvaded sagebrush systems, following individual seed
 performance for 3 years. We found evidence for divergent selection between
 invaded and uninvaded sagebrush systems, with contrasting phenotypic
 traits associated with greater survival or plant size in these different
 growing conditions at all three field sites. For example, at one field
 site, P. secunda families with higher root tip production were more likely
 to survive in invaded and weeded environments, but this was not the case
 in uninvaded environments. Similarly, for E. multisetus, root mass
 fraction, seed mass and allocation to coarse or fine roots affected
 survival and plant size, again with contrasting relationships across
 invaded, weeded or uninvaded environments. Synthesis. Impacts of invasive
 species extend beyond ecosystem and community composition changes and can
 affect the evolutionary trajectory of native populations. By quantifying
 natural selection in invaded landscapes, we identified phenotypic traits
 that are potentially adaptive in these invaded systems. Importantly, these
 traits differed from traits associated with success in uninvaded
 communities. This insight into adaptive, contemporary evolution in native
 species can guide restoration and conservation efforts.
description: Leger and Goergen Poa
 and Elymus 2017Bedell performance,
 Bordertown performance, and McClellan performance worksheets contain data
 used to analyze the relationship between plant performance and plant
 traits for Elymus multisetus (Bordertown) and Poa secunda (Bedell,
 Bordertown) plant families seeded into three common gardens in Northern
 Nevada. Performance worksheets indicate Location, Family (siblings from a
 single parent plant), Treatment (InvadedBT= invaded; Invadedno BT =
 weeded, Uninvadedno BT = uninvaded), and plot number. Values are
 proportion of seeds per family in each block that emerged and survived in
 years 1, 2, and, when available, year 3. Average leaf numbers and height
 (cm) for living plants is shown, as is average biomass in 2012 (g).Trait
 values for seed and seedling traits are given as standardized (mean 0, SD
 1) values used for analysis, with standardization indicated with
 "Z" before each trait. Traits are described in the MS text.
 Bedell emerge survival, Bordertown emerge survival, and McClellan emerge
 survival worksheets show Location, Family, Treatment, Plot number, and
 row/column for each seed planted in each plot. Plants that emerged or
 survived in years 1, 2, and when available, 3, are shown as 0 or 1;
 missing data is indicated with "." These last three worksheets
 include all families planted in the field, including some for which
 seedling traits were not available, and thus not included in the
 performance analysis.Leger and Goergen
 2017.xlsx