Native Perennial Grasses Show Evolutionary Response to Bromus tectorum (Cheatgrass) Invasion

Abstract

Invasive species can change selective pressures on native plants by altering biotic and abiotic conditions in invaded habitats. Although invasions can lead to native species extirpation, they may also induce rapid evolutionary changes in remnant native plants. We investigated whether adult plants of five native perennial grasses exhibited trait shifts consistent with evolution in response to invasion by the introduced annual grass Bromus tectorum L. (cheatgrass), and asked how much variation there was among species and populations in the ability to grow successfully with the invader. Three hundred and twenty adult plants were collected from invaded and uninvaded communities from four locations near Reno, Nevada, USA. Each plant was divided in two and transplanted into the greenhouse. One clone was grown with B. tectorum while the other was grown alone, and we measured tolerance (ability to maintain size) and the ability to reduce size of B. tectorum for each plant. Plants from invaded populations consistently had earlier phenology than those from uninvaded populations, and in two out of four sites, invaded populations were more tolerant of B. tectorum competition than uninvaded populations. Poa secunda and one population of E. multisetus had the strongest suppressive effect on B. tectorum, and these two species were the only ones that flowered in competition with B. tectorum. Our study indicates that response to B. tectorum is a function of both location and species identity, with some, but not all, populations of native grasses showing trait shifts consistent with evolution in response to B. tectorum invasion within the Great Basin.

Physical disturbance shapes vascular plant diversity more profoundly than fire in the sagebrush steppe of southeastern Idaho, U.S.A

“…6, lower left panel). Consequently, selection of species for restoration purposes should focus on lineages preadapted to specific disturbance regimes, in addition to gene pools (e.g., Jones and Monaco 2009) and competitive genotypes (Goergen et al 2011). …”

Mapping and Monitoring Cheatgrass Dieoff in Rangelands of the Northern Great Basin, USA

“…The cheatgrass invasion and its challenges have been well documented (Young et al 1987;Whisenant 1990;Mack 2011), but research regarding cheatgrass and its effects on the ecosystems it has invaded has continued (Chambers et al 2007;Bromberg et al 2011;Goergen et al 2011;Baynes et al 2012). Another challenge recently M A N U S C R I P T ACCEPTED MANUSCRIPT 4 observed (since at least 2003) in the Great Basin by a longtime Bureau of Land Management (BLM) employee is cheatgrass dieoff (M. Zielinski, personal communication, September 2010).…”

Coevolution between invasive and native plants driven by chemical competition and soil biota

“…However, this dominance likely imposes intense selection pressures on native species, potentially resulting in new coevolutionary relationships that may act to integrate the exotic species into its new community (27). Exotic species can evolve rapidly in their new range (28), and some native species have evolved adaptations to invaders (29), including native plants responding to invasive plant competitors (30)(31)(32)(33). However, no study to date has documented reciprocal coevolution between native and exotic plant species (27).…”