Climate and Soil Effects on Fitness of Southeastern Idaho Invasive Bromus tectorum Populations
Faculty Mentor Information
Dr. Kathryn Turner (Mentor), Idaho State University
Abstract
Cheatgrass (Bromus tectorum, Poaceae) is a well known invasive grass that has spread across the United States after introduction from Europe and Eurasia around the mid- to- late 1800s in the New York and Pennsylvania area. This grass has been present in southeastern Idaho, the study area, since roughly 1900. Bromus tectorum is a species of interest due to the negative ecological impacts to the surrounding habitat and is particularly impactful in the sagebrush steppe of western North America. The sagebrush steppe is roughly 165 million acres of land that is home to several kinds of sagebrush as well as many other native grasses, plants, and animals. The sagebrush steppe has been reduced by roughly 1.3 million acres per year since 2001 and much of the steppe remains at risk. Cheatgrass has proved to be a hardy species that outcompetes many other plants for nutrients and recovers quickly from the fires it helps fuel. Understanding what factors may affect the reproductive success or biomass of cheatgrass may provide insight into sagebrush steppe recovery. At five sites in southeastern Idaho with varying burn history, and soil and climatic characteristics, 265 individuals from local cheatgrass populations were monitored for germination and seed set, with and without a competition treatment. Mature plants were harvested and seed production and biomass were measured as indicators of the population’s fitness. Using open-access climate and soil data gathered from WorldClim and the USGS Web Soil Survey and general linear models, we ask if burn history, climatic, and soil factors had significant impact on growth and reproduction of the sampled cheatgrass populations. Using biomass along with the numbers of seeds produced for each sample as a proxy for overall fitness allows us to determine which environmental factors may benefit cheatgrass population growth in this region. This work, as part of the BromeCast experimental network (https://bromecast.wixsite.com/home), will be beneficial to understanding current cheatgrass invasions, and preventing future spread.
Climate and Soil Effects on Fitness of Southeastern Idaho Invasive Bromus tectorum Populations
Cheatgrass (Bromus tectorum, Poaceae) is a well known invasive grass that has spread across the United States after introduction from Europe and Eurasia around the mid- to- late 1800s in the New York and Pennsylvania area. This grass has been present in southeastern Idaho, the study area, since roughly 1900. Bromus tectorum is a species of interest due to the negative ecological impacts to the surrounding habitat and is particularly impactful in the sagebrush steppe of western North America. The sagebrush steppe is roughly 165 million acres of land that is home to several kinds of sagebrush as well as many other native grasses, plants, and animals. The sagebrush steppe has been reduced by roughly 1.3 million acres per year since 2001 and much of the steppe remains at risk. Cheatgrass has proved to be a hardy species that outcompetes many other plants for nutrients and recovers quickly from the fires it helps fuel. Understanding what factors may affect the reproductive success or biomass of cheatgrass may provide insight into sagebrush steppe recovery. At five sites in southeastern Idaho with varying burn history, and soil and climatic characteristics, 265 individuals from local cheatgrass populations were monitored for germination and seed set, with and without a competition treatment. Mature plants were harvested and seed production and biomass were measured as indicators of the population’s fitness. Using open-access climate and soil data gathered from WorldClim and the USGS Web Soil Survey and general linear models, we ask if burn history, climatic, and soil factors had significant impact on growth and reproduction of the sampled cheatgrass populations. Using biomass along with the numbers of seeds produced for each sample as a proxy for overall fitness allows us to determine which environmental factors may benefit cheatgrass population growth in this region. This work, as part of the BromeCast experimental network (https://bromecast.wixsite.com/home), will be beneficial to understanding current cheatgrass invasions, and preventing future spread.