Location: Range and Meadow Forage Management Research
Project Number: 2070-30400-001-000-D
Project Type: In-House Appropriated
Start Date: Mar 3, 2026
End Date: Mar 2, 2031
Objective:
Objective 1: Determine methods for preserving and/or creating seed source islands of key desired species.
Sub-objective 1.A: Determine the degree to which broadcast seeding, hand plugging, watering, and weeding influence the establishment of locally collected native plants in seed source islands.
Sub-objective 1.B: Determine parental plant reproductive ecophysiological characteristics that contribute to establishment success of locally collected bunchgrass plants in seed source islands.
Objective 2: Document the natural rate of spread of desired species from seed source islands across landscapes.
Sub-objective 2.A: Quantify the short-term (4-years) spread of species from a seed source island comprised of an established plant community mimicking an intact Wyoming big sagebrush/bluebunch wheatgrass habitat type.
Objective 3: Develop techniques to accelerate the spread and establishment of species from seed source islands.
Sub-objective 3.A: Determine if creating safe sites by drag harrowing or lightly disking areas adjacent to seed source islands accelerates the spread of native species into those areas.
Approach:
For Objective 1, to test the hypothesis that native plants planted by hand using greenhouse-grown plugs and watered where all invasive weeds are removed will have the greatest plant density, diversity, and seed production relative to plots that are broadcast seeded. We will utilize a field study replicated at two sites and incorporating factorial combinations of treatments (two planting methods, two watering treatments, and two weeding systems) in small plots at each site. Plots will be rototilled in the fall prior to fall planting or seeding. Planting success data will be collected in June of each year of the study (3 years) and analyzed using analysis of variance for a complete randomized block design. To test the hypothesis that seeds having traits associated with successful establishment will originate from parental plants that have higher reproductive photosynthetic capacity, we will use a common garden study with data collected over a 3-year period. Subsamples of seeds will be analyzed to determine average seed area, seed mass, and seed specific mass (mass/area). Seeds will be planted in containers and allowed to germinate and emerge before planting into a common garden that has been rototilled and weeded. Plant growth will be quantified over a 3-year period using a digital camera to measure Normalized Difference Vegetation Index. Gas exchange characteristics and seed production will be measured on 10 individuals of each species in each of the following three years. Plants will be harvested to determine biomass in the last year of the study. At the end of each reproductive period, seeds will be gathered from each plant, grown in growth chambers, and seedling root production will be assessed. Data will be analyzed using two-way analysis of variance to test for differences between source populations. Based on these analyses, linear and non-linear regressions will be used to relate parental plant ecophysiological attributes to subsequent seed characteristics. For Objective 2, we will evaluate the short- and long-term rate of spread of locally collected native plant species planted in seed islands. Two treatments (non-planted islands and islands seeded with native species) will be replicated four times at three sites. Whole plots will sprayed with a pre-emergent herbicide during the first year, prior to planting. Small islands within larger plots will be planted with transplants of target species. Any live plants of the target species that were not planted will be removed from the entire area to ensure plants found within the whole plot originated from the seed source island. We will document spread of planted species in the whole plot using transects radiating from the seed source island for 4 years and treatment responses compared using analysis of variance. For Objective 3, we will test the hypothesis that harrowing or light disking will increase density of planted species around seed source islands. This study will employ a similar experimental approach to Objective 2, except the vegetated area in each cardinal direction surrounding the seed island will be left natural, harrowed, lightly disked, or sprayed with a pre-emergent herbicide.