Transplanted sagebrush “wildlings” exhibit high survival, but greenhouse-grown tubelings compensate for their lower survival via recruitment

Authors: BAILEY, E.C. - UTAH STATE UNIVERSITY; THACKER, E. - UTAH STATE UNIVERSITY; Monaco, Thomas; VEBLEN, K.E. - UTAH STATE UNIVERSITY

Submitted to: BMC Ecology and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/4/2024
Publication Date: 4/22/2024
Citation: Bailey, E., Thacker, E., Monaco, T.A., Veblen, K. 2024. Transplanted sagebrush “wildlings” exhibit high survival, but greenhouse-grown tubelings compensate for their lower survival via recruitment. BMC Ecology and Evolution. 24, 50 (2024). https://doi.org/10.1186/s12862-024-02236-z.
DOI: https://doi.org/10.1186/s12862-024-02236-z

Interpretive Summary: We compared the success and cost of planting containerized seedlings (“tubelings”) and wild collected plants (“wildlings”) in southeastern Idaho. We found high (79%) tubeling and low (10%) wildling mortality within the first year. Three years post-planting, chance of survival for wildlings was greater than that of tubelings (85% and 14% respectively). Despite high up-front costs of planting wildlings, high survival rates resulted in their being <50% of the cost of tubelings on a per-surviving plant basis. However, regeneration from seed produced by surviving tubelings equalized overall big sagebrush densities between tubeling and wildling treatment plots by year 3, such that overall project costs for wildlings were twice that of tubelings.

Technical Abstract: Land uses such as crop production, livestock grazing, mining and urban development have contributed to degradation of drylands worldwide. Loss of big sagebrush (Artemisia tridentata) on disturbed drylands across the western U.S. has prompted massive efforts to re-establish this foundational species. There has been growing interest in avoiding the severe limitations experienced by plants at the seed and seedling stages by instead establishing plants from containerized greenhouse seedlings (“tubelings”). In some settings, a potential alternative approach is to transplant larger locally-collected plants (“wildlings”). We compared the establishment of mountain big sagebrush (A. tridentata ssp. vaseyana) from tubelings vs. wildlings in southeastern Idaho. A mix of herbaceous species were drill-seeded in a pasture previously dominated by the introduced forage grass, smooth brome (Bromus inermis). We then established 80m x 80m treatment plots where we planted sagebrush tubelings (n=12 plots, 1200 plants) and wildlings (n=12 plots, 1200 plants). We also established seeded plots (n=12) and untreated control plots (n=6) for long-term comparison. We tracked project expenses in order to calculate costs of using tubeling vs. wildlings as modified by probability of success. There was high (79%) tubeling and low (10%) wildling mortality within the first year. Three years post-planting, chance of survival for wildlings was significantly higher than that of tubelings (85% and 14% respectively). Despite high up-front costs of planting wildlings, high survival rates resulted in their being <50% of the cost of tubelings on a per-surviving plant basis. However, recruitment via seed produced by surviving tubelings equalized overall big sagebrush densities between tubeling and wildling treatment plots by year 3, such that overall project costs for wildlings were twice that of tubelings. Our results indicate that larger plants with more developed root systems (wildlings) may be a promising avenue for increasing early establishment rates of sagebrush plants in restoration settings. Transplanting smaller greenhouse-reared plants (tubelings) remains a cost-effective alternative because successfully established tubelings, though few in number, recruited additional big sagebrush plants to compensate for their low early establishment. Our results also illustrate the potential for tubelings and wildlings to improve restoration outcomes by “nucleating” the landscape via natural regeneration during ideal climate conditions.