Pollinator Studies, Willamette Valley, OR
Project ID: W912HZ-19-2-0008
Federal Agency: U.S. Army Corps of Engineers
Partner Institution: Institute for Applied Ecology
Fiscal Year: 2019
Initial Funding: $56,978
Total Funding: $201,970
Principal Investigator: Kaye, Tom
Agreement Technical Representative: Carmichael, Deberay
Abstract: Conservation of endangered plants may rely on successful habitat management that includes protection of pollinators. Plants that rely on pollinators for sexual reproduction through seeds must have adequate pollinator populations available. Understanding the relationship between plants and pollinators may be key to long term recovery of species that have become so rare that their survival is in jeopardy. Information on 1) importance of pollinators for reproduction and 2) the identity and habitat requirements of those pollinators can directly assist land managers with priority recovery actions.
Willamette daisy (Erigeron decumbens Nutt. [Asteraceae]) is endemic to grasslands in the Willamette Valley of Oregon, and is listed by the US Fish and Wildlife Service (USFWS) and Oregon Department of Agriculture as an endangered species. We have observed that very small populations of Willamette daisy lack seed production and reproductive failure is a serious concern for the conservation of this species (Thorpe and Kaye 2011), suggesting that pollinator conservation could be crucial for population viability of this species. Previous observations of pollinators of Willamette daisy have been restricted to a few sites and a single season, but have shown that a diversity of insects, including lepidoptera, flies and solitary bees, may be frequent visitors (Jackson 1996). Therefore, insects may be needed for pollinator service in this species, and these insects may depend on well managed prairie habitat to support their full, and varied, life cycles (Wojcik et al. 2018).
Pollinator abundance tends to be lower in smaller habitat fragments. While the pollination of Willamette daisy in small populations may be limited by infrequent pollination service by insects (low pollen quantity), this species may also suffer from stigma contamination with pollen from other plant species by generalist pollinators (low pollen quality). The chance of generalist pollinators visiting and transferring competing pollen from different species increases in small populations. Understanding the pollinators available to service Willamette daisy populations is important to better manage pollinator populations and improve reproduction in this endangered species.
We propose to examine the mating system and pollination biology of Willamette daisy, as well as document the availability of pollinators at prairie sites and document the effects of restoration practices on pollinator assemblages. This research will provide important information for the conservation and management of Willamette daisy in particular and prairie habitats in general throughout the ecoregion.
PROJECT DESCRIPTION
We propose a multi-phase project to address the importance of pollinators, breeding system of Willamette daisy, pollinator diversity and network for Willamette daisy floral visitors, and the effects of fire as a management tool on pollinator communities in Willamette daisy habitats.
1. Seed limitation of Willamette Daisy (2019)
In Phase 1, we propose to conduct research to determine if Willamette daisy seed production is limited by pollinator availability.
2. Mating system of Willamette Daisy (2019 and 2020)
We propose to conduct research to determine the mating system of Willamette daisy. This effort will require seed collection at wild sites in 2019 to support propagation and hand pollinations in 2020. In 2019 we will collect seed and begin cold-stratification procedures to grow out seed from multiple populations. In 2020 we will grow plants in a greenhouse and perform controlled cross-pollinations to determine the effect of different cross types on seed set and seed viability.
3. Pollinator availability at prairie sites (2020-2022)
In 2020-2022, we propose to conduct field studies to determine the availability of pollinators to service Willamette daisy populations.
Objective: Document the availability of pollinators that can service Willamette daisy at multiple locations to understand the suitability of individual sites for Willamette daisy by comparing pollinators in existing populations and unoccupied habitats.
4. Effects of restoration on pollinator assemblages (2021-2023)
Objective: Document changes in pollinator community at multiple sites to understand the effects of management actions.