Implementing and testing early season milkweed restoration in “Priority 1 Western Monarch Early Breeding Zone”

Project Dates

May 2023 - May 2025


Migratory western monarchs are facing substantial risk of extinction (USFWS 2020). They require immediate interventions, focused on the most vulnerable periods of their annual cycle, to save the migration. The most limiting part of the western monarch migratory cycle appears to be during the overwintering stage and during early-season breeding (Esperet et al. 2016, Pelton et al. 2019). Management and restoration of the early breeding zone is considered one of the highest priorities for recovering western monarchs.

Below we describe a portfolio of interconnected projects that will meet these needs by accomplishing the following goals simultaneously:

  1. Identify areas where early-season milkweed is growing on the landscape, including seed collection for plant materials and leaf collection for pesticide sampling. (SBBG’s role)
  2. Determine monarchs’ usage of early-season milkweed at known native stands (UC Davis).
  3. Evaluate the effectiveness of existing plantings at early-season milkweed sites (UC Davis, WSU), and
  4. Conduct new plantings of early-season milkweed to provide additional early spring larval and adult resources and determine the components of restoration that will increase performance for migratory monarchs (California Central Coast Joint Venture).


Current Status (as of early 2024):

The first year of surveys is complete. Currently, we are working with MEDS BREN students at the University of California, Santa Barbara to model milkweed distribution and inform 2024 surveys. In 2024, surveys will begin in late spring and continue through September, when we’ll collect seeds. Surveys will focus on the northern half of the Los Padres National Forest, especially the Monterrey Ranger District/ Bug Sur. This is the last year of funding for the project.


Identify areas where early-season milkweed grows on the landscape, including seed collection for plant materials and leaf collection for pesticide sampling.

This is a collaboration with the Santa Barbara Botanic Garden to determine early-season milkweed occurrences, collect seeds for future plantings, and pesticide leaf sampling in Los Padres National Forest (NF). This project would facilitate the implementation of a conservation strategy for Western Monarch that is currently being developed with Los Padres NF.

This project will provide previously unknown information about the current distribution and quality of early breeding habitat in Los Padres NF. This information would inform Los Padres NF’s management and protection of early breeding habitat. Commercial availability of early-season milkweed species is extremely limited, this project will provide plant materials for the proposed restoration projects.

Team Members

Collaborative project across the Garden’s staff, led by Sarah Cusser, Ph.D.


UC Davis, Washington State University, California Central Coast Joint Venture



California Department of Fish and Wildlife

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