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Two MJV Programs Track Monarchs and Habitat Across California

Mar 24, 2022


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If you follow monarch conservation news, you know that both eastern and western populations of North American monarchs are in steep decline. That said, right now monarchs west of the Rockies run the greatest risk of passing the quasi-extinction threshold of 20,000 to 40,000 monarchs (quasi-extinction is the point at which extinction is likely inevitable). In fact, western monarchs passed that threshold in 2018 and 2019, and in 2020 the reported overwintering numbers in California dipped to an all-time low of 1,914 individual monarchs. The 2021 Thanksgiving Count showed a welcome increase to almost 250,000 individuals, but just two months later the 2022 New Year’s Count decreased to 150,000. By all accounts, the western population is in grave danger of becoming extinct within the next half century (Schultz et al., 2017).

Because of this risk, conservation efforts have ramped up on many levels, from tri-national government-led strategies to community science efforts across the monarch’s range. It’s not too late to protect monarchs and their migration, but the moment calls for all hands on deck

2022 MJV California field crews and project managers.

As part of this effort, the Monarch Joint Venture (MJV) administers numerous conservation science and habitat programs in the western U.S., including two California monitoring projects. In different contexts, both projects quantify the presence (or absence) of monarchs and assess the quality and quantity of breeding habitat across diverse California landscapes and land-use types. This work contributes to a better understanding of where and how to focus state and national conservation efforts. 

Right now, two teams of MJV field technicians are kicking off the 2022 season by traveling the backroads and remote wildlands of California to survey for monarchs, with one team surveying restored pollinator habitat and the other establishing baseline data across the state’s public lands. This article offers a summary of the parameters and goals for each project, and gives a sense of what’s on the horizon this field season. Be sure to join us on Instagram and Facebook for regular updates from the field, and subscribe to our monthly newsletter to stay in the loop on these and other projects.

MJV Enters Fourth Year of Monitoring Restored Habitat in NFWF Partnership

Continuing a partnership that started in 2019, we’re working with the National Fish and Wildlife Foundation (NFWF) to evaluate restored habitat sites that have received funding from NFWF’s Monarch Butterfly and Pollinators Conservation Fund (MBPCF). Previous years focused on the eastern monarch range, including restored tallgrass and shortgrass prairie, conservation lands, and private working lands throughout the Midwest and southern U.S. So far we’ve monitored over 200 sites; the 2022 season expands these monitoring areas to the West with 35 more sites. To learn more about the past three years of this project, check out this blog article from summer 2020 and our 2021 Summer Review, under “Caterpillar Resources on Restoration Lands.”

IMMP in action for western monarchs and habitat.

Our field technicians use the Integrated Monarch Monitoring Program (IMMP) to survey for adult monarchs, monarch eggs and larvae, flowering plants, and milkweed. We use these data to look at different metrics of success for the restorations, such as how many sites are supporting breeding monarchs and how much milkweed these projects contribute to national milkweed goals. “We also teach land managers and volunteers the IMMP so they can continue monitoring in future years,” says Jennifer Thieme, MJV science coordinator and manager of the NFWF project. “This enables them to track metrics that are important to them, such as what pollinator plant species germinate best from seed. It also builds a robust IMMP dataset that can address research questions on small or large scales.”

In the east, the team has found that MBPCF sites in the southern U.S. tend to have a lower density of milkweed than in the Midwest (324 vs. 1,052 stems per acre). All sites surveyed in the north during spring, summer, and fall had at least three blooming nectar species during each season and contained milkweed, meeting the MBPCF habitat goals.

This year, MJV monitoring will span the western monarch’s breeding season (March – Sept.) to document when monarchs first arrive at sites, the timing and extent to which they breed there, their use of nectar plants on site, and various habitat characteristics. Five repeat surveys throughout this six-month season will track monarch use of the site and how the breeding resources change throughout the season.

By the end of this year’s project, the team will know what proportion of western MBPCF sites meet the program’s goal of providing milkweed for breeding and at least three nectar species during spring, summer, and fall for nectaring. 

For Second Year, MJV Surveys California’s BLM Lands for Monarchs

The California Bureau of Land Management (BLM) oversees 15 million acres of public land (15% of California’s total land area), which encompass high mountains, open deserts, rangelands, and forest. As part of the Western Association of Fish and Wildlife Agencies (WAFWA), the BLM has a stake in the Association’s Western Monarch Conservation Plan, which has a goal to maintain a five-year average of 500,000 butterflies at the overwintering sites in California by 2029. Given the record lows in the western monarch population, the BLM is intensifying monarch conservation efforts in order to reach this population target. 

This will be the first time monarch and habitat monitoring has occurred in some areas.

But in order to establish and enhance habitat, we must first understand the characteristics of “good” monarch breeding habitat, and the geographic areas and habitat types most beneficial to monarchs. And that’s where the MJV comes in. For a second year, our field crews will be collecting vital data on the quality and distribution of pollinator habitat and use of that habitat by monarchs on BLM lands throughout California.

The primary goals of this project are to better understand the availability of milkweeds and nectar resources throughout the monarch  breeding season in California and document use of this habitat by monarchs of all life stages. We also aim to quantify and characterize the general availability of habitat across the western landscape that supports the breeding population. Better understanding these plant-insect interactions will directly contribute to several WAFWA Monarch Conservation Plan research and monitoring goals.

Field season kicks off with the wildflowers.

In 2021, MJV field crews sampled 210 BLM sites between March and September, and identified over 500 flowering plant species, five milkweed species, and counted more than 8,000 milkweed plants. The crews examined all milkweed plants they encountered for monarch eggs and larvae, but the rapidly declining western monarch population has made them difficult to find. The crew found just one monarch caterpillar during their entire six-month season and only a handful of adults. Though monarch sightings were scarce, and may be scarce again this year, the habitat data gathered is an important step toward identifying locations of potential breeding and migratory habitat, and understanding how BLM lands might play a role in supporting monarch butterflies and other pollinator species. 

“While very few monarchs were identified during the 2021 field season, the data we are collecting is critical for understanding how we can best focus our efforts to aid not only the recovery of western monarchs, but also to protect important pollinator habitat across California. BLM land is a big piece of that puzzle,” says Kristen Nelson, MJV western science coordinator and manager of the CA BLM project. To learn more about last year’s field season, check out our Summer 2021 Summer Review, under “Milkweed, Nectar Plants, & Monarchs on California BLM Lands.”

Right now, the 2022 field crew is starting the season in the desert region of southern California and moving generally north as plants at higher latitude and/or elevation come into peak bloom in the later spring and summer. They plan to work across the Central Valley, eastern Sierra, Sierra foothills, and perhaps a bit farther north. Nelson adds, “We are optimistic that higher population numbers observed at overwintering grounds this past winter compared to a year ago will result in more direct observations of monarchs at various life stages.”

The BLM field crew started the season in desert scrub habitat.

Because the BLM manages land across vast and often remote landscapes, our field crews are the first to survey for monarchs and pollinator habitat in some of these landscapes. Using IMMP protocols, this project addresses critical information gaps in monarch habitat availability and distribution as well as use by monarchs in the West. By focusing on BLM lands, we acquire information on habitats that have the potential to be positively impacted by this important land management entity and partner in monarch conservation. Additionally, the project will offer opportunities for BLM staff to engage in this nationwide program and apply it on any land to achieve their own research and monitoring goals.

All IMMP data from both projects will be available to researchers, and both field crews will be entering monarch and milkweed observations into the Western Monarch Milkweed Mapper throughout the season, so the larger monarch conservation community can utilize the data.

Did you know that the IMMP is a community science program, and anyone can participate? Find the information you need to get started here, and learn more about the significant impact IMMP makes in monarch conservation