Milkweed and floral resource availability for monarch butterflies (Danaus plexippus) in the United States
The global decline of pollinators, particularly insects, underscores the importance of enhanced monitoring of their populations and habitats. However, monitoring some pollinator habitat is challenging due to widespread species distributions and shifts in habitat requirements through seasons and life...
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Frontiers Media S.A.
2024-05-01
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| Series: | Frontiers in Ecology and Evolution |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fevo.2024.1330583/full |
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| author | Laura Lukens Laura Lukens Jennifer Thieme Wayne E. Thogmartin |
| author_facet | Laura Lukens Laura Lukens Jennifer Thieme Wayne E. Thogmartin |
| author_sort | Laura Lukens |
| collection | DOAJ |
| description | The global decline of pollinators, particularly insects, underscores the importance of enhanced monitoring of their populations and habitats. However, monitoring some pollinator habitat is challenging due to widespread species distributions and shifts in habitat requirements through seasons and life stages. The monarch butterfly (Danaus plexippus), a migratory insect pollinator that breeds widely throughout North America, presents a unique case study for testing a sampling framework to overcome these challenges. Monarchs exhibit discrete resource needs across life stages (e.g., larval requirement for milkweed, adult requirement for floral nectar), utilizing many land use types across their extensive geographic range during breeding and migration seasons. The Integrated Monarch Monitoring Program (IMMP) uses a standardized protocol with a generalized random tessellation stratified (GRTS) sampling design to gather spatially balanced and ecologically representative information on monarch habitats within the United States. The IMMP is applicable to various land use types and habitats used by breeding monarchs and may be extended to sites outside of the GRTS design to collect data on non-random sites of interest, such as legacy or conservation sites. Additionally, the IMMP’s modular design and publicly available training allows for broad participation, including involvement from community scientists. Here, we summarize habitat metrics (milkweed and floral resources) across 1,233 sites covering much of the monarch’s breeding range. We examine variation in milkweed density and floral resource availability on probabilistic (random) and non-probabilistic (convenience) samples and among land use types (site types). Additionally, we assess resource availability within core geographies for monarch breeding and migration, specifically within the U.S. Fish and Wildlife Service’s Monarch Conservation Units (western, northern, and southern United States). Milkweed density, floral frequency, and floral richness were higher on non-random sites and in the North region. Among site types, milkweed density was highest on Rights-of-Way and Unclassified Grassland, while floral frequency was lowest on Rights-of-Way. The IMMP represents the first field-based habitat monitoring program of this scale for monarchs, yielding a robust dataset on monarchs and their habitats across their breeding range and offering a framework for surveying the habitat of insect species with diverse habitat requirements or widespread distributions. |
| format | Article |
| id | doaj-art-942d7eb6e4e94a83a22fbdd04f423e48 |
| institution | DOAJ |
| issn | 2296-701X |
| language | English |
| publishDate | 2024-05-01 |
| publisher | Frontiers Media S.A. |
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| series | Frontiers in Ecology and Evolution |
| spelling | doaj-art-942d7eb6e4e94a83a22fbdd04f423e482025-08-20T02:57:47ZengFrontiers Media S.A.Frontiers in Ecology and Evolution2296-701X2024-05-011210.3389/fevo.2024.13305831330583Milkweed and floral resource availability for monarch butterflies (Danaus plexippus) in the United StatesLaura Lukens0Laura Lukens1Jennifer Thieme2Wayne E. Thogmartin3Monarch Joint Venture, Saint Paul, MN, United StatesDepartment of Forest & Rangeland Stewardship, Colorado State University, Fort Collins, CO, United StatesMonarch Joint Venture, Saint Paul, MN, United StatesUnited States Geological Survey, Upper Midwest Environmental Sciences Center, La Crosse, WI, United StatesThe global decline of pollinators, particularly insects, underscores the importance of enhanced monitoring of their populations and habitats. However, monitoring some pollinator habitat is challenging due to widespread species distributions and shifts in habitat requirements through seasons and life stages. The monarch butterfly (Danaus plexippus), a migratory insect pollinator that breeds widely throughout North America, presents a unique case study for testing a sampling framework to overcome these challenges. Monarchs exhibit discrete resource needs across life stages (e.g., larval requirement for milkweed, adult requirement for floral nectar), utilizing many land use types across their extensive geographic range during breeding and migration seasons. The Integrated Monarch Monitoring Program (IMMP) uses a standardized protocol with a generalized random tessellation stratified (GRTS) sampling design to gather spatially balanced and ecologically representative information on monarch habitats within the United States. The IMMP is applicable to various land use types and habitats used by breeding monarchs and may be extended to sites outside of the GRTS design to collect data on non-random sites of interest, such as legacy or conservation sites. Additionally, the IMMP’s modular design and publicly available training allows for broad participation, including involvement from community scientists. Here, we summarize habitat metrics (milkweed and floral resources) across 1,233 sites covering much of the monarch’s breeding range. We examine variation in milkweed density and floral resource availability on probabilistic (random) and non-probabilistic (convenience) samples and among land use types (site types). Additionally, we assess resource availability within core geographies for monarch breeding and migration, specifically within the U.S. Fish and Wildlife Service’s Monarch Conservation Units (western, northern, and southern United States). Milkweed density, floral frequency, and floral richness were higher on non-random sites and in the North region. Among site types, milkweed density was highest on Rights-of-Way and Unclassified Grassland, while floral frequency was lowest on Rights-of-Way. The IMMP represents the first field-based habitat monitoring program of this scale for monarchs, yielding a robust dataset on monarchs and their habitats across their breeding range and offering a framework for surveying the habitat of insect species with diverse habitat requirements or widespread distributions.https://www.frontiersin.org/articles/10.3389/fevo.2024.1330583/fullmonarch butterflymilkweedAsclepiasfloral resourceshabitat assessmentmonitoring |
| spellingShingle | Laura Lukens Laura Lukens Jennifer Thieme Wayne E. Thogmartin Milkweed and floral resource availability for monarch butterflies (Danaus plexippus) in the United States Frontiers in Ecology and Evolution monarch butterfly milkweed Asclepias floral resources habitat assessment monitoring |
| title | Milkweed and floral resource availability for monarch butterflies (Danaus plexippus) in the United States |
| title_full | Milkweed and floral resource availability for monarch butterflies (Danaus plexippus) in the United States |
| title_fullStr | Milkweed and floral resource availability for monarch butterflies (Danaus plexippus) in the United States |
| title_full_unstemmed | Milkweed and floral resource availability for monarch butterflies (Danaus plexippus) in the United States |
| title_short | Milkweed and floral resource availability for monarch butterflies (Danaus plexippus) in the United States |
| title_sort | milkweed and floral resource availability for monarch butterflies danaus plexippus in the united states |
| topic | monarch butterfly milkweed Asclepias floral resources habitat assessment monitoring |
| url | https://www.frontiersin.org/articles/10.3389/fevo.2024.1330583/full |
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