Join Us in Recovery Efforts
Provide habitat for endangered the island marble butterfly. You can get involved in species recovery by volunteering to grow host plants in protected habitat areas, by adding habitat to your property, or by donating to support volunteers renewing annual host plants for butterflies.

What Can You Do?

Volunteer to Grow Host Plants With Us 
Provide Habitat on Your Property
​Give to the Volunteer Program

Habitat Conservation

• Expand, restore, maintain, and enhance habitat
• Add more habitat area
• Habitat connectivity
• Captive rearing program
• Host plant seed collection and propagation
• Invasive species removal
• Development of methods to support habitat expansion
• Inter-agency and landowner collaboration 
• Timing of management actions
• Landowner agreements through the Partners for Fish and Wildlife program, contact Walt Andrews at walt@sjicd.org for more information
• Native prairie restoration to support complete life history

Deer-fenced Habitat Plots

Deer fencing is critical to protect eggs and young larvae from browsing deer and to provide stable, protected year-round habitat for chrysalises. It is important to both provide habitat to support the island marble butterfly's life cycle and to protect against sources of island marble butterfly loss. Field mustard, or Brassica rapa (shown below) is planted in habitat plots in grassland ecosystems.

Photo credit above: Walt Andrews courtesy of San Juan Preservation Trust

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Host Plants and Their Habitats

The island marble butterfly uses both introduced and native mustard host plants in several different environments. Over time, the butterfly has come to rely upon introduced, weedy species to complete its life cycle, while also relying on native host plants. 

    Photo credits, left to right: USFWS, Andrews

Introduced Host Plant Species
Introduced mustard are currently critical to supporting the life cycle and recovery of the island marble butterfly. In this context, mustard is beneficial to butterflies through island marble butterfly conservation. Weed control and invasive species eradication remain important.

​Field Mustard, Common Mustard, or Wild Turnip, Brassica rapa
More robust in grassland or prairie habitats
Disturbances include intermittent human or small mammals such as voles

Photo credits above and below: Ben Legler, Burke Herbarium Image Collection

Tumble Mustard or Tall Rocket, Sisymbrium altissimum
More robust in dune habitats
Wind provides a major source of disturbance

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Native Host Plant Species
Coastal Peppergrass or Hairy Peppergrass, Lepidium virginicum menziesii
More robust in coastal lagoon and shoreline habitats
Disturbances include tidal and seasonal flood events

Disturbance
Disturbance is an important ecological process that can maintain biodiversity. Early succession annuals or biennials, like mustard, need disturbance to germinate and carry out their life cycle. Historically, disturbance has included fire, grazing, trampling, drought, and storms. Species can be adapted to disturbance. To promote mustard in habitat plots, various techniques are used to disturb the soil. Land managers also remove shrubs and trees encroaching into grasslands, use fire restoration treatments, and remove invasive species. This recent historical trend toward altered patterns of disturbance is a problem for imperiled butterfly species that rely on host plant availability in their environments.  
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Disturbance is an important requirement for island marble butterfly habitat. Volunteers are needed to actively work in the islands to create conditions for optimal host plant growth to expand habitat. Host plants must find the right conditions to grow in patches across the islands on a yearly basis. Due to the island marble butterfly's current status, combined needs for disturbance and host plant protection from deer results in the need for volunteers to cultivate mustard inside fenced habitats.   ​

List of Island Marble Butterfly Nectar Plants
The island marble butterfly need sources of nectar to carry out their adult life stage as butterflies and reproduce. These coevolved relationships involve island marble butterfly pollinating nectar-producing plants in grassland, remnant prairie, dune, lagoon, and shoreline ecosystems. Pollinators are of vital importance to the plants they visit. This list provides an overview of nectar sources for the species.

yellow sand verbena, Abronia latifolia, native perennial

yarrow, Achillea millefolium, native and introduced populations, perennial, white-flowering—can be preferred for mating
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small-flowered fiddleneck, Amsinckia menziesii, native annual

american sea rocket, Cakile edentula, introduced annual, bienniel, perennial 

field chickweed, Cerastium arvense, native perennial, white-flowering—preferred for mating 

common stork’s bill, Erodium cicutarium, introduced annual

dovefoot geranium, Geranium molle, introduced annual

hairy cat’s ear, Hypochaeris radicata, introduced perennial 

common lomatium, Lomatium utriculatum, native perennial

seashore lupine, Lupinus littoralis, native perennial

common forget-me-not, Myosotis discolor, introduced annual

california buttercup, Ranunculus californicus, native perennial

trailing blackberry, Rubus ursinus, native perennial, white-flowering—can be preferred for mating

common dandelion, Taraxacum officinale, introduced perennial

death camas, Toxicoscordion venenosum, native perennial, white-flowering—can be preferred for mating

​Howell’s brodiaea, Triteleia grandiflora var. howellii, native perennial

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