What Monarch Butterflies Can Tell Us About Climate Change

UCSB student, Esteni Dominguez, enjoying a morning with the monarchs

UCSB student, Esteni Dominguez, enjoying a morning with the monarchs

Winter in Santa Barbara—the time of year where butterfly pictures can take over your Instagram feed. They may be comfortably sitting on your friends’ noses or turning a eucalyptus branch to a bright orange color. Yet, seeing the thousands of butterflies in person is a much more overpowering experience than any picture could create. Every year at the City of Goleta’s Ellwood Butterfly Grove, Santa Barbara’s close neighbor, the monarchs fill the sky and group themselves on tree branches by the thousands, gathering the community to enjoy their beauty and learn about our environment.

These delicate insects create a winter refuge for themselves in Goleta’s Ellwood Grove from November through February, bringing approximately 85,000 visitors from all over the world to admire their majestic colors. Whether it is students taking a break from midterms on a Sunday morning, children learning about ecology on field trips, or tourists stopping by on their coastal road trip, the butterflies create a tranquil space for recreation that brings together all members of the community, while helping us learn about nature’s wonders.

Monarch butterflies resting on eucalyptus branch at Ellwood Butterfly Grove, Photo by Kenneth Tatro

Monarch butterflies resting on eucalyptus branches at Ellwood Butterfly Grove, Photo by Kenneth Tatro

The Santa Barbara Land Trust maintains the 9.3 acres known as the Coronado Butterfly Preserve, which serves as a gateway to Elwood Mesa, 137 acres of coastal open space in the City of Goleta. The Land Trust is safeguarding their property and establishing a habitat the butterflies need to thrive by collaborating with wildlife experts and volunteers to plant native flora – conserving the land for the benefit of the community and the thousands of butterflies that visit each year.

The monarch populations were first documented in the California coastline in the early 1900s. Ellwood Cooper, a local horticulturalist, brought eucalyptus trees over from Australia in 1870 and planted them throughout the state in hopes of using them as a renewable wood source. But the trees became too frail from the California weather, and instead developed into a hub for thousands of butterflies that began migrating from northern climates towards milder temperatures and shelter from the wind.

The newly introduced trees brought monarchs to over two hundred sites across the state. The sites of Natural Bridges State Beach in Santa Cruz also create a shelter for butterflies each winter as up to 100,000 monarchs stop here along their migration from the west side of the Rocky Mountains.

Monarch butterfly migration patterns in North America. Photo by Monarch Joint Venture

Monarch butterfly migration patterns in North America. Photo by Monarch Joint Venture

Although fairly new to California, the monarch butterflies have been documented to migrate south to Mexico for over two thousand years. Many monarchs coming from the east of the Rocky Mountains congregate at the Monarch Butterfly Biosphere Reserve World Heritage site, located 100 km away from Mexico City, after migrating up to three thousand miles. Millions of butterflies gather in these pine forests along their migration pattern, making this the largest monarch preserve in the world, and bringing in thousands of visitors every year.

Aside from bringing joy and allure to select communities across North America, the monarchs provide us with a deeper understanding of the natural world as their migration patterns and ecological responses can help us better understand climate change.

Brian Haggerty, a PhD candidate in the Ecology, Evolution & Marine Biology Department at UCSB, explains that climate change has many implications that could disturb monarch habitats, including, but not limited to, temperature, precipitation, and drought. Haggerty explains a few potential impacts climate change can have on these fragile insects. “Climate change can have direct effects on butterfly populations and indirect effects mediated through their host plants. Warmer temperatures as a result of climate change might speed up development rates in their larval stage, which would lead to an earlier appearance in butterflies. As their habitat is on edge due to the drought, host plants are themselves stressed, resulting in fewer green leaves and healthy branches for the butterflies to rest on.

Caterpillar found in Goleta yard. Photo by Kenneth Tatro

Caterpillar found in Goleta yard in 2013. Photo by Kenneth Tatro

Lynn Kirby, a docent for the City of Goleta Ellwood Butterfly Grove, has a similar explanation as to how the current drought is affecting the monarchs. She explains that the eucalyptus trees are currently very stressed, and the severe winds last Christmas caused butterflies to fall from the frail trees. Prey such as rats and birds snatch those butterflies that survive the fall. For these reasons, Goleta’s monarchs are declining in numbers and are more congregated in one particular area of the grove this year.

Butterfly ecosystems are as fragile as the insects themselves, and vulnerable to human impacts. Monarch populations throughout California have been on the decline due to habitat loss through development and agricultural practices. Herbicide used in agriculture led to a decrease in their host plant, milkweed, which the monarchs depend on to lay their eggs, drink nectar as an adult butterfly, and ingest as a toxin that protects them from natural predators.

Monarch butterfly feeding on milkweed plant. Photo by Big Blog of Gardening

Monarch butterfly feeding on milkweed plant. Photo by Big Blog of Gardening

Protecting the monarch overwintering sites is crucial in maintaining their populations. Luckily, at Goleta’s butterfly grove, the community was able to protect them when threatened by development. Kirby states, “I am proud of the City of Goleta and our community and how we came together to save the Ellwood Grove from developers. At the time the acquisition of the Ellwood site took place (2005), the developer agreed to move the building site to another less environmentally sensitive area of the Mesa.”

Pollinator garden provides nectar and pollen for the insects to feed on. Signs provided by the Xerces Invertebrate Conservation Society share your message of helping the pollinators and engage the community into doing the same. Photo by the Xerces Society for Invertebrate Conservation

Pollinator garden provides nectar and pollen for the insects to feed on. Signs provided by the Xerces Invertebrate Conservation Society share your message of helping the pollinators and engage the community into doing the same. Photo by the Xerces Society for Invertebrate Conservation

There are things we can do in our own backyards to further increase monarch populations. Gardening for pollinators is a rather recent phenomenon, which involves planting nectar sources and native milkweeds in school or home gardens for pollinators to feed on. These host plants feed the adults and breed the larvae. The monarchs, in particular, need milkweed to breed future generations along their flight path through the United States. For this reason, planting milkweed in gardens can be very beneficial to butterfly populations and can benefit pollinators throughout the world.

Monarchs not only provide a natural beauty for us to enjoy, but serve irreplaceable roles for our planet and our people. Pollinators are of great economic value as they help us with agriculture, especially in fruit and root crop production. Ecologically, and through their food-chain relationships, they maintain many plant communities, which in turn provide us with services like water filtration, carbon sequestration and erosion control. Lastly, the monarch butterflies offer us a sense of wonder about the natural world, encouraging us to cherish our planet and value its resources.

Make sure to check out the monarchs as they fill the sky and tree branches at the City of Goleta’s Ellwood Grove. Just don’t forget to tread lightly…it’s an enchanting and sensitive place.

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