“Monarch Butterflies Drop Stuns Scientists” was the SF Chronicle front-page headline on January 17, 2019. The story covers the results of the winter 2018 monarch count in 213 forested groves in California this last winter. The results are alarming: the count showed an 86% drop from a year ago, a 99.4% drop since the 1980s, and “...an all-time low for the Pacific Coast, where an estimated 10 million monarchs once blanketed trees from Marin County to the Baja California peninsula…”.
Eastern Monarchs overwinter in Mexico and migrate north through the eastern United States. They had a much better year. The number of Monarchs (scientific name Danaus plexippus plexippus) that overwintered in Mexico was more than twice as large as the prior year. Something to celebrate, certainly, but the long-term trend is not as rosy. The total population is still only about ⅓ of what it was two decades ago.
The Monarch is beloved because it’s big and showy (have you ever seen a eucalyptus grove full of monarch butterflies? If not, take a look at this video. But it’s not just Monarchs; many other butterfly species have seen steep population declines or even gone extinct in the recent past. Dr. Arthur Shapiro, Professor of Evolution and Ecology at UC Davis, is one of the world’s leading butterfly experts. He’s been monitoring butterfly populations in California since 1972. In this interview, he notes that what is happening to Monarchs is also happening to many species in our state, due to the “...large loss of habitat and habitat connectivity, and the [landscape] is increasingly becoming more butterfly-sterile.”
Among the Lepidoptera species that have seen steep population declines in the past 10-20 years are the beautiful blue-and-black pipevine swallowtail (Battus philenor), the callippe silverspot (Speyeria callippe callippe), the mission blue (Icaricia icarioides missionensis), the San Bruno elfin blue (Incisalia mossii bayensis) and the Bay checkerspot (Euphydryas editha bayensis). Battus philenor, for example, has nearly disappeared due to loss of habitat.
The focus of our next few posts is on pollinators and how we can help them thrive. The transfer of pollen in and between flowers of the same species leads to successful seed and fruit production for plants, ensuring full-bodied fruit and a full set of viable seeds. Loss of pollinators means many plants can’t reproduce at all, with catastrophic consequences up and down the food chain.
The economic cost of pollinator loss is also high: globally, the annual value of global crops directly affected by pollinators is between US$235 to US$577 billion, according to the Food and Agriculture Organization of United Nations. According to the USDA, “Three-fourths of the world's flowering plants and about 35 percent of the world's food crops depend on animal pollinators to reproduce.
More than 3,500 species of native bees help increase crop yields.”Most of the plants grown for food, beverages, fibers, spices, and medicines depend on pollination to produce the goods on which we depend. Just a few of the foods and beverages produced with the help of pollinators include: apples, blueberries, chocolate, coffee, melons, peaches, potatoes, pumpkins, vanilla, almonds, and tequila. Without pollinators, our plant food options would be few and dull, just grains and greens.
Three-fourths of the world's flowering plants and about 35 percent of the world's food crops depend on animal pollinators to reproduce. More than 3,500 species of native bees help increase crop yields.
Human survival is intimately linked with many species of insects, especially pollinators. Unfortunately for them, and for us, huge areas of pollinator habitat have been and continue to be destroyed due to land development and large-scale, corporate forms of agriculture. As human populations grow, we eradicate crucial food and shelter sources for pollinator species in order to build homes, shopping centers, schools, industrial parks and agribusiness - the business of agricultural production, which includes agrichemicals (fertilizers and pesticides), breeding, crop production, distribution, farm machinery, processing, seed supply, and marketing and sales. The reduction in habitat areas, especially over the past 20 years, has resulted in a large decline in pollinator populations all over the world.
Agricultural areas in particular have had a huge impact on pollinator populations. As small farms continue to be consumed by giant agribusiness corporations, loss of habitat occurs as corporate farms convert large areas of land from a mixed group of crops and plant cover into a monoculture where only one type of plant is allowed to grow. This lack of diversity in rural areas is detrimental to all kinds of pollinators.
Finally, the increased use of pesticides, as well as the increased toxicity of modern pesticides, further diminishes the ability of pollinators to thrive. The irony of this situation is that farmers need to pay beekeepers to move their bees onto the farms in order to pollinate food crops. Bees that travel across the country to serve as pollinators tend to be weaker. These weaker, stressed bees are believed to be a part of what is leading to colony collapse disorder.
Fortunately, it’s easy to incorporate pollinator habitat into our own gardens. By adding food, shelter, and water to the garden, we can improve conditions for pollinators, and help ensure that food sources are secure for future generations. We’ll talk more about how to add these things to the garden in the next few posts. In the next post, we'll talk about ways to add food for pollinators to your garden.
March is a time of year in the Bay Area that sees a fluctuation in temperatures and in precipitation. This year, we were lucky in January to see so much rain, and then to have a warm and dry February. This brought out the blooms. When it comes to blooming, at Mariposa, we love to see as much late winter and early spring bloom as we can. Not only is it beautiful, after the cold grey days of December and January, but it is also important for our winged friends, the butterflies and the bees. Blooming flowers provide nectar and nourishment when the weather starts to get warm and the pollinators emerge from winter dormancy.
Fuschia thymilfolia is an excellent garden performer. It keeps its flowers year round, and provides nectar to a host of pollinators, including bumblebees and hummingbirds. In addition, it does well in dry shade. Often, trying to find plants that work in dry shade is a gardener’s dilemma.
Cerinthe is a flower that will readily reseed itself in your garden. It’s lovely blue flowers are one of our first blooms of the year. Bumblebees and honey bees will be glad that you’ve planted it, as it is blooming right when they start to actively forage again.
Lantana is blooming in my garden right now, however, I normally think of Lantana as a summer bloomer. Maybe it is the effects of the drought that has it blooming out of season. At any rate, it is blooming, and I have seen several bumblebees visiting during our warmer days in Late February.
Ceanothus is one of my favorite late winter and early spring bloomers! It’s beautiful soft blue flowers make it a true gem in the garden. The heavenly and faint scent send me swooning every time I leave in the morning, as I have a full blooming Ceanothus ‘Ray Hartman’ blooming right outside my front door. The bumblebees love Ceanothus, and on a sunny day, one can see several of them working the deep blue blooms.
The fairest of all Early Spring blooms is the lovely Ribes sanguineum. It’s graceful plumes of pink flowers are truly lovely to behold. Right now, in many parts of the Bay Area, they are at their peak. Enjoy them while you can. Once the flowers have faded, they will produce currants that are loved by our local birds.