By: Gary Paul Nabhan and Ina Warren, MakeWayforMonarchs.org
Two monarchs on a pink milkweed blossom. By Ina Warren
When Pope Francis recently released his encyclical on climate change, people of many faiths finally realized how climate change is ultimately an issue of social and environmental justice that bringing caring for creation and “the right to life” to all species, races, cultures and classes. But it should explicitly be added that climate-related “social justice” needs to be applied to “social insects” like some bees and butterflies, not just to “social hominids” like human beings? Indeed, the plight of monarchs, honeybees and bumblebees in the face of climate change directly affects us. They are parts of the earth itself that is groaning under the pressures of climate change. Lets see how:
Monarch butterflies: They are the iconic symbols of international cooperation in North America in the face of climate change. Because of their long distance migration across a variety of climates and habitats, monarchs serve as a messenger of the collective global effects of climate change interacting with a variety of other stressors, natural and human-triggered. Their numbers on the North American continent are less than 10% of what they were two decades ago, so there are international efforts initiated in collaborative conservation to ensure their recovery by planting 1.2-1.4 billion milkweeds to host and to nourish them over the next decade.
Domestic honeybees and wild bumblebees: Populations of the once ubiquitous honeybee as well as those of at least ten endangered species of native bumblebees are at their lowestknown levels in human history. Diseases, neonicitinoid pesticides as well as climate change have not only reduced their populations but have lessened their capability to migrate elevationally to avoid extreme heat and drought.
Here is what these harbingers are telling us about climate change:
1. The disappearing oyamel fir forests in Mexico are expected to decline beyond their capacity to support monarchs’ winter roosts as global warming affects germination, seedling establishment and survival, tree longevity and wildfire frequency. Losing these high altitude forests in central Mexico could affect the water supply in and near Mexico City since much of their water comes from these watersheds. In addition to the loss of the natural wonders of the forest is a cultural one as well. The people of Mexico have shown their affection for the monarchs for centuries, honoring their key role in the Dias de los Muertos ceremonies, i.e.: the Mexican Christian celebration of the Day of the Dead. At the same time, many populations and even some species of bumblebees have failed to adapt to changing climates by moving upward along mountainsides.
2. As the oyamel forests become more fragmented, monarchs themselves are increasingly vulnerable to catastrophic freezes that can kill many millions of monarchs on a single night. Farmers in the central highlands of Michoacan also face additional challenges making a living with these dramatic climate changes. They need water and therefore need intact forests to protect/provide the local water. Likewise, bees are being stressed or killed by catastrophic freezes.
3. Monarch winter roosts on the Pacific coast of Baja and Alta California are already affected by prevailing drought and warmer winters, with the most southerly roosts being progressively abandoned. Honeybees and bumblebees have also lost nectar resources due to drought and heat waves. Replenishing native trees, shrubs and perennials along the California coast would benefit monarchs and other pollinators by restoring the rich diversity of native plants as larval host plants and availability of nectar-rich flowers.
4. Bee and monarch nutrition during migration will likely be affected by the “phenological mismatches” between incrementally earlier flowering of milkweeds and other nectar-rich flowers, and the northward arrivals of monarchs themselves. This will also affect migratory hummingbirds and neotropical songbirds that depend on the fruits, nuts, seeds and berries available only from effective pollination.
5. Monarch egg-laying and bee nectaring may be affected by the scarcity of milkweeds, which have been decimated by both herbicides and drought to the point that 1.1 to 1.5 billion milkweed stems have been lost from summer breeding grounds in the last fifteen years. Over 100 kinds of native bees formerly used milkweed nectar as a nutritional resource in North America. Fewer milkweeds in Texas will negatively affect the spring’s first-generation monarchs in years with heavy fire ant predation on monarch larvae and also from extreme weather events.
6. Monarch larval survival may also be at risk by the scarcity of milkweed larval host plants in the summer breeding and feeding grounds. This creates a remarkable opportunity for schools nationwide to participate in active Citizen Science programs by planting, caring for, and monitoring native ‘Asclepias’ milkweed species in their local school yards, back yards, church yards and court yards.
7. Milkweeds are perennial native wildflowers that not only provide monarchs with critical foliage required for their larval cycle and native bees with needed nectar, but also sequesters carbon in the soil that counters greenhouse emission buildup.
8. Taking agriculture out of row annual forage crop production and planting perennial prairies and savannas with milkweeds in them also retains carbon and pollinators while providing climate-reliant native forages for livestock and bison.
9. Engaging federal, state and county agencies in planting perennial milkweeds and wildflowers along roadsides, railroad lines and energy transmission lines further builds carbon-sequestering corridors across our landscapes useful for monarchs, other butterflies, bees and migratory wildlife.
10. Reducing the use of fossil fuel based agrichemicals and transitioning to a more sustainable agriculture is not only good for wildlife like monarchs, but adds resilience to our food system.
References by paragraphs:
1.] Estimated reduction of climate habitat for Abies religiosa (sacred fir or oyamel fir). Implications for monarch butterfly conservation by Cuauhtémoc Sáenz-Romero and Climate change impacts on bumblebees converge across continents by Jeremy T. Kerr et al.
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