Mexico’s monarch butterflies are suffering from an usual cold weather system that began two days ago with severe rain, wind, and cold temperatures battering butterflies to the ground. As snow falls in the Monarch Biosphere, conservation of the other end of the monarchs’ life is criticized as inadequate. U.S. conservation groups today issued a suit against the government for failing to protect the monarchs under the Endangered Species Act. SEE THE END OF THIS ARTICLE FOR UPDATES ON MONARCHS AND HABITAT CONSEQUENCES AND HELP FOR LOCAL RESIDENTS.
Although some monarchs have left the Biosphere and begun migrating to their summer ranges, none has been seen yet entering Texas, which means they are still flying along the spine of the Sierra Madre mountains included in the winter storm. The cold wet weather and high winds have created conditions that are deadly to the one-half or more of this year’s population still remaining in the Biosphere. Snowfall today may benefit the butterflies by insulating the clusters hanging from trees, but many will die anyway. The 8 to 13 inches of snow in El Rosario and adjacent villages hasn’t been seen since the 5 inches that fell in 1995 and caused a population crash, although the population then was nearly double this season’s.
People living near the Biosphere also suffer from cold as their homes are not built for this weather and they lack heating and sufficient blankets. These people have shifted their lifestyles to protect the butterflies. They are dependent now on ecotourism instead of forest trees for their income and the handy source of firewood is no longer legal to cut. Tree seedling nurseries and reforested areas help ensure the monarch’s habitat and a new visitor’s center with food and crafts vendor spaces was just completed. As much as the monarchs depend on clement weather to survive, now so do the human residents.
Two weeks ago these monarchs were cheered as the largest overwintering population in five years. They are responsible for the entire population summering in the US and Canada east of the Rocky Mountains. Their summer homes aren’t secure enough, either, but many of these problems can be addressed if proper actions are taken. Lack of such action is the focus of a lawsuit issued today.
The Center for Biological Diversity (CBD), Center for Food Safety and others (such as monarch researcher Dr. Lincoln Brower) are suing the U.S. Fish and Wildlife Service for not following through on legal deadline to issue a final decision regarding the petition to list the monarchs under the Endangered Species Act (ESA).* An announcement issued today by CBD describes the reason for the lawsuit.
Center for Food Safety, the Center for Biological Diversity and allies formally petitioned the Service in August 2014 to protect the monarch as a “threatened” species following a 90 percent population decline over the preceding two decades. In December 2014 the Service determined that protection may be warranted, triggering an official review of the butterfly’s status that, by law, must be completed within 12 months. More than a year later, however, the Service has failed to issue a final decision on whether to protect the charismatic orange and black butterfly under the Act. Today’s lawsuit requests that the court set a deadline for that decision.
The deathly weather in the Biosphere today speaks to how threatened are these butterflies and is coincidentally mirrored in CBD’s announcement (my bold added).
While this year’s winter count is better than the record lows of the previous three years, it still represents a decline of 78 percent from the known population highs of the mid-1990s and is well below the population size needed for recovery. Monarchs require a much larger population to be resilient to severe weather events and other threats. A single winter storm in 2002 killed an estimated 500 million monarchs — more than three times the size of the entire current population
Studies conducted by scientists and conservation groups point to several threats that can be altered if the legal basis through the ESA exists to enforce actions.
The butterfly’s dramatic decline has been driven in large part by the widespread planting of genetically engineered crops in the Midwest, where most monarchs are born. The vast majority of genetically engineered crops are made to be resistant to Monsanto’s Roundup herbicide, which is a potent killer of milkweed, the monarch caterpillar’s only food source. The dramatic surge in Roundup use and “Roundup Ready” crops has virtually wiped out milkweed plants in midwestern corn and soybean fields. It is estimated that in the past 20 years these once-common butterflies may have lost more than 165 million acres of habitat — an area about the size of Texas — including nearly a third of their summer breeding grounds.
Monarchs are also threatened by global climate change, drought and heat waves, other pesticides, disease and predation, urban sprawl and logging on their Mexican wintering grounds.
We can’t turn back climate change induced threats fast enough to benefit the monarchs and many other species, but we can limit harmful pesticides, habitat losses, and practices like captive breeding and release and careless use of non-native milkweeds.
* A pdf copy of the lawsuit is available online.
Today, Friday 11 March, the snow is melting and temperatures are warming in Angangueo, the village below El Rosario Monarch Sanctuary. While melting snow indicates higher temperatures, this doesn’t necessarily benefit the monarchs as they lose the insulation from snow and are saturated. If the sun shines for hours, the monarchs can dry enough to not freeze when night temperatures drop. The past storm blew over hundreds of trees in this one overwintering site (and presumably in others) and by opening up gaps in the canopy the protection of intertwined sheltering branches is reduced and the monarchs are exposed to colder temperatures.
Saturday 12 March
An update on the storm and consequences to the monarchs and their habitat from the El Rosario manager indicates some monarch losses and more serious habitat losses. Although government officials visited the Biosphere Friday and issued a statement claiming the monarchs had migrated and those remaining were all safe, the actual situation assessed by those who work daily in the Biosphere varies somewhat.
Right now, losses to monarchs are estimated at 2 to 3 percent of the population of El Rosario (the largest of the sites open to the public). Tourism will continue through March as many monarchs won’t leave for weeks. The more serious consequence is the thousands of forest trees blown over b the storm. These fragment the suitable habitat and can expose the remaining monarchs to weather variations. For subsequent overwintering populations, the loss of mature trees may reduce the number of sites and total area available to shelter the monarchs.
Also yesterday, a truckload of supplies arrived to help local residents stay warmer. Blankets and corrugated panels were the main items provided. The panels are needed to cover gaps in homes and help retain heat indoors.
UPDATE # 3 Saturday 12 March 12:30pm from Dr. Chip Taylor of Monarch Watch
Information is still sketchy about the level of mortality due to the late winter storm at the monarch overwintering sites in Mexico. Most claims, observations and images suggest that mortality is low to moderate. There is no evidence to date to indicate levels of catastrophic mortality (70-80%) that followed the winter storms of 2002 and 2004.
Assessing the impact of these storms is difficult for a number of reasons: 1) not all dead butterflies drop immediately from the trees.Therefore, estimates of mortality based on dead on the ground are likely to be underestimates. 2) monarchs damaged by ice crystals that penetrate some tissues do not alway die immediately 3) some undamaged butterflies are likely to die simply due to the long periods of inactivity that prevented them from getting the water needed to convert fats to trehalose. It will take a week or more to obtain a better estimate of the impact of this storm.
It’s worth keeping in mind that a significant portion of the population had already left some of the colonies before the storm.. Nothing is known about the fate of these butterflies.
There is no freezing weather in the long term forecast and daytime highs in the high 60s and 70s should allow healthy monarchs to begin the migration northward in the next few days. The is no shortage of water in the area so imbibing water and converting fats to sugars to fuel the flights should not be a problem.
As to nectar, there is almost always some in the area but never enough for the number of monarchs in the region. Relatively few monarchs actually visit flowers within the colony areas perhaps because those present have already been visited and depleted of nectar." - Dr. Orley "Chip" Taylor, Univ. Kansas, Lawrence. Founder and director of monarch Watch