June 25th, 2013 by Michael Ricciardi
[Special Note: see the note at bottom for a link to a new bird species discovery!]
The decline in Monarch butterfly (Danaus plexippus) numbers has been transpiring for at least two decades, but in recent years, these declines have become more dramatic.
Each year, vast numbers of the ornately-winged insect engage in their famous, ritual migration — some covering nearly 3000 miles — from habitats in Canada and the US to the lush forests of central Mexico.
However, since December of 2011, there has been a 59% decline in overwintering monarchs in these forested areas, according to reports from Mexico’s National Commission of Natural Protected Areas. Further, over a twelve year period (1997 – 2009), overwintering populations along California’s Southern coastline have shrunk from over a million individuals (located at 101 sites) to less than 60,000 (at 74 sites), according to the World Wildlife Fund.
The International Union for the Conservation of Nature (IUCN), which maintains the ‘red list” of the world’s endangered and threatened species, has proclaimed the monarch butterfly’s annual migration an “endangered biological phenomenon.”
The twin culprits of these dramatic declines appears to be habitat destruction (like so many other endangered species around the world) due to housing and industrial development, road building, and agricultural expansion. In addition, the past year (2012) saw drought and record high temperatures which, according to numerous observations, seems to have triggered an early migration. This early migration, in turn, severely disrupted the insect’s breeding cycle by causing their eggs to dry out.
Secondly, warmer than normal weather tends to reduce the amount of nectar found in milkweed plants — the main food source of butterfly larvae. But the milkweed plants aren’t just suffering from high temperatures; they face an added, perhaps more potent, threat from herbicides. Farmers are increasingly using herbicide resistant (GM) strains of crops, which means that more herbicide can be used on them. But milkweed plants, which are commonly found in areas around farm lands, cannot tolerate the increased dosages of herbicide, and are quickly being killed off.
Despite these worrisome trends, there is some hope for the Monarch. In 2008, the Commission for Environmental Cooperation (set up as part of the original NAFTA agreement), published its North American Monarch Conservation Plan which includes the conservation of overwintering sites and the restoration of breeding habitat throughout the insect’s 2,800 mile range. However, the conservation plan is not backed up by enforced laws but is based upon “finding incentives” (usually, this means monetary pay-offs) to accomplish its goals.
Helpfully, the Mexican government is working with the WWF and other conservation groups to restrict logging in the forest areas that support the overwintering populations of the migratory insect. Additionally, California and a few other states have made solid efforts in monarch habitat restoration.
The success of these efforts may prove to be the deciding factor in the Monarch butterfly’s near-term survival.
To learn more about butterflies and the various threats that they are facing, check out the popular ExpertSure (formally Ecolocalizer) article from 2010: California Butterflies See Big Declines from Eco Double Blow
Some source material for this post came the Sci Am article Royal Descent: Monarch Butterflies Suffer Sharp Drop in Numbers
One in Eight Bird Species Facing Extinction
Canada-based Birdlife International — the world’s largest nature conservation partnership — has released a report asserting that, world-wide, one in eight bird species are threatened with extinction, citing unsustainable agriculture and global warming as the primary causes. The report draws upon data collected from 120 of its affiliated national bird organizations
The report elaborates: 1,253 bird species (which is 12.5 % of the total number of known bird species*) are threatened with extinction due to declining populations and/or ranges. Of these, 189 bird species are “critically endangered” which means they are at high risk for extinction in the near-term.
These are not just “exotic” bird species living in remote corners of the globe; many are species common to the US and Canada, like barn swallows and purple martins.
In a press statement, Birdlife International chief scientist Stuart Butchart, commented:
“Natural habitats are being converted and many, many species are losing large parts of their population and their range. Unless we take action now to improve their fortunes, these are species that are going to go extinct in the coming years.”
As an example, Butchart noted that birds in forested parts Southeast Asia and Africa are particularly vulnerable, as their habitat is being cut down to grown oil palms.
Like many seasoned observers of Nature, Butchart sees the decline in bird species as a sign or indicator of where we are heading; a warning that the health of the entire natural world, not just birds, is at stake.
“Birds are fantastic indicators. They are good at telling us where other wildlife is found and their trends also closely mirror what’s happening to other wildlife groups,” he said. “So the fact that many bird species are declining, many are threatened with extinction, really should be ringing alarm bells.”
* These numbers reflect counts from the most recent (completed) year, and do not include new bird species finds, such as the recent, multiple new bird species found in the Amazon, or, the even more recent discovery of the Cambodian tailorbird (in an urban locale environment, no less); such new species finds (especially multiple new finds) are relatively rare.
For more information, visit the Birdlife international website.
Some source material (including quotes) for this post cam from the UPI science article: ‘International bird group warns of extinction threat’
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