Aflockalypse Now: Mass animal die-offs and the ongoing extinction crisis | Science Matters | David Suzuki Foundation
Photo: Aflockalypse Now: Mass animal die-offs and the ongoing extinction crisis

Credit: Dave Govoni via Flickr

By David Suzuki with Faisal Moola

On New Year's Eve, 5,000 red-winged blackbirds dropped out of the sky in Beebe, Arkansas. Necropsies revealed no evidence of poisoning but did indicate the birds had suffered massive internal trauma. Days later, fisherman observed schools of fish floating belly up on Chesapeake Bay. In England, tens of thousands of dead crabs washed up on local beaches, and reports come in almost daily of penguins, turtles, and even dolphins dying unexpectedly in the wild. Are these events signs of the "aflockalypse", as the media have dubbed the recent die-offs? The answer is yes. And no.
 
Our inherent love and respect for the natural world compels us to take notice when animals die in large numbers, but observations going back more than a century suggest that the mass-mortality events of recent weeks aren't as unusual as we might think, and they are often the result of natural causes, such as adverse weather, disease outbreaks, or stress associated with long-distance migration.
 
In analyzing bird counts, journal records, and other observations dating back to the late 19th century, European researchers found frequent reports of deaths of birds in the hundreds and thousands. One massive kill occurred in spring 1964, when an estimated 100,000 king eiders, representing nearly a tenth of the species' western Canadian population, perished in the Beaufort Sea. These large, beautiful ducks starved when pools of open water among the sea-ice re-froze suddenly, preventing them from getting to the food in the water below. More recently, an estimated 40,000 individual birds from 45 different species were killed on April 8, 1993, when a tornado crossed their migration routes off the coast of Louisiana.
 
While the sudden death of wildlife in great numbers is alarming, the unravelling of entire food webs is happening all around us and every day — but in a far less obvious manner. With every patch of forest cut, wetland drained, or grassland paved, our ongoing destruction of wildlife habitat is leading to population declines, and even driving some species to extinction.
 
According to the experts, more than 17,000 plants and animals are threatened with extinction because of human activity, mostly through habitat loss. This includes 12 per cent of all known birds, nearly a quarter of known mammals, and a third of known amphibians. Climate change is predicted to sharply increase the risk of species extinction within our own children's lifetime. According to the Intergovernmental Panel on Climate Change, 20 to 30 per cent of plant and animal species assessed will likely be at increased risk of extinction if global average temperatures continue to rise with escalating emissions of carbon pollution.
 
This wildlife crisis has been described as a silent epidemic by scientists like famed Harvard entomologist E.O. Wilson, because it receives so little attention from governments. The David Suzuki Foundation recently released a study of government records showing that nearly half of all known wildlife species in British Columbia are at risk, including grizzly bears, caribou, and orca whales. Yet, B.C. has no endangered species law to protect its wildlife and habitat from logging, mining, urban sprawl, and other human activity.
 
Canada has a federal endangered species law, but the government is dragging its feet on implementing it. As a consequence, some wildlife populations, like the northern spotted owl in southwestern B.C., have declined precipitously under the watch of our politicians and are now on the verge of extinction in Canada.
 
The unsettling events of recent weeks reveal the inherent vulnerability of wildlife to sudden and dramatic population declines, often as a result of natural causes. This is all the more reason to ensure we don't exacerbate the challenges faced by wildlife in an increasingly busy world. We need to reduce the environmental stressors that we impose on wildlife, so that they can better cope with and survive the challenges they face every day. We need to eliminate dangerous pesticides and other toxic materials, protect the habitat of endangered plants and animals like caribou, and get serious about tackling climate change.
 
It's good that people are concerned about the recent animal die-offs, but if we really care about the future of wildlife, we need to start paying more attention to our own role in the extinction crisis — and urge our elected officials to take concrete steps to protect the biological richness with which our planet is blessed.

January 13, 2011
http://www.davidsuzuki.org/blogs/science-matters/2011/01/aflockalypse-now-mass-animal-die-offs-and-the-ongoing-extinction-crisis/

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6 Comments

Feb 15, 2011
5:56 AM

That would have been such a traumatic event to witness, but you’re right the more devestating deaths which lead to extinctions so often go unreported and unnoticed. What can we do to change this?

I’ve been blogging about extinctions in the serengeti and the effect on the foodweb. Will one extinction lead to another?

http://thesciencesays.southernfriedscience.com/?p=342

Climate change means the instability in ecosystems caused by extinctions could lead to collapse.

Feb 01, 2011
11:42 AM

NATURAL SELECTION Dead crabs and fish wash up on shores, dead birds drop from the skies, and dead cows and water buffalo drop in the fields. One hundred and fifty one years ago, Charles Darwin and Alfred Russel Wallace knew that birds dropping from the skies, dead fish and crabs washing up from the sea, and cows flopping in the fields, are nature’s spectacular staging of what Darwin termed natural selection. Darwin wrote, “As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle of inheritance, any selected variety will tend to propagate its new and modified form.” “It may metaphorically be said,” Darwin wrote, “that natural selection is daily and hourly scrutinizing, throughout the world, the slightest variations; rejecting those that are bad, preserving and adding up all that are good; silently and insensibly working, whenever and wherever opportunity offers….We see nothing of these slow changes in progress, until the hand of time has marked the lapse of ages, and then so imperfect is our view into long-past geological ages, that we see only that the forms of life are now different from what they formerly were.” Wallace wrote, “An antelope with shorter or weaker legs must necessarily suffer more from the attacks of the feline carnivora; the passenger pigeon with less powerful wings would sooner or later be affected in its powers of procuring a regular supply of food … If, on the other hand, any species should produce a variety having slightly increased powers of preserving existence, that variety must inevitably in time acquire a superiority in numbers… . Now, let some alteration of physical conditions occur in the district — a long period of drought, a destruction of vegetation by locusts, the irruption of some new carnivorous animal seeking “pastures new” … it is evident that, of all the individuals composing the species, those forming the least numerous and most feebly organized variety would suffer first, and, were the pressure severe, must soon become extinct.” In experiments conducted in the department of obstetrics at the Columbia Medical School in the 1920’s, Raphael Kurzrock and Charles Lieb noticed, that when they attempted artificial insemination the uterus often expelled the semen. They found that human seminal fluid could affect the state of contraction of strips of muscle from the uterus, either contracting or relaxing them. They remarked in a paper published in 1930 that the history of the patients from whom the muscle strips were obtained made their experiments even more intriguing. Muscle from patients with a history of successful pregnancy responded to semen by relaxing, while semen always induced contractions in uterine muscle from women with a history of long acting sterility. This suggested to Kurzrock and Lieb the presence of factors in semen and uteri that differentiate between infertility and fertility. After studying this paper on numerous occasions, I realized that these factors are also those of natural selection.

In the early 1930’s, Maurice Goldblatt in the United States and Ulf von Euler in Sweden showed that factors in the seminal fluid of boars act on various smooth muscles and lower blood pressure. Von Euler named these substances “prostaglandins” because the prostate contains small amounts of them, and he assumed that what he had extracted from semen must have come from that gland. Today we know that every cell manufactures prostaglandins, or other members of the eicosanoid family.
Prostaglandins are ephemeral, infinitesimal, and powerful molecules that signal throughout each cell, from cell to cell, organ to organ, brain to body, body to brain, and body to environment. Prostaglandins are not produced under resting conditions, but only in response to stimuli. If the enzymes that produce and degrade prostaglandins are resilient, they can absorb stress. and continue to function physiologically; if not, physiology becomes pathology.

At the Karolinska Institute in Stockholm, Sune Bergstrom purified several prostaglandins, determined their chemical structure, and showed that they are formed from essential fatty acids. After collaborating with Bergstrom from 1959-1962 on the structure of prostaglandins, Bengt Samuelsson provided a detailed picture of arachidonic acid and prostaglandin metabolism, and defined the chemical processes involved in their synthesis and breakdown. Samuelsson showed that blood platelets convert arachidonic acid to thromboxanes (TX’s), while white blood cells convert it to leukotrienes (LT’s). Thromboxanes constrict blood vessels and cause platelets to clump together and release more clotting factors. This is useful when clotting is necessary to stop bleeding; when this mechanism is overactive, it plays a pivotal role in heart attacks and strokes. And thromboxanes directly stimulate the smooth muscles of blood vessels to contract, including those of the heart and brain.

At Oxford University in the mid-sixties, Sir John Vane and his colleagues developed the cascade superfusion bioassay technique for measurement of the release and fate of vasoactive hormones in the circulation or in the perfusion fluid of isolated organs. In 1971 Vane made the fundamental discovery that anti-inflammatory compounds such as aspirin block the formation of prostaglandins and thromboxanes. Later Vane and Salvador Moncada isolated a prostaglandin in the wall of blood vessels and named it prostacyclin (PGI2). In dilating blood vessels and inhibiting the aggregation of platelets, prostacyclin opposes the actions of thromboxanes. In some countries patients with such vasoconstrictive disorders as Raynaud’s disease, peripheral vascular disease and pulmonary hypertension, whether spontaneous or caused by certain appetite suppressants, are treated with infusions of synthetic prostacyclin. For their pioneering research on prostaglandins, Bergstrom, Samuelson and Vane were awarded the Nobel Prize in Medicine in 1982. . Prostaglandins orchestrate cognitive, emotional, behavioral, physiological, pathological, and reproductive responses to the environment, the latter including heat, cold, gravity, gases, humidity, light, dark, sound, electromagnetic fields, water, venom, microorganisms, and food. Electromagnetic fields regulate enzymes directly, and indirectly, by acting on cell membranes.

In Arkansas, thousands of red-winged blackbirds dropped dead out of the sky. 100,000 drum fish died in the Arkansas River, birds in Louisiana and Kentucky . Pundits allowed that the birds died of blunt trauma to their organs and blood clots, resulting from a midair collision instigated by the sound of fireworks. Devil crabs, sardines, croaker, catfish, bream, carp, roach fish, starlings, Cowbirds, and jackdaw crows perished in their hundreds, thousands or millions. More than two hundred cows dropped dead in a field in Wisconsin, seven thousand water buffalo in Vietnam. The blackbirds showed no signs of trauma or infection, but did have evidence of bleeding and clotting, indicating that thromboxane synthase, the enzyme that produces thromboxane B2, was induced by environmental stress, the enzyme a variant that Darwin and Wallace had in mind. .In other sudden deaths, induction of an enzyme in the prostaglandin pathways was probably responsible. Emil Zuckerkandl and Linus Pauling advanced the idea that enzymes, they referred to a semantides, fulfill the functions of biological clocks, changing slowly over time.

Could this tragic fate befall humans? Death and extinction are essential components of natural selection and evolution, as Darwin and Wallace revealed. Individuals whose enzymes of prostaglandin E2 production resisted a microbes attempt to increase it survive, while those unable to are sickened or perish. Increased synthesis of prostaglandin E2 induces both depression and defective immune function, and depressed individuals constitute a substantial segment of society. The human immunodeficiency virus is capable of raising prostaglandin E2 to levels higher than others, with prostaglandin E2 the most powerful naturally occurring immunosuppressant known. Of the altered physical conditions responsible for the mass deaths, rapid movement of the Magnetic North Pole towards Russia has the edge.

Jan 18, 2011
3:25 PM

The comments left already are each and all right on…my feelings already expressed. Deeply troubling especially when one feels so ineffective in holding onto their own unweildy life — yet we cannot let that define and defeat our continuing to remain aware and alert to changes in Earth and her brood (including the human ones).

Jan 18, 2011
11:12 AM

Bog brother keeping us to busy to pay attention to what is happening all around us? Keep the masses stressed, ignorant and too busy to bother with activism on any scale. Corporations are now considered individuals and are therefore legally exempt from the ceo’s and boards actions! truly psychopathic behaviour.

Jan 13, 2011
10:36 PM

Makes me wonder how many people get to live, before nature balances us out?

Jan 13, 2011
6:08 PM

Very saddening and disheartening that there is not a mass and overwhelming public outcry!

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