Wildlife Extinction: Critical and Manmade

Wildlife Extinction: Critical and Manmade

Introduction:

Scientists are of a consensus opinion that wildlife extinction: critical and manmade is reaching a dangerous level.  This article presents a summary of four extinct species that have recently disappeared from earth and the contributing causes of their demise.  Subsequently, the current rate of extinction is compared to the background rate to determine if the issue is critical.  Lastly, the article is recommending “The Sixth Extinction” by Elizabeth Kolbert as an excellent read to indulge the issue on a more detailed level.

Recent extinctions

The Dodo Bird

The Dodo was a large flightless bird that inhabited the Island of Mauritius in the eastern Indian Ocean.  Tangible and detailed accounts of the bird are limited because it became extinct in the latter part of the 17th century. 

What we do know about the Dodo’s extinction is that the causes for its extinction were similar to those that afflict wildlife, fauna and the natural world today.  The island inhabitants ate the birds, but that seems to be a minor contribution because the human population was always scant.  Like most newly discovered lands, the explorers chose to plunder the resources.  The newcomers chose to cut most of the forest.

Invasive species, considered by scientists to be the second leading cause of extinction today, was most certainly a factor in the extinction.  Rats, cats, and pigs were some of the new introduced species that the early inhabitants introduced to the island.  The bird’s ground-dwelling nesting habits and lack of flight certainly made them vulnerable to aggressive newcomers.

The Dodo’s encountered their destiny in the latter part of the 17th century, with the last reported sighting reported in 1662. Unfortunately, mankind was unable to see the forthcoming calamity of extinction: critical and manmade.

Great Auk

The Great Auk was another sizeable flightless bird that resembled penguins, despite that fact that they were not closely related.  They inhabited the northern Atlantic from prehistoric times and were a known food staple for Neanderthal people.  The bird’s destiny of extinction was realized somewhere around the mid 19th century.

The bird’s extinction was due to man’s reckless harvesting habits and inadequate conservation considerations.  The offending people killed the birds of food and plucked their down feathers for pillows.  Unfortunately, the offending people harvested the eggs for food and as collector’s items. Additionally, the large size made them a valued collector’s item.  By the mid 19th century the bird was considered extinct. Again mankind was unable to foresee the forthcoming trend of wildlife extinction: critical and manmade.

The Passenger Pigeon

The Passenger Pigeon once inhabited the eastern half of North America in numbers described in the billions.  They migrated and nested in huge flocks and were said to have shaded parts of the earth from the sun as they flew over.  Like the Great Auk, indigenous people considered them a food staple for thousands of years without degrading their numbers.

The extinction of the Passenger Pigeon is considered by most scientists to be one of the most egregious examples of man’s lack of restraint and inability to conserve the natural world.  The fact that the birds migrated and nested in huge flocks made them venerable to predation.  A single shotgun blast into a migrating flock would bring down five to eight birds. 

Frequently, the offending people cut the trees to harvest the nestlings.

Additionally, deforestation played a role in the bird’s demise; consequently, the deforestation deprived the birds of nesting and food habitat.

Martha was the last known living Passenger Pigeon, and she died in 1914 in the Cincinnati Zoo.  As a well-publicized incident, Martha, at last, and too late, triggered the collective remorse for the unnecessary and abusive lose of one of nature’s creations. By 1914 it should have been apparent that wildlife extinction: critical and manmade was a trend.

The Carolina Parakeet

The Carolina Parakeet was one of only two parrot species indigenous to the United States.  Small and green with yellow heads they inhabited the eastern and central parts of the United States.  Due to their seed consumption habits, people considered the parakeets to be pests and killed them indiscriminately.  “Incas” the last known living specimen of the Carolina Parakeet died in the Cincinnati Zoo in 1918.

As with the previous examples, deforestation is considered a contributing factor to the Carolina Parakeet’s demise.  Additionally, their flocking habits made them vulnerable to intentional slaughter.  However, due to the sudden disappearance of the species, some scientists also speculate that poultry disease contributed to the bird’s disappearance.

Time and time again, mankind has failed to foresee the pattern that wildlife extinction: critical and manmade was developing.

Amphibians

At the publication of this article, the wildlife species most impacted by extinction is the amphibian class of animals.  Scientists estimate that 120 to 150 species of amphibians have gone extinct since 1980.  It seems that the culprit behind these extinctions is an infectious disease (Chytridiomycosis) caused by the chytrid fungi.  The disease attacks the amphibian’s skin, which is a vital organ in that class of animal.  The impact of Chytridiomycosis upon the amphibian world has been described as an epidemic and sometimes referenced as a plague.

Resolving the epidemic must firstly take a backseat to analysis.  Some members of the amphibian class are more resistant to fungi infections than others.  However, these frogs/amphibians with a degree of resistance might also be carriers of the fungi.  So in the newly globalized world where pets are shipped from one part of the world to another or transported with exports, the disease is carried to numerous vulnerable species.  It is not by accident that another post titled “Florida’s Assault preceded this post by Invasive Species” preceded this.  The theme of that post was that invasive species are the second leading cause of wildlife extinction.  So invasive species, whether man facilitates that invasion or not, is a leading component behind the plague of extinctions that affect the amphibian world.

An additional factor that is suspected to influence the growth of Chytridiomycosis is climate change.  Warmer and wetter environments appear to facilitate the fungi growth that causes the disease. As per this post’s theme, all factors suggest wildlife extinction: critical and manmade.



Wildlife Extinction: Critical and Manmade

Scientists compare current extinction rates with what they call background extinction rates.  The background rates are the average rate of extinction over an extended geological time (millions of years).  One way of expressing the background rate is in “million species years.”  In other words, one would expect one out of one million species to go extinct each year.  In other words, if there were only one species, it would be expected to go extinct within one million years.

David Biello, writing for Scientific American (Bird Extinction Estimates May Be Too Low) specified that out of 9,975 bird species, 154 birds had gone extinct over the last 500 years.  That data translates into 26 extinctions yearly or 26 times the average background rate.  In analyzing this data, one should acknowledge the title of Biello’s article: “Bird Extinction Estimates May Be Too Low.” After clarifying the concept of background extinction rate, he goes on to illustrate how the noted statistics could easily be an underestimate.

Unfortunately, the above data only applies to birds, and the most endangered class of animal is currently amphibians. 

Comparing amphibian extinction rates to the background standards, their extinction rate alone could be 211 times the background rate. Considering endangered amphibians along with the extinctions, the extinction rate compared to the background rate jumps to 25,000 to 45,000 times the background rate.

Within the scientific arena, there is no doubt that the earth’s extinction is critical and manmade or Anthropocene.  Topping that list of causes is deforestation and urban and commercial development.  When humans move in, there is less space for other living organisms.  Additionally, no rational argument can object to the fact that invasive species is the second leading cause of extinction, and that it too is human-made. See the post “Florida’s Assault by Invasive Species” for examples.

Climate change and ocean acidification also receive much attention as contributors to current extinction rates.  Climate change possibly accounts for one and possibly two recent extinctions; however, many species listed as endangered have their predicaments nested under the category of climate change.

Elizabeth Kolbert, “The Sixth Extinction”

The above data on extinction was the background upon which Elizabeth Kolbert published, in 2014, her book titled “The Sixth Extinction.”  Ms. Kolbert’s book is a masterful collection of research that describes five previous times that the earth has gone through five mass extinctions where the vast majority of life on earth was wiped out.  Additionally, she proclaims, with critical scientific data, that we are in the midst of the sixth extinction and the earth’s extinction rate is manmade.

Elizabeth Kolbert’s Pulitzer Prize-winning book “The Sixth Extinction” is a highly researched and informative read that paints a persuasive picture for “The Sixth Extinction.”  She details the five previous mass extinctions, and then fast-forwards to the modern age and carefully illustrates how man is negligently destroying life on earth.  She presents a significant amount of evidence on the adverse impact of global warming and ocean acidification.  She provides a substantial amount of research on the impact of ocean acidification upon the loss of coral reefs. Likewise, Kolbert suggests that man’s lack of discretion might threaten our existence.

Not only is Kolbert’s book persuasive, but it is also an enjoyable read.  Buy the book here.

Conclusion

The Dodo, Great Auk, Passenger Pigeon, and Carolina Parakeet encountered their demise within several lifetimes of each other, but the rate of extinction on earth is escalating dramatically.  Even though birds are easy to recognize and relate to, they are not the most critical animal classification to experience the phenomenon of extinction.  That award currently goes to the amphibians as illustrated above.  Scientists, with significant data support, indicate that we are in the midst of the earth’s sixth mass extinction.  They also suggest that the wildlife extinction is critical and manmade.

A great resource that presents the noted issues about today’s plague of extinction is Elizabeth Kolbert’s “ Sixth Extinction.”

Photographic Attributions:

Artist/photographer

  • Passenger Pigeon: Louis Agassiz Fuertes
  • Dodo Bird: Frederick William Frohawk
  • Great Auk: John Gerrard Keulemans
  • Carolina Parakeet: James St. Johns

All photographs are available under a creative commons license available at https://creativecommons.org/licenses/by-sa/2.5/   {{PD-US-expired}}

No alterations were made in any photos except that of the Great Auk.  It was cropped to reduce the original height.

Sources:

Unless specified differently, all of the referenced data came from “Wikipedia” the online encyclopedia at https://www.wikipedia.org/ .

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