Category: biodiversity

Categories
biodiversity Environment

Woodman, Spare that Tree

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                       Woodman, spare that tree!

                           Touch not a single bough!

                        In youth it sheltered me,

                             And I’ll protect it now.

                                                George Pope Morris

 

Twelve years ago at this time we had just returned from Costa Rica to celebrate Christmas at home. Close to where we had stayed we watched the beginning of a new building going up, using steel instead of wood.

In this country with vast forests and where all steel is imported, why wouldn’t they use wood? I was told that it was to preserve the trees. When I asked what the building was going to be, I was told… but you need to read to the end of this column to find out!

There is an estimate that humans have cut down or damaged three quarters of the forests that existed before we became the dominant animal on the planet. Costa Rica is no exception; Ticos had cut down large portions of its forests. Fortunately, thanks to that country’s exceptionally good conservation policies and good luck, second growth forests now cover about a seventh of the country’s land area.

We rented a cozy cabin for most of the 3 months that we lived in Monteverde. Perhaps its best quality was its location, bordering the Children’s Eternal Rain Forest. Trees in this area had been cut down for agriculture, and more recently they were allowed to regrow. The land was bought with donations from all over the world. Most impressively, the movement to preserve and rehabilitate this land was started by Swedish elementary school children.

Trees are pretty amazing. In addition to being attractive and fun to climb, they provide shade and purify air and water. They are also part of the carbon cycle, as many kids can tell you. Using sunlight for energy, they suck out carbon dioxide from the air, synthesize cellulose and release oxygen. If that wood burns, the CO2 is returned to the atmosphere. If a tree is allowed to slowly decompose, some of its carbon joins the soil and increases its fertility.

All trees are not created equal, however. In a natural forest there are many different species of trees, plus undergrowth, all filling different ecological niches. On the other hand, a tree monoculture, especially if treated with lots of chemicals, is a poor substitute for a natural forest.

Shade-grown coffee is an example of a good compromise between agricultural production and good ecology. Trees shade the coffee bushes as well as providing homes for many beneficial animals. Hungry birds gobble up harmful insects on the coffee bushes, for example.

Part of the reason we selected Monteverde, Costa Rica as the place to spend a sabbatical was the Quaker connection. Several Quaker families chose to live in the only country in the world that did not have a military force; they founded Monteverde in 1951. They bought a large amount of land very inexpensively, and preserved much of it to insure the purity of their water supply. This uncut, undeveloped cloud forest has become a haven for plants and animals—and for the biologists who study them.

Brazil, in stark contrast to Costa Rica, has been unable to control devastation of its Amazon rainforest. Called the “lungs of the planet”, the Amazon is the world’s largest rainforest and is key for the planet’s health. In 2014 the destruction (by harvesting tropical wood and clearing for cattle and other agriculture) has increased by 16%. An area larger than Delaware was cut down in just one year!

Palm oil production is big business in some Asian countries. Often grown in huge plantations, in Indonesia alone the land devoted to palm oil monoculture is almost as large as Connecticut. The native forest is often burned to prepare for the land for planting oil palms, causing terrible air quality. Sadly, this has lead to the destruction of habitat for orangutans and tigers, among other creatures.

What can we do to spare tropical trees? Avoid buying products made with exotic woods. Eat less beef—you’ll be healthier, too! When possible, pass up foods that contain tropical oils such as palm oil.

We visited Monteverde about a year after the sabbatical and found a group of people outside that little building built with steel instead of wood. Most of them were kids, since school had just let out, and they all looked happy—for a good reason. The shop was selling locally made ice cream! Indeed, Monteverde has some of the best ice cream I’ve ever tasted—coffee is my favorite flavor.

© Richard Grossman MD, 2015

Categories
biodiversity conservation biology

Mourn for Martha

“You don’t know what you’ve got till its gone”
Joni Mitchell

Although the Ebola epidemic is terrible, there is an invisible epidemic that might end up being even worse for humanity. We depend on the great web of life, but paradoxically we are constantly weakening that web.
We receive services from many different biological species and communities. Plants remove carbon dioxide and harmful chemicals, purifying the air we breathe and liberating oxygen. Various invertebrate animals cleanse both salt and fresh water. Bees pollinate a quarter of our crops. And the list goes on.
Unfortunately, we humans are causing species of animals and plants to go extinct at a terrible rate. There have been five prior eras of mass extinction—the most recent was 65 million years ago when a huge meteor plunged to Earth. The resulting explosion threw up dust that altered the climate for centuries, and ended most of then current life—including dinosaurs.
Scientists estimate that the current rate of extinction of species is about 1000 times normal. The causes of this epidemic include loss of habitat, climate change, introduction of exotic species and pollution. What do these have in common? they are all human-caused. The more people there are, and the more each of us consumes, the more species we unwittingly kill off.
The dodo is a classic example. It was a flightless bird that lived on the island of Mauritius. In the 17th century sailors stopped there to replenish food and water supplies. The dodo had no fear of humans and was an easy target—sailors could walk right up and club them for fresh meat. The last of these innocent animals was slaughtered before 1700.
Closer to home, the passenger pigeon cluttered the skies of North America in the 19th century. Their annual migrations were estimated to encompass several billion birds! They were easy prey for hunters; sometimes people brought them down simply by throwing sticks or rocks in the air. It was thought that the supply of this delicious meat would never end.
You probably already know the end of this story. The last passenger pigeon, “Martha”, died in the Cincinnati Zoo 100 years ago this month. Attempts to find a mate for Martha had been unsuccessful. Causes of the extinction were overhunting and loss of habitat, since much of the North American forest was being cut down and plowed.
We now know that, even if an amorous male had been found, the species still wouldn’t have been saved. Some species have complex social systems and require large numbers to survive. Passenger pigeons were gregarious—they needed huge flocks to breed successfully. Furthermore, from a genetic standpoint, diversity is important to prevent lethal mutations from gaining sway,
With only a small number of individuals the genetic code is likely to have enough errors that the species will inbreed and die out. We are incredibly fortunate that two other species of birds, the California condor and the whooping crane, were saved from extinction before their numbers reached the critical figure. There were just 23 whoopers alive in 1941 when protection and a captive breeding program saved the tallest of all American birds. Luckily, this small number of individuals must have had adequate genetic diversity to keep the species healthy, because now there are about 600 of these magnificent birds.
Why not splice some of Martha’s genetic material into the DNA of a related pigeon so the passenger pigeon species can be resurrected? Theoretically, “de-extinction” might be possible using modern genetics, but the concept has problems. Remember they need a huge flock to be sustainable. The major problem, however, is that de-extinction is a diversion from saving species from extermination in the first place. What we really need is the humility to share resources with other species.
To commemorate the centennial of Martha’s final flight, the Smithsonian has established the multimedia program “Once There Were Billions”. Striking statues of passenger pigeons, part of The Lost Bird Project (www.lostbirdproject.org), will be on display in Washington.
Bees are in trouble. Colony Collapse Disorder has devastated almost a third of honeybee colonies worldwide. Many native bees species are also being ravaged. What is causing this collapse? research points to climate change (some flowers bloom before the insects are ready), harmful mites and a virus. In addition, omnipresent neonicotinoid insecticides are probably killing bees.
Biological diversity is essential for human survival, yet, unthinkingly, we are rapidly destroying species in unprecedented numbers. We should safeguard the web of life, for our own species’ sake.
© Richard Grossman MD, 2014