Archive for February, 2012

Tortoises Long Believed Extinct Are Alive!

Wednesday, February 29th, 2012

A species of giant tortoise thought to have been extinct for 150 years has not disappeared from the earth after all!

Thanks to sophisticated DNA analysis techniques and diligent fieldwork, scientists have learned that some giant tortoises recently discovered on an island in the Galapagos are immediate descendants of a tortoise species long thought extinct. And it gets better: scientists and conservationists are confident that they can restore a sizeable population of the tortoise species to its original home of the Galapagos island called Floreana.

SCIENCE TO THE RESCUE

Several years ago, scientists discovered on the Galapagos island called Isabela a colony of giant tortoises living on the slopes of a volcano. Then, in 2008, scientists returned to Isabela to conduct DNA tests on some of the tortoises they’d found. Blood samples taken from more than 1,600, or about 20% of the tortoises, showed that 84 of them had a pure Floreana tortoise as a parent.

Since giant tortoises typically live more than 100 years, and because 30 of the 84 tortoises with a Floreana tortoise parent were under the age of 15, it seemed highly likely that some of the tortoises on Isabela were pure Floreana tortoises.

A BRIGHT FUTURE FOR FLOREANA TORTOISES

Such encouraging news offers great hope for recovery of this giant tortoise species, researchers say. One reason for optimism is that over the last 50 years, other Galapagos tortoise species have responded well to recovery efforts. In the 1960s, the number of tortoises was as low as 14 individuals on one island. But since that time, more than 4,000 young tortoises have been returned to the wild in the Galapagos. Many have been reproducing, and populations have been increasing.

The newly launched Floreana tortoise rescue mission will be part of Project Floreana, a comprehensive effort to restore the island, as nearly as possible, to the way it was in 1835, when Charles Darwin first visited it, explains Dr. Linda Cayot, science advisor to the Galapagos Conservancy. “Restoring true Floreana tortoises as part of that effort is now a dream that could come true,” she says.

Scientists and conservationists will increase the Floreana tortoise population by carefully breeding those tortoises that have one Floreana parent and also by breeding pure Floreana tortoises.

Project Floreana is also dedicated to ensuring a sustainable community for the island’s several hundred human residents and to involving the people in all phases of the conservation program.

GREAT VALUE OF GIANT TORTOISES

Restoration of the Floreana tortoise is a good thing not just because a fellow species is being brought back from the brink of extinction. The Floreana tortoise plays a vital role in maintaining healthy Galapagos ecosystems. As the only grazing herbivores in the Galapagos, giant tortoises keep invasive plants in check, disperse seeds, and, in general, maintain habitat diversity which allows many native species to thrive.

A TORTOISE MYSTERY

Perhaps you wonder how the Floreana giant tortoises came to be living on a different island, Isabela, 150 years after they had disappeared from their native Floreana. During the nineteenth century, pirates and other visitors to the Galapagos frequently picked up giant tortoises on one island and kept them aboard ship to use later as food. Tortoises were often left behind on one island or another when they were no longer needed. Pirates probably left some of the Floreana tortoises on Isabela, afterwhich those on Floreana were hunted until all had been killed.

A FEW FACTS ABOUT GIANT TORTOISES

  • A giant tortoise can reach a length of almost six feet and a weight of 880 pounds.
  • With a lifespan of more than 100 years, giant tortoises are one of the longest living animals on earth.
  • Giant tortoises are native to seven Galapagos islands. (The Galapagos archipelago consists of 13 large islands, six small ones, and more than 40 islets).
  • ‘Galapago’ means ‘turtle’ in Spanish.
  • Differences in tortoise size and shape from island to island helped Charles Darwin develop his theory of evolution.
  • In the 1600s, there were more than 250,000 giant tortoises in the Galapagos. Today there are about 15,000 tortoises, of several different species.

800px-galapagos_giant_tortoise_geochelone_elephantopus

Earth–As It’s Meant to Be

Monday, February 20th, 2012

     It took my breath away !   

     The natural world around us at Costa Rica’s Esquinas Rainforest Lodge was so healthy, so intact!   From the smallest plants to the tallest trees, all the leaves shone a vibrant, vivid green. 

     Simply sitting in front of our cabin and looking for a minute or two yielded one thrill after another:  a brilliant red and black Cherrie’s tanager flitting about;  a green heron standing stock still in the pond waiting for lunch to appear;  a foot-long lizard first pushing rapidly along, then stopping, utterly  motionless;  an army of leaf-cutter ants marching along their trail, each holding aloft a piece of green leaf.

     All this and so much more.  The big, colorful toucan using its gargantuan beak to pluck fruits from high in a tree and then tossing them down the hatch.  Other giant birds I’d never heard of–much less observed–thriving in their natural habitat:  a small group of crested guans moving languidly in a treetop;  and a great curassow, with its ornate black crest,  ambling about.  

     And the water, flowing past the lodge in a clear stream, was so pure that no treatment at all was needed before it was piped into the lodge and cabins for drinking.

     I felt moved by the vibrant health of my surroundings.  I couldn’t remember ever being in a place where the earth felt so clean and alive, so completely undamaged!  

     The contrast between this verdant Costa Rican rainforest and so much of the rest of the planet made me very sad.  Even though I normally spend a great deal of time enjoying nature, nearly every place I have been, including my beloved forest around our house, has been degraded to some extent.  

     But there is a bright side to this stark contrast.

    

                                               

     The reason the Esquinas Rainforest is so beautifully intact is not that humans have simply left it alone.  Not at all. 

     In the late 1980s, it appeared that this area would succumb to logging, as had most of the rest of the lowland tropical  forest on Costa Rica’s Pacific coast.  Then an Austrian musician, Michael Schnitzler, who had visited Costa Rica and fallen in love with its remaining rainforest, decided to act to protect it.  He founded an organization called Rainforest of the Austrians, and set about to raise money to purchase parcels of Esquinas rainforest to protect it and its biodiversity.

     Rainforest of the Austrians raised millions of dollars, including donations from children at 250 schools in Austria.  The Austrian government also jumped in to help, making protection of Costa Rica’s last remaining rainforest a focus of its Third World aid program.  Other environmental protection organizations like the Nature Conservancy and the Rainforest Alliance also joined the effort.

     Over the last 20 years, funds raised from many sources have been used to purchase–and protect–10,000 acres of rainforest land.  The land has been donated to the Costa Rican National Park Service for inclusion in Costa Rica’s Piedras Blancas National Park.  And efforts are underway to expand the protected acreage.  Former farms that border the national park have recently been purchased and are being reforested with native tree species.  And plans are underway to create biological corridors between isolated patches of rainforest outside the national park.  

     At Esquinas, conservation is combined with climate protection, as each planted tree absorbs 750 kilograms of carbon dioxide during its lifetime. 

     Rainforest of the Austrians and its partner organizations have worked hard to ensure that the people of La Gamba, the small town near the Esquinas Rainforest, benefit from rainforest conservation efforts.   The Esquinas Rainforest Lodge has become the area’s main employer of local people, and Schnitzler created the La Gamba Fund to support public welfare projects to improve the quality of life in the village.  The Fund has invested $200,000 in projects proposed by local residents, such as secondary school education for young people, renovation of the town school and community hall, and the restoration of a potable water system for 70 houses. 

     Not only are such efforts on behalf of local people the right thing to do, but these efforts have made conservation efforts more effective.  After all, when people benefit economically and in other ways from protecting the rainforest, they are far more likely to support conservation over the short-term jobs created by forest destruction.  The people of La Gamba are invested in rainforest conservation. 

     I salute Michael Schnitzler, Rainforest of the Austrians, and the Austrian government for their dedication to protecting such an important geographic area, its biodiversity, and the well-being of local people.  I can think of no better way to invest money and time.–April Moore  

 

 

a male Cherries tanager

a male Cherrie's tanager

 

 

 

 

   

Birds of North and South

Friday, February 17th, 2012

     As I was held in the thrall of Costa Rica’s fascinating birds during our recent visit to that country, I got into reading what I could find about these amazing creatures with exotic crests, giant beaks, and extravagant appendages at the end of already-long tails.    

      I learned that many of these neotropical (the tropics of the western hemisphere) birds differ from their North American cousins in some interesting ways.

     The heart of the differences between birds of the north and those of Central America is that “neotropical birds do things slowly, much more slowly than their North American counterparts,” explains ornithologist Alexander Skutch.  For example, neotropical birds tend to have a much slower metabolic rate than do northern birds.  Probably related to the difference in metabolic rate, neotropical birds tend to live much longer than North American birds, on the order of two to three times longer.    

     In keeping with a slower life, the typical Central American bird’s first breeding is later than that of a typical North American bird.  And the ‘slower’ birds of Costa Rica incubate their eggs longer and care for their chicks longer than do most birds of North America.

      So what are the reasons for these differences between ’our’ birds of the north and those of Costa Rica? 

     The main reason for the differences appears to be climate.  The more ‘speeded up’ lives of North American birds helps them to survive in an environment where food is not abundant all year and where harsh winters force birds to work to stay warm.  A rapid metabolic rate generates needed body heat.

     The breeding differences also make sense in the different climates.  In the north, getting an early start on breeding increases the number of offspring a bird will likely produce in its lifetime.  And that’s important, since the lifespan of many North American birds is so short, only two or three years for many common species.  Likewise, a shorter incubation period and an earlier fledging for offspring, gets more birds ‘out there’ sooner.  A higher number of individuals strengthens the species as a whole against a harsher climate and frequent food scarcity. 

     Not only do neotropical birds start breeding later, incubate longer, and care for their young longer than do birds in northern climes, but they also tend to lay fewer eggs per clutch than their northern cousins, typically just one or two.  Scientists explain that predation of eggs is a bigger problem in southern climes than in North America.  An egg in a nest in Costa Rica is far more vulnerable to snakes and to a variety of mammals than are eggs in a nest in North America.  But by laying just a single egg, or two at the most, Central American birds lose fewer eggs to predation.  Many Central American birds ’make up’ for the small number of eggs per clutch by breeding several times a year, unlike northern birds, who are limited by climate in the number of clutches they can produce in a year.

     Another difference between Central and North American birds I found interesting is that far more Central American species engage in ‘lek’ breeding than do northern birds.  Lek breeding is when the males of a species gather in a particular area for the purpose of a competitive mating display.  Females visit the ‘arena’ and choose a mate from among the displaying males.  After mating, the male and female are done with each other.  The male plays no role in nest building, in helping the female during incubation, nor in caring for the young.  The reason lek breeding is much more prevalent in the neotropics than in North America, scientists say, is that food is so much more easily available in the warmer climate that the female does not need the male’s help the way northern female birds do, to help ensure their young’s survival.–April Moore

a chestnut mandibled toucan

a chestnut mandibled toucan

 

a mot-mot
a mot-mot

 

 

 

 

 

 

 

 

 

 

The Wood Thrush–in Winter?

Thursday, February 9th, 2012

     My husband and I just returned from a wonderful 15-day trip to Costa Rica.  The occasion was our dear daughter Terra’s wedding.  Andy and I also spent about 10 days exploring and hiking in incredible cloud and rain forests.  The following is a short piece Andy wrote while we were there. 

     Don’t forget to click on the link at the end, and scroll down to hear the wood thrush’s song!

WE’VE RUN INTO FRIENDS FROM VIRGINIA
     by Andy Schmookler

 

photo by Lang Elliott

photo by Lang Elliott

 

 Among all the sounds one hears in the Virginia woods, is there any more lovely than the pure, melodic, piping sound of the wood thrush? For April and me, it’s always a thrill to hear the thrush’s simple but unearthly sweet musical song. It’s not, however, a song we hear in winter. 

Now we know where that song goes when our woods freeze. It’s down here to Costa Rica — or some such place. We’ve heard that pure piping down here. We don’t really know these are the same birds that grace our woods in summer, and the thrushes down here are not telling where up north they spend the warmer months.

But we were glad to run into what we regard as friends from Virginia.  http://www.allaboutbirds.org/guide/Wood_Thrush/sounds/ac

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