nsf.gov - National Science Foundation - Fruits of the forest gone: Overhunting of large animals has catastrophic effects on trees.- Frutos del bosque ido: Durante caza de animales grandes tienen efectos catastróficos sobre los árboles

Hola amigos: A VUELO DE UN QUINDE EL BLOG., hemos recibido información de la Fundación Nacional de Ciencias de Los Estados Unidos, que no dice que la caza sin piedad de los grandes animales del bosque  han tenido efectos catastróficos, como por ejemplo tenemos: "El elefante ha sido durante mucho tiempo un símbolo espiritual, cultural y nacional importante en Tailandia. A principios del siglo 20, sus números superaron 100.000........
Hoy en día, esos números han caído a 2.000. Los elefantes, así como otros animales grandes, carismáticos, como los tigres, monos y gatos de algalia, están bajo el ataque de los cazadores y los cazadores furtivos..........

 

Mientras que la pérdida de estos animales es preocupante para la conservación de especies, ahora los investigadores de la Universidad de Florida han demostrado que la caza excesiva puede tener efectos generalizados en el bosque mismo.

Caza excesiva conduce a la extinción de una especie arbórea dominante, Miliusa horsfieldii, o el haya Miliusa, con efectos en cascada sobre la probable otra biota del bosque.

Los científicos informan de sus resultados en la edición actual de la revista Proceedings de la Royal Society B....................

As the animals go, so go tropical forests

The cherry-sized fruits of a tree species in Thailand are eaten by large animals, including bears. Credit and Larger Versión

November 12, 2014

The elephant has long been an important spiritual, cultural and national symbol in Thailand. At the beginning of the 20th century, its numbers exceeded 100,000.

Today, those numbers have plunged to 2,000. Elephants, as well as other large, charismatic animals such as tigers, monkeys and civet cats, are under attack from hunters and poachers.

 

Overhunting of animals affects entire forest

 

While the loss of these animals is concerning for species conservation, now researchers at the University of Florida have shown that overhunting can have widespread effects on the forest itself.

Overhunting leads to the extinction of a dominant tree species, Miliusa horsfieldii, or the Miliusa beech, with likely cascading effects on other forest biota.

The scientists report their results in the current issue of the journal Proceedings of the Royal Society B.

Co-authors of the paper are Trevor Caughlin and Jeremy Lichstein of the University of Florida and Doug Levey, formerly of the University of Florida and now a program director in the National Science Foundation's Division of Environmental Biology.

Other co-authors are researchers at King Mongkut's University of Technology Thonburi in Thailand, Wageningen University in the Netherlands and the Royal Thai Forest Department.

 

Loss of one tree species has far-reaching implications

 

The ecologists show how vital large animals are to maintaining the biodiversity of tropical forests in Thailand.

The team looked at how these mammals contribute to moving seeds through the forest.

"It's not surprising that seed dispersers help trees get to new places," says Levey. "The effects of hunting can extend far beyond the hunted, threatening the overall health of the trees that make up the forest."

Adds Caughlin, "On the surface, it doesn't seem that seed dispersal would be important for tree populations. But seed dispersal has an effect over the whole life of a tree."

 

Animals critical to seed transport through the forest

 

The scientists looked at the growth and survival of trees that sprouted from parent trees and grew up in crowded environs, compared to trees from seeds that were widely transported across the forest by animals.

The information was supplemented with a dataset from the Thai Royal Forest Department that contains more than 15 years of data on trees.

The researchers then created a long-term simulation and ran it on the University of Florida's supercomputer, the HiPerGator.

"Having that computing power was very important," says Caughlin, "because we had to simulate the fate of millions of seeds."

The scientists discovered that trees that grow from seeds transported by now-overhunted animals are hardier and healthier.

"Our study is the first to quantify the decades-long effects of animal seed dispersal across the entire tree life cycle, from seeds to seedlings to adult trees," says Lichstein.

 

Probability of tree extinction increased tenfold

 

The results show that loss of animal seed-dispersers increases the probability of tree extinction by more than tenfold over a 100-year period.

"The entire ecosystem is at risk," says Caughlin.

"We hope the study will provide a boost for those trying to curb overhunting," he says, "and provide incentives to stop the wildlife trade."

--	Cheryl Dybas, NSF (703) 292-7734 cdybas@nsf.gov
--	Gigi Marino, University of Florida (352) 294-3393 gigimarino@ufl.edu

Related WebsitesNSF Discovery: Seed dispersal study shows value of conservation corridors: http://www.nsf.gov/news/news_summ.jsp?cntn_id=130515
NSF Discovery: Seeing the Forest for the Trees: Seed Dispersal, Environmental Conditions Matter in African Forests:
 http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=127949&org=NSF
NSF Discovery: Landscape Corridors Provide Pathway for Seed Dispersal: http://www.nsf.gov/news/news_summ.jsp?cntn_id=104277
NSF Discovery: Border crossing: 10 things to know about invasive fire ants on the march: http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=132165&org=NSF
NSF Award: Spatial Ecology and Evolution: Quantitative Training in Biology, Statistics, and Mathematics:
 http://www.nsf.gov/awardsearch/showAward?AWD_ID=0801544&HistoricalAwards=false

An Asian black bear photographed by a camera-trap; the overhunted bears disperse tree seeds.
Credit and Larger Version

A full-grown adult Thai forest study tree; the trees are threatened by overhunting of animals.
Credit and Larger Version

Researcher surveying the tropical forest at the Huai Kha Khaeng Wildlife Sanctuary in Thailand.
Credit and Larger Version

Thousands of seedlings were tagged to learn how trees and seed-disperser animals interact.
Credit and Larger Version

One of countless tree seedlings growing in the understory of the Thai tropical forest.
Credit and Larger Versión
The National Science Foundation (NSF)
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@yahoo.com
ayabaca@hotmail.com
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Science: Scientists Trace Evolutionary History of What Mammals Eat

Black bears are fond of berries, and will go far out of their way to find them. Credit: National Park Service Download the high-resolution JPG version of the image. (15 KB)

Black bears are fond of berries, and will go far out of their way to find them.

Credit: National Park Service

Download the high-resolution JPG version of the image. (15 KB)

The adaptable coyote, usually considered a carnivore, will also eat berries. Credit: National Park Service Download the high-resolution JPG version of the image. (50 KB)

Deer browse on plants, often defoliating shrubs and trees in suburban yards.

Credit: National Park Service

Download the high-resolution JPG version of the image. (108 KB)

Tigers are carnivores with a shrinking range in Asia and the Russian Far East. Credit: U.S. Fish and Wildlife Service Download the high-resolution JPG version of the image. (72 KB)

Pronghorn antelope graze their way across fields in the U.S. mountain west. Credit: National Park Service Download the high-resolution JPG version of the image. (30 KB)

 The feeding habits of mammals haven't always been what they are today, particularly for omnivores.

Some groups of mammals almost exclusively eat meat--take lions and tigers and other big cats as examples.

Other mammals such as deer, cows and antelope are predominantly plant-eaters, living on a diet of leaves, shoots, fruits and bark.

But particularly for omnivores that live on plant foods in addition to meat, the situation wasn't always that way, finds a new study by researchers working at the National Evolutionary Synthesis Center in Durham, North Carolina.

The results appear today in the online edition of the journal Proceedings of the National Academy of Sciences.

"The research links dietary strategy, a basic aspect of animal ecology, with macroevolutionary diversification of mammals," said George Gilchrist, program director in the National Science Foundation's (NSF) Division of Environmental Biology, which funded the research.

"It's impressive that ecology has such a strong and clear influence on lineages stretching back millions of years. Darwin would be delighted with this paper."

Past research shows that animals with similar diets tend to share certain characteristics.

But this study is the first of its kind to look across all mammal groups, including omnivores, to reconstruct how evolutionary time changed mammal diets.

To do that, the researchers compiled previously published diet data for more than 1,500 species representing more than one third of mammals alive today, including primates, ungulates, bats, rabbits and rodents.

By mapping that data onto the mammal family tree, the researchers were able to trace backward in time and infer what the ancestors of each species most likely ate.

They found that while some groups of mammals maintained steady diets, others changed their feeding strategies over time.

Today's omnivores in particular--a group that includes primates, bears, dogs and foxes--came from ancestors that primarily ate plants, or animals, but not both, said paper co-author Samantha Price of the University of California Davis.

While omnivorous mammals weren't always that way, plant-eaters and meat-eaters have diversified within a more well-worn path.

Radical shifts were unlikely for these animals. Mammals that eat meat for a living, for example, didn't give up their taste for flesh without transitioning through an omnivorous stage first.

"Direct transitions from carnivory to herbivory were essentially nonexistent," said co-author Louise Roth of Duke University.

"It's an intuitive result because it takes very different kinds of equipment to have those kinds of diets."

"Plant- and animal-based foods require different digestive chemistries and different processing mechanisms in the mouth and stomach," said co-author Samantha Hopkins of the University of Oregon.

The kinds of teeth adapted for tearing and slicing meat are different than the large, flat-topped molars adapted for grinding nuts and roots.

"It makes sense that you couldn't easily transition from one to the other in one step," Price said.

The researchers also found that diet is linked to how fast mammals spawn new species.

As new species arise and others go extinct, the plant-eaters proliferate faster than their meat-eating counterparts, with omnivores lagging behind both groups.

"If there was an evolutionary race to evolve 100 species, it would take three times longer for omnivores compared to herbivores, and carnivores would be in the middle," Price said.

-NSF-

 Guillermo Gonzalo Sánchez Achutegui
 ayabaca@gmail.com
ayabaca@hotmail.com 
 ayabaca@yahoo.com
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