Land fragmentation causes population to plummet
November 2011: 300 orang-utans have been lost in just seven years in Lower Kinabatangan on Sabah's east coast. Forest isolation and loss of habitat are to blame according to Dr Marc Ancrenaz, scientific director of HUTAN - Kinabatangan Orang-utan Conservation Programme (KOCP).
‘What we are seeing with our latest surveys within the Lower Kinabatangan is a clear population decline of the orang-utans,' said Dr Ancrenaz who hoped such issues would add urgency to events such as the Roundtable for Sustainable Oil Palm (RSPO) being held this month in Kota Kinabalu.
Isolated islands of forestThe biggest threat to orang-utan and other wildlife populations in Sabah is fragmentation. What this means is that agriculture development - primarily oil palm -has created small islands of forest which are isolated and completely surrounded by human-made landscape.
‘Because it is difficult for wildlife to move from one forest patch to the next, this situation leads to inbreeding and eventual population decline, which is what we are witnessing today in the Lower Kinabatangan,' said Dr Ancrenaz.
He points out that this issue is inherently related to the oil palm industry and he believes it should take action to rectify the situation. ‘We can still improve the situation for the Lower Kinabatangan's orang-utan and other wildlife by actually replanting and planning for actual wildlife corridors or patches of forest to support wildlife movement between protected or forested areas,' Dr Ancrenaz added.
http://www.wildlifeextra.com/go/news/orangutan-sabah.html
Showing posts with label habitat loss. Show all posts
Showing posts with label habitat loss. Show all posts
Thursday, November 24, 2011
Tuesday, November 22, 2011
Amphibians face spread of 3 threats
WASHINGTON — Frogs, salamanders and other amphibians might eventually have no haven left on the globe because of a triple threat of worsening scourges, a new study predicts.
Scientists have long known that amphibians are under attack from a killer fungus, climate change and shrinking habitat. In the study, appearing online in the journal Nature, computer models project that
in about 70 years, those three threats will spread, leaving no part of the world immune to one of them.
Several important U.S. amphibian species — such as boreal toads in the Rocky Mountains, and the mountain yellow legged frog in the Sierra Nevada — are shrinking in numbers, said zoologist Steve Corn, who is part of the U.S. Geological Survey’s Amphibian Research and Monitoring Initiative. The problem is worse in the western United States.
About one-third of the world’s amphibian species are known to be threatened with extinction.
“It’s no fun being a frog,” said biodiversity conservationist Stuart Pimm of Duke University, who wasn’t part of the study or the USGS effort. “They are getting it from all three different factors.”
http://www.dispatch.com/content/stories/national_world/2011/11/19/amphibians-face-spread-of-3-threats.html
Scientists have long known that amphibians are under attack from a killer fungus, climate change and shrinking habitat. In the study, appearing online in the journal Nature, computer models project that
in about 70 years, those three threats will spread, leaving no part of the world immune to one of them.
Several important U.S. amphibian species — such as boreal toads in the Rocky Mountains, and the mountain yellow legged frog in the Sierra Nevada — are shrinking in numbers, said zoologist Steve Corn, who is part of the U.S. Geological Survey’s Amphibian Research and Monitoring Initiative. The problem is worse in the western United States.
About one-third of the world’s amphibian species are known to be threatened with extinction.
“It’s no fun being a frog,” said biodiversity conservationist Stuart Pimm of Duke University, who wasn’t part of the study or the USGS effort. “They are getting it from all three different factors.”
http://www.dispatch.com/content/stories/national_world/2011/11/19/amphibians-face-spread-of-3-threats.html
Friday, May 20, 2011
Extinction rates 'overestimated', says study
19 May 2011
By Mark Kinver
Science and environment reporter, BBC News
Current extinction rate projections may be overestimating the role of habitat loss on species, a study suggests.
Current methods are too simplistic and fail to take into account the full complexity of what influences species numbers, researchers observed.
Writing in the journal Nature, they said present figures overestimated rates by up to 160%, and called for updated, more accurate calculations.
But they did add that habitat loss was still the main threat to biodiversity.
Co-authors Professor Stephen Hubbell, from the University of California Los Angeles, and Professor Fangliang He, from Sun Yat-sen University, China, said existing mathematical models were flawed.
"The most widely used indirect method is to estimate extinction rates by reversing the species-area accumulation curve, extrapolating backwards to smaller areas to calculate expected species loss," they wrote.
"Estimates based on this method are almost always much higher than actually observed."
In ecology, a species-area curve is used to highlight a relationship between and area of habitat and the number of species found in the area.
They added that they defined extinction rate as the fraction of species lost as a result of habitat loss over a period of time.
"The area that must be added to find individual of a species is, in general, much smaller than the area that must be removed to eliminate the last individual of a species," the professors observed.
"Therefore, on average, it takes a much greater loss of area to cause the extinction of a species."
'Severe reservations'
Probably the most authoriative global assessment of the status of species is the Red List of Threatened Species, co-ordinated and published by the International Union for Conservation of Nature (IUCN).
Jean Christophe Vie, IUCN's species programme deputy director - who was not involved in the research - said it was good that it was a clear effort to "get the science right", but had very severe reservations about how it could be interpreted.
"I am quite worried about how this report could be used by people who are reluctant to take environmental issues seriously,"he told BBC News.
"We (IUCN assessors) do not use this system between area and species because we know there are flaws.
"We have explicit details in our guidelines that to estimate extinction is not something we should do; for example, we know that species are not evenly distributed in ecosystems; habitat loss is not the only threat."
Dr Vie explained that, very often, conservation agencies and NGOs tended to mobilise support when species crept towards extinction thresholds.
"What is the actual concern is the rate of decline in populations," he went on to say.
"You do not see that many extinctions, but you do see many more species that are ending up with very small populations.
"So, focusing purely on extinctions is - to me - a problem."
In their paper, Professors He and Hubbell warned that their study must not "lead to complacency about extinction (as a result of) habitat loss", which was a "real and growing concern".
"We have bought a little more time with this discovery, but not a lot," Professor Hubbell observed.
http://www.bbc.co.uk/news/science-environment-13438610
(Submitted by Dawn Holloway)
By Mark Kinver
Science and environment reporter, BBC News
Current extinction rate projections may be overestimating the role of habitat loss on species, a study suggests.
Current methods are too simplistic and fail to take into account the full complexity of what influences species numbers, researchers observed.
Writing in the journal Nature, they said present figures overestimated rates by up to 160%, and called for updated, more accurate calculations.
But they did add that habitat loss was still the main threat to biodiversity.
Co-authors Professor Stephen Hubbell, from the University of California Los Angeles, and Professor Fangliang He, from Sun Yat-sen University, China, said existing mathematical models were flawed.
"The most widely used indirect method is to estimate extinction rates by reversing the species-area accumulation curve, extrapolating backwards to smaller areas to calculate expected species loss," they wrote.
"Estimates based on this method are almost always much higher than actually observed."
In ecology, a species-area curve is used to highlight a relationship between and area of habitat and the number of species found in the area.
They added that they defined extinction rate as the fraction of species lost as a result of habitat loss over a period of time.
"The area that must be added to find individual of a species is, in general, much smaller than the area that must be removed to eliminate the last individual of a species," the professors observed.
"Therefore, on average, it takes a much greater loss of area to cause the extinction of a species."
'Severe reservations'
Probably the most authoriative global assessment of the status of species is the Red List of Threatened Species, co-ordinated and published by the International Union for Conservation of Nature (IUCN).
Jean Christophe Vie, IUCN's species programme deputy director - who was not involved in the research - said it was good that it was a clear effort to "get the science right", but had very severe reservations about how it could be interpreted.
"I am quite worried about how this report could be used by people who are reluctant to take environmental issues seriously,"he told BBC News.
"We (IUCN assessors) do not use this system between area and species because we know there are flaws.
"We have explicit details in our guidelines that to estimate extinction is not something we should do; for example, we know that species are not evenly distributed in ecosystems; habitat loss is not the only threat."
Dr Vie explained that, very often, conservation agencies and NGOs tended to mobilise support when species crept towards extinction thresholds.
"What is the actual concern is the rate of decline in populations," he went on to say.
"You do not see that many extinctions, but you do see many more species that are ending up with very small populations.
"So, focusing purely on extinctions is - to me - a problem."
In their paper, Professors He and Hubbell warned that their study must not "lead to complacency about extinction (as a result of) habitat loss", which was a "real and growing concern".
"We have bought a little more time with this discovery, but not a lot," Professor Hubbell observed.
http://www.bbc.co.uk/news/science-environment-13438610
(Submitted by Dawn Holloway)
Monday, February 14, 2011
The 'weird' predatory fossa of Madagascar is threatened
By Matt Walker
Editor, Earth News
It is one of the most unusual of all big predators, but the odd-looking, cat-like fossa, the largest carnivore on the island of Madagascar, faces an uncertain future.
Few fossa can now be found in a place that was once a stronghold, as villagers hunt the animal as bushmeat and in a bid to protect their own livestock, which the fossa eats.
Its population may be declining rapidly, says one of the few scientists to have studied it in the wild, and it could already be critically endangered.
Fossa are a highly specialised predator.
Secretive and cat-like, they are expert climbers and well equipped for chasing down lemurs in the forest, preying on even the largest lemur species.
But they also take small shrew-like creatures called tenrecs and almost any other vertebrate animal living in Madagascar's forests, with the exception of humans, crocodiles and possibly wild boar.
However, very little is known about them, as only a handful of scientists have been able to study fossa closely in the wild.
For example, it was once thought to be closely related to civets and their relatives, but genetic evidence suggests it is actually related to other Malagasy carnivores that together are related to mongooses.
Little is also known about how many fossa exist on Madagascar, with official estimates suggesting that fewer than 2500 survive and the animal should be considered as Endangered.
But according to one scientist studying it, the fossa could be in an even more perilous state.
Ms Mia-Lana Lührs is currently studying the fossa for her PhD at Germany's University of Göttingen and the German Primate Center.
She has also helped the upcoming BBC natural history series Madagascar film the creatures in the wild.
Within the past three years, she has recorded a substantial fall in the numbers of fossa living in Kirindy, a reserve within forests on the west of the island.
This area was considered to be a stronghold of the fossa.
In 2007, Ms Lührs recorded 18 different males regularly visiting a particular tree that male and female fossa use to mate in.
In 2008, she recorded 14 males, and in 2009 just ten.
Last year, only two males were sighted.
"Fortunately, I have seen seven males shortly before in another part of the forest where I observed, so I know that at least nine males are still alive," she told BBC News.
But overall, her studies, which use GPS tracking collars to follow individual fossa, suggest no more than 30 fossa of either sex now exist in Kirindy.
A forest fragment that size would be expected to be home to many times that number.
"That is not sufficient for the population to survive without management," she says.
Habitat destruction is one significant cause of the fossa's recent decline reason.
But the large predator is also coming into conflict with people, as it leaves the dwindling forest in search of food.
A survey conducted last year by colleague Moritz Rahlfs in villages surrounding Kirindy found that 12 fossa had been killed recently by people living in just eight villages, to prevent the fossa from stealing their chickens.
"If the killings continue at such high rates, we have three years left to see fossas in Kirindy," says Ms Lührs.
The carnivore also faces other threats.
A separate recent piece of research by PhD student Christopher Golden of the University of California, Berkeley, has already found that fossa are hunted for food by people within 55 to 60% of those villages studied in northeastern Madagascar.
Fossa body parts are also used in traditional medicines in some parts of the island.
Ms Lührs suspects the fossa may already be critically endangered.
"There is this fascinating weird creature at the other end of the world and it might soon go extinct," she says.
The story of the fossa will be told in the natural history series Madagascar, which broadcasts on BBC Two on Wednesday 9 February at GMT 20.00.
http://news.bbc.co.uk/earth/hi/earth_news/newsid_9385000/9385018.stm
Sunday, December 19, 2010
Endangered Bornean Clouded Leopard Facing Habitat Loss
Bandar Seri Begawan - A Recent sighting of the endangered Bornean Clouded Leopard during daylight in a populated neighbourhood in Labi showed that the nocturnal wild-cat species are disturbed and facing habitat loss, a wildlife expert said yesterday.
One of the most elusive animals in the world, the Clouded Leopard inhabits dense forests.
But on October 31 this year, a local man managed to capture a photo of the clouded leopard, scientifically known as Neofelis diardi, behind his old house on Jalan Labi Lama in Mukim Labi, in Belait District.
Dr Joseph Charles, a senior lecturer at Universiti Brunei Darussalam's (UBD) Biology Department and project leader of a faunal biodiversity survey in the forests of Sg Ingei in Belait, commented that the surrounding of the house where the picture was taken was of secondary forest.
"You see in the picture, the cat was walking on a fallen tree trunk, surrounded by bushes and further up there is a forest, so when it comes down there (closer to a neighbour-hood), it's because the forest is gone," he explained to The Brunei Times.
He added: "This animal is nocturnal, if they come down to the place (a neighbourhood), either it's hungry, couldn't sleep anywhere in peace (or) is very disturbed."
Sharing his sighting with the paper, Adi Aizal said he and his family were cleaning up the old house which belong to the family when he saw the leopard climbed down a tree.
"We were at the back of the old family house, clearing and cleaning up when I realised there were some noise and movements up in the trees," said the 34-year-old.
"When it came down, the tail was as long as its body, so it was actually very surreal to me, as I've never seen a cat as big as this before," said Adi, who never knew the existence of the leopard before die sighting.
He then ran to his car to get his camera and took a picture of the cat.
"It looked dazed, as if it just woke up. It was looking at us for a good one or two minutes, then walked away," said the Kuala Belait native who is a helicopter pilot with Bristow Helicopters International operating in Libya.
After the sighting, he searched for information of the leopard on the Internet and contacted an administration member of the Sg Ingei project to inform them about his sighting.
Dr Charles had earlier said that a team would come back to the location of the sighting in January next year to set up camera traps and collect data of the animal.
Deforestation in the tropical regions of Southeast Asia is the most serious threat to the clouded leopard.
The species natural habitat has been fragmented and decreasing at a rate of 10 per cent a year since 1997, according to an information on the World Wildlife Fund (WWF) website. -- Courtesy of The Brunei Times
http://www.brudirect.com/index.php/2010121835537/Local-News/endangered-bornean-clouded-leopard-facing-habitat-loss.html
One of the most elusive animals in the world, the Clouded Leopard inhabits dense forests.
But on October 31 this year, a local man managed to capture a photo of the clouded leopard, scientifically known as Neofelis diardi, behind his old house on Jalan Labi Lama in Mukim Labi, in Belait District.
Dr Joseph Charles, a senior lecturer at Universiti Brunei Darussalam's (UBD) Biology Department and project leader of a faunal biodiversity survey in the forests of Sg Ingei in Belait, commented that the surrounding of the house where the picture was taken was of secondary forest.
"You see in the picture, the cat was walking on a fallen tree trunk, surrounded by bushes and further up there is a forest, so when it comes down there (closer to a neighbour-hood), it's because the forest is gone," he explained to The Brunei Times.
He added: "This animal is nocturnal, if they come down to the place (a neighbourhood), either it's hungry, couldn't sleep anywhere in peace (or) is very disturbed."
Sharing his sighting with the paper, Adi Aizal said he and his family were cleaning up the old house which belong to the family when he saw the leopard climbed down a tree.
"We were at the back of the old family house, clearing and cleaning up when I realised there were some noise and movements up in the trees," said the 34-year-old.
"When it came down, the tail was as long as its body, so it was actually very surreal to me, as I've never seen a cat as big as this before," said Adi, who never knew the existence of the leopard before die sighting.
He then ran to his car to get his camera and took a picture of the cat.
"It looked dazed, as if it just woke up. It was looking at us for a good one or two minutes, then walked away," said the Kuala Belait native who is a helicopter pilot with Bristow Helicopters International operating in Libya.
After the sighting, he searched for information of the leopard on the Internet and contacted an administration member of the Sg Ingei project to inform them about his sighting.
Dr Charles had earlier said that a team would come back to the location of the sighting in January next year to set up camera traps and collect data of the animal.
Deforestation in the tropical regions of Southeast Asia is the most serious threat to the clouded leopard.
The species natural habitat has been fragmented and decreasing at a rate of 10 per cent a year since 1997, according to an information on the World Wildlife Fund (WWF) website. -- Courtesy of The Brunei Times
http://www.brudirect.com/index.php/2010121835537/Local-News/endangered-bornean-clouded-leopard-facing-habitat-loss.html
Endangered Bornean Clouded Leopard Facing Habitat Loss
Bandar Seri Begawan - A Recent sighting of the endangered Bornean Clouded Leopard during daylight in a populated neighbourhood in Labi showed that the nocturnal wild-cat species are disturbed and facing habitat loss, a wildlife expert said yesterday.
One of the most elusive animals in the world, the Clouded Leopard inhabits dense forests.
But on October 31 this year, a local man managed to capture a photo of the clouded leopard, scientifically known as Neofelis diardi, behind his old house on Jalan Labi Lama in Mukim Labi, in Belait District.
Dr Joseph Charles, a senior lecturer at Universiti Brunei Darussalam's (UBD) Biology Department and project leader of a faunal biodiversity survey in the forests of Sg Ingei in Belait, commented that the surrounding of the house where the picture was taken was of secondary forest.
"You see in the picture, the cat was walking on a fallen tree trunk, surrounded by bushes and further up there is a forest, so when it comes down there (closer to a neighbour-hood), it's because the forest is gone," he explained to The Brunei Times.
He added: "This animal is nocturnal, if they come down to the place (a neighbourhood), either it's hungry, couldn't sleep anywhere in peace (or) is very disturbed."
Sharing his sighting with the paper, Adi Aizal said he and his family were cleaning up the old house which belong to the family when he saw the leopard climbed down a tree.
"We were at the back of the old family house, clearing and cleaning up when I realised there were some noise and movements up in the trees," said the 34-year-old.
"When it came down, the tail was as long as its body, so it was actually very surreal to me, as I've never seen a cat as big as this before," said Adi, who never knew the existence of the leopard before die sighting.
He then ran to his car to get his camera and took a picture of the cat.
"It looked dazed, as if it just woke up. It was looking at us for a good one or two minutes, then walked away," said the Kuala Belait native who is a helicopter pilot with Bristow Helicopters International operating in Libya.
After the sighting, he searched for information of the leopard on the Internet and contacted an administration member of the Sg Ingei project to inform them about his sighting.
Dr Charles had earlier said that a team would come back to the location of the sighting in January next year to set up camera traps and collect data of the animal.
Deforestation in the tropical regions of Southeast Asia is the most serious threat to the clouded leopard.
The species natural habitat has been fragmented and decreasing at a rate of 10 per cent a year since 1997, according to an information on the World Wildlife Fund (WWF) website. -- Courtesy of The Brunei Times
http://www.brudirect.com/index.php/2010121835537/Local-News/endangered-bornean-clouded-leopard-facing-habitat-loss.html
One of the most elusive animals in the world, the Clouded Leopard inhabits dense forests.
But on October 31 this year, a local man managed to capture a photo of the clouded leopard, scientifically known as Neofelis diardi, behind his old house on Jalan Labi Lama in Mukim Labi, in Belait District.
Dr Joseph Charles, a senior lecturer at Universiti Brunei Darussalam's (UBD) Biology Department and project leader of a faunal biodiversity survey in the forests of Sg Ingei in Belait, commented that the surrounding of the house where the picture was taken was of secondary forest.
"You see in the picture, the cat was walking on a fallen tree trunk, surrounded by bushes and further up there is a forest, so when it comes down there (closer to a neighbour-hood), it's because the forest is gone," he explained to The Brunei Times.
He added: "This animal is nocturnal, if they come down to the place (a neighbourhood), either it's hungry, couldn't sleep anywhere in peace (or) is very disturbed."
Sharing his sighting with the paper, Adi Aizal said he and his family were cleaning up the old house which belong to the family when he saw the leopard climbed down a tree.
"We were at the back of the old family house, clearing and cleaning up when I realised there were some noise and movements up in the trees," said the 34-year-old.
"When it came down, the tail was as long as its body, so it was actually very surreal to me, as I've never seen a cat as big as this before," said Adi, who never knew the existence of the leopard before die sighting.
He then ran to his car to get his camera and took a picture of the cat.
"It looked dazed, as if it just woke up. It was looking at us for a good one or two minutes, then walked away," said the Kuala Belait native who is a helicopter pilot with Bristow Helicopters International operating in Libya.
After the sighting, he searched for information of the leopard on the Internet and contacted an administration member of the Sg Ingei project to inform them about his sighting.
Dr Charles had earlier said that a team would come back to the location of the sighting in January next year to set up camera traps and collect data of the animal.
Deforestation in the tropical regions of Southeast Asia is the most serious threat to the clouded leopard.
The species natural habitat has been fragmented and decreasing at a rate of 10 per cent a year since 1997, according to an information on the World Wildlife Fund (WWF) website. -- Courtesy of The Brunei Times
http://www.brudirect.com/index.php/2010121835537/Local-News/endangered-bornean-clouded-leopard-facing-habitat-loss.html
Saturday, November 6, 2010
Moving Animals Not a Panacea for Habitat Loss
ScienceDaily (Nov. 3, 2010) - New University of Georgia research suggests moving threatened animals to protected habitats may not always be an effective conservation technique if the breeding patterns of the species are influenced by a social hierarchy.
Research, published in the early online edition of the journal Biological Conservation, found an initial group of gopher tortoises released on St. Catherine's Island, Ga. were three times more likely to produce offspring than a later-introduced group, although the initial group had a much smaller proportion of reproduction-aged males.
"There definitely appeared to be an advantage to the order that the tortoises were released," said lead author Tracey Tuberville, an assistant research scientist at UGA's Savannah River Ecology Laboratory. "The earlier the males were released, the more likely they were to be successful fathering offspring for the next generation."
Moving multiple groups of gopher tortoises at different times may disrupt their social structure, explained Tuberville, resulting in differential success in reproduction among potential breeders. Introducing a specific number of males to reach a target population size may not achieve the desired results if all of the males are not reproducing.
"We found that females released later were not excluded from reproduction," she said. "If you need to augment a population, you might consider targeting females as opposed to males or introducing more females than males, because females produce the eggs, and they also seem to be incorporated into the breeding and social structure faster than males."
Gopher tortoises are federally listed as a threatened species in the western part of their range, though not in Georgia and Florida, where much of the destruction of their habitat has occurred. Gopher tortoises are highly social and live in sandy burrows. They prefer open-canopied longleaf pine forests, which now cover only two percent of their historic range. Gopher tortoise habitats are ideal sites for human development, and Tuberville said that in the past, land developers were required to do little to protect their habitats at development sites.
Gopher tortoises from various locations were first introduced to St. Catherine's in the 1980s. A second group from a single population was later introduced in 1994. Biologists and veterinarians working on the island recorded health and survivorship data on the tortoises, each of which were permanently and uniquely marked to be easily identifiable. The researchers sought to identify which tortoises from each group were successfully reproducing after release. After a site-wide capture of all the potential breeders, researchers collected DNA samples. Once the eggs hatched, they also tested the DNA of the young to determine the parents.
"If we find that the pattern of differential mating success is consistent, or if it is observed in other places, it will inform us whether or not we want to establish populations through multiple releases and also whether or not we want to augment an existing population," said Tuberville. Study co-author Travis Glenn, associate professor in the department of environmental health science in the UGA College of Public Health, said that new DNA technologies increasingly are being used in conservation and environmental health efforts. "We're trying to use these techniques in new and interesting ways," said Glenn. "That requires partnerships between a greater variety of people.:
"The technology is getting better and better, so the answers will be better and more informative," Glenn added. "The ability to address conservation concerns will be faster, cheaper and more accurate." Story Source: The above story is reprinted from materials provided by University of Georgia.
From: HerpDigest Volume # 10 Issue # 47 11/5/10 (A Not-for-Profit Publication)
Research, published in the early online edition of the journal Biological Conservation, found an initial group of gopher tortoises released on St. Catherine's Island, Ga. were three times more likely to produce offspring than a later-introduced group, although the initial group had a much smaller proportion of reproduction-aged males.
"There definitely appeared to be an advantage to the order that the tortoises were released," said lead author Tracey Tuberville, an assistant research scientist at UGA's Savannah River Ecology Laboratory. "The earlier the males were released, the more likely they were to be successful fathering offspring for the next generation."
Moving multiple groups of gopher tortoises at different times may disrupt their social structure, explained Tuberville, resulting in differential success in reproduction among potential breeders. Introducing a specific number of males to reach a target population size may not achieve the desired results if all of the males are not reproducing.
"We found that females released later were not excluded from reproduction," she said. "If you need to augment a population, you might consider targeting females as opposed to males or introducing more females than males, because females produce the eggs, and they also seem to be incorporated into the breeding and social structure faster than males."
Gopher tortoises are federally listed as a threatened species in the western part of their range, though not in Georgia and Florida, where much of the destruction of their habitat has occurred. Gopher tortoises are highly social and live in sandy burrows. They prefer open-canopied longleaf pine forests, which now cover only two percent of their historic range. Gopher tortoise habitats are ideal sites for human development, and Tuberville said that in the past, land developers were required to do little to protect their habitats at development sites.
Gopher tortoises from various locations were first introduced to St. Catherine's in the 1980s. A second group from a single population was later introduced in 1994. Biologists and veterinarians working on the island recorded health and survivorship data on the tortoises, each of which were permanently and uniquely marked to be easily identifiable. The researchers sought to identify which tortoises from each group were successfully reproducing after release. After a site-wide capture of all the potential breeders, researchers collected DNA samples. Once the eggs hatched, they also tested the DNA of the young to determine the parents.
"If we find that the pattern of differential mating success is consistent, or if it is observed in other places, it will inform us whether or not we want to establish populations through multiple releases and also whether or not we want to augment an existing population," said Tuberville. Study co-author Travis Glenn, associate professor in the department of environmental health science in the UGA College of Public Health, said that new DNA technologies increasingly are being used in conservation and environmental health efforts. "We're trying to use these techniques in new and interesting ways," said Glenn. "That requires partnerships between a greater variety of people.:
"The technology is getting better and better, so the answers will be better and more informative," Glenn added. "The ability to address conservation concerns will be faster, cheaper and more accurate." Story Source: The above story is reprinted from materials provided by University of Georgia.
From: HerpDigest Volume # 10 Issue # 47 11/5/10 (A Not-for-Profit Publication)
Moving Animals Not a Panacea for Habitat Loss
ScienceDaily (Nov. 3, 2010) - New University of Georgia research suggests moving threatened animals to protected habitats may not always be an effective conservation technique if the breeding patterns of the species are influenced by a social hierarchy.
Research, published in the early online edition of the journal Biological Conservation, found an initial group of gopher tortoises released on St. Catherine's Island, Ga. were three times more likely to produce offspring than a later-introduced group, although the initial group had a much smaller proportion of reproduction-aged males.
"There definitely appeared to be an advantage to the order that the tortoises were released," said lead author Tracey Tuberville, an assistant research scientist at UGA's Savannah River Ecology Laboratory. "The earlier the males were released, the more likely they were to be successful fathering offspring for the next generation."
Moving multiple groups of gopher tortoises at different times may disrupt their social structure, explained Tuberville, resulting in differential success in reproduction among potential breeders. Introducing a specific number of males to reach a target population size may not achieve the desired results if all of the males are not reproducing.
"We found that females released later were not excluded from reproduction," she said. "If you need to augment a population, you might consider targeting females as opposed to males or introducing more females than males, because females produce the eggs, and they also seem to be incorporated into the breeding and social structure faster than males."
Gopher tortoises are federally listed as a threatened species in the western part of their range, though not in Georgia and Florida, where much of the destruction of their habitat has occurred. Gopher tortoises are highly social and live in sandy burrows. They prefer open-canopied longleaf pine forests, which now cover only two percent of their historic range. Gopher tortoise habitats are ideal sites for human development, and Tuberville said that in the past, land developers were required to do little to protect their habitats at development sites.
Gopher tortoises from various locations were first introduced to St. Catherine's in the 1980s. A second group from a single population was later introduced in 1994. Biologists and veterinarians working on the island recorded health and survivorship data on the tortoises, each of which were permanently and uniquely marked to be easily identifiable. The researchers sought to identify which tortoises from each group were successfully reproducing after release. After a site-wide capture of all the potential breeders, researchers collected DNA samples. Once the eggs hatched, they also tested the DNA of the young to determine the parents.
"If we find that the pattern of differential mating success is consistent, or if it is observed in other places, it will inform us whether or not we want to establish populations through multiple releases and also whether or not we want to augment an existing population," said Tuberville. Study co-author Travis Glenn, associate professor in the department of environmental health science in the UGA College of Public Health, said that new DNA technologies increasingly are being used in conservation and environmental health efforts. "We're trying to use these techniques in new and interesting ways," said Glenn. "That requires partnerships between a greater variety of people.:
"The technology is getting better and better, so the answers will be better and more informative," Glenn added. "The ability to address conservation concerns will be faster, cheaper and more accurate." Story Source: The above story is reprinted from materials provided by University of Georgia.
From: HerpDigest Volume # 10 Issue # 47 11/5/10 (A Not-for-Profit Publication)
Research, published in the early online edition of the journal Biological Conservation, found an initial group of gopher tortoises released on St. Catherine's Island, Ga. were three times more likely to produce offspring than a later-introduced group, although the initial group had a much smaller proportion of reproduction-aged males.
"There definitely appeared to be an advantage to the order that the tortoises were released," said lead author Tracey Tuberville, an assistant research scientist at UGA's Savannah River Ecology Laboratory. "The earlier the males were released, the more likely they were to be successful fathering offspring for the next generation."
Moving multiple groups of gopher tortoises at different times may disrupt their social structure, explained Tuberville, resulting in differential success in reproduction among potential breeders. Introducing a specific number of males to reach a target population size may not achieve the desired results if all of the males are not reproducing.
"We found that females released later were not excluded from reproduction," she said. "If you need to augment a population, you might consider targeting females as opposed to males or introducing more females than males, because females produce the eggs, and they also seem to be incorporated into the breeding and social structure faster than males."
Gopher tortoises are federally listed as a threatened species in the western part of their range, though not in Georgia and Florida, where much of the destruction of their habitat has occurred. Gopher tortoises are highly social and live in sandy burrows. They prefer open-canopied longleaf pine forests, which now cover only two percent of their historic range. Gopher tortoise habitats are ideal sites for human development, and Tuberville said that in the past, land developers were required to do little to protect their habitats at development sites.
Gopher tortoises from various locations were first introduced to St. Catherine's in the 1980s. A second group from a single population was later introduced in 1994. Biologists and veterinarians working on the island recorded health and survivorship data on the tortoises, each of which were permanently and uniquely marked to be easily identifiable. The researchers sought to identify which tortoises from each group were successfully reproducing after release. After a site-wide capture of all the potential breeders, researchers collected DNA samples. Once the eggs hatched, they also tested the DNA of the young to determine the parents.
"If we find that the pattern of differential mating success is consistent, or if it is observed in other places, it will inform us whether or not we want to establish populations through multiple releases and also whether or not we want to augment an existing population," said Tuberville. Study co-author Travis Glenn, associate professor in the department of environmental health science in the UGA College of Public Health, said that new DNA technologies increasingly are being used in conservation and environmental health efforts. "We're trying to use these techniques in new and interesting ways," said Glenn. "That requires partnerships between a greater variety of people.:
"The technology is getting better and better, so the answers will be better and more informative," Glenn added. "The ability to address conservation concerns will be faster, cheaper and more accurate." Story Source: The above story is reprinted from materials provided by University of Georgia.
From: HerpDigest Volume # 10 Issue # 47 11/5/10 (A Not-for-Profit Publication)
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