Bhopal, Oct 25: With the objective of promoting biodiversity, the Madhya Pradesh Council Of Science and Technology (MPCOST) will establish Centres of Excellence in the state. ''The centres -- whose setting up coincides with completion of MPCOST's silver jubilee -- will serve as a medium for enhancing scientific efficiency, technical capability, quality control, according priority to work relating to medicinal and aromatic herbs,'' MPCOST Working Committee Chairman Mahesh Sharma told reporters here today.
The conclusion of the jubilee year would be marked by a three-day Indian Science Conference to get underway here on November 23. The October 27 meeting of MPCOST's Permanent Committee would provide final shape to Conference programmes. A Youth Science Conference is also on the cards.
''Decisions were taken to constitute a Madhya Pradesh Science and Technology Network for MPCOST's statewide expansion, make the Council's Remote-Sensing Centre more effective, initiating programmes for improving MPCOST activities and recruiting scientists,'' Dr Sharma added.
The centres would focus on special skill upgradation of students, youth, farmers, craftspersons and women in the unorganised sector. In three months, MPCOST intends to create a network with two other agencies.
''The Remote-Sensing Centre has begun working on a project affiliated to the Indian Space Research Organisation and on schemes related to the state government's Education, Public Health, Tourism, Environment and Housing departments. Through the medium of the United Nations International Children's Emergency Fund, the Remote-Sensing Centre has taken up a programme for improving potable water sources,'' Dr Sharma explained. Data was prepared on 80,000 of the state's total four lakh sources and a Telemedicine Scheme prepared.
Showing posts with label Eddy Alfian Bin Azmi. Show all posts
Showing posts with label Eddy Alfian Bin Azmi. Show all posts
Monday, October 29, 2007
Biofuels Damaging Ecosystems And Biodiversity
LONDON (Dow Jones)--Increased demand for biofuels, along with other agricultural commodities, is resulting in ecosystem degradation and biodiversity loss, said the U.N. Thursday.
Expansion of the agricultural industry, including the rise in land used for biofuel production, could impact particularly negatively on ecosystems supporting poor populations, according to the U.N.'s Global Environment Outlook 4 report.
With the world population forecast to grow to over 9 billion by 2050, food production will need to increase significantly to meet demand, the report said, noting the conflict between agricultural commodity demands for both food and fuel.
However, the U.N. was not particularly optimistic about any near-term relief to the food versus fuel tension or technology developments within inedible biofuel sources.
"Forest products and the nonfood cellulose component of food crops have a huge potential as an energy source, but technologies are still too costly to compete with fossil fuels at current prices," said the report.
Expansion of the agricultural industry, including the rise in land used for biofuel production, could impact particularly negatively on ecosystems supporting poor populations, according to the U.N.'s Global Environment Outlook 4 report.
With the world population forecast to grow to over 9 billion by 2050, food production will need to increase significantly to meet demand, the report said, noting the conflict between agricultural commodity demands for both food and fuel.
However, the U.N. was not particularly optimistic about any near-term relief to the food versus fuel tension or technology developments within inedible biofuel sources.
"Forest products and the nonfood cellulose component of food crops have a huge potential as an energy source, but technologies are still too costly to compete with fossil fuels at current prices," said the report.
Drought Can Destroy Biodiversity
Tue Oct 23
The skimmer and swimmer critters in ponds dried out by drought end up looking the same as each other when waters return, causing a decline in biodiversity, a new study finds.
In worst-case outcomes, drops in biodiversity—the variety and number of species, in a given locale can lead to more serious consequences, such as resulting in ecosystem collapses that affect the web of life and food that supports all animals and humans.
Scientists are more interested than ever in the effects of extreme climate swings, such as prolonged drought, because the computer models predict wilder extremes as one effect of the climate change now underway.
To learn how drought affects pond life, Jonathan Chase, an ecologist at Washington University in St. Louis, imposed drought conditions on 20 artificial ponds and investigated how the harsh conditions affected the species counts and varieties.
Each pond community had the same environmental conditions, but Chase varied the timing of the introduction of species, such as dragonflies, water-bugs, frogs, water fowl and algae, before letting the species naturally flourish.
As the communities began to thrive, the species took hold to varying extents pond by pond, with some harboring only 10 to 20 percent of species in common. Some of the variation was due to plants being randomly introduced as they fell from the feathers of a duck, for example.
After pond communities established themselves, Chase imposed the drought conditions on half. When those ponds were allowed to recover from drought and life moved back in, their species content looked much more similar to each other.
“Drought homogenizes the variance among communities,” Chase said. “It takes all these communities that used to be very different from each other and makes them very similar to each other.”
Why? Because certain species are much hardier than others and are quicker to re-establish themselves once the drought subsides.
"When it comes to drought, there are wimpy species and hardy species," Chase said. "Several types of zooplankton, many water-bugs and some frogs are the hardy ones. A wimpy species, perhaps surprisingly, is the bullfrog. Their tadpoles require two years to grow, so they often don’t rebound very well from drought. “
Zooplankton deposit their eggs in mud, so they lay low until waters return, whereas frogs leave the pond when it dries up. Algae and a few plant species that make lots of seeds also weather droughts fairly well, Chase said.
His study, detailed in the Oct. 15 issue of the journal Proceedings of the National Academy of Sciences, establishes an important distinction between local biodiversity (in one pond) and regional diversity (between several ponds), the latter of which is often overlooked, Chase said.
“I found drought had less than a 10-percent reduction on local diversity, but a nearly 50-percent reduction on regional diversity," Chase said. "This is important because if you just count the number of species in any given pond you might say that drought had little effect on species diversity. But if you take exact data and you ask: 'Did drought affect regional diversity?' I found it had a huge effect on regional diversity.”
The skimmer and swimmer critters in ponds dried out by drought end up looking the same as each other when waters return, causing a decline in biodiversity, a new study finds.
In worst-case outcomes, drops in biodiversity—the variety and number of species, in a given locale can lead to more serious consequences, such as resulting in ecosystem collapses that affect the web of life and food that supports all animals and humans.
Scientists are more interested than ever in the effects of extreme climate swings, such as prolonged drought, because the computer models predict wilder extremes as one effect of the climate change now underway.
To learn how drought affects pond life, Jonathan Chase, an ecologist at Washington University in St. Louis, imposed drought conditions on 20 artificial ponds and investigated how the harsh conditions affected the species counts and varieties.
Each pond community had the same environmental conditions, but Chase varied the timing of the introduction of species, such as dragonflies, water-bugs, frogs, water fowl and algae, before letting the species naturally flourish.
As the communities began to thrive, the species took hold to varying extents pond by pond, with some harboring only 10 to 20 percent of species in common. Some of the variation was due to plants being randomly introduced as they fell from the feathers of a duck, for example.
After pond communities established themselves, Chase imposed the drought conditions on half. When those ponds were allowed to recover from drought and life moved back in, their species content looked much more similar to each other.
“Drought homogenizes the variance among communities,” Chase said. “It takes all these communities that used to be very different from each other and makes them very similar to each other.”
Why? Because certain species are much hardier than others and are quicker to re-establish themselves once the drought subsides.
"When it comes to drought, there are wimpy species and hardy species," Chase said. "Several types of zooplankton, many water-bugs and some frogs are the hardy ones. A wimpy species, perhaps surprisingly, is the bullfrog. Their tadpoles require two years to grow, so they often don’t rebound very well from drought. “
Zooplankton deposit their eggs in mud, so they lay low until waters return, whereas frogs leave the pond when it dries up. Algae and a few plant species that make lots of seeds also weather droughts fairly well, Chase said.
His study, detailed in the Oct. 15 issue of the journal Proceedings of the National Academy of Sciences, establishes an important distinction between local biodiversity (in one pond) and regional diversity (between several ponds), the latter of which is often overlooked, Chase said.
“I found drought had less than a 10-percent reduction on local diversity, but a nearly 50-percent reduction on regional diversity," Chase said. "This is important because if you just count the number of species in any given pond you might say that drought had little effect on species diversity. But if you take exact data and you ask: 'Did drought affect regional diversity?' I found it had a huge effect on regional diversity.”
Parasites A Key To The Decline Of Red Colobus Monkeys In Forest Fragments
Oct. 28, 2007) — Forest fragmentation threatens biodiversity, often causing declines or local extinctions in a majority of species while enhancing the prospects of a few. A new study from the University of Illinois shows that parasites can play a pivotal role in the decline of species in fragmented forests. This is the first study to look at how forest fragmentation increases the burden of infectious parasites on animals already stressed by disturbances to their habitat.
The study, of black-and-white colobus monkeys and red colobus monkeys in tropical forests in western Uganda, appears in the American Journal of Primatology.
Once dominated by vast forests, Uganda now has less than one-twentieth of its original forest cover. According to the World Resources Institute, its tropical forests are being logged and converted to agricultural land at a rate that outpaces sub-Saharan Africa as a whole. Small tracts remain, however, hemmed in by pastures and croplands. Many of the species that thrived in the original forests are struggling to survive in these parcels, which can be as small as one hectare in size.
“In Uganda, just looking at the primates, it’s one of the most biodiverse places on the earth,” said professor of pathobiology Thomas Gillespie, principal investigator on the study. “You’ve got 12 to 13 species of primates in a core undisturbed forest. But if you go into these forest fragments, you’ll find only three or four species of primates.”
Populations of black-and-white colobus monkeys appear to be stable in the Ugandan forest remnants, while their cousins, the red colobus monkeys, are in decline.
Gillespie and his colleague, Colin Chapman, of McGill University in Montreal, surveyed 20 forest fragments near the western boundary of Kibale National Park, in western Uganda.
They compared the abundance, variety and density of potentially harmful parasites in these fragments to the undisturbed “core forest” of the park.
The researchers followed the monkeys for four years, collecting data on how far the animals ranged, what they ate and which parasites were infecting them.
In those four years, red colobus populations in forest fragments declined 20 percent, whereas populations of black-and-white colobus monkeys remained relatively stable. Both species maintained stable populations in the undisturbed forest.
Scientists have struggled to explain why closely related animals, like these two species of monkeys, can fare so differently in forest fragments. The answer, Gillespie said, lies in a complex interplay of factors, with parasites and nutrition playing key roles.
The researchers focused on two nematodes known to cause significant pathology in monkeys: a whipworm, (Trichuris sp.), and a nodule worm (Oesophagostomum sp.). While feeding on leaves, the monkeys ingest the larval forms of these worms. The larvae mature in the intestines, where they can cause blockages or other damage. The nematodes migrate through blood vessels, causing inflammation, organ damage and, sometimes, death.
The researchers found a higher density of parasites in the forest fragments than in the undisturbed forest. They also found new parasites not seen in the undisturbed forest.
“Several of the parasites in these animals in the fragments never occur in undisturbed forest, and some of these novel parasites are definitely from livestock or people,” Gillespie said. The red colobus monkeys were infected with five of these human or livestock parasites; the black and white colobus carried only two.
Other differences between the two species affect their vulnerability to parasitic infection. Red colobus monkeys congregate and live in large groups, with up to 50 members, compared with about 10 members in the black-and-white groups. Red colobus monkeys eat a much more varied diet. This causes them to travel farther, searching for the foods they need. But many of the plants that make up their diet simply aren’t available in disturbed forest fragments.
“The red colobus typically eat 40 to 50 species of plants, but in these forest fragments we might only have 12 tree species, so there’s a dramatic reduction in what we typically would see them feed on,” Gillespie said.
“The black-and-white colobus tend to feed on whatever’s dominant. They make do with what’s there.”
The black-and-white colobus monkeys’ ability to eat well under a variety of circumstances enhances their ability to withstand parasitic infections, Gillespie said.
Red colobus monkeys’ travels bring them into contact with more parasites. Their compromised nutritional status also weakens them, giving parasites the edge, Gillespie said.
“We asked how parasitism plays into this dynamic of some species doing well and others not doing well after forest fragmentation,” Gillespie said. “This is giving us a new window into what’s happening.”
The study, of black-and-white colobus monkeys and red colobus monkeys in tropical forests in western Uganda, appears in the American Journal of Primatology.
Once dominated by vast forests, Uganda now has less than one-twentieth of its original forest cover. According to the World Resources Institute, its tropical forests are being logged and converted to agricultural land at a rate that outpaces sub-Saharan Africa as a whole. Small tracts remain, however, hemmed in by pastures and croplands. Many of the species that thrived in the original forests are struggling to survive in these parcels, which can be as small as one hectare in size.
“In Uganda, just looking at the primates, it’s one of the most biodiverse places on the earth,” said professor of pathobiology Thomas Gillespie, principal investigator on the study. “You’ve got 12 to 13 species of primates in a core undisturbed forest. But if you go into these forest fragments, you’ll find only three or four species of primates.”
Populations of black-and-white colobus monkeys appear to be stable in the Ugandan forest remnants, while their cousins, the red colobus monkeys, are in decline.
Gillespie and his colleague, Colin Chapman, of McGill University in Montreal, surveyed 20 forest fragments near the western boundary of Kibale National Park, in western Uganda.
They compared the abundance, variety and density of potentially harmful parasites in these fragments to the undisturbed “core forest” of the park.
The researchers followed the monkeys for four years, collecting data on how far the animals ranged, what they ate and which parasites were infecting them.
In those four years, red colobus populations in forest fragments declined 20 percent, whereas populations of black-and-white colobus monkeys remained relatively stable. Both species maintained stable populations in the undisturbed forest.
Scientists have struggled to explain why closely related animals, like these two species of monkeys, can fare so differently in forest fragments. The answer, Gillespie said, lies in a complex interplay of factors, with parasites and nutrition playing key roles.
The researchers focused on two nematodes known to cause significant pathology in monkeys: a whipworm, (Trichuris sp.), and a nodule worm (Oesophagostomum sp.). While feeding on leaves, the monkeys ingest the larval forms of these worms. The larvae mature in the intestines, where they can cause blockages or other damage. The nematodes migrate through blood vessels, causing inflammation, organ damage and, sometimes, death.
The researchers found a higher density of parasites in the forest fragments than in the undisturbed forest. They also found new parasites not seen in the undisturbed forest.
“Several of the parasites in these animals in the fragments never occur in undisturbed forest, and some of these novel parasites are definitely from livestock or people,” Gillespie said. The red colobus monkeys were infected with five of these human or livestock parasites; the black and white colobus carried only two.
Other differences between the two species affect their vulnerability to parasitic infection. Red colobus monkeys congregate and live in large groups, with up to 50 members, compared with about 10 members in the black-and-white groups. Red colobus monkeys eat a much more varied diet. This causes them to travel farther, searching for the foods they need. But many of the plants that make up their diet simply aren’t available in disturbed forest fragments.
“The red colobus typically eat 40 to 50 species of plants, but in these forest fragments we might only have 12 tree species, so there’s a dramatic reduction in what we typically would see them feed on,” Gillespie said.
“The black-and-white colobus tend to feed on whatever’s dominant. They make do with what’s there.”
The black-and-white colobus monkeys’ ability to eat well under a variety of circumstances enhances their ability to withstand parasitic infections, Gillespie said.
Red colobus monkeys’ travels bring them into contact with more parasites. Their compromised nutritional status also weakens them, giving parasites the edge, Gillespie said.
“We asked how parasitism plays into this dynamic of some species doing well and others not doing well after forest fragmentation,” Gillespie said. “This is giving us a new window into what’s happening.”
Biodiversity takes a hit
October 28, 2007
Wildfires last week have engulfed nearly 360,000 acres of the county, burning the life out of plants and animals that help make the region a jewel of biological diversity.
Massive blazes also render the land less hospitable for humans by increasing the likelihood of future wildfires, debris flows, erosion and water pollution.
“These fires are a staggering tragedy for both people and nature,” said David Hogan of San Diego, a conservation manager for the Center for Biological Diversity, a national environmental group.
“This may be the last straw for endangered species that have already suffered so much habitat loss to development and overly frequent fire.”
Native chaparral and coastal sage scrub in the overlapping burn zones may not recover in time to prevent the spread of fast-growing, non-native grasses. The areas were home to most of San Diego County's more than 40 species listed as threatened or endangered by the federal government.
In addition, grasslands are more vulnerable to wildfires than healthy coastal sage scrub and chaparral. A carelessly tossed cigarette is more likely to ignite the exotic invading grasses than it would the native chaparral.
“The backcountry is converting to a simpler, more weedy, less beautiful landscape than the California most of us moved into,” said Wayne Spencer of the Conservation Biology Institute in Encinitas.
A similar pattern has played out across the West, with virtually every state in the region having to battle the problem.
In areas such as eastern Oregon and the Rockies, native plants repeatedly burned by wildfires cannot regain a foothold because cheat grass and other invaders quickly move in and dominate the terrain.
“It's widespread and it does seem to be increasing,” said Christopher Dionigi, assistant director of the National Invasive Species Council in Washington, D.C.
Russian thistle Even before the latest inferno began Sunday, drought had taken a toll on many of San Diego County's native plants. The dry conditions killed scores of oak trees and allowed bark beetles to finish off weakened pines.
Contrary to popular thought, Southern California is not a desert. Shrubland, a mix of sage scrub and chaparral, is the native landscape for much of the region between the Pacific shoreline and the foothills of coastal mountains.
For instance, nearly 90 percent of the Cleveland National Forest is shrubland rather than coniferous forest.
California has about 8.6 million acres of chaparral, but that figure is declining rapidly. From 1946 to 1987, 1.5 million acres were lost because of urban expansion, ranching and wildfires.
Likewise, development and agriculture have reduced coastal sage scrub to less than 15 percent of its expanse when California became a state.
Coastal sage and chaparral have adapted to withstand periodic fires of 20 to 60 years apart. In fact, the seeds of several native plants need fire and smoke to prepare them to germinate.
“Chaparral requires roughly 20 years or more to recover from a fire to be able to withstand a repeat fire,” said Jon Keeley, a fire ecologist with the U.S. Geological Survey near Fresno.
“The native vegetation typically doesn't recover once it has been taken over by alien grasses.”
Researchers studying the aftermath of the 2003 Cedar fire said pines and other trees in Rancho Cuyamaca State Park are not returning as quickly as originally anticipated.
Several environmentally important parts of the county have been scarred by the latest fires, but ecologists haven't been able to go into those areas to assess the extent of the damage.
Properties that appear to have sustained damage include sections of Palomar Mountain and the Ramona grasslands, Santa Ysabel Open Space Preserve and Volcan Mountain Preserve.
Last week, officials at the South County wildlife refuge were assessing fire damage and planning to keep invasive grasses from taking over on roughly 4,000 burned acres. Their efforts will include replanting native species and using herbicides to knock out unwanted plants.
Advertisement However, ecologists said, limited resources will make it impossible to apply similar measures to most of the county's charred zones.
About 60,000 acres burned in areas set aside for dozens of species under the Multiple Species Conservation Program, said Thomas Oberbauer, who oversees the county's portion of the program. The plan was created in the late 1990s to preserve open spaces while making room for development.
Scott Morrison, an ecologist with The Nature Conservancy in San Diego, said many of the organization's properties in San Diego County have been ravaged in recent days.
“What these fires remind us is that ... we need to make sure that our natural conservation lands are larger than the largest catastrophic fire we face ... so that some places remain unburned and provide a refuge for species,” Morrison said.
Wildfires last week have engulfed nearly 360,000 acres of the county, burning the life out of plants and animals that help make the region a jewel of biological diversity.
Massive blazes also render the land less hospitable for humans by increasing the likelihood of future wildfires, debris flows, erosion and water pollution.
“These fires are a staggering tragedy for both people and nature,” said David Hogan of San Diego, a conservation manager for the Center for Biological Diversity, a national environmental group.
“This may be the last straw for endangered species that have already suffered so much habitat loss to development and overly frequent fire.”
Native chaparral and coastal sage scrub in the overlapping burn zones may not recover in time to prevent the spread of fast-growing, non-native grasses. The areas were home to most of San Diego County's more than 40 species listed as threatened or endangered by the federal government.
In addition, grasslands are more vulnerable to wildfires than healthy coastal sage scrub and chaparral. A carelessly tossed cigarette is more likely to ignite the exotic invading grasses than it would the native chaparral.
“The backcountry is converting to a simpler, more weedy, less beautiful landscape than the California most of us moved into,” said Wayne Spencer of the Conservation Biology Institute in Encinitas.
A similar pattern has played out across the West, with virtually every state in the region having to battle the problem.
In areas such as eastern Oregon and the Rockies, native plants repeatedly burned by wildfires cannot regain a foothold because cheat grass and other invaders quickly move in and dominate the terrain.
“It's widespread and it does seem to be increasing,” said Christopher Dionigi, assistant director of the National Invasive Species Council in Washington, D.C.
Russian thistle Even before the latest inferno began Sunday, drought had taken a toll on many of San Diego County's native plants. The dry conditions killed scores of oak trees and allowed bark beetles to finish off weakened pines.
Contrary to popular thought, Southern California is not a desert. Shrubland, a mix of sage scrub and chaparral, is the native landscape for much of the region between the Pacific shoreline and the foothills of coastal mountains.
For instance, nearly 90 percent of the Cleveland National Forest is shrubland rather than coniferous forest.
California has about 8.6 million acres of chaparral, but that figure is declining rapidly. From 1946 to 1987, 1.5 million acres were lost because of urban expansion, ranching and wildfires.
Likewise, development and agriculture have reduced coastal sage scrub to less than 15 percent of its expanse when California became a state.
Coastal sage and chaparral have adapted to withstand periodic fires of 20 to 60 years apart. In fact, the seeds of several native plants need fire and smoke to prepare them to germinate.
“Chaparral requires roughly 20 years or more to recover from a fire to be able to withstand a repeat fire,” said Jon Keeley, a fire ecologist with the U.S. Geological Survey near Fresno.
“The native vegetation typically doesn't recover once it has been taken over by alien grasses.”
Researchers studying the aftermath of the 2003 Cedar fire said pines and other trees in Rancho Cuyamaca State Park are not returning as quickly as originally anticipated.
Several environmentally important parts of the county have been scarred by the latest fires, but ecologists haven't been able to go into those areas to assess the extent of the damage.
Properties that appear to have sustained damage include sections of Palomar Mountain and the Ramona grasslands, Santa Ysabel Open Space Preserve and Volcan Mountain Preserve.
Last week, officials at the South County wildlife refuge were assessing fire damage and planning to keep invasive grasses from taking over on roughly 4,000 burned acres. Their efforts will include replanting native species and using herbicides to knock out unwanted plants.
Advertisement However, ecologists said, limited resources will make it impossible to apply similar measures to most of the county's charred zones.
About 60,000 acres burned in areas set aside for dozens of species under the Multiple Species Conservation Program, said Thomas Oberbauer, who oversees the county's portion of the program. The plan was created in the late 1990s to preserve open spaces while making room for development.
Scott Morrison, an ecologist with The Nature Conservancy in San Diego, said many of the organization's properties in San Diego County have been ravaged in recent days.
“What these fires remind us is that ... we need to make sure that our natural conservation lands are larger than the largest catastrophic fire we face ... so that some places remain unburned and provide a refuge for species,” Morrison said.
Marine Bioblitz uncovers biodiversity bonanza
Monday, 29 October 2007
Wellington’s Marine Bioblitz has uncovered a biodiversity bonanza, identifying 551 species – including at least four new species during the month-long search.
Marine Bioblitz Co-ordinator Heather Anderson says the Marine Bioblitz – the world’s first – was a tremendous success in revealing the incredible diversity and richness of plant and animal life in Wellington’s marine environment.
“We knew that Wellington was rich in an abundance of marine life, but the variety and number of species found has been really exciting, and demonstrates how little we know about the underwater life that exists right on our doorstep.”
The Bioblitz, conducted in the area off Wellington’s south coast to be announced as the Kupe-Kevin Marine Reserve in January, found four new species:• A many-tentacled tube anemone found by NIWA scientist Malcolm Francis • A tiny red and green nudibranch (sea slug) found by Forest & Bird marine advocate Kirstie Knowles • A bryozoan (a tiny animal that builds a stony skeleton, also known as moss animals or sea mats) found by Kirstie Knowles and NIWA’s Adam Smith• A diatom (a single-celled phytoplankton) found by Margaret Harper of Victoria University.
Dive teams from Island Bay Divers and Dive HQ also found six more potential new species, including a minute “red blob” – the origin of which is so puzzling that the experts are completely baffled about what phylum it might belong to.
These discoveries will now be analysed in more detail by experts to determine whether they are indeed new species previously unknown to science
Another highlight of the Bioblitz was the appearance of two species of whale – an orca and a southern right whale.
Heather Anderson says the Bioblitz brought together scientists, conservationists, divers and the Wellington public and raised public awareness of Wellington’s unique marine biodiversity.
“The Kupe-Kevin Smith Marine Reserve will be New Zealand’s first marine reserve located so close to a major urban centre, and will be the first marine reserve in Cook Strait, which has a diversity of unique marine plants and animals. The marine reserve will play an important role in protecting this rich underwater world.”
Wellington’s Marine Bioblitz has uncovered a biodiversity bonanza, identifying 551 species – including at least four new species during the month-long search.
Marine Bioblitz Co-ordinator Heather Anderson says the Marine Bioblitz – the world’s first – was a tremendous success in revealing the incredible diversity and richness of plant and animal life in Wellington’s marine environment.
“We knew that Wellington was rich in an abundance of marine life, but the variety and number of species found has been really exciting, and demonstrates how little we know about the underwater life that exists right on our doorstep.”
The Bioblitz, conducted in the area off Wellington’s south coast to be announced as the Kupe-Kevin Marine Reserve in January, found four new species:• A many-tentacled tube anemone found by NIWA scientist Malcolm Francis • A tiny red and green nudibranch (sea slug) found by Forest & Bird marine advocate Kirstie Knowles • A bryozoan (a tiny animal that builds a stony skeleton, also known as moss animals or sea mats) found by Kirstie Knowles and NIWA’s Adam Smith• A diatom (a single-celled phytoplankton) found by Margaret Harper of Victoria University.
Dive teams from Island Bay Divers and Dive HQ also found six more potential new species, including a minute “red blob” – the origin of which is so puzzling that the experts are completely baffled about what phylum it might belong to.
These discoveries will now be analysed in more detail by experts to determine whether they are indeed new species previously unknown to science
Another highlight of the Bioblitz was the appearance of two species of whale – an orca and a southern right whale.
Heather Anderson says the Bioblitz brought together scientists, conservationists, divers and the Wellington public and raised public awareness of Wellington’s unique marine biodiversity.
“The Kupe-Kevin Smith Marine Reserve will be New Zealand’s first marine reserve located so close to a major urban centre, and will be the first marine reserve in Cook Strait, which has a diversity of unique marine plants and animals. The marine reserve will play an important role in protecting this rich underwater world.”
Estimating the value of biodiversity
One ground-breaking aspect of the Global Environment Outlook 2007 issued last week is the attempt to estimate the monetary value of biodiversity.
For instance, the value of coral reefs for fisheries and tourism is estimated at US$30 billion per year, and the value of the herbal medicine market at roughly US$43 billion in 2001 figures.
Although such estimates are often attempted at local levels, expanding the effort to a global level significantly inflates the figure, thus enhancing the shock value of the potential damage and giving it a greater sense of priority.
The authors of the Global Environment Outlook are clearly hoping to build on the success in calculating the economic value of travel and tourism as a job creator and foreign exchange earner, which has helped policy-makers create the conditions for generating phenomenal tourism growth in the last few decades.
They believe the same can be done by estimating the value of biodiversity and its value to tourism.
The report says: "Identifying economic values of ecosystem services, together with the notions of intrinsic value and other factors, will assist significantly in future decisions relating to trade-offs in ecosystem management."
Citing one example, the report says that the global net value of coral reefs relating to fisheries, coastal protection, tourism and biodiversity is estimated at US$29.8 billion oer year. It highlights the Caribbean, a popular tourist region, where human activities reportedly threaten nearly two-thirds of coral reefs.
The report also notes that countries are attempting new ways of raising revenues for environmental protection.
For example, it says, the Protected Areas Conservation Trust in Belize receives most of its revenue from an airport tax of about US$3.75, paid by all visitors upon departure, together with a 20% commission on cruise ship passenger fees. The British overseas island territory of Turks and Caicos designates 1% of a 9% hotel tax to support the maintenance and protection of the country's protected areas.
These so-called "green taxes", although opposed by industry interest groups, are putting pressure on the world's major polluters and environment destroyers, the report says.
At the same time, it says, Environmental degradation due to development raises deep ethical questions that go beyond economic cost-benefit ratios.
"The question of justice is perhaps the greatest moral question emerging in relation to environmental change and sustainable development. Growing evidence indicates that the burden of environmental change is falling far from the greatest consumers of environmental resources, who experience the benefits of development," the report says.
"Often, people living in poverty in the developing world, suffer the negative effects of environmental degradation. Furthermore, costs of environmental degradation will be experienced by humankind in future generations. Profound ethical questions are raised when benefits are extracted from the environment by those who do not bear the burden."
Both tourism and its first-cousin, the air transport industry, produce many economic benefits but are criticised for not doing enough on the ecological front.
Tourism is an economic mainstay in many parts of the world, especially island nations such as the Seychelles, as well as the Mediterranean coastal areas.
At the same time, it cites the urban sprawl of Las Vegas, the fastest-growing metropolitan area in the United States _ a reference that may soon be applicable to Singapore and Macau as they seek to develop their gaming industries on the Las Vegas model.
"As the (Las Vegas) gaming and tourism industry blossomed, so has the city's population," the report says.
"Population growth has put a strain on water supplies," it adds. "Satellite imagery of Las Vegas provides a dramatic illustration of the spatial patterns and rates of change resulting from the city's urban sprawl."
Another example is the state of Quintana Roo in Mexico, which is experiencing a significant growth in tourism infrastructure all along the Caribbean coast.
The conversion of mangrove forest into beachfront tourist resorts along the Mayan Riviera, south of Cancu{aac}n, has left the coastlines vulnerable. Playa del Carmen, at 14%, has the fastest growth in tourism infrastructure in Mexico. Threats to the aquifers come from increasing water use, of which 99% is withdrawn from groundwater and wastewater disposal, the report says.
For instance, the value of coral reefs for fisheries and tourism is estimated at US$30 billion per year, and the value of the herbal medicine market at roughly US$43 billion in 2001 figures.
Although such estimates are often attempted at local levels, expanding the effort to a global level significantly inflates the figure, thus enhancing the shock value of the potential damage and giving it a greater sense of priority.
The authors of the Global Environment Outlook are clearly hoping to build on the success in calculating the economic value of travel and tourism as a job creator and foreign exchange earner, which has helped policy-makers create the conditions for generating phenomenal tourism growth in the last few decades.
They believe the same can be done by estimating the value of biodiversity and its value to tourism.
The report says: "Identifying economic values of ecosystem services, together with the notions of intrinsic value and other factors, will assist significantly in future decisions relating to trade-offs in ecosystem management."
Citing one example, the report says that the global net value of coral reefs relating to fisheries, coastal protection, tourism and biodiversity is estimated at US$29.8 billion oer year. It highlights the Caribbean, a popular tourist region, where human activities reportedly threaten nearly two-thirds of coral reefs.
The report also notes that countries are attempting new ways of raising revenues for environmental protection.
For example, it says, the Protected Areas Conservation Trust in Belize receives most of its revenue from an airport tax of about US$3.75, paid by all visitors upon departure, together with a 20% commission on cruise ship passenger fees. The British overseas island territory of Turks and Caicos designates 1% of a 9% hotel tax to support the maintenance and protection of the country's protected areas.
These so-called "green taxes", although opposed by industry interest groups, are putting pressure on the world's major polluters and environment destroyers, the report says.
At the same time, it says, Environmental degradation due to development raises deep ethical questions that go beyond economic cost-benefit ratios.
"The question of justice is perhaps the greatest moral question emerging in relation to environmental change and sustainable development. Growing evidence indicates that the burden of environmental change is falling far from the greatest consumers of environmental resources, who experience the benefits of development," the report says.
"Often, people living in poverty in the developing world, suffer the negative effects of environmental degradation. Furthermore, costs of environmental degradation will be experienced by humankind in future generations. Profound ethical questions are raised when benefits are extracted from the environment by those who do not bear the burden."
Both tourism and its first-cousin, the air transport industry, produce many economic benefits but are criticised for not doing enough on the ecological front.
Tourism is an economic mainstay in many parts of the world, especially island nations such as the Seychelles, as well as the Mediterranean coastal areas.
At the same time, it cites the urban sprawl of Las Vegas, the fastest-growing metropolitan area in the United States _ a reference that may soon be applicable to Singapore and Macau as they seek to develop their gaming industries on the Las Vegas model.
"As the (Las Vegas) gaming and tourism industry blossomed, so has the city's population," the report says.
"Population growth has put a strain on water supplies," it adds. "Satellite imagery of Las Vegas provides a dramatic illustration of the spatial patterns and rates of change resulting from the city's urban sprawl."
Another example is the state of Quintana Roo in Mexico, which is experiencing a significant growth in tourism infrastructure all along the Caribbean coast.
The conversion of mangrove forest into beachfront tourist resorts along the Mayan Riviera, south of Cancu{aac}n, has left the coastlines vulnerable. Playa del Carmen, at 14%, has the fastest growth in tourism infrastructure in Mexico. Threats to the aquifers come from increasing water use, of which 99% is withdrawn from groundwater and wastewater disposal, the report says.
Sunday, September 30, 2007
China Starts Countdown To Save Biodiversity By 2010
September 27, 2007 , from The World Conservation Union .
As the rate of biodiversity loss accelerates worldwide, civil society organizations and governments are joining forces to fight the global extinction crisis. On September 7 in Beijing, twenty Chinese and international organizations signed the Countdown 2010 declaration, committing themselves to additional efforts to reduce biodiversity loss by the year 2010.
As the rate of biodiversity loss accelerates worldwide, civil society organizations and governments are joining forces to fight the global extinction crisis. On September 7 in Beijing, twenty Chinese and international organizations signed the Countdown 2010 declaration, committing themselves to additional efforts to reduce biodiversity loss by the year 2010.
According to the 2007 IUCN Red List of Threatened Species, China has a "particularly large number" of species in danger of extinction. China is also one of the world’s biologically richest countries. At the Countdown 2010 Launch, organizations ranging from local Chinese NGOs to international organizations active in China to government-affiliated institutions joined together to declare their commitment to saving biodiversity in China. With this decision, they honor the global 2010 biodiversity target, a commitment made by state representatives at the World Summit on Sustainable Development in 2002 to significantly reduce biodiversity loss by 2010.
Countdown 2010 is a network of active partners working together towards the 2010 biodiversity target. Each partner commits to additional efforts to tackle the causes of biodiversity loss. The secretariat – hosted by the World Conservation Union (IUCN) – facilitates and encourages action, promotes the importance of the 2010 biodiversity target and assesses progress towards 2010. Countdown 2010 now has hubs in Europe, Asia, Africa and South America, and the establishment of a Countdown 2010 hub in China has been spearheaded by the IUCN China Program.
"We're excited to be bringing Countdown 2010 to China, one of the world's greatest storehouses of biodiversity," said Wiebke Herding, of the Countdown 2010 secretariat. "Countdown 2010 is starting with an impressive array of organizations here. I'm sure that by 2010 we'll see the positive impact of this network on China's biodiversity."
Prior to the Launch, a consultation was held with key partners to discuss how best to promote the 2010 biodiversity target in China. IUCN Chief Scientist Jeffrey A. McNeely led discussion on monitoring progress towards the 2010 biodiversity target, while others discussed communications challenges, civil society capacity needs, and the necessity of effective information exchange, offering concrete suggestions for potential actions to be taken by Countdown 2010 and partners.
Wednesday, September 26, 2007
UN names Noosa a "biodiversity museum"
NOOSA Shire has been named a "biodiversity museum" by the United Nations – the first such recognition of any site in Queensland.
The nomination recognises an environmentally sound balance between people and environmental protection.
It was also seized on by anti-amalgamation campaigners as further proof the shire should not be merged with its southern neighbours.
The nomination said the shire was "critical to maintaining overall biodiversity representation and quality in southeast Queensland".
"In order to conserve and use in a sustainable way the rich natural and cultural resources of the site, Noosa communities endeavour to manage urban growth in a sustainable manner and develop sustainable tourism strategies in the buffer and transition zones."
The anti-amalgamation group Friends of Noosa will now start a letter-writing campaign to Premier Anna Bligh, asking what she is doing to save the region.
The nomination recognises an environmentally sound balance between people and environmental protection.
It was also seized on by anti-amalgamation campaigners as further proof the shire should not be merged with its southern neighbours.
The nomination said the shire was "critical to maintaining overall biodiversity representation and quality in southeast Queensland".
"In order to conserve and use in a sustainable way the rich natural and cultural resources of the site, Noosa communities endeavour to manage urban growth in a sustainable manner and develop sustainable tourism strategies in the buffer and transition zones."
The anti-amalgamation group Friends of Noosa will now start a letter-writing campaign to Premier Anna Bligh, asking what she is doing to save the region.
DNA barcodes 'tackle disease, protect biodiversity'
21 September 2007
A mosquito of the culex genus, which transmits West Nile virus
DNA 'barcoding' offers rapid and low cost ways to monitor human disease vectors and biodiversity in developing countries, scientists told a conference this week.
The comments came during the Second International Barcode of Life Conference in Taipei, Taiwan (18–20 September).
The technique identifies known species and records new ones by sequencing a specific, short area of mitochondrial DNA, previously identified and agreed by scientists.
This "barcode region" of mitochondrial DNA mutates at a rate fast enough to create differences between species, but slow enough to leave members of the same species with nearly identical barcodes. Species that divided recently or are still interbreeding can be difficult to separate using this method.
Comparing the sequence to all others in a database produces a picture of how similar the specimens are. The process takes a few hours and costs as little as US$2.
Yvonne-Marie Linton of the UK's Natural History Museum, and leader of the Mosquito Barcoding Initiative, told SciDev.Net that barcoding should help control mosquitoes carrying diseases like malaria, West Nile disease and dengue fever.
"Often only one or two mosquito species are capable of transmitting disease," she says.
"It is important to know exactly which these are and then we can tie this information in with the ecology of these species, work out where they breed and use larvicidal techniques to control the mosquitoes, not 'blanketly' spray all of them."
And Eldredge Bermingham, acting director of the Smithsonian Tropical Research Institute in Panama, says DNA barcoding helps to identify and protect tropical biodiversity. The Institute has collected many samples that are as yet unclassified and DNA barcoding lets non-experts help classify these cheaply.
"Barcoding efforts based in labs in Mexico, Brazil, Argentina and Panama are discovering new species, and providing geo-referenced data for informed conservation decisions," Bermingham told SciDev.Net.
But David Schindel, executive secretary of the Consortium for the Barcode of Life, based in Washington DC, United States, explains that barcoding's low cost reflects only the sequencing.
Building a reference library of barcode sequences is more expensive.
"Borrowing a book from a public library is free, but someone had to pay for writing and printing and buying the books in the library," he points out.
Wednesday, September 19, 2007
Impact of Human Activities and Loss of Biodiversity in Freshwater Ecosystems in China
Freshwater resources are fundamental
Water and atmosphere are the most fundamental materials of the world for the existence of humans and all other organisms. Water covers 2/3 of the earth's surface and is the most abundant structural component of organisms. Life is essentially based on the continuous exchange of water between an organism and its environment. Freshwater constitutes only 3% of the total water of the world; of which 77.2% is stored as ice, 22.4% as underground and soil water, and about 0.4% is in lakes, rivers and other water bodies (i.e., pond, bogs, etc.) (IIED, 1987). Although freshwater is much less abundant than salt water, it is the essential material for terrestrial organisms and fundamental to the civilization of humans. It also serves as the bridge between terrestrial and marine ecosystems. In recent years, at least 43 countries have experienced water shortage, and one hundred million people are confronted with worse drinking water. At present, water shortage has become one of the most serious global environmental problems which threatens human society.
China is poor in water supply, with the average annual supply for each person around 2,600 tons, which is only 1/4 of the world's average (IIED, 1987). The quantity of freshwater resources is also declining, while the demand for it is increasing; moreover, about half of the lakes have already been polluted to some extent by the increasing industrialization, human and agricultural wastes. Because increasing freshwater shortage is becoming an important limiting factor for the economic growth and development of China, it is important for our existence to protect freshwater resources.
Freshwater fishes are important food resources
Fish make up the most abundant group of vertebrates, and there are in excess of 22,000 described species. Global fish production exceeds that of cattle, sheep, poultry or eggs, and is the largest source of either wild or domestic animal protein for the world's expanding human population (Norse, 1992). Of total world fish landings in 1989, marine landings comprised 86.2% while inland fisheries (aquaculture and capture fisheries) accounted for the remaining 13.8% (FAO, 1991). In 1990, total fish landings in China was 1,236 tons, while inland fisheries accounted for as high as 42%. Therefore, freshwater fishes comprised one of the fundamental elements for the existence of Chinese people. There are around 8,400 described species of freshwater fishes in the world, which comprise approximately 40% of total fish species. Around 1,500 species of freshwater fish have been described in Asia (Nelson, 1984). In China, there are in excess of 800 primary freshwater fishes (those confined to freshwater), among which about 500 species are endemic.
It is estimated that there is around 100,000km3 of water for each marine species but only 15km3 for each freshwater species; and that the population level of a marine species may be around 109. but ranges down to around 106 for freshwater species (Groombridge, 1992). Compared with marine ecosystems, freshwater ecosystems are usually smaller, more isolated from each other, and the distributions of freshwater fish species are more limited. Freshwater ecosystems are also less stable, and much more susceptible to environmental disturbance. For example, more than one decade ago in Lake Luguhu (located in the intersectional area between Sichuan and Yunnan provinces), local people had tried to introduce grass carp. However, by mistake they introduced Pseudorasbora parva, which not only have little commercial value but also made three species of Schizothoracine fishes endangered to near extinction (Liang, pers. comm.).
It is estimated that at least 20% (ca. 1,800 species) of the world's freshwater fish species are seriously threatened or extinct, which is mainly caused by habitat modification (competition for water, drainage, pollution), introduced species and commercial exploitation (Groombridge, 1992). In North America, nearly 1/3 of the total fish species are endangered, threatened or listed as species of special concern (Williams et al., 1989). In China, there are 92 vulnerable of endangered species of freshwater fishes which account for 10% of the total number of freshwater fish; Cyprinus yilongensis, an endemic species in Yunnan Province, has become extinct, and Psephurs gladius, Macrura reevesi and Hucho bleekeri are in danger of extinction (Le, 1995a,b).
Lake ecosystems in the middle and lower basins of the Yangtze River
The total surface area of all Chinese lakes is around 74,300km2, of which 42% is in humid eastern China. The Yangtze River, located in the eastern plain, is the longest river in China and the third longest river in the world. It has a total length of more than 6,300km. The middle and lower basins of the Yangtze are one of the major distribution areas of freshwater lakes in China, and the surface area of lakes constitutes around 1/8 of the total surface area of this region.
The Yangtze basin is the most important commercial fishing base in China with a fish yield comprising around 2/3 of the total (Liu and He, 1992). In addition, waters of the Yangtze basins are not only essential for water supplies (drinking water, irrigation, etc.) but also for many other purposes such as recreation, and are therefore, very important for the economic development.
The middle and lower basins of the Yangtze River are influenced by the wet monsoon, and the lakes of the basin were formed by flood of the river in the Late Tertiary. These lakes are shallow (without thermal stratification), and interlaced with the main river and its branches into a unique complex river-lakes ecosystem. These shallow lakes usually have a high productivity, abundant vegetation cover, and a developed littoral zone communities. Because of the differences between the river and the lakes, and the flooding caused by the wet monsoon there are obvious changes in water level. In this environment have evolved unique migrating fish, for example: Hypophthalmichthys molitrix, Aristichys nobilis, Ctenopharyngodon idellus, Mylopharyngodon piceus, Ochetobius elongatus, Luciobrama macrocephalus, Squaliobarbus curriculus, and Parabramis pekinensis. Among these are some of major commercial importance in China and the world (The Fourth Laboratory of the Institute and the Tunghu Fish Farm, 1976). In the Yangtze basin, there are about 300 fish species, of which more than half belong to the Cyprinidae, the most commercially important fishes are also cyprinids (Liu and He, 1992). The Yangtze basins are considered to be the center of origin and evolution of many freshwater fishes in East Asia, preserving some remnant fish species (Cao and Chen, pers. comm.). Natural lakes of the Yangtze basins, superior in water quality and abundant in species diversity, provide essential freshwater resources for our existence.
Biodiversity problems of lake ecosystems
For several decades, inappropriate construction of dikes, dams and levees, unreasonable fishing and fishery management, and the extremely strong pressure of the rapidly increasing human population on lake ecosystems, have brought severe damage to the biodiversity from genetic to ecosystem levels. This has resulted in the destruction of many natural resources of the lakes and have posed a threat to the stability of our society and the sustainable development of the economy.
1. Shrinking and fragmentation of lake ecosystems
Fragmentation of lakes by continuous subsidence of mud from river water and by extensive reclamation of farmland from the lakes is a serious problem in China. Not only are the lakes in the western part of China shrinking, but those in the eastern part are also contracting. In the western regions, drought has fragmented many lakes into smaller lakes (Shi, 1989). While in the eastern regions, shrinking of lakes is mainly caused by subsidence of mud from river water, and by reclamation of farmland from lakes. In the eastern part of China, the superior natural conditions for agriculture has been accompanied with a rapid increase in human population, and consequently a rapid decline in land area per capita, so conversion of lakes for farmland has become an historical by-product. For example, the total surface area of Lake Dongtin was 4,350km2 in 1949, but declined to 2,619km2 in 1983, due to continuous subsidence of river water and extensive reclamation of farmland from the lake. The total surface area of Lake Honghu was about 760km2 in the early 1950's, but subsequent portioning and reclamation work in the 1960's and 1970's around the lake caused the continual shrinkage of the surface area of the lake to 350km2 of 1979. The Gianghan Plain contained 1,066 various sized lakes (surface area of 8,300km2 ), however, by the early 1980's, only 309 lakes (surface area of 5,600km2) were left due to similar reasons (Shi, et al., 1985).
Welcomme (1979) reported that the number of fish species present in subtropical and tropical rivers was highly correlated with the area of the river basin. Temperate rivers showed a similar pattern, although the number of species rises more steeply with increasing basin area in tropical systems than in higher latitudes. Two factors are important here: (1) the area of a lake sets an upper limit to the maximum population size of each fish species and (2) small populations are inherently more prone to extinction than large ones. From this alone it can be predicted that shrinking of lake ecosystems will contract the living spaces of many freshwater species, and therefore make more and more fish species endangered or extinct.
2. Destruction of lake-river ecosystem by severance of lakes from the Yangtze River
Severance of lakes from the river by construction of sluices and dikes have led to the impoverishment of the natural fish resource--especially of migratory fishes--causing the lakes to be dominated by species of small size. The Yangtze basin was originally a network of water systems, including all of the large and small tributaries of the river, and many interconnected shallow lakes. This complex river-lakes system provided superior living conditions for many commercially important migratory fish species (including four domestic carp) which can spawn only in the river and regularly migrate into lakes for feeding (Fish Laboratory, 1976). Over the past decades, most lakes have been artificially severed from the river by hydroelectric and irrigation projects, and as a result, the migratory fish can no longer enter into these lakes from the river. This has lead to a sharp decline of their population size in both the lakes and the river.
In the middle and lower region of the Yangtze River, there averages around a hundred fish species in natural lakes, but only 30-40 species in severed lakes. For instance, according to a survey of fish species made in the 1990's in Honghu Lake, there were no less than 90 species in the lake. In 1958, a sluice was constructed in the canal linking the lake with the river, thus severing the intercommunication between the river and the lake. The survey in 1964 listed 74 species, in 1981-1982, 54 species, of which only 33 species were obtained from the lake, while the remaining 21 species were riverine fishes carried into the lake during the channeling of the Changjiang River water for the purpose of irrigation.
There is also a shortage of large-sized economic fish species which are mostly migratory between the lake and the river (Honghu Research Group, 1991). Fishery resources of the three domestic carp (siluer, bighead and grass carp) in the Yangtze River are also decreasing: the catch of marketable-sized fishes in the 1980's was just half as much as that in the 1950's, whereas the catch of natural fries was only one quarter as much as that in the 1960's. Changes in composition of the catch also occurred: proportion of migratory fishes declined, whereas that of small-sized lake-dwelling species increased (Li, et al., 1990).
Fingerlings of the four domestic carp used as stocking are now mainly from artificial reproduction, but retrogression due to successive inbreeding has occurred (i.e., both growth and mature age decline, adult fish become smaller, and incidence of diseases become higher). For example, in natural populations of silver carp, the mature age of females is 3-4 years with an average body weight of 4.85kg, and the mature age of males is 3 years with a average body weight of 3.81kg. After inbreeding for five generations, the mature age of females declined to 2 years with a body weight of only 1.25kg (the minimum reached as low as 0.3kg) and the mature age of males declined to one year with a body weight of only 0.69kg. Moreover, the inbreeding offsprings had a higher malformation rate, a weaker constitution, and an eleven times higher incidence of diseases. Therefore, it is harmful to inbreed for many generations, and it is essential to restore the population by natural fingerlings. At present, adult fishes of the Yangtze River are mainly from Lake Boyang and Lake Dongtin which have not yet been severed from the river, and fate of these two lakes remains unclear (Liang, pers. comm). Severance of lakes from the river by hydroelectric and irrigation projects has changed or disrupted dispersal and migration of drastic changes in environments will accelerate distinction of remnant species, and consequently decrease the abundant biodiversity.
3. Decline in biodiversity of fish species by reckless over fishing
Over fishing is commonly occurring in large lakes which are too large to cultivate fish and manage fisheries efficiently. In addition to the severance of lake from the river, reckless over fishing of natural fish populations has resulted in severe decline of species diversity, and decreased drastically the population sizes of commercially important large-sized fish species (mostly migratory fishes). Consequently, a lack of top consumers (carnivores) has usually caused an explosive population increase of small-sized fishes (swamping also favors small sized species), leading to a low fish yield, low fish quality, and low profit (Liang, pers. comm.).
For instance, fish production of Honghu Lake witnessed a steady decline. In the 1950's, the annual fish yield was around 10,000 tons and the dominant species were the four-domestic-carp, Cyprinus carpio and Parabramis pekinensis. However, excessive overfishing and inadequate protection of the spawners caused the diminution both in the size of fish species and in the size of individual fish, the lake being dominated by species of small size as well as by population of stunted growth. In the 1980's, the annual fish yield declined to 3,000-4,000 tons, and 87% were composed of the small-sized Carassium auratus auratus, Pseudobagrus fulvidraco and Culter erythropterus (Honghu Research Goup, 1991).
In Lake Dongtin, the maximum recorded annual fish yield reached as high as 45,000 tons, and the average annual yield was 30,700 tons in the 1950's, but declined to 15,000 tons in the 1980's. The composition of fish yield also changed obviously: the proportion of migrating fishes declined (mainly the four domestic carp), while that of lake-dwelling fishes (Cyprinus carpio, Carassium auratus auratus and Silurus asotus) greatly increased. Of the major economic fishes captured, the proportion of young ages increased and the average individual size of a certain age was also decreased. A large number of young individuals and small-sized species became the targets of fishing (Shan, et al., 1990).
A quite similar phenomenon also occur in some of the lakes of the middle and lower basins of the Yangtze River such as in Lake Caohu, Lake Taihu and Lake Hongzhe, where three small-sized species of Coilia became dominant (Liang, pers. comm.; Shun & Huang, 1993).
4. Seconday Extinction following destruction of climax macrophyte communities
Over-stocking of plant-eating carps has usually caused severe destruction of climax macrophyte communities, and consequently led to a series of extinction of animal species. Like our ancestors who had advanced from collecting wild plants and animals to cultivating crops and domestic animals, artificial breeding, stocking and cultivating fish have developed rapidly. We have succeeded in changing the fish composition for our purposes and cultivating some commercially important fish species. This kind of fishery has applied not only to ponds but also to small/middle-sized lakes (especially urban lakes), and has made it possible to greatly increase fish yield, and to lessen the danger of over-capture on natural populations of some species. However, it has been accompanied with serious problems. In order to get short-term profit over-stocking of fish has led to overgrazing of prey organisms, which has conversely exerted great impact on the whole ecosystem. The most significant events are the destruction of vegetation cover, especially submerged macrophytes, and the dominance of increased r-selected organisms.
In many lakes, the over-stocking of plant-eating carp (especially grass carp) has usually led to destruction of macrophyte communities, and led to the shift of dominant primary producers from macrophytes to phytoplankton. For instance, in the Guozheng area of Lake Donghu, the biomass of macrophytes was as high as 1,779.8g/m2, but declined to 5.8g/m2, which was mainly due to over-stocking of the grass carp. The high destructive power of grass carp on macrophytes is not only due to their low digestion of macrophytes but also because the grass carp suppress the recovery of macrophytes by grazing on new shoots. To macrophytes, algae are r-selected species with a small body and a high turnover rate, and their ability to store nutrients is low. Therefore, in lakes dominated by macrophytes, since a lot of nutrients are stored in macrophytes, the growth of algae is suppressed, and the water is clear. This process is sometimes referred to as the cleanup ability of macrophytes. As the abundance of macrophytes declines, nutrients stored in macrophytes are released into lake water by grazing and excretion of the grass carp. This favors the growth of phytoplankton. Moreover, increased phytoplankton biomass decreases both water transparency and compensative depth of macrophytes, which in return decreases living extent of the macrophytes. Such a vicious circle usually leads to less and less macrophytes of even their extinction. Now, in the Guozheng area of Lake Donghu, the climax macrophyte community in the 1950's has disappeared completely, and consequently, it is followed by secondary succession of the primary producer community in which the dominants are r-selected algae, which is just like the consequences of deforestation for agriculture (Liang, pers. comm.).
Secondary extinction. Macrophyte communities are associated with many periphyton and mollusc, and also serve both as living space and as the substrata for the spawning of many fishes. Therefore, an abundant macrophyte community is accompanied with a high biodiversity of the whole community of plants and animals. The destruction of macrophytes not only leads to the crash of the grass carp populations, but also causes secondary extinction of those organisms depending on these macrophytes and of those fish associated with these directly-related organisms. For example, with the disappearance of macrophytes, many periphytons and molluscs are prone to extinction. This causes the spawning substrata of Cyprinus carpio, Carassium auratus and Ophicephalus argus to also be decreased. The destruction of living environments for molluscs then results in the decline of the available food for Cyprinus carpio and Mylopharyngogon piceus. The dominance of grass carp is then replaced by filter-feeding planktivorous fishes, and so on.
Decline in stability of ecosystems. Disappearance of macrophytes not only causes increase in nutrient concentrations, but also leads to obvious decline in biodiversity of plankton community. In four lake areas (with different nutrient levels) of Lake Donghu, three biodiversity indicies (Margalef, Sympson and Shannon-Weaver) and the number of species of diatoms showed obvious negative relationships with nutrient levels (Lei Anping, Unpubl.). In two sampling stations of Lake Donghu, the Margalef Index of rotifers in 1991 (with high nutrient levels) was only 1/3 that in 1992 (with low nutrient levels). A similar decline in species number was also observed, and eutrophication of the lake decreased the biodiversity of rotifers (Zhuge Yan, Unpubl.). Similar phenomenon might have occurred to other groups of plankton.
However, it remains unknown why eutrophication decreases biodiversity of plankton communities. On the other hand, in hypertrophic waters (probably due to low biodiversity) stability of the systems declines severely, and an outbreak of a few algal species, typically the cyanobacterium water bloom, frequently occurs. In recent years, the frequent outburst of blood poisoning fish disease by bacteria in the lakes of the middle and lower regions of the Yangtze River is probably related to the simplification of the aquatic community (it is also possibly attributed by too high fish stocking density and decreasing water quality). This is very similar to the frequent outburst of insect or disease in the highly-simplified agricultural ecosystems with only one or a few crops.
5. Chemical pollution and accelerated eutrophication in urban lakes
In terrestrial ecosystems, human agricultural activities usually lead to decline in soil nutrients. From southern to northern parts of China, nutrient concentrations in the soil cultivated for 200-500 years, are only half that in the original soil covered with primary vegetation (Heilongjiang Term, 1982). However, during the ontogeny of a lake, organic and inorganic nutrients from the surrounding terrestrial ecosystems accumulates continuously. Trophic status of the lake changes from oligotrophic to eutrophic, and the lake finally appears as land. The process of natural eutrophication is very slow, usually on the time scale of centuries or more. But in recent decades (especially in many urban lakes) the rapid increase in the human population around lakes has resulted in outpouring of untreated industry and organic wastes into the lakes. Also because of unreasonable fishery management, eutrophication in these lakes have been accelerated at an extremely fast rate (i.e., it only needs decades, or even several years to change the lakes from mesotrophic to hypertrophic levels). Lake Donghu in Wuhan City and Lake Xuanwu in Nankin City are good examples of this. The water in lake ecosystems is directly comparable to the soil in terrestrial ecosystems. Soil is important because it supports terrestrial animals and plants. However, water in freshwater ecosystems is important not only because it provides aquatic food but also because it supplies freshwater resources. Severe eutrophication in aquatic ecosystems results in destruction of water supply, and although productivity of the ecosystem may be high, decreasing water quality may be a great threat to human health.
At present, nearly all urban lakes have been seriously eutrophicated. This is not only due to the rapid increase in surrounding human population, but also related with unreasonable fish cultivation. Overstocking of plant-eating carp has resulted in the destruction of submerged macrophytes. This practice is more or less intentional because it is thought that the deforestation by grass carp not only makes people get high fish yield, but also increases the fish yield of the planktivorous silver and bighead carp (as more nitrogen and phosphorous change into plankton biomass). For example, in 1963 in the Guozheng area of Lake Donghu, the biomass of macrophytes was 1779.8 g/m2, and phytoplankton production was only 1 g/m2/day. However, in 1975, the biomass of macrophytes declined to 5.8 g/m2, while phytoplankton production increased to 4.1 g 0.2/m2 (Chen, 1989). During the same period, fish yield of Lake Donghu increased from 93.8 to 276.0kg/ha (Liu, 1984), and proportion of silver and bighead carp was 83% (Section of Fish Ecology, 1976) (now more than 98%). On the other hand, water quality of Lake Donghu became worse and worse: low transparency, outburst of cyanobacterium water bloom, stinking odor of the polluted lake water (Jao & Zhang, 1980). These decreased the lakes multi-functions such as providing drinking water supply and recreation.
Recent studies further indicate that algal blooms (specifically, microcystins) a symptom of lake eutrophication, are harmful to the human liver (Falconer, 1983; Hasser, 1989; Mirura, 1991; Runneger, 1987, 1991). Microcystins not only inhibits the activity of protein phosphates, but also acts as a tumor promoter (Erikson, 1990; Honkanen, 1990; Matsushima, 1990; Nishiwaki-Matsushima, 1991; Yoshizawa, 1990), and is a health threat to humans..
Conclusions
Habitat loss, modification or fragmentation, reckless overfishing, overstocking of plant-eating carp and deterioration of the ecological environment appears to be the most serious current threats to biodiversity in freshwater lakes and species are faced by several of these threats operating simultaneously. Generally, aquatic ecosystems have received little attention in comparison with terrestrial ecosystems, and only a few scattered surveys (mainly on fish) have so far been conducted. Severe decline in species diversity of fish, coupled with inadequate knowledge of freshwater faunas, indicates that biological diversity in aquatic systems require increased conservation attention.
Acknowledgments
We wish to express deep thanks to Prof. Liang Yangling who kindly provided the unpublished manuscript titled: "On the current status and the future of Chinese fisheries from ecological viewpoint." Thanks are also to Mmes Lei Anping and Zhuge Yan for the kind provision of their unpublished data.
Water and atmosphere are the most fundamental materials of the world for the existence of humans and all other organisms. Water covers 2/3 of the earth's surface and is the most abundant structural component of organisms. Life is essentially based on the continuous exchange of water between an organism and its environment. Freshwater constitutes only 3% of the total water of the world; of which 77.2% is stored as ice, 22.4% as underground and soil water, and about 0.4% is in lakes, rivers and other water bodies (i.e., pond, bogs, etc.) (IIED, 1987). Although freshwater is much less abundant than salt water, it is the essential material for terrestrial organisms and fundamental to the civilization of humans. It also serves as the bridge between terrestrial and marine ecosystems. In recent years, at least 43 countries have experienced water shortage, and one hundred million people are confronted with worse drinking water. At present, water shortage has become one of the most serious global environmental problems which threatens human society.
China is poor in water supply, with the average annual supply for each person around 2,600 tons, which is only 1/4 of the world's average (IIED, 1987). The quantity of freshwater resources is also declining, while the demand for it is increasing; moreover, about half of the lakes have already been polluted to some extent by the increasing industrialization, human and agricultural wastes. Because increasing freshwater shortage is becoming an important limiting factor for the economic growth and development of China, it is important for our existence to protect freshwater resources.
Freshwater fishes are important food resources
Fish make up the most abundant group of vertebrates, and there are in excess of 22,000 described species. Global fish production exceeds that of cattle, sheep, poultry or eggs, and is the largest source of either wild or domestic animal protein for the world's expanding human population (Norse, 1992). Of total world fish landings in 1989, marine landings comprised 86.2% while inland fisheries (aquaculture and capture fisheries) accounted for the remaining 13.8% (FAO, 1991). In 1990, total fish landings in China was 1,236 tons, while inland fisheries accounted for as high as 42%. Therefore, freshwater fishes comprised one of the fundamental elements for the existence of Chinese people. There are around 8,400 described species of freshwater fishes in the world, which comprise approximately 40% of total fish species. Around 1,500 species of freshwater fish have been described in Asia (Nelson, 1984). In China, there are in excess of 800 primary freshwater fishes (those confined to freshwater), among which about 500 species are endemic.
It is estimated that there is around 100,000km3 of water for each marine species but only 15km3 for each freshwater species; and that the population level of a marine species may be around 109. but ranges down to around 106 for freshwater species (Groombridge, 1992). Compared with marine ecosystems, freshwater ecosystems are usually smaller, more isolated from each other, and the distributions of freshwater fish species are more limited. Freshwater ecosystems are also less stable, and much more susceptible to environmental disturbance. For example, more than one decade ago in Lake Luguhu (located in the intersectional area between Sichuan and Yunnan provinces), local people had tried to introduce grass carp. However, by mistake they introduced Pseudorasbora parva, which not only have little commercial value but also made three species of Schizothoracine fishes endangered to near extinction (Liang, pers. comm.).
It is estimated that at least 20% (ca. 1,800 species) of the world's freshwater fish species are seriously threatened or extinct, which is mainly caused by habitat modification (competition for water, drainage, pollution), introduced species and commercial exploitation (Groombridge, 1992). In North America, nearly 1/3 of the total fish species are endangered, threatened or listed as species of special concern (Williams et al., 1989). In China, there are 92 vulnerable of endangered species of freshwater fishes which account for 10% of the total number of freshwater fish; Cyprinus yilongensis, an endemic species in Yunnan Province, has become extinct, and Psephurs gladius, Macrura reevesi and Hucho bleekeri are in danger of extinction (Le, 1995a,b).
Lake ecosystems in the middle and lower basins of the Yangtze River
The total surface area of all Chinese lakes is around 74,300km2, of which 42% is in humid eastern China. The Yangtze River, located in the eastern plain, is the longest river in China and the third longest river in the world. It has a total length of more than 6,300km. The middle and lower basins of the Yangtze are one of the major distribution areas of freshwater lakes in China, and the surface area of lakes constitutes around 1/8 of the total surface area of this region.
The Yangtze basin is the most important commercial fishing base in China with a fish yield comprising around 2/3 of the total (Liu and He, 1992). In addition, waters of the Yangtze basins are not only essential for water supplies (drinking water, irrigation, etc.) but also for many other purposes such as recreation, and are therefore, very important for the economic development.
The middle and lower basins of the Yangtze River are influenced by the wet monsoon, and the lakes of the basin were formed by flood of the river in the Late Tertiary. These lakes are shallow (without thermal stratification), and interlaced with the main river and its branches into a unique complex river-lakes ecosystem. These shallow lakes usually have a high productivity, abundant vegetation cover, and a developed littoral zone communities. Because of the differences between the river and the lakes, and the flooding caused by the wet monsoon there are obvious changes in water level. In this environment have evolved unique migrating fish, for example: Hypophthalmichthys molitrix, Aristichys nobilis, Ctenopharyngodon idellus, Mylopharyngodon piceus, Ochetobius elongatus, Luciobrama macrocephalus, Squaliobarbus curriculus, and Parabramis pekinensis. Among these are some of major commercial importance in China and the world (The Fourth Laboratory of the Institute and the Tunghu Fish Farm, 1976). In the Yangtze basin, there are about 300 fish species, of which more than half belong to the Cyprinidae, the most commercially important fishes are also cyprinids (Liu and He, 1992). The Yangtze basins are considered to be the center of origin and evolution of many freshwater fishes in East Asia, preserving some remnant fish species (Cao and Chen, pers. comm.). Natural lakes of the Yangtze basins, superior in water quality and abundant in species diversity, provide essential freshwater resources for our existence.
Biodiversity problems of lake ecosystems
For several decades, inappropriate construction of dikes, dams and levees, unreasonable fishing and fishery management, and the extremely strong pressure of the rapidly increasing human population on lake ecosystems, have brought severe damage to the biodiversity from genetic to ecosystem levels. This has resulted in the destruction of many natural resources of the lakes and have posed a threat to the stability of our society and the sustainable development of the economy.
1. Shrinking and fragmentation of lake ecosystems
Fragmentation of lakes by continuous subsidence of mud from river water and by extensive reclamation of farmland from the lakes is a serious problem in China. Not only are the lakes in the western part of China shrinking, but those in the eastern part are also contracting. In the western regions, drought has fragmented many lakes into smaller lakes (Shi, 1989). While in the eastern regions, shrinking of lakes is mainly caused by subsidence of mud from river water, and by reclamation of farmland from lakes. In the eastern part of China, the superior natural conditions for agriculture has been accompanied with a rapid increase in human population, and consequently a rapid decline in land area per capita, so conversion of lakes for farmland has become an historical by-product. For example, the total surface area of Lake Dongtin was 4,350km2 in 1949, but declined to 2,619km2 in 1983, due to continuous subsidence of river water and extensive reclamation of farmland from the lake. The total surface area of Lake Honghu was about 760km2 in the early 1950's, but subsequent portioning and reclamation work in the 1960's and 1970's around the lake caused the continual shrinkage of the surface area of the lake to 350km2 of 1979. The Gianghan Plain contained 1,066 various sized lakes (surface area of 8,300km2 ), however, by the early 1980's, only 309 lakes (surface area of 5,600km2) were left due to similar reasons (Shi, et al., 1985).
Welcomme (1979) reported that the number of fish species present in subtropical and tropical rivers was highly correlated with the area of the river basin. Temperate rivers showed a similar pattern, although the number of species rises more steeply with increasing basin area in tropical systems than in higher latitudes. Two factors are important here: (1) the area of a lake sets an upper limit to the maximum population size of each fish species and (2) small populations are inherently more prone to extinction than large ones. From this alone it can be predicted that shrinking of lake ecosystems will contract the living spaces of many freshwater species, and therefore make more and more fish species endangered or extinct.
2. Destruction of lake-river ecosystem by severance of lakes from the Yangtze River
Severance of lakes from the river by construction of sluices and dikes have led to the impoverishment of the natural fish resource--especially of migratory fishes--causing the lakes to be dominated by species of small size. The Yangtze basin was originally a network of water systems, including all of the large and small tributaries of the river, and many interconnected shallow lakes. This complex river-lakes system provided superior living conditions for many commercially important migratory fish species (including four domestic carp) which can spawn only in the river and regularly migrate into lakes for feeding (Fish Laboratory, 1976). Over the past decades, most lakes have been artificially severed from the river by hydroelectric and irrigation projects, and as a result, the migratory fish can no longer enter into these lakes from the river. This has lead to a sharp decline of their population size in both the lakes and the river.
In the middle and lower region of the Yangtze River, there averages around a hundred fish species in natural lakes, but only 30-40 species in severed lakes. For instance, according to a survey of fish species made in the 1990's in Honghu Lake, there were no less than 90 species in the lake. In 1958, a sluice was constructed in the canal linking the lake with the river, thus severing the intercommunication between the river and the lake. The survey in 1964 listed 74 species, in 1981-1982, 54 species, of which only 33 species were obtained from the lake, while the remaining 21 species were riverine fishes carried into the lake during the channeling of the Changjiang River water for the purpose of irrigation.
There is also a shortage of large-sized economic fish species which are mostly migratory between the lake and the river (Honghu Research Group, 1991). Fishery resources of the three domestic carp (siluer, bighead and grass carp) in the Yangtze River are also decreasing: the catch of marketable-sized fishes in the 1980's was just half as much as that in the 1950's, whereas the catch of natural fries was only one quarter as much as that in the 1960's. Changes in composition of the catch also occurred: proportion of migratory fishes declined, whereas that of small-sized lake-dwelling species increased (Li, et al., 1990).
Fingerlings of the four domestic carp used as stocking are now mainly from artificial reproduction, but retrogression due to successive inbreeding has occurred (i.e., both growth and mature age decline, adult fish become smaller, and incidence of diseases become higher). For example, in natural populations of silver carp, the mature age of females is 3-4 years with an average body weight of 4.85kg, and the mature age of males is 3 years with a average body weight of 3.81kg. After inbreeding for five generations, the mature age of females declined to 2 years with a body weight of only 1.25kg (the minimum reached as low as 0.3kg) and the mature age of males declined to one year with a body weight of only 0.69kg. Moreover, the inbreeding offsprings had a higher malformation rate, a weaker constitution, and an eleven times higher incidence of diseases. Therefore, it is harmful to inbreed for many generations, and it is essential to restore the population by natural fingerlings. At present, adult fishes of the Yangtze River are mainly from Lake Boyang and Lake Dongtin which have not yet been severed from the river, and fate of these two lakes remains unclear (Liang, pers. comm). Severance of lakes from the river by hydroelectric and irrigation projects has changed or disrupted dispersal and migration of drastic changes in environments will accelerate distinction of remnant species, and consequently decrease the abundant biodiversity.
3. Decline in biodiversity of fish species by reckless over fishing
Over fishing is commonly occurring in large lakes which are too large to cultivate fish and manage fisheries efficiently. In addition to the severance of lake from the river, reckless over fishing of natural fish populations has resulted in severe decline of species diversity, and decreased drastically the population sizes of commercially important large-sized fish species (mostly migratory fishes). Consequently, a lack of top consumers (carnivores) has usually caused an explosive population increase of small-sized fishes (swamping also favors small sized species), leading to a low fish yield, low fish quality, and low profit (Liang, pers. comm.).
For instance, fish production of Honghu Lake witnessed a steady decline. In the 1950's, the annual fish yield was around 10,000 tons and the dominant species were the four-domestic-carp, Cyprinus carpio and Parabramis pekinensis. However, excessive overfishing and inadequate protection of the spawners caused the diminution both in the size of fish species and in the size of individual fish, the lake being dominated by species of small size as well as by population of stunted growth. In the 1980's, the annual fish yield declined to 3,000-4,000 tons, and 87% were composed of the small-sized Carassium auratus auratus, Pseudobagrus fulvidraco and Culter erythropterus (Honghu Research Goup, 1991).
In Lake Dongtin, the maximum recorded annual fish yield reached as high as 45,000 tons, and the average annual yield was 30,700 tons in the 1950's, but declined to 15,000 tons in the 1980's. The composition of fish yield also changed obviously: the proportion of migrating fishes declined (mainly the four domestic carp), while that of lake-dwelling fishes (Cyprinus carpio, Carassium auratus auratus and Silurus asotus) greatly increased. Of the major economic fishes captured, the proportion of young ages increased and the average individual size of a certain age was also decreased. A large number of young individuals and small-sized species became the targets of fishing (Shan, et al., 1990).
A quite similar phenomenon also occur in some of the lakes of the middle and lower basins of the Yangtze River such as in Lake Caohu, Lake Taihu and Lake Hongzhe, where three small-sized species of Coilia became dominant (Liang, pers. comm.; Shun & Huang, 1993).
4. Seconday Extinction following destruction of climax macrophyte communities
Over-stocking of plant-eating carps has usually caused severe destruction of climax macrophyte communities, and consequently led to a series of extinction of animal species. Like our ancestors who had advanced from collecting wild plants and animals to cultivating crops and domestic animals, artificial breeding, stocking and cultivating fish have developed rapidly. We have succeeded in changing the fish composition for our purposes and cultivating some commercially important fish species. This kind of fishery has applied not only to ponds but also to small/middle-sized lakes (especially urban lakes), and has made it possible to greatly increase fish yield, and to lessen the danger of over-capture on natural populations of some species. However, it has been accompanied with serious problems. In order to get short-term profit over-stocking of fish has led to overgrazing of prey organisms, which has conversely exerted great impact on the whole ecosystem. The most significant events are the destruction of vegetation cover, especially submerged macrophytes, and the dominance of increased r-selected organisms.
In many lakes, the over-stocking of plant-eating carp (especially grass carp) has usually led to destruction of macrophyte communities, and led to the shift of dominant primary producers from macrophytes to phytoplankton. For instance, in the Guozheng area of Lake Donghu, the biomass of macrophytes was as high as 1,779.8g/m2, but declined to 5.8g/m2, which was mainly due to over-stocking of the grass carp. The high destructive power of grass carp on macrophytes is not only due to their low digestion of macrophytes but also because the grass carp suppress the recovery of macrophytes by grazing on new shoots. To macrophytes, algae are r-selected species with a small body and a high turnover rate, and their ability to store nutrients is low. Therefore, in lakes dominated by macrophytes, since a lot of nutrients are stored in macrophytes, the growth of algae is suppressed, and the water is clear. This process is sometimes referred to as the cleanup ability of macrophytes. As the abundance of macrophytes declines, nutrients stored in macrophytes are released into lake water by grazing and excretion of the grass carp. This favors the growth of phytoplankton. Moreover, increased phytoplankton biomass decreases both water transparency and compensative depth of macrophytes, which in return decreases living extent of the macrophytes. Such a vicious circle usually leads to less and less macrophytes of even their extinction. Now, in the Guozheng area of Lake Donghu, the climax macrophyte community in the 1950's has disappeared completely, and consequently, it is followed by secondary succession of the primary producer community in which the dominants are r-selected algae, which is just like the consequences of deforestation for agriculture (Liang, pers. comm.).
Secondary extinction. Macrophyte communities are associated with many periphyton and mollusc, and also serve both as living space and as the substrata for the spawning of many fishes. Therefore, an abundant macrophyte community is accompanied with a high biodiversity of the whole community of plants and animals. The destruction of macrophytes not only leads to the crash of the grass carp populations, but also causes secondary extinction of those organisms depending on these macrophytes and of those fish associated with these directly-related organisms. For example, with the disappearance of macrophytes, many periphytons and molluscs are prone to extinction. This causes the spawning substrata of Cyprinus carpio, Carassium auratus and Ophicephalus argus to also be decreased. The destruction of living environments for molluscs then results in the decline of the available food for Cyprinus carpio and Mylopharyngogon piceus. The dominance of grass carp is then replaced by filter-feeding planktivorous fishes, and so on.
Decline in stability of ecosystems. Disappearance of macrophytes not only causes increase in nutrient concentrations, but also leads to obvious decline in biodiversity of plankton community. In four lake areas (with different nutrient levels) of Lake Donghu, three biodiversity indicies (Margalef, Sympson and Shannon-Weaver) and the number of species of diatoms showed obvious negative relationships with nutrient levels (Lei Anping, Unpubl.). In two sampling stations of Lake Donghu, the Margalef Index of rotifers in 1991 (with high nutrient levels) was only 1/3 that in 1992 (with low nutrient levels). A similar decline in species number was also observed, and eutrophication of the lake decreased the biodiversity of rotifers (Zhuge Yan, Unpubl.). Similar phenomenon might have occurred to other groups of plankton.
However, it remains unknown why eutrophication decreases biodiversity of plankton communities. On the other hand, in hypertrophic waters (probably due to low biodiversity) stability of the systems declines severely, and an outbreak of a few algal species, typically the cyanobacterium water bloom, frequently occurs. In recent years, the frequent outburst of blood poisoning fish disease by bacteria in the lakes of the middle and lower regions of the Yangtze River is probably related to the simplification of the aquatic community (it is also possibly attributed by too high fish stocking density and decreasing water quality). This is very similar to the frequent outburst of insect or disease in the highly-simplified agricultural ecosystems with only one or a few crops.
5. Chemical pollution and accelerated eutrophication in urban lakes
In terrestrial ecosystems, human agricultural activities usually lead to decline in soil nutrients. From southern to northern parts of China, nutrient concentrations in the soil cultivated for 200-500 years, are only half that in the original soil covered with primary vegetation (Heilongjiang Term, 1982). However, during the ontogeny of a lake, organic and inorganic nutrients from the surrounding terrestrial ecosystems accumulates continuously. Trophic status of the lake changes from oligotrophic to eutrophic, and the lake finally appears as land. The process of natural eutrophication is very slow, usually on the time scale of centuries or more. But in recent decades (especially in many urban lakes) the rapid increase in the human population around lakes has resulted in outpouring of untreated industry and organic wastes into the lakes. Also because of unreasonable fishery management, eutrophication in these lakes have been accelerated at an extremely fast rate (i.e., it only needs decades, or even several years to change the lakes from mesotrophic to hypertrophic levels). Lake Donghu in Wuhan City and Lake Xuanwu in Nankin City are good examples of this. The water in lake ecosystems is directly comparable to the soil in terrestrial ecosystems. Soil is important because it supports terrestrial animals and plants. However, water in freshwater ecosystems is important not only because it provides aquatic food but also because it supplies freshwater resources. Severe eutrophication in aquatic ecosystems results in destruction of water supply, and although productivity of the ecosystem may be high, decreasing water quality may be a great threat to human health.
At present, nearly all urban lakes have been seriously eutrophicated. This is not only due to the rapid increase in surrounding human population, but also related with unreasonable fish cultivation. Overstocking of plant-eating carp has resulted in the destruction of submerged macrophytes. This practice is more or less intentional because it is thought that the deforestation by grass carp not only makes people get high fish yield, but also increases the fish yield of the planktivorous silver and bighead carp (as more nitrogen and phosphorous change into plankton biomass). For example, in 1963 in the Guozheng area of Lake Donghu, the biomass of macrophytes was 1779.8 g/m2, and phytoplankton production was only 1 g/m2/day. However, in 1975, the biomass of macrophytes declined to 5.8 g/m2, while phytoplankton production increased to 4.1 g 0.2/m2 (Chen, 1989). During the same period, fish yield of Lake Donghu increased from 93.8 to 276.0kg/ha (Liu, 1984), and proportion of silver and bighead carp was 83% (Section of Fish Ecology, 1976) (now more than 98%). On the other hand, water quality of Lake Donghu became worse and worse: low transparency, outburst of cyanobacterium water bloom, stinking odor of the polluted lake water (Jao & Zhang, 1980). These decreased the lakes multi-functions such as providing drinking water supply and recreation.
Recent studies further indicate that algal blooms (specifically, microcystins) a symptom of lake eutrophication, are harmful to the human liver (Falconer, 1983; Hasser, 1989; Mirura, 1991; Runneger, 1987, 1991). Microcystins not only inhibits the activity of protein phosphates, but also acts as a tumor promoter (Erikson, 1990; Honkanen, 1990; Matsushima, 1990; Nishiwaki-Matsushima, 1991; Yoshizawa, 1990), and is a health threat to humans..
Conclusions
Habitat loss, modification or fragmentation, reckless overfishing, overstocking of plant-eating carp and deterioration of the ecological environment appears to be the most serious current threats to biodiversity in freshwater lakes and species are faced by several of these threats operating simultaneously. Generally, aquatic ecosystems have received little attention in comparison with terrestrial ecosystems, and only a few scattered surveys (mainly on fish) have so far been conducted. Severe decline in species diversity of fish, coupled with inadequate knowledge of freshwater faunas, indicates that biological diversity in aquatic systems require increased conservation attention.
Acknowledgments
We wish to express deep thanks to Prof. Liang Yangling who kindly provided the unpublished manuscript titled: "On the current status and the future of Chinese fisheries from ecological viewpoint." Thanks are also to Mmes Lei Anping and Zhuge Yan for the kind provision of their unpublished data.
Biodiversity - What's the problem?
Biodiversity is in trouble, in Flintshire and throughout the world. There is a demand to build more roads, houses, shops, factories and power stations, but Flintshires plants and animals need this land too. There is a demand for resources such as minerals, sand and gravel for building and industry, but this will often lead to the loss of plants and animals living in the areas we quarry.
We affect biodiversity by polluting air, water and land with wastes from agriculture, industry and domestic activities. We remove hedgerows, trees, and ponds, the homes of plants and animals, to increase our field sizes and "tidy up" the countryside. We use artificial fertilisers and pesticides in an attempt to increase our food production, which leads to a loss of plants and animals.
The Common Toad - under threat The Common toad - not so common anymore!
The red squirrel is probably extinct in Flintshire, as there have been no recent sightings!
Habitat management
Beech forest managementDifferent plants and animals need different types of habitats (the places where they live). Often these habitats will only survive in a suitable condition with management. For example most of our grasslands only exist because farmers have utilised these areas for low level grazing by stock for hundreds of years. Because of changes in farming practices farmers have been put under pressure to increase stocking levels, therefore the interesting and important fauna and flora assemblages that have developed on these areas over centuries are being lost.
The loss of traditional management skills and practices, such as coppicing of woodlands and laying of hedgerows, has also led to a loss of suitable habitat for many plants and animals, such as the dormouse, and the barn owl.
Species loss
Sometimes plants or animals only live in a small area, and once lost from this area the whole species becomes extinct. Not only can species be lost forever, but also the genetic variety that lets them adapt to changes in the environment. The loss of one species is likely to have a knock on effect on other species in that area, for example if a certain nectar rich plant is lost, the insects that feed on that plant will decline, the birds that feed on those insects will also decline, then because there are fewer birds their seed dispersal function will be reduced, so the number of other plants will be effected aswell, then other species may also be effected by this. It is very difficult to predict the outcome of a species extinction because even at a local level the connections between species - the web of life - is very complex.
THE IMPORTANCE OF BIODIVERSITY
t the ecosystem level, biodiversity provides the conditions and drives the processes that sustain the global economy – and our very survival as a species. The benefits and services provided by ecosystems include:
>> Generation of soils and maintenance of soil quality
The activities of microbial and animal species – including bacteria, algae, fungi, mites, millipedes and worms – condition soils, break down organic matter, and release essential nutrients to plants. These processes play a key role in the cycling of such crucial elements as nitrogen, carbon and phosphorous between the living and non-living parts of the biosphere.
>> Maintenance of air quality
Plant species purify the air and regulate the composition of the atmosphere, recycling vital oxygen and filtering harmful particles resulting from industrial activities.
>> Maintenance of water quality
Wetland ecosystems (swamps, marshes, etc.) absorb and recycle essential nutrients, treat sewage, and cleanse wastes. In estuaries, molluscs remove nutrients from the water, helping to prevent nutrient over-enrichment and its attendant problems, such as eutrophication arising from fertilizer run-off. Trees and forest soils purify water as it flows through forest ecosystems. In preventing soils from being washed away, forests also prevent the harmful siltation of rivers and reservoirs that may arise from erosion and landslides.
>> Pest control
Around 99 per cent of potential crop pests are controlled by a variety of other organisms, including insects, birds and fungi. These natural pesticides are in many ways superior to their artificial equivalents, since pests can often develop resistance to chemical controls.
>> Detoxification and decomposition of wastes
Some 130 billion metric tons of organic waste is processed every year by earth’s decomposing organisms. Many industrial wastes, including detergents, oils, acids and paper, are also detoxified and decomposed by the activities of living things. In soils, the end product of these processes – a range of simple inorganic chemicals – is returned to plants as nutrients. Higher (vascular) plants can themselves serve to remove harmful substances from groundwater.
>> Pollination and crop production
Many flowering plants rely on the activities of various animal species – bees, butterflies, bats, birds, etc. – to help them reproduce through the transportation of pollen. More than one-third of humanity’s food crops depend on this process of natural pollination. Many animal species have evolved to perform an additional function in plant reproduction through the dispersal of seeds.
>> Climate stabilization
Plant tissues and other organic materials within land and ocean ecosystems act as repositories of carbon, helping to slow the build-up of atmospheric carbon dioxide, and thus contributing to climate stabilization. Ecosystems also exert direct influences on regional and local weather patterns. Moisture released into the atmosphere by rainforests, for example, causes regular rainstorms, limiting water loss from the region and helping to control the surface temperature. In cold climates, meanwhile, forests act as insulators and as windbreaks, helping to mitigate the impacts of freezing temperatures.
>> Prevention and mitigation of natural disasters
Forests and grasslands protect landscapes against erosion, nutrient loss, and landslides through the binding action of roots. Ecosystems bordering regularly flooding rivers (floodplain forests and wetlands) help to absorb excess water and thus reduce the damage caused by floods. Certain coastal ecosystems (salt marshes, mangrove forests, etc.) prevent the erosion of coastlines.
>> Provision of food security
Biodiversity provides the vast majority of our foodstuffs. The annual world fish catch, for example (averaging 100 million metric tons), represents humanity’s most important source of wild animal protein, with over 20 per cent of the population in Africa and Asia dependent on fish as their primary source of protein. Terrestrial animals, meanwhile, supply an array of food products: eggs, milk, meat, etc. Wild biodiversity provides a wide variety of important foodstuffs, including fruits, game meats, nuts, mushrooms, honey, spices and flavorings. These wild foods are especially important when agricultural supplies fail. Indeed, wild biodiversity guards against the failure of even the most advanced agricultural systems. For example, the productivity of many of the developed world’s agricultural crops is maintained through the regular assimilation of new genes from wild relatives of these crops. These wild genes offer resistance to the pests and diseases that pose an ever-evolving threat to harvests.
The annual world fish catch represents humanity’s most important source of wild animal protein
>> Provision of health care
The World Health Organization estimates that 80 per cent of people in the developing world rely on traditional medicines derived mainly from plants. In Southeast Asia, for example, traditional healers use some 6,500 different plant species to treat malaria, stomach ulcers, syphilis, and other diseases. Biodiversity is also critical to the 'formal' health sector of the developed world. A recent survey showed that of the top 150 prescription drugs used in the United States, 118 are based on natural sources. Of these, 74 per cent are derived from plants. Microbes and animal species have also contributed a range of medicines, including Penicillin (derived from the fungus Pencillium notatum) and several drugs – including anesthetics– derived from the skin secretions of tree-frog species. The medicinal importance of biodiversity is particularly impressive considering that only a tiny fraction of earth’s species have been thoroughly investigated for medicinal properties. The investigative process is continually turning up new pharmaceuticals of great promise. A recent study of cone snails, for example, has identified a painkiller that is up to a thousand times more effective than morphine, but without morphine’s addictive properties.
>> Income generation
Needless to say, the above services are all essential to the functioning of the global economy. Yet biodiversity also has great importance as a direct source of incomes and economic development. One example is 'bioprospecting' (the search for previously unknown biotic products of specific utility, such as natural pesticides, anti-fungal toxins and ‘oil-eating’ enzymes). Such discoveries join an impressive list of ‘miscellaneous’ goods provided by biodiversity, including many of our most important building materials, fibres, fuels, waxes, resins, aromatics, dyes and gums. Even in its wholly untapped state, biodiversity does great service to economies through ‘ecotourism’. People taking nature-related holidays contribute at least $500 billion per year to the national incomes of the countries they visit. Florida’s coral reefs, for example, earn around $1.6 billion per year through tourism alone.
>> Spiritual / cultural value
It’s no mystery why people are prepared to spend so much to get close to nature. Human beings instinctively derive aesthetic and spiritual satisfaction from biodiversity. Recent studies have begun to confirm what has always been known: our emotional wellbeing is enhanced by the proximity of natural beauty. The umbilical bond between humanity and biodiversity is reflected in the art, religions and traditions of diverse human cultures: a spiritual heritage that will be lost for all time if its basis – nature itself – continues to be destroyed.
Further information:
Millennium Ecosystem Assessment (PDF)
Comprehensive analysis of the range and importance of the 'services' provided by ecosystems and biodiversity.
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