Global biodiversity: The rise of knowledge and the fall of species
When in February, more than 2,000 representatives of governments, international institutions, civil society groups and indigenous peoples’ organisations meet in Kuala Lumpur to review the progress in protecting our planet’s diversity of life under the Convention on Biological Diversity, they will have to confront some painful truths. Ten years after the Convention entered into force, species continue to be threatened, changed and even wiped out. From logging to genetic engineering, human activities are still more destructive than sustainable.
BIODIVERSITY is a relatively new term. It attempts, in a word, to describe the plethora of plant and animal species that inhabit the various biomes and ecosystems on the planet. This tremendous biological diversity is captured in genes, organisms, species and ecosystems and manifests itself in life forms as different as elephants to E. coli.
Human growth and disappearing nature
Humans are also part of the biological mix. We are now exceeding six billion and are expected to reach 7.7 billion - considered a manageable population - by 2050, but may possibly explode to 12.5 billion with catastrophic consequences.1 As the world population grows, the Earth’s natural resources continue to be depleted to fuel the rise in economic production and consumerism. The total demands are great; the resources are finite and running out.
Natural communities are being logged, grazed, invaded and fragmented with extensive changes to plant species composition. Some ecosystems, such as native grasslands, no longer exist and two centuries of intensive logging and replanting, with introduced species, of temperate forests in North America and Europe have changed the landscape.2 In the 1980s, 10 million hectares of humid tropical forests - about 1% per year globally - were lost to conversion.3 Dry tropical forests in Central America remain at less than 2% of their original area and over 50% of wetlands and mangroves, in some countries, are gone.4 And 10% of the world’s coral reefs are eroded beyond recovery.5
Animal species are also in decline. An astonishing 80% of the 128 known bird extinctions over the last 500 years have occurred since 1800.6 The World Conservation Union reported that at least one-fifth of all mammals (25%), reptiles (20%), amphibians (25%) and fish (34%) surveyed are at risk of becoming extinct.7 Almost half of the world’s 233 primate species are threatened, and 70% of primates found in the tropical forests of Brazil, Madagascar and South-East Asia face extinction.8 For marine fish, 60% of major species are overexploited, resulting in the decline of 11 out of 15 of the most important fishing areas.9 And the extent of global trade has brought forth biological pollution in the form of non-native species that overcome natural boundaries to invade and suppress local species, thus thwarting biological diversity.10
Biodiversity takes root
The concern over biodiversity was brought to global attention in 1988 when the National Academy of Sciences published Biodiversity. It forewarned that the environments responsible for the diversity of life forms were being rapidly destroyed and altered. It also took note of the new alliances among governments, scientific institutions and commercial interests to forge and redesign the international conservation movement. At the same time, conservation biology took root to redefine resource management.
At the same time, the United Nations Environment Programme (UNEP) started in 1987 to convene a number of experts’ meetings which led to the negotiations and adoption of the Convention on Biological Diversity (CBD) in 1992. In June 1992 at the Rio Earth Summit, heads of State and Government of more than 150 countries signed on to the CBD. There are now 188 Parties which have taken on the legal commitments of the CBD, making it the most-widely supported international environmental agreement.
In 1995, UNEP published the Global Biodiversity Assessment (GBA) to gather the views and analyses of the global scientific community to better understand biodiversity and the inter-connections and impacts with society. Since the CBD, unlike the Conventions on Climate Change and Ozone Depletion, was negotiated without prior scientific assessments, the GBA attempted to fill the existing knowledge gap. However, it is an independent assessment without any official endorsement from the CBD.
At the second meeting of the Conference of the Parties (COP2) to the CBD in 1995, a summary of the status of biological diversity was mooted that led to the initial Global Biodiversity Outlook (GBO) report in 2001. It sought to ‘illustrate the urgency of the issues relating to the loss of global biodiversity, and how the Convention seeks to address these issues’. More importantly it recognised that while the concept of biodiversity, and stopping its decline, are now part of mainstream decision-making processes, many people are still unclear on how to address these problems and turn international commitments into effective action. The second GBO report is expected out in 2004.
A companion UNEP series, known as the Global Environment Outlook, began in 1997 as a response to reporting requirements of Agenda 21 to present a comprehensive global picture of the environment. GEO-3 came out in 2002 with an emphasis on assessing 30 years of environmental trends to investigate the relationships between policy and environment. It synthesises environmental conditions and human vulnerability to environmental change.
A different tack was taken by the Millennium Ecosystem Assessment, initiated to help achieve the UN Millennium Development Goals and carry out the Plan of Implementation of the 2002 World Summit on Sustainable Development. It recognises that a dynamic interaction exists between people and ecosystems and that direct and indirect change affect each. It seeks to assess the consequences for human well-being and options for enhancing the protection and contributions of global habitats. It targets issues pertinent to policy-makers and formal support from the CBD. To date only a framework document describing the methods and approaches used has been published; technical assessment reports are expected in 2005.
Biodiversity by the numbers
So what does two decades’ worth of data show and tell us about biodiversity and the environmental state of the planet?
According to the GBA, there are 1.75 million recognised species. Other estimates revise this total to 1.5 million species, after accounting for historical errors in taxonomy, and anticipate that another 13,000 new species are added each year.11 That’s the figure for species that have been found, caught, described and formally named.
Millions of species exist that are undiscovered. The GBA also set low and high estimates in assessing the total number of species on Earth: 3.6 million and 111.6 million, respectively. The latter figure, dominated by 100 million insect species, is now thought to be extremely excessive; more conservative estimates now put the total around 13 to 14 million.12
The total numbers are not to be interpreted merely as some sort of academic exercise. They have practical value. As expressed by E O Wilson in The Diversity of Life, the numbers show where the biological gaps occur on the biodiversity map and give direction for innovative research to discover ‘large pools of species diversity in previously obscure or unknown groups’. For the 10,000 or so bird species and nearly 5,000 mammal species, most discoveries have probably been made. But the quest has just started for arthropods, bacteria, parasites, fungi and insects. Biological exploration is not over since most species remain unknown, but extinction and habitat degradation will plague the pursuit.
Plants, animals and people
Three billion years of evolution is responsible for the distribution and extent of biodiversity today. Migration, speciation and extinction have always played a role, but in the recent past the impacts of human activities have accelerated ecosystem deterioration and genetic erosion. Environmental alterations are proceeding at unacceptable rates and pose threats to not only the variety and abundance of species, but sustainable economic development as well. The adverse effects from the depletion of biological resources are numerous and costly: diminished food and wood supplies, loss of medicines and energy, disruption of ecological functions (water regulation, nutrient recycling, erosion control) and tourism shortfalls.
A multitude of causes contribute to biodiversity loss. The GBA pinpointed several factors that relate to economics, institutions, governments and human populations. Economic markets fail to recognise the true value of biological resources and fail to apply their global worth to local situations. Institutions fail to regulate the use of biodiversity and adopt appropriate responses to urban growth, changes in property rights and shifting cultural attitudes. Government policies fail to address the extraction of resources and degradation of habitats. Increases in population intensify the demand for natural products and wild habitats for economic development, and eventually add to the pollution of soil, water and the atmosphere.
Unsustainable consumption patterns as a major cause of resource depletion, including biodiversity loss, was targeted for action in Agenda 21. Failure to address this led to the adoption of a 10-year work programme on sustainable production and consumption patterns at the 2002 World Summit on Sustainable Development. The Summit also signalled the urgency by agreeing to significantly reduce the current rate of biodiversity loss by 2010. At the CBD COP7 in February, Parties will be challenged to commit themselves to more action, in scale and intensity.
The emphasis on extinction is warranted because biodiversity losses occur in nearly all types of ecosystems. On a global scale, the causes of extinction are ranked starting from the top as follows: habitat destruction, the spread of exotic species, pollution, over-harvesting, and disease.13 On a local scale, wild population extinction rates can be devastating: an exotic snake introduced into Guam has wiped out nearly all of its songbirds.
To know what’s missing, first you have to know what’s out there. There are only a few groups - birds, mammals, and flowering plants - that have been studied thoroughly enough on a global scale to ascertain absolute numbers of extinction rates. The rest of the biological world is measured with rough estimations of the percentage of species extinctions. Various studies put the rate of species extinctions per decade between 1 and 10%14; while the GBA reported that flowering plants and vertebrate animals become extinct at rates 50 to 100 times the average expected natural rate.
The fate of species is usually tied to habitats. Substantial reductions in habitat area result in significant losses in the number of species. The loss of 80% of Madagascar’s old-growth forests drove 15 species of lemurs to extinction and decades of logging in South-East Asia contributed to leaving 90% of primates threatened with extinction.15 One of the dilemmas of saving biodiversity is that major concentrations of habitat reductions are occurring in regions where biodiversity flourishes.
Hot spots and tight spots
Hot spots are geographic areas that usually contain threatened ecosystems with large numbers of unique flora and fauna species, many of which are restricted to specific localities. There are 12 countries recognised for their biological richness: Australia, Brazil, China, Colombia, Congo, Ecuador, India, Indonesia, Madagascar, Malaysia, Mexico, and Peru. The majority (60-75%) of the world’s biological diversity is found in these nations. The onus of slowing the rates of extinction may fall to these, and a few other, mostly equatorial countries, but safeguarding the planet’s remaining biodiversity is inclusive of a greater number of nations.
The World Conservation Monitoring Centre analysed data on mammals, birds, amphibians, reptiles, butterflies and plants to come up with the 50 most biodiverse countries, or those possessing the most species and endemism, and 20 more island nations with large proportions of native species.16 Of the total, 60 are less developed countries. The WCMC recognised the special value of these nations to preserve biodiversity and recommended that they receive substantial resources to develop capacities to manage biodiversity as guided by the CBD.
The knock on mapping out biodiversity hot spots comes from those who want to pursue unfettered economic expansion, usually to the detriment of conservation. But the argument loses ground because hot spots only take up a fraction of the Earth’s surface. A survey by Conservation International revealed that 17 of the world’s hottest spots occupied less than 1.5% of the land area, but contained one-fourth of its terrestrial vertebrate species and 40% of its plants.17 Thus some argue for conservation to concentrate on saving hot spots and wilderness areas first. However, it is also important to bear in mind that these hot spots are almost always within the territories of indigenous peoples. Conservation with respect for land rights has to be the way forward for the CBD.
The CBD and biological frontiers
The objectives of the CBD are threefold: conserve biological diversity, use the components of biological diversity in a sustainable manner, and provide fair and equitable sharing of the benefits arising out of the world’s genetic resources. Almost nothing, large or small, is left out. The objectives are the same, whether conserving the riches of rainforest ecosystems or mining the DNA strands of gene pools. However, human genetic resources are excluded from the CBD in a COP2 decision to avoid endorsement of their commercialisation.
Biological frontiers are found everywhere: in soil, in water, in forest canopies and in cells. A key factor in stable environments is species and genetic diversity. In general, more species living in an ecosystem leads to higher productivity and a better ability to fend off environmental stress. Genetic diversity tends to enable better adaptations in organisms to cope with environmental changes and plays an increasingly important role in sourcing biodiversity benefits for social and economic gains.
Genetic erosion is a product of centuries of human activities that led to changes in the diversity of wild and domestic populations. With the advent of genetic engineering, humans have been influencing genetic diversity by artificial, not evolutionary, means. As long as like individuals were selected, the lineages remained the same with improved features, such as was accomplished for livestock and crops. The manipulation of genetic material nowadays is fundamentally different. Genes that were once reproductively isolated by nature can now be spliced together to form new lineages. And these modified organisms can move into other organisms.
What is uncertain is what level of risk is being taken to achieve these new forms. The Cartagena Protocol on Biosafety arose from concerns over the release of genetically modified organisms and how to control the risk to conservation and human health.
From genes to species to ecosystems, the loss of biological diversity is the core problem. The data shows that, roughly, science has documented only 12% of the species on the planet. The ‘2010’ goal of the WSSD to achieve a significant reduction in the current rate of loss within the next six years is a challenging target.
Climate change alone is expected to wipe out one million species in the next 50 years as many plant and animal species are unlikely to survive this disruption. New analyses published in Nature suggest that 15-37% of a sample of 1,103 land plants and animals would eventually become extinct as a result of climate changes expected by 2050. For example, Boyd’s forest dragon, Hypsilurus boydii, is found in Queensland, Australia. About 90% of its distribution would become climatically unsuitable by 2050, on maximum climate warming scenarios.18 For some of these species there will no longer be anywhere suitable to live. Others will be unable to reach places where the climate is suitable. A rapid shift to technologies that do not produce greenhouse gases, combined with carbon sequestration, could save 15-20% of species from extinction.
The situation calls for extraordinary efforts to boost scientific assessments and conservation measures, while applying the Precautionary Principle to safeguard against environmentally unsound practices and inappropriate organisms.
Rick Gregory is an environmental consultant/writer based in Malaysia working on biodiversity and environmental policy issues.
1 Wilson, E.O. 2001. The Diversity of Life, Foreword, p.viii, Penguin Books.
2 UNEP Global Biodiversity Assessment, 1995.
6 Worldwatch Institute, ‘State of the World 2003’, Press Release 9 January 2003
7 Worldwatch Institute, ‘Mammals, Birds, Fish, Reptiles and Amphibians Suffering Major Declines’, Press Release 23 May 1998
9 Worldwatch Institute, ‘Hidden Forces Mask Crisis in World Fisheries’, Press Release 18 June 1998
10 Worldwatch Institute, ‘Global Economy Spreading Destructive Species: The Invisible Threat of Bioinvasion’, Press Release 10 October 1998
11 Wilson, E.O. 2001. The Diversity of Life, Foreword, pp. xi-xii, Penguin Books
12 Wilson, E.O. 2001. The Diversity of Life, Foreword, p. xii, Penguin Books
13 Wilson, E.O. 2001. The Diversity of Life, Foreword, p. xv, Penguin Books
14 Wilson, E.O. 2001. The Diversity of Life, Foreword, p. xvi, Penguin Books.
15 Worldwatch Institute, ‘Half of all Primate Species Face Extinction’, Press Release, 28 August 1997
16 World Conservation Monitoring Centre, 1994. Priorities for Conserving Global Species Richness and Endemism, Biodiversity Series No. 3, World Conservation Press.
17 Wilson, E.O. 2001. The Diversity of Life, Foreword, p. xx, Penguin Books.
18 Thomas, Chris D. et al, ‘Extinction risk from climate change’, Nature 427, 145-148 (8 January 2004).
Status and trends of global biodiversity
THE Global Biodiversity Outlook attempted to summarise the status of biodiversity and its trends in the major biomes and agro-ecosystems. The goal of the GBO is to provide a tool for use by CBD Parties and others to:
· review progress made by the Convention toward its three objectives,
· identify barriers to implementation,
· help set priorities for implementation, and
· communicate progress and advocate needs to decision-makers.
Below are some highlights:
· Boreal and temperate needleleaf forests cover a larger area of the world than any other forest type. Species diversity is usually relatively low, dominated by a very small number of tree species and not highly threatened with extinction. These forests are of great importance in the carbon cycle, acting as major reservoirs of organic carbon both above and below ground.
· Temperate broadleaf and mixed forests are generally characteristic of the warmer temperate latitudes, tend to be structurally more complex than needleleaf forests, and have considerably higher species diversity, many of which are localised and more vulnerable to extinction.
· Tropical moist forests include many different forest types and are the most diverse ecosystems on earth. Some estimates suggest that at least 60% of all species (and possibly near 90%) occur in them, despite the fact that they cover little more than 7% of the world’s land surface. Far more tropical forest species are considered threatened than species from any other habitat.
· Historical forest loss shows that in the northern hemisphere forest cover continued to decline until the 19th century; while current data suggests that rates of deforestation are high in developing countries of the tropics and lower in temperate countries.
Critically Endangered Species:
· Black-faced lion tamarin, Brazil. Restricted to 300 km2 of forest, with a total population of about 300 individuals.
· Golden bamboo lemur, Madagascar. The small population of a few hundred animals is threatened by rainforest deforestation.
· Sumatran rhinoceros, Indonesia and Malaysia. Formerly widespread in upland forests and now reduced to a few hundred animals by deforestation and hunting.
· Djibouti francolin, Djibouti. Fewer than 1,000 birds exist and are declining because of habitat degradation and hunting.
· Chisos oak, Texas, USA. A small isolated population exists in riparian oak woodland and threatened by the activities of tourists and occasional drought.
· The diversity of organisms in inland waters is considerably lower than on land or in the sea; however, species richness compared to habitat extent may be very high. For example, of known fish species around 40% (ca 10,000) are freshwater forms and 60% marine. Overall species richness increases strongly toward the equator to produce far more species in tropical than in temperate or polar regions.
· A common finding among global assessments of the status and trends of biological diversity is that inland waters are those suffering the greatest deleterious impact from human activities at present.
· The status of inland water faunas has been considerably worse than originally suspected. In 20 countries studied 20% of fish fauna were found to be threatened. The proportion of tortoises and turtles threatened is even higher at more than 30%.
Critically Endangered Species:
· Baiji, Yangtze River, China. An endemic freshwater dolphin with fewer than 200 remaining individuals that are threatened by entanglement in fishing gear, collisions with boats, pollution, and hydroelectric schemes.
· Striped narrow-headed softshell turtle, Thailand. Restricted to the Mae Klong River basin with a single population of 16 turtles remaining, it is threatened by the pet trade.
· Common sturgeon, France and Georgia. Previously widespread in large European river basins, the species now spawns in only two river basins due to habitat loss, pollution and overfishing.
· Shasta crayfish, California, USA. Limited to the Pit River basin, the few remaining populations are threatened due to introduced crayfishes, stream modification and pollution.
· Marine capture fisheries have increased in volume nearly five-fold in the past 50 years, rising to nearly 90 million tonnes in the late 1990s, more than 70% of the total world production of aquatic resources. Analysis by FAO and others indicates that marine stocks are widely overexploited and in urgent need of remedial management.
· Fishery operations have a destructive physical impact on the seabed, and affect population levels of non-target species through incidental catch, for example cetaceans, sea turtles and seabirds.
· Globally, coral bleaching related to periodic climatic events is the primary threat to coral reefs. The increase in sea-surface temperature associated with the major El Nino and La Nina climate switches resulted in extensive mortality - levels greater than 90% on some reefs - over large portions of the Indian Ocean and South-East and East Asia.
· As with mangroves, the centre of diversity of reef-building corals is South-East Asia, with an estimated minimum of 450 species of corals found associated with reefs around the Philippines, Borneo, Sulawesi and associated islands.
· Generally, marine species appear to be somewhat less prone to extinction than inland water or terrestrial ones, but this is difficult to acknowledge since marine species are less observable. Oceans also buffer them from human impacts and allow species to be more widespread and less vulnerable to extinction.
Critically Endangered Species:
· Vaquita, Gulf of California, Mexico. A small porpoise that is threatened by accidental entanglement and drowning in fishing nets.
· Galapagos Petrel, Galapagos Islands, Ecuador. A bird that breeds only in the highlands and is in decline due to the destruction of nest sites and predation by introduced animals.
· Spotted handfish, Tasmania, Australia. Endemic to the Derwent estuary, the causes of its decline are not clear but predation of its eggs by an introduced starfish and increases in soil runoff from surrounding agricultural land may be the principal factors.
· Largetooth sawfish, oceans. A large fish that occurs mainly in the shallow estuarine waters of the Atlantic, eastern Pacific and possibly the Mediterranean, its decline is attributed to excess fishing.
· The fundamental and distinct property of agricultural biodiversity is that it is largely created, maintained and managed by humans - originally by subsistence farming communities, but more recently by biotechnologists - in part using material in ex situ genetic resource collections in contrast to wild biodiversity, which is most valued in situ as a product of natural evolution.
· Agricultural land now forms a significant proportion, some 38%, of the world’s total land area, with arable land (11%), permanent crops (fruit and nut trees: 1%) and permanent pasture (26%).
· Some locally distributed plant genetic resources, particularly wild relatives of crop plants, have been lost as a result of land conversion or preferred use of varieties with superior production qualities, each resulting in genetic erosion. Replacement by modern, genetically more uniform, breeds that are specialised for intensive systems is the main cause of loss of livestock breeds.
· There are significant declines in the abundance of some pollinators. It is estimated that two-thirds of the world’s species of agricultural crops require animals for pollination. By far the greatest part is provided by bees; however, the numbers of native bees are dwindling with losses due mostly to the use of agrochemicals, monocultures, and deforestation.
· The rapid development of transgenic crops raises additional causes for concern, as the employment of a herbicide or pesticide coupled with a variety of crop resistant to this could eradicate all alternative forage for pollinators, leading to devastation in their numbers.
Loss of Plant Genetic Resources:
· Wheat varieties, China. Of the 10,000 varieties used before 1950 only 1,000 remained by the 1970s, a loss of 90%.
· Maize varieties, Mexico. Only 20% of the maize plants used in the 1930s remain, most being replaced by more profitable crops.
· Apple, cabbage, pea, tomato and field maize varieties, USA. The last century saw an 80% to 95% loss of these crop varieties in comparison to the varieties grown from 1804 to 1904.
SOURCE: UNEP, Global Biodiversity Outlook, 2001.