ENVIRONMENT: Disappearance of Amphibians – a Warning to Humanity

By Mario Osava Reprint | | Print |

Mario Osava

RIO DE JANEIRO, Sep 9 1999 (IPS) - Amphibians are dying all over the world, even in protected areas – a living gauge of the extent of pollution, states the annual World Wildlife Fund International (WWF) report released Thursday in this Brazilian city.

Freshwater systems like rivers, lakes and wetlands are hit hardest by pollution, according to the report. The populations of nearly half of the species inhabiting such areas, including fish, reptiles, birds and especially amphibians, have shrunk.

According to the WWF’s Live Planet Index, an indicator of the planet’s health, around 30 percent of the world’s wildlife was destroyed from 1970 to 1995 – or one percent a year.

The Index points to the loss of 10 percent of the world’s forest cover, a 35 percent reduction in the populations of 102 marine species, and a 45 percent decline in 102 species found in freshwater ecosystems.

The data indicates that water ecosystems must be granted top priority, said Claude Martin, secretary-general of WWF International, a network of 27 national non-governmental organisations (NGOs) and five affiliates, with 21 offices in various countries.

Rio de Janeiro was chosen for the release of this year’s report to symbolise the WWF’s emphasis on Brazil, which accounts for 20 percent of the world’s freshwater reserves and has the world’s largest wetland system, the Mato Grosso Pantanal in southwestern Brazil, said Garo Batmanian, executive director of WWF-Brazil.

Latin America’s giant, which is also home to one-third of the world’s tropical forests and 10 percent of biodiversity, hosted the 1992 Earth Summit.

The fast decline of amphibian species on all continents is one of the most novel aspects of the report, said Jonathan Loh, the study’s technical coordinator.

The causes of that phenomenon are varied, with the loss of natural habitat being the key factor. In Great Britain, for example, 99 percent of the lakes and wetlands where amphibians bred no longer exist. The destruction of primary tropical forests in South America and Africa has meant a similar loss of breeding- grounds.

A previously unknown fungus decimated 20 percent of frog species in Australia, the United States and Panama. And climate changes are blamed for the disappearance of 40 percent of the species inhabiting the Monteverde forest reserve in Costa Rica.

Amphibians are a sensitive thermometer of the state of the environment, said Brazilian researcher José Pombal, because they breed in freshwater and breathe through their skin, and thus are highly vulnerable to pollution. They are also extremely sensitive to ultraviolet rays, which the thinning ozone layer is less and less able to block.

For all of these reasons, amphibians are the first to vanish – and their disappearance constitutes a warning to humanity, said Pombal.

Another cause of the disappearance of amphibians, especially in the United States, is the use of pesticides, which are generally applied in springtime during the breeding season of frogs. Amphibians are particularly vulnerable to damages caused by chemicals in the formative stages of their lives, which explains the widespread occurrence of deformed frogs.

The WWF report also expresses concern over the annual destruction of 150,000 square kms of forests, an area bigger than Bangladesh or Greece.

Despite the resolutions and conventions adopted by governments at the 1992 Earth Summit in Rio de Janeiro, little has been done in terms of effectively resolving problems like climate change, which threaten life on earth, lamented Martin.

Carbon dioxide emissions, for example, continue to increase, and global treaties only provide for the implementation of measures designed to cut emissions as of next year.

From 1960 to 1996, emissions of carbon dioxide – one of the causes of the greenhouse effect and the heating up of the earth’s surface – climbed from 10 to 23 billion tonnes a year, without counting an additional 10 billion tonnes caused by deforestation, reported the WWF.

Population growth and consumption of natural resources, billions of dollars spent on subsidising unsustainable activities, the weakening of the state and growing power of the private sector are all leading to environmental disaster, warned Martin.

To counteract that tendency, the WWF recommended that economists take loss of wildlife into account when calculating gross national product and formulating policies, and called for a price system favouring sustainability, taxation of polluting activities, and other measures.