Briefing: habitat and biodiversity

Biologically, China is one of the world’s “mega-diverse” countries, but threats to that legacy persist, writes Maryann Bird, in the sixth of a series of guides to hot topics in a warming world.

Biodiversity – or biological diversity – means the variety of life on earth, and is measured within species, between species and in the plenitude of ecosystems (the system of interactions between living organisms and their environment). In its biodiversity, China is one of the richest countries on earth. It is also one in which biodiversity has been most seriously damaged – and is still threatened.

With its huge population and long history of agriculture, China has been cultivating its vast territory for centuries. Forests and other types of vegetation were destroyed to clear land to cultivate more crops to feed more people. Wars and other chaos throughout China’s history have had their negative effects on the land and its life forms, and now climate change is playing a part. More recently, says China’s Biodiversity: A Country Studylabelled “a preliminary summary of China’s biodiversity and of the work needed for its preservation” — both the government and the public are more aware of the importance of biodiversity conservation. But threats to the country’s biodiversity legacy – one that is rich and varied, but also broken and incomplete — are still growing.

Forests, says the 1998 report — organised by China’s State Environmental Protection Administration (SEPA) and compiled with the support of the United Nations Environment Programme (UNEP) – have been “broken into small, fragmented areas”. Rangelands have been “overgrazed and severely degraded”. Animal and plant resources have been overexploited and over utilised. Atmospheric pollution, particularly in the form of acid rain, endangers plants, soil, lakes, fish and other resources. Invasive exotic weeds and animal pests have damaged indigenous life. Human activities, including tourism, mining and wetlands reclamation, produce a range of harmful effects.

As the report unequivocally states: “The survival of mankind cannot be separated from that of other species. Numerous plants, animals and micro-organisms provide indispensable human food, fibre, wood, medicine and industrial raw materials. … The many beautiful and aesthetic life forms on the earth also give human beings much enjoyment. They are also sources of artistic creation and scientific invention. Most of the functions of living organisms cannot be replaced by other things. Today, man is modifying the features of the earth at an unprecedented rate. This creates raw materials for human survival on the one hand, but has changed the living environment of other living things, continuously decreasing biodiversity, and has led to the extinction of large numbers of species, on the other. The basis for human survival is gradually disintegrating and the protection of biodiversity is currently of worldwide concern.”

Experts, including the UNEP, consider China one of the earth’s 12 “mega-diverse” countries, ranking it third in the world for biodiversity in GEO-2000, the Global Environment Outlook, and first in the northern hemisphere. With more than 30,000 species of advanced plants and 6,347 kinds of vertebrates, representing 10 and 14 percent, respectively, of the world’s total (according to 1996 SEPA figures). Additionally, China is credited with 1,000 species of economic trees and more than 11,000 species of medicinal plants. Countless species are endemic to the country – ancient flora and fauna – and are both rare and endangered.

Washington-based Conservation International (CI), which works to protect the earth’s richest regions of plant and animal diversity, has identified 34 “biodiversity hotspots” globally. These are regions that contain at least 1,500 endemic species of vascular plants (greater than 0.5% of the world’s total) and which have lost at least 70% of their original habitat. Among the 34 hotspots on CI’s list are the mountains of southwest China, stretching over 262,400 square kilometres of temperate to alpine peaks between the easternmost edge of the Tibetan plateau and the central China plain. The mountains feed the most species-rich temperate and tropical river systems in Asia and “support a wide array of habitats, including the most endemic-rich temperate flora in the world.”

The region has evolved into “cluster of distinctive mini-hotspots,” each with its own unique flora and fauna, says CI, due to its dramatic differences in topography, climate and vegetation. The mountains are home to an estimated 12,000 species of plants, 237 of mammals, 611 of birds, and at least 90 each of reptiles, amphibians and freshwater fish – many of which are found nowhere else in the world. Two-hundred thirty rhododendron species – more than a quarter of the world’s total – are found there. So, too, is the richest variety of pheasants and their relatives – about 25 species – and, among mammals, there is the very symbol of China and of conservation: the giant panda. The animal, says CI, is “almost entirely restricted to the shrinking forests of this hotspot.” Other important mammals include the golden monkey, the Yunnan or black snub-nosed monkey, the takin (a large goat antelope), the Chinese forest musk deer and the snow leopard.

The World Conservation Union (also known as IUCN and based in Gland, Switzerland) is the world’s largest and most important conservation network. Among its functions is maintenance of the IUCN Red List of Threatened Species, a database recognised as the most authoritative guide to the status of biological diversity on the planet. It evaluates the extinction risk to thousands of species and subspecies. Its 2006 figures list 804 threatened species in China: 442 plants, 84 mammals, 88 birds, 34 reptiles, 91 amphibians, 59 fishes, 1 mollusc and 5 other invertebrates.

Deforestation – for agriculture, logging, dam construction, industry and human settlements – and climate change have played their part in the decline of China’s wildlife and habitats. So, too, has the destruction of grasslands and wetlands – such as the large freshwater swamps of the Sanjian plain in northeastern China. While habitats shrink, so too does the varied life of ecosystems.

And as Jared Diamond writes in his book Collapse: How Societies Choose to Fail or Survive, “Other biodiversity losses with big economic consequences include the severe degradation of both freshwater and coastal marine fisheries by overfishing and pollution, because fish consumption is rising with growing affluence. … The white sturgeon has been pushed to brink of extinction, the formerly robust Bohai prawn harvest declined 90%, formerly abundant fish species like the yellow croaker and hairtail must now be imported, the annual take of wild fish in the Yangtze river has declined 75%, and that river had to be closed to fishing for the first time ever in 2003.”

As China pursues its aspirations to a “First World lifestyle,” the impact on human-resource use and the environment is certain to be immense.