GRE写作Issue部分精品素材分享之生物多样性的威胁
- 2015年08月14日17:47 来源：小站整理
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生物多样性的益处之五： 休闲、 文化和审美价值
8. Leisure, cultural and aesthetic value
Many people derive value from biodiversity through leisure activities such as hiking in the countryside, bird-watching or natural history study.
Biodiversity has inspired musicians, painters, sculptors, writers and other artists. Many cultural groups view themselves as an integral part of the natural world and show respect for other living organisms.
Popular activities such as gardening, caring for aquariums and collecting butterflies are all strongly dependent on biodiversity. The number of species involved in such pursuits is in the tens of thousands, though the great majority does not enter mainstream commercialism.
作物多样性有助于其遭疾病侵袭后的恢复
Crop diversity is also necessary to help the system recover when the dominant crop type is attacked by a disease, for instance:
The Irish potato blight of 1846, which killed a million people and forced another million to emigrate, was the result of planting only two potato varieties, both of which were vulnerable.
When the rice grassy stunt virus struck rice fields from Indonesia to India in the 1970s, 6,273 varieties were tested. Only one was luckily found to be resistant, a relatively feeble Indian variety, known to science only since 1966, with the desired trait. It was hybridized with other varieties and now widely grown.
生物多样性面临的威胁
During the last century, erosion of biodiversity has been increasingly observed. Some studies show that about one eighth known plant species is threatened with extinction. Some estimates put the loss at up to 140,000 species per year (based on Species-area theory) and subject to discussion. This figure indicates unsustainable ecological practices, because only a small number of species come into being each year. Almost all scientists acknowledge that the rate of species loss is greater now than at any time in human history, with extinctions occurring at rates hundreds of times higher than background extinction rates.
Declines in amphibian populations have been observed since 1980s. Because of the sensitivity of these organisms, they are regarded by many scientists as a marker for the overall health of an ecosystem. Their decline has led to concern about the general current state of biodiversity.
国际协议对生物多样性的动态保护
New global agreements (e.g.Convention on Biological Diversity), now give sovereign national rights over biological resources (not property). The idea of static conservation of biodiversity is disappearing and being replaced by the idea of dynamic conservation, through the notion of resource and innovation.
Sovereignty principles can rely upon what is better known as Access and Benefit Sharing Agreements (ABAs). The Convention on Biodiversity spirit implies a prior informed consent between the source country and the collector, to establish which resource will be used and for what, and to settle on a fair agreement on benefit sharing. Bioprospecting can become a type of biopiracy when those principles are not respected.Uniform approval for use of biodiversity as a legal standard has not been achieved, however. At least one legal commentator has argued that biodiversity should not be used as a legal standard, arguing that the multiple layers of scientific uncertainty inherent in the concept of biodiversity will cause administrative waste and increase litigation without promoting preservation goals.
