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生物多样性测量的三大指标

Biodiversity is usually plotted as taxonomic richness of a geographic area,

with some reference to a temporal scale. Whittaker described three common

metrics used to measure species-level

biodiversity, encompassing attention to species richness or species

evenness:

1. Species richness—the least sophisticated of the indices available

2. Simpson index

3. Shannon index

There are three other indices which are used by ecologists:

1. Alpha diversity refers to diversity within a particular area, community or

ecosystem, and is measured by counting the number of taxa within the ecosystem

(usually species).

2. Beta diversity is species diversity between ecosystems; this involves

comparing the number of taxa that are unique to each of the ecosystems.

3. Gamma diversity is a measure of the overall diversity for different

ecosystems within a region.

生物多样性的衡量

Biodiversity is a broad concept, so a variety of objective measures have been

created in order to empirically measure biodiversity. Each measure of

biodiversity relates to a particular use of the data.

For practical conservationists, this measure should quantify a value that is

broadly shared among locally affected people. For others, a more economically

defensible definition should allow the ensuring of continued possibilities for

both adaptation and future use by people, assuring environmental

sustainability.

As a consequence, biologists argue that this measure is likely to be

associated with the variety of genes. Since it cannot always be said which genes

are more likely to prove beneficial, the best choice for conservation is to

assure the persistence of as many genes as possible. For ecologists, this latter

approach is sometimes considered too restrictive, as it prohibits ecological

succession.

生物多样性与立法

Biodiversity is beginning to be evaluated and its evolution analyzed (through

observations, inventories, conservation...) as well as being taken into account

in political and judicial decisions.

The relationship between law and ecosystems is very ancient and has

consequences for biodiversity. It is related to property rights, both private

and public. It can define protection for threatened ecosystems, but also some

rights and duties (for example, fishing rights, hunting rights).

Law regarding species is a more recent issue. It defines species that must be

protected because they may be threatened by extinction. The U.S. Endangered

Species Act is an example of an attempt to address the “law and species”

issue.