填空题
At picnics, ants are pests. But they have their uses. In
industries such as mining, farming and forestry, they can help gauge the health
of the environment by just crawling around and being antsy.
It
has been recognized for decades that ants--which are highly sensitive to
ecological change—can provide a near-percent barometer of the state of an
ecosystem. Only certain species, for instance, will continue to thrive at a
forest site that has been cleared of trees.{{U}} (41) {{/U}} And still
others will move in and take up residence.
By looking at which
species populate a deforested area, scientists can determine how "stressed" the
land is.{{U}} (42) {{/U}}Ants are used simply because the>; are so
common and comprise so many species.
Where mine sites are being
restored, for example, some ant species will recolonize the stripped land
more quickly than others.{{U}} (43) {{/U}}Australian mining company
Capricorn Coal Management has been successfully using ant surveys for years to
determine the rate of recovery of land that it is replanting near its German
Creek mine in Queensland. Ant surveys also have been used with
mine-site recovery projects in Africa and Brazil, where warm climates encourage
dense and diverse ant populations. "We found it worked extremely well there,'
says Jonathan Majer, a professor of environmental biology. Yet the surveys are
perfectly suited to climates throughout Asia, he says, because ants are so
common throughout the region. As Majer puts it. "That's the great thing about
ants.'
Ant surveys are so highly-regarded
as ecological indicators that governments
worldwide accept their results when assessing the environmental impact of mining
and tree harvesting.{{U}} (44) {{/U}}.
Why not? Because
many companies can't afford the expense or the laboratory time needed to sift
results for a comprehensive survey. The cost stems, also, from the scarcity of
ant specialists.{{U}} (45) {{/U}}.
[A] This allowed scientists to
gauge the pace and progress of the ecological recovery.
[B] Yet in other
businesses, such as farming and property development, ant surveys aren't used
widely.
[C] Employing those people are expensive.
[D] They do this by
sorting the ants, counting their numbers and comparing the results with those of
earlier surveys.
[E] The evolution of ant species may have a strong impact on
our ecosystem.
[F] Others will die out for lack of food.'
[G] Gretaceous
ants shared a couple of wasp-like traits together with modern ant-like
characteristics.