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VOCABULARY: SCIENCE USAGE V. COMMON
USAGE
corridor
Science usage:
a passageway between two habitat fragments
The deer uses the corridor to safely travel between the two
habitat fragments.
Common usage:
a passageway, as in a hotel, into which rooms
open
The ice machine is in the hotel corridor by the elevators.
CROSSCUTTING CONCEPTS
Scale, Proportion, and Quantity
In considering phenomena,
it is critical to recognize what is relevant at different measures
of size, time, and energy. Biologists have debated whether
conservation efforts should be focused on biodiversity
hotspots. Write a brief argument for or against focusing efforts
on hotspots. Consider measures of size, time, and energy. Cite
evidence that supports your argument.
International protected areas
The United States is not the only country to establish national parks and nature
reserves. Currently, about ten to fifteen percent of the world’s land is set aside as some
type of reserve. Historically, these protected areas have been small islands of habitat
surrounded by areas that contain human activity. Because the reserves are small, they
are impacted heavily by human activity. Costa Rica has established megareserves. These
reserves contain one or more zones that are protected from human activity by buffer
zones, areas in which sustainable use of natural resources is permitted. This approach
creates large managed areas for preserving biodiversity while providing natural
resources to local populations.
Biodiversity hotspots
Conservation biologists have identified locations around the world that are
characterized by exceptional levels of
endemic
species—species that are only found in
that specific geographic area—and critical levels of habitat loss. They have termed these
areas hotspots. To be called a hotspot, a region must meet two criteria. First, there must
be at least 1500 species of vascular plants that are endemic, and the region must have
lost at least 70 percent of its original habitat. The 36 internationally recognized hotspots
are shown in
Figure 19
on the next page.
Approximately half of all plant and animal species are found in hotspots. These hotspots
originally covered 17 percent of Earth’s surface; however, only about a tenth of that
habitat remains.
Biologists who are in favor of recovery efforts in these biological hotspots argue that
focusing on a limited area would save the greatest number of species. Other biologists
argue that concentrating funding on saving species in these hotspots does not address
the serious problems that are occurring elsewhere. For example, saving a wetland area
might save fewer species, but the wetland provides greater services by filtering water,
regulating floods, and providing a nursery for fish. These biologists think that funding
should be spent in areas around the world rather than focused on the biodiversity
hotspots. Scientists often use computer simulations to test different ways of solving a
problem or to see which one is most efficient or economical.
Get It?
Explain
how protected areas preserve biodiversity.
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Module 5 • Biodiversity and Conservation